DAWN / Day One Biopharmaceuticals, Inc. - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

Day One Reports Second Quarter 2025 Financial Results and Corporate Progress OJEMDATM (tovorafenib) net product revenue of $33.6 million in Q2 2025, a 10% quarter-over-quarter increase OJEMDA full-year 2025 net product revenue expected to be $140 to

Exhibit 99.1 Day One Reports Second Quarter 2025 Financial Results and Corporate Progress OJEMDATM (tovorafenib) net product revenue of $33.6 million in Q2 2025, a 10% quarter-over-quarter increase OJEMDA full-year 2025 net product revenue expected to be $140 to $150 million Ended the second quarter with $453.1 million in cash, cash equivalents and short-term investments Company to host conference

Targeted therapies for people of all ages August 2025 Day One Biopharmaceuticals

Targeted therapies for people of all ages August 2025 Day One Biopharmaceuticals Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

AUGUST 2025 Second Quarter 2025 Financial Results & Corporate Progress

AUGUST 2025 Second Quarter 2025 Financial Results & Corporate Progress Forward Looking Statements This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

FORM 8-K Item 2.02 Results of Operations and Financial Condition. Item 7.01 Regulation FD Disclosure. Item 9.01 Financial Statements and Exhibits.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 05, 2025 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (C

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 2, 2025) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE

Targeted therapies for people of all ages May 2025 Day One Biopharmaceuticals

Targeted therapies for people of all ages May 2025 Day One Biopharmaceuticals Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

Day One Reports First Quarter 2025 Financial Results and Corporate Progress OJEMDATM (tovorafenib) prescriptions grew 16% in Q1 2025 compared to Q4 2024 Achieved Q1 2025 OJEMDATM (tovorafenib) net product revenue of $30.5 million Ended the first quar

Exhibit 99.1 Day One Reports First Quarter 2025 Financial Results and Corporate Progress OJEMDATM (tovorafenib) prescriptions grew 16% in Q1 2025 compared to Q4 2024 Achieved Q1 2025 OJEMDATM (tovorafenib) net product revenue of $30.5 million Ended the first quarter with $473.0 million in cash, cash equivalents and short-term investments Company to host conference call and webcast today, May 6, 4:

MAY 2025 First Quarter 2025 Financial Results & Corporate Progress

MAY 2025 First Quarter 2025 Financial Results & Corporate Progress Forward looking statements This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 06, 2025 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Comm

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant  ☐ Check the appropriate box:  ☐ Preliminary Proxy Statement  ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Proxy St

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

TABLE OF CONTENTS   UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1)

l UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1) (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001

Insider Trading Policy

Exhibit 19.1 1.0 Purpose Day One Biopharmaceuticals, Inc. (the “Company,” “we,” “us” or “our”) is committed to promoting high standards of honest and ethical business conduct and compliance with laws, rules and regulations. Because stock is an important part of the Company’s compensation program, our Board of Directors (“Board”) has adopted this Insider Trading Policy (“Policy”) governing the purc

Targeted therapies for people of all ages February 2025 Day One Biopharmaceuticals

Targeted therapies for people of all ages February 2025 Day One Biopharmaceuticals Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

Day One Reports Fourth Quarter and Full Year 2024 Financial Results and Corporate Progress Achieved Q4 2024 and full year 2024 OJEMDATM (tovorafenib) net product revenues of $29.0 million and $57.2 million, respectively Ended 2024 with $531.7 million

Exhibit 99.1 Day One Reports Fourth Quarter and Full Year 2024 Financial Results and Corporate Progress Achieved Q4 2024 and full year 2024 OJEMDATM (tovorafenib) net product revenues of $29.0 million and $57.2 million, respectively Ended 2024 with $531.7 million in cash, cash equivalents and short-term investments Company to host conference call and webcast today, February 25, 4:30 p.m. ET BRISBA

Compensation Recovery Policy

Exhibit 97.1 Day One Biopharmaceuticals, Inc. Compensation Recovery Policy (Adopted December 5, 2023) The Board has determined that it is in the best interests of the Company and its stockholders to adopt this Policy enabling the Company to recover from specified current and former Company executives certain incentive-based compensation in the event of an accounting restatement resulting from mate

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 25, 2025 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Day One Biopharmaceuticals FEBRUARY 2025 Fourth Quarter & Full-Year 2024 Financial Results & Corporate Progress

Day One Biopharmaceuticals FEBRUARY 2025 Fourth Quarter & Full-Year 2024 Financial Results & Corporate Progress Forward looking statements This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

l UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-40431 DAY ONE BIOPH

Subsidiaries of the Registrant

Exhibit 21.1 Subsidiaries of Day One Biopharmaceuticals, Inc. None.

Office Lease, dated June 26, 2024, by and between Arcus Biosciences, Inc., a Delaware corporation, and Day One Biopharmaceuticals, Inc.

Exhibit 10.6 SUBLEASE THIS SUBLEASE (this “Sublease”) is dated for reference purposes as of June 26, 2024 (the “Effective Date”), and is made by and between Arcus Biosciences, Inc., a Delaware corporation (“Sublessor”), and Day One Biopharmaceuticals, Inc., a Delaware corporation (“Sublessee”). Sublessor and Sublessee hereby agree as follows: 1. Recitals: This Sublease is made with reference to th

JOINT FILING AGREEMENT

EXHIBIT 99.1 JOINT FILING AGREEMENT This Joint Filing Agreement, dated as of February 14, 2025, is by and among RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah, and RA Capital Healthcare Fund, L.P. (the foregoing are collectively referred to herein as the “Filers”). Each of the Filers may be required to file with the United States Securities and Exchange Commission a statement on Schedu

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.3 Day One Biopharmaceuticals Targeted therapies for people of all ages January 2025 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of w

Forward looking statements This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking

Exhibit 99.2 Day One Biopharmaceuticals Targeted therapies for people of all ages January 2025 rd 43 Annual J.P. Morgan Healthcare Conference Forward looking statements This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statemen

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (January 13, 2025) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Day One Reports Preliminary 2024 OJEMDA™ Net Product Revenue and Highlights 2025 Corporate Priorities Preliminary 2024 OJEMDA™ (tovorafenib) net product revenue of approximately $57.2 million (unaudited) First dose cohort cleared in Phase 1a/b clinic

Exhibit 99.1 Day One Reports Preliminary 2024 OJEMDA™ Net Product Revenue and Highlights 2025 Corporate Priorities Preliminary 2024 OJEMDA™ (tovorafenib) net product revenue of approximately $57.2 million (unaudited) First dose cohort cleared in Phase 1a/b clinical trial of DAY301 (PTK7-targeted ADC) Ended 2024 with approximately $531.7 million in cash, cash equivalents and short-term investments

As filed with the Securities and Exchange Commission on January 10, 2025

As filed with the Securities and Exchange Commission on January 10, 2025 Registration No.

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables S-8 DAY ONE BIOPHARMACEUTICALS, INC. Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee 1 Equity Common Stock, par value $0.0001 per share  Other 5,131,836 $12.76 $65,482,227.36 0.00015

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (November 20, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

DAWN / Day One Biopharmaceuticals, Inc. / Atlas Venture Fund XI, L.P. - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 3)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) COMMON STOCK, $0.0001 PAR VALUE (Title of Class of Securities) 23954D 109 (CUSIP Number) September 30, 2024 (Date of Event Which Requires Filing of This Statement) Check the appropriate box to designate

Day One Biopharmaceuticals Targeted Therapies for People of All Ages October 2024

Day One Biopharmaceuticals Targeted Therapies for People of All Ages October 2024 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY

Day One Reports Third Quarter 2024 Financial Results and Corporate Progress Achieved $20.1 million in OJEMDATM (tovorafenib) net product revenue Ended the third quarter with $558.4 million in cash, cash equivalents and short-term investments Company

Exhibit 99.1 Day One Reports Third Quarter 2024 Financial Results and Corporate Progress Achieved $20.1 million in OJEMDATM (tovorafenib) net product revenue Ended the third quarter with $558.4 million in cash, cash equivalents and short-term investments Company to host conference call and webcast today, October 30, 4:30 p.m. Eastern Time BRISBANE, Calif., Oct. 30, 2024 – Day One Biopharmaceutical

Exclusive License Agreement by and between Day One Biopharmaceuticals, Inc. and Ipsen Pharma SAS dated July 23, 2024.

