This Amendment No. 1 (this “Amendment”) amends and supplements the Tender Offer
Statement on Schedule TO filed by (i) GSK plc, a public limited company organized under the laws of England and Wales (“Ultimate Parent”), (ii) GlaxoSmithKline LLC, a Delaware limited liability company and an indirect
wholly-owned subsidiary of Ultimate Parent (“Parent”), and (iii) Redrose Acquisition Co., a Delaware corporation (“Purchaser”) and a direct wholly-owned subsidiary of Parent on February 2, 2026
(together with any amendments and supplements thereto, including this Amendment, the “Schedule TO”), relating to the offer by Purchaser to purchase all of the outstanding shares of common stock, par value, $0.0001 per share (each,
a “Share” and, collectively, the “Shares”), of RAPT Therapeutics, Inc., a Delaware corporation (the “Company”), for $58.00 per Share in cash (such amount or any higher amount per share paid
pursuant to the Offer, being the “Offer Price”), without interest, subject to any applicable withholding taxes, and upon the terms and subject to the conditions set forth in the Offer to Purchase, dated February 2, 2026
(together with any amendments or supplements thereto, the “Offer to Purchase”) and in the accompanying 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”), copies of which are annexed to and filed with the Schedule TO
as Exhibits (a)(1)(A) and (a)(1)(B), respectively.
All information contained in the Offer to Purchase (including Schedule I to the Offer to Purchase) and
the accompanying Letter of Transmittal is hereby expressly incorporated herein by reference in response to Items 1 through 9 and Item 11 of this Schedule TO and is supplemented by the information specifically provided in this Amendment, except as
otherwise set forth below. This Amendment should be read together with the Schedule TO. Capitalized terms used and not otherwise defined in this Amendment have the meanings given to such terms in the Offer to Purchase.
Item 1 through 9; Item 11.
The Offer to
Purchase and Items 1 through 9 and Item 11 of the Schedule TO, to the extent such Items incorporate by reference the information contained in the Offer to Purchase, are hereby amended and supplemented as follows:
| 1. |
The second paragraph of the subsection entitled “U.S. Antitrust Compliance” in Section 16
— “Certain Legal Matters; Regulatory Approvals” is amended and supplemented by replacing the second paragraph with the following: |
“Under the HSR Act, the purchase of Shares may not be completed until the expiration or termination of a
15-calendar day waiting period following the filing of certain required information and documentary material concerning the Offer with the FTC and the Antitrust Division, unless the waiting period is
earlier terminated by the FTC and the Antitrust Division. The waiting period under the HSR Act expired, effective February 23, 2026, at 11:59 p.m. Eastern Time. Accordingly, the Regulatory Conditions to the Offer have been
satisfied.”
| 2. |
Section 16 — “Certain Legal Matters; Regulatory Approvals” is amended and
supplemented by adding the following to the end of such Section after the subsection captioned “State Takeover Laws”: |
“As of February 24, 2026, two complaints were filed in state court by purported stockholders of the Company regarding the Transactions. The
complaint filed on February 3, 2026 in the Supreme Court of the State of New York, County of New York is captioned Morgan v. Rapt Therapeutics, Inc. et al., Index No. 650698/2026 (the “Morgan Complaint”). The
complaint filed on February 5, 2026 in the Supreme Court of the State of New York is captioned Walsh v. Rapt Therapeutics, Inc. et al., Index No. 650718/2026 (together with the Morgan Complaint, the “Complaints”).
The Complaints name as defendants the Company and each member of the Company Board. The Complaints assert New York common law claims for negligent misrepresentation and concealment based on allegedly false and misleading statements in the Schedule 14D-9. In addition, the Company received twelve demand letters from purported stockholders relating to alleged disclosure deficiencies in the Schedule 14D-9.
Additional lawsuits or demand letters may be filed against or received by the Company, the Company Board, Ultimate Parent, Parent and/or Purchaser in
connection with the Transactions, the Schedule TO and the Schedule 14D-9. If additional similar complaints are filed or demand letters received, absent new or different allegations that are material, the
Company, Ultimate Parent, Parent and Purchaser will not necessarily announce such additional filings.”
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