内克塔治疗美股招股说明书(2026-04-20版)

Shares of Common Stock Pre-Funded Warrants to Purchase up toShares of Common Stock Shares ofCommon Stock Underlying the Pre-Funded Warrants We are offering $250,000,000 of shares of our common stock, par value $0.0001 per share, or common stock, and, in lieu of shares ofcommon stock to investors that so choose, pre-funded warrants to purchase up toshares of our common stock, or the pre-fundedwarrants (and the shares of common stock issuable from time to time upon exercise of the pre-funded warrants), pursuant to this prospectussupplement and the accompanying prospectus. The pre-funded warrants will be exercisable immediately and are exercisable for one share ofour common stock. The purchase price of each pre-funded warrant is equal to the purchase price at which a share of our common stock is soldin this offering, minus $0.0001, and the exercise price of each pre-funded warrant is $0.0001 per share of our common stock. Our common stock is listed on the Nasdaq Capital Market under the symbol “NKTR”. On April17, 2026, the last reported sale price forour common stock on the Nasdaq Capital Market was $84.86 per share. There is no established public trading market for the pre-fundedwarrants, and we do not expect a market to develop. In addition, we do not intend to apply for listing of the pre-funded warrants on anysecurities exchange or recognized trading system. We are a “smaller reporting company” under the federal securities laws and, as such, we have elected to comply with certain reducedpublic company reporting requirements for this prospectus supplement and for future filings. See “Prospectus Supplement Summary—Implications of Being a Smaller Reporting Company.” Public offering price We have granted the underwriters an option for a period of 30 days to purchase an additionalus, at the public offering price, less the underwriting discounts and commissions. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-11 ofthis prospectus supplement and page 6 of the accompanying prospectus, and in the documents incorporatedby reference herein. You should read the entire prospectus supplement and the accompanying prospectus,including any information incorporated by reference, carefully, before investing in our securities. The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to these securities has been filed withthe Securities and Exchange Commission and is effective. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell thesesecurities and they are not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation tothe contrary is a criminal offense. The underwriters expect to deliver the shares of common stock and pre-funded warrants to purchasers on or about April, 2026. Piper Sandler Table of Contents TABLE OF CONTENTSPROSPECTUS SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENTSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSPROSPECTUS SUPPLEMENT SUMMARYRISK FACTORSUSE OF PROCEEDSDILUTIONDIVIDEND POLICYMATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERSDESCRIPTION OF PRE-FUNDED WARRANTSUNDERWRITINGLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINCORPORATION OF CERTAIN INFORMATION BY REFERENCE PROSPECTUS ABOUT THIS PROSPECTUSSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSABOUT THE COMPANYRISK FACTORSUSE OF PROCEEDSDIVIDEND POLICYGENERAL DESCRIPTION OF SECURITIESDESCRIPTION OF CAPITAL STOCKDESCRIPTION OF DEBT SECURITIESDESCRIPTION OF WARRANTSDESCRIPTION OF UNITSPLAN OF DISTRIBUTIONLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINCORPORATION OF CERTAIN INFORMATION BY REFERENCE Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering of common stockand pre-funded warrants and also adds to and updates information contained in the accompanying prospectus and the documents incorporated byreference into this prospectus supplement and the accompanying prospectus. The second part is the accompanying prospectus dated November12, 2025,included in our registration statement on Form S-3 (File No.333-291466), along with the documents incorporated by reference therein, which providesmore general information, some of which may not apply to this offering. Generally, when we refer to this prospectus, we are referring to both parts ofthis document combined. To the extent there is a conflict between the information contained in this prospectus supplement and the information contained in theaccompanying prospectus or in