Exhibit 10.1 CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY [*], HAS BEEN OMITTED BECAUSE IT IS NOT MATERIAL AND IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE OR CONFIDENTIAL. EXCLUSIVE LICENSE AGREEMENT BY AND BETWEEN DAY ONE BIOPHARMACEUTICALS, INC. AND IPSEN PHARMA SAS JULY 23, 2024 37942/00605/FW/20045121.1 Confidential Execution Version EXCLUSIVE LICENSE AGREEMENT

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 30, 2024 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (

Third Quarter 2024 Financial Results and Corporate Progress October 2024 Nasdaq: DAWN

Third Quarter 2024 Financial Results and Corporate Progress October 2024 Nasdaq: DAWN Forward-Looking Statements This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

As filed with the Securities and Exchange Commission on August 28, 2024

Table of Contents As filed with the Securities and Exchange Commission on August 28, 2024 Registration No.

Filing Fee Table

EXHIBIT 107.1 CALCULATION OF FILING FEE TABLES Form S-3 (Form Type) Day One Biopharmaceuticals, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1 - Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Fees to be Paid Equity

Joint Filing Agreement

EX-99.12 2 d881380dex9912.htm EX-99.12 Exhibit 99.12 Joint Filing Agreement The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1) promulgated under the Securities Exchange Act of 1934, as amended. Each of them is responsible for the timely filing of such Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information

DAWN / Day One Biopharmaceuticals, Inc. / AI Day1 LLC - SC 13D/A Activist Investment

SC 13D/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 4)* Day One Biopharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Alejandro Moreno Langhorne S. Perrow c/o Access Industries, Inc. 40 West 57th Street, 28th Floor

Exclusive License Agreement by and between MabCare Therapeutics and Day One Biopharmaceuticals, Inc. dated June 17, 2024.

Exhibit 10.2 CONFIDENTIAL Execution Version CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY [*], HAS BEEN OMITTED BECAUSE IT IS NOT MATERIAL AND WOULD LIKELY CAUSE COMPETITIVE HARM TO DAY ONE BIOPHARMACEUTICALS, INC. IF PUBLICLY DISCLOSED. EXCLUSIVE LICENSE AGREEMENT BY AND BETWEEN MABCARE THERAPEUTICS (上海麦科思生物医药有限公司) AND DAY ONE BIOPHARMACEUTICALS, INC. JUNE 17, 2024 Table

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE

Asset Purchase Agreement, dated May 29, 2024.

Exhibit 10.1 Execution Version CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY [*], HAS BEEN OMITTED BECAUSE IT IS NOT MATERIAL AND WOULD LIKELY CAUSE COMPETITIVE HARM TO DAY ONE BIOPHARMACEUTICALS IF PUBLICLY DISCLOSED. ASSET PURCHASE AGREEMENT BY AND BETWEEN [*] AND DAY ONE BIOPHARMACEUTICALS, INC. May 29, 2024 TABLE OF CONTENTS Page ARTICLE 1 DEFINITIONS 1 1.1 Certain Def

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 30, 2024 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Com

Form of Registration Rights Agreement

EX-10.2 Exhibit 10.2 REGISTRATION RIGHTS AGREEMENT THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of July 30, 2024, is entered into by and among Day One Biopharmaceuticals, Inc., a Delaware corporation (the “Company”), and the several investors signatory hereto (individually as an “Investor” and collectively together with their respective permitted assigns, the “Investors”). Capit

Form of Pre-Funded Warrant

EX-4.1 Exhibit 4.1 THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON THE EXERCISE OF THIS WARRANT (THE “SECURITIES”) HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR THE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES. THE SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE SOLD, TRANSFERRED OR ASSIGNED UNLESS (I) SUCH SECURITIES HA

Form of Securities Purchase Agreement

EX-10.1 Exhibit 10.1 SECURITIES PURCHASE AGREEMENT This SECURITIES PURCHASE AGREEMENT (this “Agreement”) is dated as of July 30, 2024, by and among Day One Biopharmaceuticals, Inc., a Delaware corporation (the “Company”), and each of the entities listed on Exhibit A attached to this Agreement (each, an “Investor” and together, the “Investors”). WHEREAS, the Company and the Investors are executing

Day One Reports Second Quarter 2024 Financial Results and Corporate Progress Achieved $8.2 million in OJEMDATM (tovorafenib) net product revenues in initial 2 months of launch Expanded pipeline with DAY301, potential first-in-class Antibody Drug Conj

Exhibit 99.1 Day One Reports Second Quarter 2024 Financial Results and Corporate Progress Achieved $8.2 million in OJEMDATM (tovorafenib) net product revenues in initial 2 months of launch Expanded pipeline with DAY301, potential first-in-class Antibody Drug Conjugate (ADC) targeting PTK7 Entered into exclusive licensing agreement with Ipsen to commercialize tovorafenib outside of the U.S. for app

Day One Announces Oversubscribed $175.0 Million Private Placement

EX-99.1 Exhibit 99.1 Day One Announces Oversubscribed $175.0 Million Private Placement BRISBANE, Calif., July 30, 2024 – Day One Biopharmaceuticals, Inc. (Nasdaq: DAWN) (“Day One” or the “Company”), a commercial-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced it has entered into an

Second Quarter 2024 Financial Results and Corporate Progress July 2024 Click to add text Nasdaq: DAWN

Second Quarter 2024 Financial Results and Corporate Progress July 2024 Click to add text Nasdaq: DAWN Forward-Looking Statements This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (July 30, 2024) DAY ONE BIOPHARMA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (July 30, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact Name of Registrant as Specified in its Charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of (Commission (I.R.

Day One Biopharmaceuticals Targeted Therapies for People of All Ages July 2024

Day One Biopharmaceuticals Targeted Therapies for People of All Ages July 2024 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

1

EX-99.1 Exhibit 99.1 Ipsen and Day One enter into exclusive ex-U.S. licensing agreement to commercialize tovorafenib for the most common childhood brain tumor » Ipsen secures ex-U.S. regulatory and commercial rights to tovorafenib for most common childhood brain tumor, pediatric low-grade glioma (pLGG), and any future indications » OJEMDA™ (tovorafenib) is the first FDA-approved treatment for rela

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 23, 2024 Month DAY ONE BIOPH

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 23, 2024 Month DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages June 2024 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of wh

Day One Expands Pipeline with Potential First-in-Class Clinical-Stage Antibody Drug Conjugate (ADC) Targeting PTK7 in Solid Tumors for Adult and Pediatric Day One receives exclusive license for development and commercialization of MTX-13 (DAY301), wh

Exhibit 99.1 Day One Expands Pipeline with Potential First-in-Class Clinical-Stage Antibody Drug Conjugate (ADC) Targeting PTK7 in Solid Tumors for Adult and Pediatric Cancers Day One receives exclusive license for development and commercialization of MTX-13 (DAY301), which received IND clearance by the FDA in April 2024 Targets PTK7, highly expressed in broad range of adult and pediatric solid tu

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 17, 2024 Month DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

EX-99.1 Exhibit 99.1 Day One Biopharmaceuticals Targeted Therapies for People of All Ages June 2024 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, so

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 12, 2024) DAY ONE BIOPHARMA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 12, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (C

Day One Announces Sale of Priority Review Voucher for $108 Million

Exhibit 99.1 Day One Announces Sale of Priority Review Voucher for $108 Million BRISBANE, Calif., May 30, 2024 — Day One Biopharmaceuticals (Nasdaq: DAWN) (“Day One” or the “Company”), a commercial-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced it sold its Priority Review Voucher

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages May 2024 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of whi

Regulation FD Disclosure, Entry into a Material Definitive Agreement, Completion of Acquisition or Disposition of Assets

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (May 29, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (May 23, 2024) DAY ONE BIOPHARMAC

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (May 23, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

