Company: DAWN
Filing Date: 2025-03-06
Form Type: 10-K/A
Source: 0000950170-25-034878
Chunk: 5

Company: Day One Biopharmaceuticals, Inc.
Filing Date: 2025-03-06
Form: 10-K/A
Chunk 5
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uant to Section 302 of the Sarbanes-Oxley Act of 2002. |     |      |     |           |     |                   |     | X |
| 32.1** |     | Certification of Principal Executive Officer and Principal Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.                  |     |      |     |           |     |                   |     | X |
| 97.1   |     | Compensation Recovery Policy                                                                                                                                                                            |     | 10-K |     | 001-40431 |     | February 25, 2025 |     |   |

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| 101.INS |     | Inline XBRL Instance Document                                                                           |     | X |
| 101.SCH |     | Inline XBRL Taxonomy Extension Schema Document                                                          |     | X |
| 101.CAL |     | Inline XBRL Taxonomy Extension Calculation Linkbase Document.                                           |     | X |
| 101.DEF |     | Inline XBRL Taxonomy Extension Definition Linkbase Document.                                            |     | X |
| 101.LAB |     | Inline XBRL Taxonomy Extension Label Linkbase Document.                                                 |     | X |
| 101.PRE |     | Inline XBRL Taxonomy Extension Presentation Linkbase Document.                                          |     | X |
| 104     |     | Cover Page Interactive Data File (Embedded within the Inline XBRL document and included in Exhibit 101) |     | X |

† Registrant has omitted portions of the exhibit as permitted under Item 601(b)(10) of Regulations S-K.
^ Indicates management contract or compensatory plan.
* Registrant has omitted schedules and exhibits pursuant to Item 601(a)(5) of Regulation S-K. The Registrant agrees to furnish supplementally a copy of the omitted schedules and exhibits to the SEC upon request

** This certification is deemed not filed for purposes of section 18 of the Exchange Act or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act.

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SIGNATURES</div>

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Report to be signed on its