INTRODUCTION
This Tender Offer Statement on Schedule TO (this “Schedule TO”) relates to the offer by Keros Therapeutics, Inc., a Delaware corporation (the “Company”), to purchase for cash up to an aggregate of 10,950,165 shares of its common stock, par value $0.0001 per share, for an aggregate purchase price of up to $194.4 million, at a purchase price of $17.75 per share, less any applicable withholding taxes and without interest, upon the terms and subject to the conditions set forth in the Offer to Purchase dated October 20, 2025 (the “Offer to Purchase”), a copy of which is attached hereto as Exhibit (a)(1)(A), and in the related Letter of Transmittal (the “Letter of Transmittal” and, together with the Offer to Purchase, as they may be amended or supplemented from time to time, the “Tender Offer”), a copy of which is attached hereto as Exhibit (a)(1)(B). This Schedule TO is intended to satisfy the reporting requirements of Rule 13e-4(c)(2) of the Securities Exchange Act of 1934, as amended.
The information contained in the Offer to Purchase and the related Letter of Transmittal is hereby incorporated by reference in response to all of the items of this Schedule TO, as more particularly described below.
ITEM 1.
SUMMARY TERM SHEET.
The information set forth under “Summary Term Sheet” in the Offer to Purchase is incorporated herein by reference.
ITEM 2.
SUBJECT COMPANY INFORMATION.
(a)
The name of the issuer is Keros Therapeutics, Inc., a Delaware corporation (the “Company”), and the address of its principal executive office is 1050 Waltham Street, Suite 302, Lexington, Massachusetts 02421. The Company’s telephone number is (617) 314-6297.
(b)
The subject securities are shares of the Company’s common stock. As of October 17, 2025, there were 30,466,069 shares of the Company’s common stock outstanding. The information set forth under the heading “Introduction” in the Offer to Purchase is incorporated herein by reference.
(c)
The information about the trading market and price of the shares of the Company’s common stock set forth in the Offer to Purchase under Section 8 (“Price Range of Shares; Dividends”) is incorporated herein by reference.
ITEM 3.
IDENTITY AND BACKGROUND OF FILING PERSON.
(a)
The Company is the filing person. The Company’s business address and telephone number are set forth in Item 2(a) above. The names and business addresses of the directors and executive officers of the Company are as set forth in the Offer to Purchase under Section 11 (“Interests of Directors and Executive Officers; Transactions and Arrangements Concerning the Shares”), and such information is incorporated herein by reference.
ITEM 4.
TERMS OF THE TRANSACTION.
(a)
The following sections of the Offer to Purchase contain a description of the material terms of the transaction and are incorporated herein by reference:
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“Summary Term Sheet”;
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“Introduction”;
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Section 1 (“Number of Shares; Proration”);
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Section 2 (“Purpose of the Tender Offer; Certain Effects of the Tender Offer; Other Plans”);
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Section 3 (“Procedures for Tendering Shares”);
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Section 4 (“Withdrawal Rights”);
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Section 5 (“Purchase of Shares and Payment of Purchase Price”);