Day One Biopharmaceuticals Targeted Therapies for People of All Ages May 2024

Day One Biopharmaceuticals Targeted Therapies for People of All Ages May 2024 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 06, 2024 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Comm

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE

Day One Reports First Quarter 2024 Financial Results and Corporate Progress OJEMDA™ (tovorafenib) launch underway following U.S. FDA accelerated approval for relapsed or refractory BRAF-altered Pediatric Low-Grade Glioma (pLGG) First prescriptions re

Exhibit 99.1 Day One Reports First Quarter 2024 Financial Results and Corporate Progress OJEMDA™ (tovorafenib) launch underway following U.S. FDA accelerated approval for relapsed or refractory BRAF-altered Pediatric Low-Grade Glioma (pLGG) First prescriptions received in the U.S. BRISBANE, Calif., May 6, 2024 – Day One Biopharmaceuticals (Nasdaq: DAWN) (“Day One” or the “Company”), a commercial-s

Day One’s OJEMDA™ (tovorafenib) Receives US FDA Accelerated Approval for Relapsed or Refractory BRAF-altered Pediatric Low-Grade Glioma (pLGG), the Most Common Form of Childhood Brain Tumor First and only FDA-approved type II RAF inhibitor for patien

Exhibit 99.1 Day One’s OJEMDA™ (tovorafenib) Receives US FDA Accelerated Approval for Relapsed or Refractory BRAF-altered Pediatric Low-Grade Glioma (pLGG), the Most Common Form of Childhood Brain Tumor First and only FDA-approved type II RAF inhibitor for patients with relapsed or refractory pLGG harboring a BRAF fusion or rearrangement, or BRAF V600 mutation RAPNO LGG overall response rate (ORR)

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (April 23, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages April 2024 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of w

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant  ☐ Check the appropriate box:  ☐ Preliminary Proxy Statement  ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Proxy St

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

TABLE OF CONTENTS   UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 4, 2024 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Com

Amendment No. 1 to the License Agreement for RAF, dated March 4, 2024, by and between Day One Biopharmaceuticals, Inc. and Sunesis Pharmaceuticals, Inc.

Exhibit 10.1 [*] = Certain confidential information contained in this document, marked by brackets, has been omitted because it is both (i) not material and (ii) is the type that the registrant treats as private or confidential. AMENDMENT NO. 1 TO LICENSE AGREEMENT FOR RAF This Amendment No. 1 to License Agreement for RAF (this “Amendment”), effective as of March 4, 2024 (the “Amendment Effective

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

l UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-40431 DAY ONE BIOPH

Subsidiaries of the Registrant

Exhibit 21.1 Subsidiaries of Day One Biopharmaceuticals, Inc. None.

Day One Reports Fourth Quarter and Full Year 2023 Financial Results and Corporate Progress PDUFA target action date for tovorafenib NDA in relapsed or progressive pLGG remains set for April 30, 2024 Phase 2 FIREFLY-1 tovorafenib registrational data p

Exhibit 99.1 Day One Reports Fourth Quarter and Full Year 2023 Financial Results and Corporate Progress PDUFA target action date for tovorafenib NDA in relapsed or progressive pLGG remains set for April 30, 2024 Phase 2 FIREFLY-1 tovorafenib registrational data published in Nature Medicine Ended 2023 with $366.3 million in cash, cash equivalents and short-term investments providing runway into 202

Compensation Recovery Policy

Exhibit 97.1 Day One Biopharmaceuticals, Inc. Compensation Recovery Policy (Adopted December 5, 2023) The Board has determined that it is in the best interests of the Company and its stockholders to adopt this Policy enabling the Company to recover from specified current and former Company executives certain incentive-based compensation in the event of an accounting restatement resulting from mate

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 26, 2024 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40431 83-2415215 (State or Other Jurisdiction of Incorporation)

Day One Biopharmaceuticals Targeted Therapies for People of All Ages February 2024

Day One Biopharmaceuticals Targeted Therapies for People of All Ages February 2024 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

Exhibit 1: Joint Filing Agreement

EX-99.1 2 tm246065d8ex1.htm EXHIBIT 1 EXHIBIT 1 AGREEMENT This Joint Filing Agreement, dated as of February 14, 2024, is by and among RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah, and RA Capital Healthcare Fund, L.P. (the foregoing are collectively referred to herein as the “Filers”). Each of the Filers may be required to file with the United States Securities and Exchange Commission

DAWN / Day One Biopharmaceuticals, Inc. / RA CAPITAL MANAGEMENT, L.P. - SC 13G/A Passive Investment

SC 13G/A 1 tm246065d8sc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 2)* Day One Biopharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this

DAWN / Day One Biopharmaceuticals, Inc. / VANGUARD GROUP INC - SCHEDULE 13G Passive Investment

SC 13G 1 tv0736-dayonebiopharmaceutic.htm SCHEDULE 13G SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 Name of issuer: Day One Biopharmaceuticals Inc Title of Class of Securities: Common Stock CUSIP Number: 23954D109 Date of Event Which Requires Filing of this Statement: December 29, 2023 Check the appropriate box to designate the ru

DAWN / Day One Biopharmaceuticals, Inc. / Atlas Venture Fund XI, L.P. - SC 13G/A Passive Investment

SC 13G/A 1 tm245803d1sc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 2)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) COMMON STOCK, $0.0001 PAR VALUE (Title of Class of Securities) 23954D 109 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of This Statement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (January 16, 2024) DAY ONE BIOPHA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (January 16, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Day One Announces Two New Appointments to Board of Directors

EX-99.1 Exhibit 99.1 Day One Announces Two New Appointments to Board of Directors BRISBANE, Calif., January 17, 2024 – Day One Biopharmaceuticals (Nasdaq: DAWN) (“Day One” or the “Company”), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced the appointments of Habib Dable

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.1 Nasdaq: DAWN Day One Biopharmaceuticals Targeted Therapies for People of All Ages nd 42 Annual J.P. Morgan Healthcare Conference January 2024 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (January 8, 2024) DAY ONE BIOPHAR

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (January 8, 2024) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages January 2024 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Day One Biopharmaceuticals, Inc.

2021 Equity Incentive Plan and forms of award agreements

Exhibit 99.1 DAY ONE BIOPHARMACEUTICALS, INC. 2021 EQUITY INCENTIVE PLAN 1. PURPOSE. The purpose of this Plan is to provide incentives to attract, retain, and motivate eligible persons whose present and potential contributions are important to the success of the Company, and any Parents, Subsidiaries, and Affiliates that exist now or in the future, by offering them an opportunity to participate in

As filed with the Securities and Exchange Commission on January 4, 2024

S-8 As filed with the Securities and Exchange Commission on January 4, 2024 Registration No.

2021 Employee Stock Purchase Plan and forms of award agreements

Exhibit 99.2 DAY ONE BIOPHARMACEUTICALS, INC. 2021 EMPLOYEE STOCK PURCHASE PLAN 1. PURPOSE. Day One Biopharmaceuticals, Inc. adopted the Plan effective as of the Effective Date. The purpose of this Plan is to provide eligible employees of the Company and the Participating Corporations with a means of acquiring an equity interest in the Company, to enhance such employees’ sense of participation in

Code of Business Conduct and Ethics

Exhibit 14.1 DAY ONE BIOPHARMACEUTICALS, INC. CODE OF BUSINESS CONDUCT AND ETHICS THIS POLICY WAS APPROVED BY THE BOARD ON DECEMBER 7, 2023 PURPOSE Our integrity and professionalism have been the cornerstone of our business. In all that we do Day One Biopharmaceuticals, Inc. (the “Company”) supports and upholds a set of core values and principles. The success of our business depends on each of us

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (December 7, 2023) DAY ONE BIOPHA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (December 7, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages November 2023 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (November 17, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

Day One Announces Tovorafenib FIREFLY-1 Data Published in Nature Medicine Data subsets to be shared today in plenary oral presentations at the 2023 Society for Neuro-Oncology Annual Meeting

Exhibit 99.1 Day One Announces Tovorafenib FIREFLY-1 Data Published in Nature Medicine Data subsets to be shared today in plenary oral presentations at the 2023 Society for Neuro-Oncology Annual Meeting BRISBANE, Calif., Nov. 17, 2023 – Day One Biopharmaceuticals (Nasdaq: DAWN) (“Day One” or the “Company”), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targ

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (November 10, 2023) DAY ONE BIOPH

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (November 10, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

Letter from Ernst & Young LLP, dated November 15, 2023.

