ImmunoGen, Inc. 11,636,364 Shares of Common Stock, par value $0.01 per share Pre-Funded Warrants to Purchase 27,363,636 Shares of Common Stock Underwriting AgreementLetter Agreement • December 3rd, 2021 • ImmunoGen, Inc. • Pharmaceutical preparations • New York
ImmunoGen, Inc., a Massachusetts corporation (the “Company”), proposes to issue and sell to the several Underwriters listed in Schedule 1 hereto (the “Underwriters”), for whom you are acting as representatives (the “Representatives”), an aggregate of 11,636,364 shares (the “Underwritten Shares”) of common stock, par value $0.01 per share, of the Company (the “Common Stock”), pre-funded warrants to purchase an aggregate of 27,363,636 shares of Common Stock in the form attached as Exhibit A (the “Warrants”) and, at the option of the Underwriters, up to an additional 5,850,000 shares of Common Stock (the “Option Shares”). The Underwritten Shares and the Warrants are herein referred to as the “Underwritten Securities.” The Underwritten Shares and the Option Shares are herein referred to as the “Shares”. The shares of Common Stock issuable upon exercise of the Warrants are herein referred to as the “Warrant Shares.” The Shares and Warrants are herein referred to as the “Securities.” The sha
