内克塔治疗美股招股说明书(2026-02-10版)

Filed Pursuant to Rule 424(b)(5)Registration No. 333-291466 The information in this preliminary prospectus supplement is not complete and may be changed. A registration statementrelating to these securities has been filed with the Securities and Exchange Commission and is effective. This preliminaryprospectus supplement and the accompanying prospectus are not an offer to sell these securities and they are not soliciting anoffer to buy these securities in any jurisdiction where the offer or sale is not permitted. Subject to completion, dated February10, 2026 Preliminary Prospectus Supplement(To Prospectus Dated November12, 2025) $300,000,000 Shares of Common Stock Pre-Funded Warrants to Purchase up toShares of Common StockShares of Common Stock Underlying the Pre-Funded Warrants We are offering $300,000,000 of shares of our common stock, par value $0.0001 per share, or common stock, and, in lieu of shares of common stock toinvestors that so choose, pre-funded warrants to purchase up toshares of our common stock, or the pre-funded warrants (and the shares of commonstock issuable from time to time upon exercise of the pre-funded warrants), pursuant to this prospectus supplement and the accompanying prospectus. Thepre-funded warrants will be exercisable immediately and are exercisable for one share of our common stock. The purchase price of each pre-funded warrant isequal to the purchase price at which a share of our common stock is sold in 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 February9, 2026, the last reported sale price for our commonstock on the Nasdaq Capital Market was $37.07 per share. There is no established public trading market for the pre-funded warrants, and we do not expect amarket to develop. In addition, we do not intend to apply for listing of the pre-funded warrants on any securities 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 reduced public companyreporting requirements for this prospectus supplement and for future filings. See “Prospectus Supplement Summary—Implications of Being a Smaller ReportingCompany.” Public offering price Underwriting discounts and commissions(1)Proceeds to us, before expenses (1) See “Underwriting” for a description of the compensation payable to the underwriters. We have granted the underwriters an option for a period of 30 days to purchase an additionaloffering price, less the underwriting discounts and commissions. shares of our common stock from us, at the public Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on pageS-12 of this prospectus supplementand page 6 of the accompanying prospectus, and in the documents incorporated by reference herein. You should read the entireprospectus supplement and the accompanying prospectus, including any information incorporated by reference, carefully, beforeinvesting in our securities. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities ordetermined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminaloffense. The underwriters expect to deliver the shares of common stock and pre-funded warrants to purchasers on or about February , 2026. Joint Bookrunning Managers Piper Sandler Jefferies TD Cowen Prospectus Supplement dated February, 2026 Table of Contents TABLE OF CONTENTS PROSPECTUS 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 November