Exhibit 16.1 November 15, 2023 Securities and Exchange Commission 100 F Street, N.E. Washington, DC 20549 Commissioners: We have read Item 4.01 of Form 8-K dated November 15, 2023, of Day One Biopharmaceuticals, Inc. and are in agreement with the statements contained in the first, second, third and fourth paragraphs included in Item 4.01(a) therein. We have no basis to agree or disagree with other

Day One Biopharmaceuticals Targeted Therapies for People of All Ages November 2023

Day One Biopharmaceuticals Targeted Therapies for People of All Ages November 2023 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY

Day One Reports Third Quarter 2023 Financial Results and Corporate Progress NDA for tovorafenib in relapsed or progressive pLGG accepted for FDA priority review PDUFA target action date of April 30, 2024

Exhibit 99.1 Day One Reports Third Quarter 2023 Financial Results and Corporate Progress NDA for tovorafenib in relapsed or progressive pLGG accepted for FDA priority review PDUFA target action date of April 30, 2024 BRISBANE, Calif., Nov. 6, 2023 – Day One Biopharmaceuticals (Nasdaq: DAWN) (“Day One” or the “Company”), a clinical-stage biopharmaceutical company dedicated to developing and commerc

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 06, 2023 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Day One Announces FDA Acceptance of NDA and Priority Review for Tovorafenib in Relapsed or Progressive Pediatric Low-Grade Glioma (pLGG) Priority review granted with PDUFA target action date of April 30, 2024

Exhibit 99.1 Day One Announces FDA Acceptance of NDA and Priority Review for Tovorafenib in Relapsed or Progressive Pediatric Low-Grade Glioma (pLGG) Priority review granted with PDUFA target action date of April 30, 2024 BRISBANE, Calif., Oct. 30, 2023 – Day One Biopharmaceuticals (Nasdaq: DAWN) (“Day One” or the “Company”), a clinical-stage biopharmaceutical company dedicated to developing and c

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (October 30, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages October 2023 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of w

DAWN / Day One Biopharmaceuticals Inc / AI Day1 LLC - SC 13D/A Activist Investment

SC 13D/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 3)* Day One Biopharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Alejandro Moreno Langhorne S. Perrow c/o Access Industries, Inc. 40 West 57th Street, 28th Floor

Joint Filing Agreement

EX-99.9 2 d514379dex999.htm EX-99.9 Exhibit 99.9 Joint Filing Agreement The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1) promulgated under the Securities Exchange Act of 1934, as amended. Each of them is responsible for the timely filing of such Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information con

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-3ASR (Form Type) Day One Biopharmaceuticals, Inc.

Form of Indenture

Exhibit 4.4 DAY ONE BIOPHARMACEUTICALS, INC. And , as Trustee INDENTURE Dated as of , TABLE OF CONTENTS ARTICLE 1 – DEFINITIONS AND INCORPORATION BY REFERENCE 1 1.1 DEFINITIONS 1 1.2. OTHER DEFINITIONS 4 1.3. INCORPORAT ION BY REFERENCE OF TRUST INDENTURE ACT 4 1.4. RULES OF CONSTRUCTION 5 ARTICLE 2 – THE SECURITIES 5 2.1. ISSUABLE IN SERIES 5 2.2. ESTABLISHMENT OF TERMS OF SERIES OF SECURITIES 5

Form of Debt Security

Exhibit 4.3 FORM OF DEBT SECURITY [Face of Security] DAY ONE BIOPHARMACEUTICALS, INC. [If applicable, insert—FOR PURPOSES OF THE ORIGINAL ISSUE DISCOUNT PROVISIONS OF THE INTERNAL REVENUE CODE OF 1986, THE ISSUE PRICE OF THIS SECURITY IS % OF ITS PRINCIPAL AMOUNT AT STATED MATURITY SET FORTH BELOW (ITS “PRINCIPAL AMOUNT”), THE AMOUNT OF ORIGINAL ISSUE DISCOUNT IS % OF ITS PRINCIPAL AMOUNT, THE YIE

As filed with the Securities and Exchange Commission on September 14, 2023

Table of Contents As filed with the Securities and Exchange Commission on September 14, 2023 Registration No.

Day One Announces Updated FIREFLY-1 Data for Tovorafenib and Completion of Rolling NDA Submission to FDA for Relapsed or Progressive Pediatric Low-Grade Glioma (pLGG) Overall response rate (ORR) greater than 50% across three assessment criteria Media

EX-99.1 Exhibit 99.1 Day One Announces Updated FIREFLY-1 Data for Tovorafenib and Completion of Rolling NDA Submission to FDA for Relapsed or Progressive Pediatric Low-Grade Glioma (pLGG) Overall response rate (ORR) greater than 50% across three assessment criteria Median duration of tovorafenib treatment of 15.8 months as of June 5, 2023, with 66% of patients remaining on treatment FDA filing dec

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (September 11, 2023) DAY ONE BIOP

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (September 11, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporatio

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages September 2023 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (August 16, 2023) DAY ONE BIOPHAR

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (August 16, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages August 2023 Day One Biopharmaceuticals Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks an

Day One Announces VRK1 License Agreement and Research Collaboration with Sprint Bioscience Day One receives an exclusive license to develop and commercialize small molecule drug candidates for pediatric and adult cancers with high unmet need Collabor

EX-99.1 Exhibit 99.1 Day One Announces VRK1 License Agreement and Research Collaboration with Sprint Bioscience Day One receives an exclusive license to develop and commercialize small molecule drug candidates for pediatric and adult cancers with high unmet need Collaboration augments Day One’s portfolio of targeted therapies in oncology BRISBANE, Calif., Aug. 15, 2023 – Day One Biopharmaceuticals

Restated Certificate of Incorporation, dated June 1, 2021, as amended June 22, 2023.

Exhibit 3.1 CERTIFICATE OF AMENDMENT OF RESTATED CERTIFICATE OF INCORPORATION OF DAY ONE BIOPHARMACEUTICALS, INC. Day One Biopharmaceuticals, Inc. (hereinafter called the “Corporation”), a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “General Corporation Law”), does hereby certify as follows: 1. That the name of this Corporatio

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

f UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 07, 2023 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (C

Day One Reports Second Quarter 2023 Financial Results and Corporate Progress Results from FIREFLY-1 demonstrate overall response rate (ORR) of 67% and clinical benefit rate (CBR) of 93% in 69 heavily pretreated Response Assessment Neuro-Oncology High

Exhibit 99.1 Day One Reports Second Quarter 2023 Financial Results and Corporate Progress Results from FIREFLY-1 demonstrate overall response rate (ORR) of 67% and clinical benefit rate (CBR) of 93% in 69 heavily pretreated Response Assessment Neuro-Oncology High-Grade Glioma (RANO-HGG) evaluable patients presented at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting Initiated r

Day One Biopharmaceuticals Targeted Therapies for People of All Ages August 2023 Day One Biopharmaceuticals

Day One Biopharmaceuticals Targeted Therapies for People of All Ages August 2023 Day One Biopharmaceuticals Disclaimer Day One Biopharmaceuticals This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

Certificate of Amendment to Restated Certificate of Incorporation, filed June 22, 2023.

