内克塔治疗美股招股说明书(2026-05-08版)

Up to $150,000,000 Common Stock We have entered into an equity distribution agreement, or the Equity Distribution Agreement, with Guggenheim Securities, LLC and H.C. Wainwright&Co., LLC, or the sales agents, relating to shares of our common stock offered by this prospectus supplement. In accordance with the terms of the EquityDistribution Agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $150,000,000 from time to timethrough the sales agents. Our common stock is listed on the Nasdaq Capital Market under the symbol “NKTR.” On May6, 2026, the last reported sale price of our common stockwas $85.09 per share. Sales of our common stock, if any, under this prospectus supplement will be made in sales deemed to be “at the market offerings” as defined in Rule 415promulgated under the Securities Act of 1933, as amended, or the Securities Act, including by means of ordinary brokers’ transactions on the NasdaqCapital Market at market prices or otherwise at prices related to prevailing market prices or at negotiated prices, by privately negotiated transactions(including block sales) or by any other methods permitted by applicable law. The sales agents are not required to sell any specific amount of securities,but will act as our sales agents using commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed termsbetween the sales agents and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement. The sales agents will be entitled to compensation at a commission rate equal to 3.0% of the aggregate gross sales sold under the Equity DistributionAgreement. In connection with the sale of the common stock on our behalf, the sales agents will be deemed to be “underwriters” within the meaning ofthe Securities Act and the compensation of the sales agents will be deemed to be underwriting commissions or discounts. We have also agreed to provideindemnification and contribution to the sales agents with respect to certain liabilities, including liabilities under the Securities Act or the SecuritiesExchange Act of 1934, as amended. Our business and an investment in our common stock involve significant risks. These risks are described under thecaption “Risk Factors” beginning on pageS-8 of this prospectus supplement and in the documents incorporated byreference into this prospectus supplement. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passedupon the accuracy or adequacy of this prospectus supplement. Any representation to the contrary is a criminal offense. GuggenheimSecurities The date of this prospectus supplement is May8, 2026. Table of Contents Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENTSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSPROSPECTUS SUPPLEMENT SUMMARYRISK FACTORSUSE OF PROCEEDSDILUTIONPLAN OF DISTRIBUTIONLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINCORPORATION OF CERTAIN INFORMATION BY REFERENCE ABOUT THIS PROSPECTUSSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSABOUT THE COMPANYRISK FACTORSUSE OF PROCEEDSDIVIDEND POLICYGENERAL DESCRIPTION OF SECURITIES DESCRIPTION OF DEBT SECURITIES DESCRIPTION OF WARRANTS DESCRIPTION OF UNITS PLAN OF DISTRIBUTION LEGAL MATTERS EXPERTS WHERE YOU CAN FIND MORE INFORMATION INCORPORATION OF CERTAIN INFORMATION BY REFERENCE We are responsible for the information contained and incorporated by reference in this prospectus supplement, in any accompanying prospectus, and inany related free writing prospectus we prepare or authorize. We have not authorized anyone to give you any other information, and we take noresponsibility for any other information that others may give you. If you are in a jurisdiction where offers to sell, or solicitations of offers to purchase,the securities offered by this documentation are unlawful, or if you are a person to whom it is unlawful to direct these types of activities, then the offerpresented in this document does not extend to you. Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement is part of a registration statement on Form S-3ASR that we filed with the Securities and Exchange Commission, or SEC,using a “shelf” registration process. Under our base prospectus included in the shelf registration statement, we may offer from time to time varioussecurities, of which this offering of shares of our common stock is a part. Under this prospectus supplement and the accompanying prospectus, we mayoffer shares of our common stock having an aggregate offering price of up to $150,000,000 from time to time at prices and on terms to be determined bymarket conditions at the time of offering. Before buying any of the common stock that we are offering pursuant to this prospectus supplement, we urge you to carefully read this prospectussupplement and the accompanying prospe