Material Event (Form 8-K)

Item 8.01 Other Events.

On October 14, 2026, Verastem, Inc. (the "Company") entered into an underwriting agreement (the "Underwriting Agreement") with Jefferies LLC and Guggenheim Securities, LLC, as representatives of the several underwriters named in Schedule I thereto (the "Underwriters"), relating to the underwritten offering, issuance and sale by the Company of: (i) 30,937,500 shares (the "Shares") of the Company's common stock, par value $0.0001 per share (the "Common Stock"), and (ii) to certain investors, pre-funded warrants (the "Pre-Funded Warrants") to purchase up to 312,503 shares of Common Stock (collectively, the "Offering"). All of the Shares and the Pre-Funded Warrants will be sold by the Company. Each share of Common Stock is being offered at an offering price of $8.00, less the underwriting discounts and commissions, and each Pre-Funded Warrant is being offered at an offering price of $7.9999, which is equal to the offering price per share of Common Stock less the $0.0001 exercise price of each Pre-Funded Warrant, less the underwriting discounts and commissions.

The Company expects to receive net proceeds from the Offering, after deducting underwriting discounts and commissions and estimated offering expenses, of approximately $234.7 million.

The Offering was made pursuant to the Company's shelf registration statement on Form S-3, as amended (File No. 333-289399), which was declared effective on August 15, 2025. The closing of the Offering is expected to take place on or about October 15, 2026, subject to the satisfaction of customary closing conditions.

Each Pre-Funded Warrant will have an exercise price equal to $0.0001 per underlying share of Common Stock. Each Pre-Funded Warrant is exercisable for the number of shares of the Company's Common Stock stated therein. The Pre-Funded Warrants will not expire and are exercisable in cash or by means of a cashless exercise.

Each Pre-Funded Warrant will be exercisable in whole or in part by delivering a duly executed exercise notice accompanied by payment in full for the number of shares of Common Stock purchased upon such exercise. The exercise price and the number of shares of Common Stock issuable upon exercise of each Pre-Funded Warrant are subject to appropriate adjustment in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Common Stock as well as upon any distribution of assets, including cash, stock or other property, to the Company's stockholders.

The Company may not effect the exercise of any Pre-Funded Warrant, and a holder will not be entitled to exercise any portion of any Pre-Funded Warrant if, upon giving effect to such exercise, the aggregate number of shares of Common Stock beneficially owned by the holder (together with its affiliates) would exceed 4.99% or 9.99%, at the election of the holder (or such higher percentage up to 19.99%, at the election of the holder) of the number of shares of Common Stock outstanding immediately after giving effect to the exercise, which percentage may be increased or decreased at the holder's election upon 61 days' notice to the Company subject to the terms of such Pre-Funded Warrants, provided that such percentage may in no event exceed 19.99%.

In addition, upon the consummation of an acquisition (as described in the Pre-Funded Warrants), each Pre-Funded Warrant will automatically be converted into the right of the holder of such Pre-Funded Warrant to receive the kind and amount of securities, cash or other property that such holders would have received had they exercised such Pre-Funded Warrant immediately prior to such acquisition, without regard to any limitations on exercise contained in the Pre-Funded Warrants. The foregoing description of the Pre-Funded Warrants is qualified in its entirety by reference to the Form of Pre-Funded Warrant filed as Exhibit 4.1 to this Current Report on Form 8-K.

The Underwriting Agreement contains customary representations, warranties, and agreements by the Company and customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act of 1933, as amended (the "Securities Act"), and termination provisions.

A copy of the Underwriting Agreement is filed as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated herein by reference.