EX-3.1 Exhibit 3.1 CERTIFICATE OF AMENDMENT OF RESTATED CERTIFICATE OF INCORPORATION OF DAY ONE BIOPHARMACEUTICALS, INC. Day One Biopharmaceuticals, Inc. (hereinafter called the “Corporation”), a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “General Corporation Law”), does hereby certify as follows: 1. That the name of this Cor

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 22, 2023) DAY ONE BIOPHARMA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 22, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (C

DAWN / Day One Biopharmaceuticals Inc / AI Day1 LLC - SC 13D/A Activist Investment

SC 13D/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 2)* Day One Biopharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Alejandro Moreno Langhorne S. Perrow c/o Access Industries, Inc. 40 West 57th Street, 28th Floor

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

EX-99.1 Exhibit 99.1 Day One Biopharmaceuticals Targeted Therapies for People of All Ages June 2023 Day One Biopharmaceuticals Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to ri

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 12, 2023 Month DAY ONE BIOPH

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 12, 2023 Month DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

Joint Filing Agreement

EX-99.8 Exhibit 99.8 Joint Filing Agreement The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1) promulgated under the Securities Exchange Act of 1934, as amended. Each of them is responsible for the timely filing of such Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information concerning such person containe

Day One Announces Pricing of Public Offering of Common Stock

EX-99.1 Exhibit 99.1 Day One Announces Pricing of Public Offering of Common Stock BRISBANE, Calif., June 6, 2023 (GLOBE NEWSWIRE) – Day One Biopharmaceuticals, Inc. (Nasdaq: DAWN), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced the pricing of its underwritten public off

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 6, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

$400,000,000 Day One Biopharmaceuticals, Inc. Common Stock, Preferred Stock, Debt Securities, Warrants, Subscription Rights and Units

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-265346 Prospectus supplement (To prospectus dated June 13, 2022) 11,538,462 shares Common stock We are offering 11,538,462 shares of our common stock. Our common stock is listed on The Nasdaq Global Select Market under the symbol “DAWN.” The last reported sale price of our common stock on The Nasdaq Global Select Market

Underwriting Agreement, dated June 6, 2023.

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Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 6, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

$400,000,000 Day One Biopharmaceuticals, Inc. Common Stock, Preferred Stock, Debt Securities, Warrants, Subscription Rights and Units

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-265346 The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are part of an effective registration statement filed with the Securities and Exchange Commission. This preliminary prospectus supplement and the acco

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 4, 2023 Month DAY ONE BIOPHA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 4, 2023 Month DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Day One Announces New FIREFLY-1 Data for Tovorafenib (DAY101) and Initiation of Rolling NDA Submission to FDA for Relapsed or Progressive Pediatric Low-Grade Glioma Overall response rate (ORR) of 67% and clinical benefit rate (CBR) of 93% in 69 heavi

EX-99.2 3 d643062dex992.htm EX-99.2 Exhibit 99.2 Day One Announces New FIREFLY-1 Data for Tovorafenib (DAY101) and Initiation of Rolling NDA Submission to FDA for Relapsed or Progressive Pediatric Low-Grade Glioma Overall response rate (ORR) of 67% and clinical benefit rate (CBR) of 93% in 69 heavily pretreated RANO-HGG evaluable patients The Company expects to complete rolling NDA submission in O

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

EX-99.1 Exhibit 99.1 Day One Biopharmaceuticals Targeted Therapies for People of All Ages June 2023 Day One Biopharmaceuticals Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to ri

Day One Reports First Quarter 2023 Financial Results and Corporate Progress FIREFLY-1 clinical abstract selected for oral presentation at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting Leadership team strengthened with executive

Exhibit 99.1 Day One Reports First Quarter 2023 Financial Results and Corporate Progress FIREFLY-1 clinical abstract selected for oral presentation at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting Leadership team strengthened with executive appointments in clinical development and commercialization Pre-New Drug Application (NDA) meeting held April 19, 2023 with U.S. Food and

Quarterly Report on Form 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE B

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 01, 2023 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Comm

Day One Biopharmaceuticals Day One Biopharmaceuticals Targeted Therapies for People of All Ages May 2023

Day One Biopharmaceuticals Day One Biopharmaceuticals Targeted Therapies for People of All Ages May 2023 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

Definitive Proxy Statement on Schedule 14A

TABLE OF CONTENTS   UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant  ☐ Check the appropriate box:  ☐ Preliminary Proxy Statement  ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Proxy St

Clinical activity of the type II pan-RAF inhibitor tovorafenib in BRAF-fusion melanoma Jeeyun Lee, MD,1 Natraj R. Ammakkanavar, MD,2 Aprajita Saini, MS,3 Mark W. Kieran MD, PhD,3 Lisa M. Kopp, DO, MPH,3 Bert H. O’Neil, MD2 1Samsung Medical Center, Su

EX-99.1 Exhibit 99.1 Clinical activity of the type II pan-RAF inhibitor tovorafenib in BRAF-fusion melanoma Jeeyun Lee, MD,1 Natraj R. Ammakkanavar, MD,2 Aprajita Saini, MS,3 Mark W. Kieran MD, PhD,3 Lisa M. Kopp, DO, MPH,3 Bert H. O’Neil, MD2 1Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; 2Community North Cancer Center, Indianapolis, IN, United Stat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (April 20, 2023) DAY ONE BIOPHARM

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (April 20, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

PRE 14A 1 ny20007645x1pre14a.htm PRE 14A TABLE OF CONTENTS   UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant  ☐ Check the appropriate box: ☒ Preliminary Proxy Statement  ☐ Confidential, for Use of the Commission O

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (March 20, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

EX-99.1 Exhibit 99.1 Day One Biopharmaceuticals Targeted Therapies for People of All Ages March 2023 Day One Biopharmaceuticals 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 06, 2023 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

Annual Report on Form 10-K

l UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-40431 DAY ONE BIOPH

Day One Reports Fourth Quarter and Full Year 2022 Financial Results and Corporate Progress First patient dosed in pivotal Phase 3 FIREFLY-2/LOGGIC trial evaluating tovorafenib (DAY101) as a frontline therapy for patients newly diagnosed with pediatri

Exhibit 99.1 Day One Reports Fourth Quarter and Full Year 2022 Financial Results and Corporate Progress First patient dosed in pivotal Phase 3 FIREFLY-2/LOGGIC trial evaluating tovorafenib (DAY101) as a frontline therapy for patients newly diagnosed with pediatric low-grade glioma (pLGG) Reported topline data in January 2023 from ongoing, pivotal Phase 2 FIREFLY-1 trial demonstrating meaningful re

Subsidiaries of the Registrant

Exhibit 21.1 Subsidiaries of Day One Biopharmaceuticals, Inc. None.

Day One Biopharmaceuticals Day One Biopharmaceuticals Targeted Therapies for People of All Ages March 2023

Day One Biopharmaceuticals Day One Biopharmaceuticals Targeted Therapies for People of All Ages March 2023 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management.

Amended and Restated Bylaws, dated February 17, 2023.

Exhibit 3.1 DAY ONE BIOPHARMACEUTICALS, INC. (a Delaware corporation) AMENDED AND RESTATED BYLAWS As Amended and Restated on February 17, 2023 TABLE OF CONTENTS Page Article I STOCKHOLDERS 1 Section 1.1. Annual Meetings 1 Section 1.2. Special Meetings 1 Section 1.3. Notice of Meetings 1 Section 1.4. Adjournments 1 Section 1.5. Quorum 2 Section 1.6. Organization 2 Section 1.7. Voting; Proxies 2 Sec

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (February 17, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

DAWN / Day One Biopharmaceuticals, Inc. / Atlas Venture Fund XI, L.P. - AMENDMENT TO FORM SC 13G Passive Investment

SC 13G/A 1 dawn-sc13ga123122.htm AMENDMENT TO FORM SC 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) COMMON STOCK, $0.0001 PAR VALUE (Title of Class of Securities) 23954D 109 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing

DAWN / Day One Biopharmaceuticals, Inc. / RA CAPITAL MANAGEMENT, L.P. - SC 13G/A Passive Investment

SC 13G/A 1 tm236221d26sc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1 )* Day One Biopharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of thi

Joint Filing Agreement

EX-1 2 ex-1.htm JOINT FILING AGREEMENT ATLAS VENTURE FUND XI, L.P. SC 13G/A EXHIBIT A JOINT FILING AGREEMENT In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Common Stock of Day One Biopharmaceuticals, Inc. and

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Day One Biopharmaceuticals, Inc.

As filed with the Securities and Exchange Commission on February 13, 2023

As filed with the Securities and Exchange Commission on February 13, 2023 Registration No.

