Tango Therapeutics Inc美股招股说明书(2026-08-11版)

PROSPECTUS SUPPLEMENT(To Prospectus dated November21, 2025) Up to $400,000,000 Common Stock We have previously entered into a Sales Agreement, or the sales agreement, with Leerink Partners LLC, or Leerink Partners, dated November21, 2025,relating to the sale of shares of our common stock, par value $0.001 per share. We previously filed a prospectus supplement on November21, 2025,relating to the offer and sale of shares of our common stock having an aggregate offering price of up to $100,000,000 from time to time through LeerinkPartners, acting as our sales agent, or the prior prospectus supplement. As of the date of this prospectus supplement, we have sold an aggregate amountof approximately $64,389,566 of shares of our common stock under the prior prospectus supplement pursuant to the sales agreement. We are terminatingthe offering pursuant to the prior prospectus supplement and we will not make any further offer or sale of shares of our common stock pursuant to theprior prospectus supplement. We are filing this prospectus supplement in accordance with the terms of the sales agreement, relating to the offer and sale of shares of our commonstock having an aggregate offering price of up to $400,000,000 from time to time through Leerink Partners acting as our sales agent. Our common stock is listed on The Nasdaq Global Market under the symbol “TNGX.” On August10, 2026, the closing sale price of our common stockon The Nasdaq Global Market was $27.67 per share. Sales of our common stock, if any, under this prospectus supplement will be made by any method permitted that is deemed to be an “at the marketoffering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended, or the Securities Act. Leerink Partners is not requiredto sell any specific number or dollar amount of securities, but will act as a sales agent using commercially reasonable efforts consistent with its normaltrading and sales practices, on mutually agreed terms between Leerink Partners and us. There is no arrangement for funds to be received in any escrow,trust or similar arrangement. Leerink Partners will be entitled to a commission of up to 3.0% of the gross sales price per share of common stock sold under the sales agreement. Inconnection with the sale of our common stock on our behalf, Leerink Partners will be deemed to be an “underwriter” within the meaning of theSecurities Act and the compensation of Leerink Partners will be deemed to be underwriting commissions or discounts. See “Plan of Distribution”beginning on page S-16 for additional information regarding the compensation to be paid to Leerink Partners. We have also agreed to provideindemnification and contribution to Leerink Partners against certain liabilities, including liabilities under the Securities Act and the Securities ExchangeAct of 1934, as amended, or the Exchange Act. Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-10 of thisprospectus supplement and under similar headings in the other documents that are incorporated by reference into thisprospectus supplement concerning factors you should consider before investing in our common stock. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or passedupon the adequacy or accuracy of this prospectus supplement. Any representation to the contrary is a criminal offense. Leerink Partners The date of this prospectus supplement is August11, 2026 Table of Contents TABLE OF CONTENTS PROSPECTUS SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENTCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSPROSPECTUS SUPPLEMENT SUMMARYTHE OFFERINGRISK FACTORSUSE OF PROCEEDSDILUTIONDIVIDEND POLICYPLAN OF DISTRIBUTIONLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINCORPORATION OF CERTAIN INFORMATION BY REFERENCE PROSPECTUS ABOUT THIS PROSPECTUSRISK FACTORSSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSOUR COMPANYUSE OF PROCEEDS Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement is part of an automatic shelf registration statement that we filed with the Securities and Exchange Commission, or the SEC,as a “well-known seasoned issuer” as defined in Rule 405 under the Securities Act. Under the shelf registration, we may offer shares of our commonstock and preferred stock, various series of warrants to purchase common stock or preferred stock, debt securities, units or any combination thereof,from time to time in one or more offerings. Under this prospectus supplement, we may offer shares of our common stock having an aggregate offeringprice of up to $400,000,000 from time to time at prices and on terms to be determined by market conditions at the time of offering. Before buying any of the shares of common stock offered hereby, we urge you to read carefully this prospectus supplement, together with theinformation incorporated herein by reference