This Amendment No. 1 (this “Amendment”) to Schedule
14D-9 amends and supplements the Schedule 14D-9 previously filed by Nuvalent, Inc., a Delaware corporation (the “Company”), with the U.S. Securities and
Exchange Commission (the “SEC”) on June 24, 2026 (as amended or supplemented from time to time, the “Schedule 14D-9”), with respect to the tender offer by Harmony Row Acquisition
Co., a Delaware corporation (“Purchaser”) and a direct wholly-owned subsidiary of GlaxoSmithKline LLC, a Delaware limited liability company (“Parent”), which is an indirect wholly owned subsidiary of GSK plc, a public limited
company organized under the laws of England and Wales (“Ultimate Parent”), to purchase any and all of the Company’s outstanding Class A Common Stock, $0.0001 par value per share (the “Class A Shares”), and
Class B Common Stock, $0.0001 par value per share (the “Class B Shares” and, together with the Class A Shares, the “Shares”) in exchange for $124.00 per Share, net to the seller in cash, without interest (such
consideration as it may be increased from time to time pursuant to the terms of the Merger Agreement, the “Offer Price”), subject to any applicable withholding taxes, and upon the terms and subject to the conditions set forth in the
Offer to Purchase, dated June 24, 2026 (together with any amendments or supplements thereto, the “Offer to Purchase”), and in the related Letter of Transmittal (together with any amendments or supplements thereto, the “Letter
of Transmittal,” which, together with the Offer to Purchase and other related materials, as they may be amended or supplemented from time to time, collectively constitute the “Offer”). The Offer is described in a Tender Offer
Statement on Schedule TO (as amended or supplemented from time to time, the “Schedule TO”) filed jointly by Ultimate Parent, Parent and Purchaser with the Securities and Exchange Commission (the “SEC”) on June 24, 2026.
The Offer to Purchase and the Letter of Transmittal have been filed as Exhibits (a)(1)(A) and (a)(1)(B) to the Schedule 14D-9, respectively, and are incorporated therein by reference.
Since the initial filing of the Schedule 14D-9 and as of the filing of this Amendment, the Company has
received 11 demand letters from purported stockholders of the Company (collectively the “Demand Letters”), challenging certain disclosures in the Schedule 14D-9. The Company believes that
the disclosures originally set forth in the Schedule 14D-9 comply fully with all applicable laws, denies the allegations in the Demand Letters, and believes that the claims in the Demand Letters are
without merit. The Company believes that no supplemental disclosure is required under applicable laws and that the Schedule 14D-9, as originally filed on June 24, 2026, disclosed all material information
required to be disclosed therein. However, solely to avoid the risk of delay to the Transactions, to minimize any associated costs, risks, and uncertainties, and to provide additional information to its stockholders, the Company is voluntarily
supplementing certain disclosures in the Schedule 14D-9 with the information set forth below under the sections titled “Item 4. The Solicitation or Recommendation” and “Item 8.
Additional Information” (collectively, the “Supplemental Disclosures”). Nothing in the Supplemental Disclosures shall be deemed an admission of the legal merit, necessity or materiality under applicable laws of any of the
disclosures set forth herein. To the contrary, the Company specifically denies all allegations in the Demand Letters, including that any additional disclosure was or is required or material.
Capitalized terms used in this Amendment but not defined herein shall have the respective meaning given to such terms in the Schedule 14D-9. The information set forth in the Schedule 14D-9 remains unchanged and is incorporated herein by reference, except that such information is hereby amended or
supplemented to the extent specifically provided herein. The Supplemental Disclosures are identified below by bold, underlined text. Stricken-through text shows text being deleted from a
referenced disclosure in the Schedule 14D-9.
Item 4. The Solicitation or Recommendation.
Item 4 is hereby amended and supplemented as follows:
The bold and underlined language is added to the first paragraph of the section “Background and Reasons for the Company Board’s
Recommendation” on page 15:
The Company Board and the Company’s senior management have periodically reviewed and evaluated the
Company’s business, financial performance, long-term strategies and strategic opportunities to enhance stockholder value, including licensing and collaboration opportunities for the Company’s oncology product candidates and other
potential financial and strategic alternatives, in light of developments at the Company, in the biopharmaceutical industry, in the economy generally and in the financial markets. As part of these activities, and in the ordinary course of its
business development efforts, the Company from time to time engaged in preliminary collaboration and strategic discussions with various participants in the biopharmaceutical industry regarding the Company’s programs, including
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