Identification of the subsidiary which acquired the security being reported on by the parent holding company

Exhibit 99.1 Identification of the subsidiary which acquired the security being reported on by the parent holding company. Takeda Pharmaceutical Company Limited’s beneficial ownership of the reported securities is comprised of zero shares of Common Stock held by Takeda Ventures, Inc., a wholly owned indirect subsidiary of Takeda Pharmaceutical Company Limited. Takeda Ventures, Inc. is owned direct

JOINT FILING AGREEMENT

Exhibit 99.2 JOINT FILING AGREEMENT In accordance with Rule 13d-1(k)(1) promulgated under the Securities Exchange Act of 1934, the undersigned agree to the joint filing of a Statement on Schedule 13G (including any and all amendments thereto) with respect to the Common Stock of Day One Biopharmaceuticals, Inc. and further agree to the filing of this agreement as an Exhibit thereto. In addition, ea

DAWN / Day One Biopharmaceuticals, Inc. / TAKEDA PHARMACEUTICAL CO LTD Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1 Exit Filing)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) Common Stock (Title of Class of Securities) 23954D109 (CUSIP Number) June 21, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursu

Day One Announces Topline Data from Pivotal Phase 2 FIREFLY-1 Trial Demonstrating Meaningful Responses with Tovorafenib (DAY101) in Recurrent or Progressive Pediatric Low-Grade Glioma

EX-99.1 2 d398949dex991.htm EX-99.1 Exhibit 99.1 Day One Announces Topline Data from Pivotal Phase 2 FIREFLY-1 Trial Demonstrating Meaningful Responses with Tovorafenib (DAY101) in Recurrent or Progressive Pediatric Low-Grade Glioma • Overall response rate (ORR) of 64% and clinical benefit rate (CBR) of 91% in 69 heavily-pretreated, RANO-evaluable patients • Median duration of 8.4 months on therap

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Day One Biopharmaceuticals Targeted Therapies for People of All Ages January 2023 Day One Biopharmaceuticals 1 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (January 8, 2023) DAY ONE BIOPHAR

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (January 8, 2023) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 07, 2022 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Day One Reports Third Quarter 2022 Financial Results and Corporate Progress Topline results for full pivotal FIREFLY-1 study population with tovorafenib (DAY101) in relapsed or progressive pediatric low-grade glioma (pLGG) are expected in the first q

Exhibit 99.1 Day One Reports Third Quarter 2022 Financial Results and Corporate Progress Topline results for full pivotal FIREFLY-1 study population with tovorafenib (DAY101) in relapsed or progressive pediatric low-grade glioma (pLGG) are expected in the first quarter of 2023 Strengthened leadership team with key appointments to senior management team and board of directors SOUTH SAN FRANCISCO, C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY O

Targeted Therapies for People of All Ages November 2022 June 2022

Targeted Therapies for People of All Ages November 2022 June 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management?s beliefs and assumptions and on information currently available to our management.

Joint Filing Agreement

EX-99.1 2 d374729dex991.htm EX-99.1 Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(f) under the Securities and Exchange Act of 1934, the persons or entities named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the shares of the Issuer and further agree that this joint filing agreement be inc

DAWN / Day One Biopharmaceuticals, Inc. / Canaan XI L.P. - SC 13D/A Activist Investment

SC 13D/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Rule 13d-101) INFORMATION INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 5)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Canaan XI L.P.

2022 Equity Inducement Plan and forms of agreement

EX-99.1 Exhibit 99.1 DAY ONE BIOPHARMACEUTICALS, INC. 2022 INDUCEMENT PLAN 1. PURPOSE. The purpose of this Plan is to provide incentives to attract and motivate eligible employees whose present and potential contributions are important to the success of the Company, and any Parents, Subsidiaries, and Affiliates that exist now or in the future, by offering them an opportunity to participate in the

As filed with the Securities and Exchange Commission on October 31, 2022

S-8 As filed with the Securities and Exchange Commission on October 31, 2022 Registration No.

Filing Fee Table

EX-FILING FEES Exhibit 107.1 Calculation of Filing Fee Tables Form S-8 (Form Type) Day One Biopharmaceuticals, Inc. (Exact Name of Registrant as Specified in its Charter) Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered(1) Proposed Maximum Offering Price Per Unit(3) Maximum Aggregate Offering Price(3) Fee Rate Amount of Registration Fee(4) Equit

DAWN / Day One Biopharmaceuticals, Inc. / Canaan XI L.P. - SC 13D/A Activist Investment

SC 13D/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Rule 13d-101) INFORMATION INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 4)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Canaan XI L.P.

Joint Filing Agreement

Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(f) under the Securities and Exchange Act of 1934, the persons or entities named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the shares of the Issuer and further agree that this joint filing agreement be included as an exhibit to this Schedule

Joint Filing Agreement

Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(f) under the Securities and Exchange Act of 1934, the persons or entities named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the shares of the Issuer and further agree that this joint filing agreement be included as an exhibit to this Schedule

DAWN / Day One Biopharmaceuticals, Inc. / Canaan XI L.P. - SC 13D/A Activist Investment

SC 13D/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Rule 13d-101) INFORMATION INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 3)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Canaan XI L.P.

DAWN / Day One Biopharmaceuticals, Inc. / Canaan XI L.P. - SC 13D/A Activist Investment

SC 13D/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Rule 13d-101) INFORMATION INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 2)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Canaan XI L.P.

Joint Filing Agreement

EX-99.1 2 d400192dex991.htm EX-99.1 Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(f) under the Securities and Exchange Act of 1934, the persons or entities named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the shares of the Issuer and further agree that this joint filing agreement be inc

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

EX-99.2 Exhibit 99.2 Targeted Therapies for People of All Ages September 2022 June 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of which ca

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (September 9, 2022) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation

Day One Appoints Garry Nicholson as Chairman of the Board of Directors

Exhibit 99.1 Day One Appoints Garry Nicholson as Chairman of the Board of Directors SOUTH SAN FRANCISCO, Calif., September 12, 2022 ? Day One Biopharmaceuticals (Nasdaq: DAWN), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced the appointment of Garry Nicholson as chairman

Targeted Therapies for People of All Ages August 2022 June 2022

Targeted Therapies for People of All Ages August 2022 June 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management?s beliefs and assumptions and on information currently available to our management.

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 04, 2022 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE BI

Day One Reports Second Quarter 2022 Financial Results and Corporate Progress Reported positive initial data from ongoing pivotal FIREFLY-1 study with tovorafenib (DAY101) in relapsed pediatric low-grade glioma (pLGG); topline results for full pivotal

Exhibit 99.1 Day One Reports Second Quarter 2022 Financial Results and Corporate Progress Reported positive initial data from ongoing pivotal FIREFLY-1 study with tovorafenib (DAY101) in relapsed pediatric low-grade glioma (pLGG); topline results for full pivotal study population expected in the first quarter of 2023 Expanded development of tovorafenib with initiation of pivotal Phase 3 FIREFLY-2/

Office Lease, dated April 1, 2022, by and between Aircraft Technical Publishers, a California corporation, and Day One Biopharmaceuticals, Inc.

Exhibit 10.1 OFFICE SUBLEASE by and between AIRCRAFT TECHNICAL PUBLISHERS, a California corporation, (?Sublandlord?) and DAY ONE BIOPHARMACEUTICALS, INC. (?Subtenant?) Dated as of April 1, 2022 737799836.2 Office lease THIS OFFICE SUBLEASE (this ?Sublease?) is made between AIRCRAFT TECHNICAL PUBLISHERS, a California corporation (?Sublandlord?), and the Subtenant described in Item 1 of the Basic Le

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.1 Targeted Therapies for People of All Ages June 2022 June 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management?s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predi

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 21, 2022) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (C

DAWN / Day One Biopharmaceuticals, Inc. / AI Day1 LLC - SC 13D/A Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* Day One Biopharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109 (CUSIP Number) Alejandro Moreno Langhorne S. Perrow c/o Access Industries, Inc. 40 West 57th Street, 28th Floor New York,

Joint Filing Agreement

Exhibit 99.6 Joint Filing Agreement The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1). Each of them is responsible for the timely filing of such Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information concerning such person contained therein; but none of them is responsible for the completeness or accurac

LOCK-UP AGREEMENT

Exhibit 99.5 LOCK-UP AGREEMENT June 10, 2022 J.P. MORGAN SECURITIES LLC COWEN AND COMPANY, LLC PIPER SANDLER & CO. As Representatives of the several Underwriters listed in Schedule 1 to the Underwriting Agreement referred to below c/o J.P. Morgan Securities LLC 383 Madison Avenue New York, NY 10179 c/o Cowen and Company, LLC 599 Lexington Avenue New York, New York 10022 c/o Piper Sandler & Co. 800

Day One Announces Pricing of Upsized Public Offering of Common Stock

Exhibit 99.1 Day One Announces Pricing of Upsized Public Offering of Common Stock SOUTH SAN FRANCISCO, Calif., June 14, 2022 (GLOBE NEWSWIRE) ? Day One Biopharmaceuticals, Inc. (Nasdaq: DAWN), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced the pricing of its upsized und

$400,000,000 Day One Biopharmaceuticals, Inc. Common Stock, Preferred Stock, Debt Securities, Warrants, Subscription Rights and Units

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-265346 Prospectus supplement (To prospectus dated June 13, 2022) 10,000,000 shares Common stock We are offering 10,000,000 shares of our common stock. Our common stock is listed on The Nasdaq Global Select Market under the symbol ?DAWN.? The last reported sale price of our common stock on The Nasdaq Global Select Market on Jun

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): (June 14, 2022) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (C

Underwriting Agreement, dated June 14, 2022.

EX-1.1 2 d264187dex11.htm EX-1.1 Exhibit 1.1 Day One Biopharmaceuticals, Inc. 10,000,000 Shares of Common Stock, par value $0.0001 per share Underwriting Agreement June 14, 2022 J.P. Morgan Securities LLC Cowen and Company, LLC Piper Sandler & Co. As Representatives of the several Underwriters listed in Schedule 1 hereto c/o J.P. Morgan Securities LLC 383 Madison Avenue New York, NY 10179 c/o Cowe

$400,000,000 Day One Biopharmaceuticals, Inc. Common Stock, Preferred Stock, Debt Securities, Warrants, Subscription Rights and Units

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-265346 The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are part of an effective registration statement filed with the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanyi

Day One Announces Positive Initial Data from Pivotal FIREFLY-1 Trial of Tovorafenib (DAY101) in Relapsed Pediatric Low-Grade Glioma Data show an overall response rate (ORR) of 64% and clinical benefit rate (CBR) of 91% in the first 22 evaluable patie

Exhibit 99.1 Day One Announces Positive Initial Data from Pivotal FIREFLY-1 Trial of Tovorafenib (DAY101) in Relapsed Pediatric Low-Grade Glioma Data show an overall response rate (ORR) of 64% and clinical benefit rate (CBR) of 91% in the first 22 evaluable patients treated with monotherapy tovorafenib Topline results from the full FIREFLY-1 trial population expected in Q1 2023 Day One plans to in

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 12, 2022 June DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are i

Exhibit 99.2 Targeted Therapies for People of All Ages June 2022 June 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management?s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predi

DAY ONE BIOPHARMACEUTICALS, INC. 395 Oyster Point Blvd., Suite 217 South San Francisco, CA 94080 June 8, 2022

DAY ONE BIOPHARMACEUTICALS, INC. 395 Oyster Point Blvd., Suite 217 South San Francisco, CA 94080 June 8, 2022 United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, DC 20549 Attention: Office of Life Sciences Re: Day One Biopharmaceuticals, Inc. Registration Statement on Form S-3 Filed June 1, 2022 File No. 333-265346 Via EDGAR - Acceleratio

Form of Indenture

Exhibit 4.4 DAY ONE BIOPHARMACEUTICALS, INC. And , as Trustee INDENTURE Dated as of , TABLE OF CONTENTS ARTICLE 1 ? DEFINITIONS AND INCORPORATION BY REFERENCE 1 1.1 DEFINITIONS 1 1.2. OTHER DEFINITIONS 4 1.3. INCORPORATION BY REFERENCE OF TRUST INDENTURE ACT 4 1.4. RULES OF CONSTRUCTION 4 ARTICLE 2 ? THE SECURITIES 5 2.1. ISSUABLE IN SERIES 5 2.2. ESTABLISHMENT OF TERMS OF SERIES OF SECURITIES 5 2

Form of Debt Security

Exhibit 4.3 FORM OF DEBT SECURITY [Face of Security] DAY ONE BIOPHARMACEUTICALS, INC. [If applicable, insert?FOR PURPOSES OF THE ORIGINAL ISSUE DISCOUNT PROVISIONS OF THE INTERNAL REVENUE CODE OF 1986, THE ISSUE PRICE OF THIS SECURITY IS % OF ITS PRINCIPAL AMOUNT AT STATED MATURITY SET FORTH BELOW (ITS ?PRINCIPAL AMOUNT?), THE AMOUNT OF ORIGINAL ISSUE DISCOUNT IS % OF ITS PRINCIPAL AMOUNT, THE YIE

Equity Distribution Agreement, dated June 1, 2022, by and among the Registrant and Piper Sandler & Co. and JonesTrading Institutional Services LLC

EX-1.2 2 d322267dex12.htm EX-1.2 Exhibit 1.2 DAY ONE BIOPHARMACEUTICALS, INC. EQUITY DISTRIBUTION AGREEMENT June 1, 2022 PIPER SANDLER & CO. U.S. Bancorp Center 800 Nicollet Mall Minneapolis, Minnesota 55402 JONESTRADING INSTITUTIONAL SERVICES LLC 211 East 43rd Street, 15th Floor New York, NY 10017 Ladies and Gentlemen: As further set forth in this agreement (this “Agreement”), Day One Biopharmace

As filed with the Securities and Exchange Commission on June 1, 2022

Table of Contents As filed with the Securities and Exchange Commission on June 1, 2022 Registration No.

Filing Fee Table

Exhibit 107 Calculation of Fee Filing Tables Form S-3 (Form Type) Day One Biopharmaceuticals, Inc.

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 12, 2022 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Comm

Targeted Therapies for People of All Ages May 2022

Targeted Therapies for People of All Ages May 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management?s beliefs and assumptions and on information currently available to our management.

Day One Reports First Quarter 2022 Financial Results and Provides Business Update Initial data from pivotal FIREFLY-1 study with tovorafenib (DAY101) in relapsed pediatric low-grade glioma (pLGG) expected in June 2022 Company plans to initiate pivota

Exhibit 99.1 Day One Reports First Quarter 2022 Financial Results and Provides Business Update Initial data from pivotal FIREFLY-1 study with tovorafenib (DAY101) in relapsed pediatric low-grade glioma (pLGG) expected in June 2022 Company plans to initiate pivotal Phase 3 FIREFLY-2 clinical trial evaluating tovorafenib as a first-line therapy in pLGG in the second quarter of 2022 Initiated Phase 1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY ONE B

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

TABLE OF CONTENTS ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ?? Check the appropriate box: ?? Preliminary Proxy Statement ?? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Definitive Proxy St

Targeted Therapies for People of All Ages April 2022

Targeted Therapies for People of All Ages April 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management?s beliefs and assumptions and on information currently available to our management.

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 13, 2022 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

Subsidiaries of the Registrant

Exhibit 21.1 Subsidiaries of Day One Biopharmaceuticals, Inc. None.

As filed with the Securities and Exchange Commission on March 7, 2022

As filed with the Securities and Exchange Commission on March 7, 2022 Registration No.

Certificate of Ownership and Merger, dated December 23, 2021

Exhibit 3.3 State of Delaware Secretary of State Division of Corporations Delivered 06:32 PM 12/23/2021 FILED 06:32 PM 12/23/2021 SR 20214210095 ? File Number 7130337 STATE OF DELAWARE CERTIFICATE OF OWNERSHIP AND MERGER MERGING DOT Therapeutics-1, Inc. DOT Therapeutics-2, Inc. (Delaware corporations) INTO Day One Biopharmaceuticals, Inc. (a Delaware corporation) Pursuant to Section 253 of the Gen

Targeted Therapies for People of All Ages March 2022

EX-99.2 3 dawn-ex992.htm EX-99.2 Targeted Therapies for People of All Ages March 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of which cann

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Day One Biopharmaceuticals, Inc.

Form of Change in Control and Severance Agreement

Exhibit 10.2 CHANGE IN CONTROL AND SEVERANCE AGREEMENT This Change in Control and Severance Agreement (the ?Agreement?) is entered into by and between [] (the ?Executive?) and Day One Biopharmaceuticals, Inc., a Delaware corporation (the ?Company?), effective as of [] (the ?Effective Date?). 1. Qualifying Termination. If the Executive is subject to a Qualifying Termination, then, subject to Sectio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-40431 DAY ONE BIOPHAR

Description of Registrant’s Securities

Exhibit 4.3 Description of the Registrant?s Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934 As of December 31, 2021, Day One Biopharmaceuticals, Inc. (the ?Company,? ?we,? or ?our?) had one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the ?Exchange Act?): our common stock. The following description summarize

Day One Reports Fourth Quarter and Full Year 2021 Financial Results and Corporate Progress Initial data from pivotal FIREFLY-1 study with DAY101 (tovorafenib) expected in June 2022 Targeted enrollment achieved in pivotal FIREFLY-1 study Topline resul

EX-99.1 2 dawn-ex991.htm EX-99.1 Day One Reports Fourth Quarter and Full Year 2021 Financial Results and Corporate Progress Initial data from pivotal FIREFLY-1 study with DAY101 (tovorafenib) expected in June 2022 Targeted enrollment achieved in pivotal FIREFLY-1 study Topline results from pivotal FIREFLY-1 study expected in Q1 2023 Current cash provides runway into 2024 and through multiple expec

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 07, 2022 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation) (Co

DAWN / Day One Biopharmaceuticals, Inc. / Atlas Venture Fund XI, L.P. - SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) COMMON STOCK, $0.0001 PAR VALUE (Title of Class of Securities) 23954D 109 (CUSIP Number) June 1, 2021 (Date of Event Which Requires Filing of This Statement) Check the appropriate box to designate the rule

Joint Filing Agreement

EX-1 2 ex-a.htm EXHIBIT A - JOINT FILING AGREEMENT Atlas Venture Fund XI, L.P. SC 13G Exhibit A JOINT FILING AGREEMENT In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Common Stock of Day One Biopharmaceuticals,

Identification of the subsidiary which acquired the security being reported on by the parent

Exhibit 99.1 Identification of the subsidiary which acquired the security being reported on by the parent holding company. Millennium Pharmaceuticals, Inc. is the direct beneficial owner of 5,955,534 shares of the Issuer?s Common Stock and Takeda Ventures, Inc. is the direct beneficial owner of 57,224 shares of the Issuer?s Common Stock. Millennium Pharmaceuticals, Inc. and Takeda Ventures, Inc. a

DAWN / Day One Biopharmaceuticals, Inc. / TAKEDA PHARMACEUTICAL CO LTD - SC 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D 109 (CUSIP Number) December 31, 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to des

Power of Attorney

EX-99.3 4 exhibit993-1011422.htm EX-99.3 Exhibit 99.3 POWER OF ATTORNEY Know all by these present, that Millennium Pharmaceuticals, Inc. (the “Reporting Person”) hereby constitutes and appoints Paul Sundberg as the Reporting Person’s true and lawful attorney-in-fact to: 1)prepare, execute in the Reporting Person’s name and on the Reporting Person’s behalf, and submit to the U.S. Securities and Exc

Joint Filing Agreement

EX-99.2 3 exhibit992-1011422.htm EX-99.2 Exhibit 99.2 JOINT FILING AGREEMENT The undersigned hereby agree that the Statement on Schedule 13G filed herewith (and any amendments thereto), relating to the Common Stock of Day One Biopharmaceuticals, Inc., a Delaware corporation, is being filed jointly with the Securities and Exchange Commission pursuant to Rule 13d-1(d) under the Securities Exchange A

Day One to Present at the 40th Annual J.P. Morgan Healthcare Conference

Day One to Present at the 40th Annual J.P. Morgan Healthcare Conference SOUTH SAN FRANCISCO, CA, January 5, 2022 ? Day One Biopharmaceuticals (Nasdaq: DAWN), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced that Dr. Jeremy Bender, chief executive officer, will present vir

Targeted Therapies for People of All Ages January 2022

EX-99.2 3 dawn-ex992.htm EX-99.2 Targeted Therapies for People of All Ages January 2022 Disclaimer This presentation and the accompanying oral commentary contain forward-looking statements that are based on our management’s beliefs and assumptions and on information currently available to our management. Forward-looking statements are inherently subject to risks and uncertainties, some of which ca

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 05, 2022 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40431 83-2415215 (State or Other Jurisdiction of Incorporation) (

Joint Filing Agreement

EX-99.1 2 d246060dex991.htm EX-99.1 Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(f) under the Securities and Exchange Act of 1934, the persons or entities named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the shares of the Issuer and further agree that this joint filing agreement be inc

DAWN / Day One Biopharmaceuticals, Inc. / Canaan XI L.P. - SC 13D/A Activist Investment

SC 13D/A 1 d246060dsc13da.htm SC 13D/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Rule 13d-101) INFORMATION INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a) (Amendment No. 1)* DAY ONE BIOPHARMACEUTICALS, INC. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 23954D109

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-40431 DAY O

Day One Reports Third Quarter 2021 Financial Results and Corporate Progress Enrollment Progresses in the Pivotal Phase 2 FIREFLY-1 Clinical Trial of DAY101 in Patients with pLGG; Initial Data Expected in 1H 2022 Upcoming CTOS Meeting to Highlight Sin

Day One Reports Third Quarter 2021 Financial Results and Corporate Progress Enrollment Progresses in the Pivotal Phase 2 FIREFLY-1 Clinical Trial of DAY101 in Patients with pLGG; Initial Data Expected in 1H 2022 Upcoming CTOS Meeting to Highlight Single Agent Activity of Lead Drug Candidate, DAY101, in Spindle Cell Carcinoma Compassionate Use Case SOUTH SAN FRANCISCO, CA, November 8, 2021 ? Day One Biopharmaceuticals (Nasdaq: DAWN), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for patients of all ages with genomically defined cancers, today announced financial results for the third quarter of 2021 and highlighted recent corporate achievements.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 08, 2021 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

EX-99.2

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 03, 2021 DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of incorporation)

Activity of pan-RAF inhibitor DAY101 in a pediatric patient with a recurrent spindle cell sarcoma harboring a novel SNX8-BRAF gene fusion Katharine Offer,1 Michael McGuire,2 Eleni Venetsanakos,3 Samuel C. Blackman,3 Kunchang Song,4 Michael Goldfische

Activity of pan-RAF inhibitor DAY101 in a pediatric patient with a recurrent spindle cell sarcoma harboring a novel SNX8-BRAF gene fusion Katharine Offer,1 Michael McGuire,2 Eleni Venetsanakos,3 Samuel C.

Day One Announces Presentation at 2021 Connective Tissue Oncology Society (CTOS) Virtual Annual Meeting

EX-99.1 2 dawn-ex991.htm EX-99.1 Day One Announces Presentation at 2021 Connective Tissue Oncology Society (CTOS) Virtual Annual Meeting  Compassionate use case of DAY101 demonstrates a complete response in a pediatric patient with a recurrent spindle cell sarcoma harboring a BRAF gene fusion SOUTH SAN FRANCISCO, CA, November 3, 2021 – Day One Biopharmaceuticals (Nasdaq: DAWN), a clinical-stage b

Day One Appoints Scott Garland to Board of Directors

EX-99.1 2 d209834dex991.htm EX-99.1 Exhibit 99.1 Day One Appoints Scott Garland to Board of Directors SOUTH SAN FRANCISCO, CA, August 17, 2021 – Day One Biopharmaceuticals (Nasdaq: DAWN), a clinical-stage biopharmaceutical company dedicated to developing and commercializing targeted therapies for patients of all ages with genomically defined cancers, today announced the appointment of Scott Garlan

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 16, 2021 (August 16, 2021) DAY ONE BIOPHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-40431 83-2415215 (State or other jurisdiction of