Aktis Oncology Inc美股招股说明书(2026-01-09版)

Prospectus 17,650,000 shares Common stock This is an initial public offering of shares of common stock by Aktis Oncology, Inc. We are offering 17,650,000 shares of our common stock. The public offering price is $18.00 per share. Prior to this offering, there has been no public market for our common stock. Our common stock has been approved for listing on theNasdaq Global Select Market under the trading symbol “AKTS.” We are an “emerging growth company” and a “smaller reporting company” as defined under the U.S. federal securities laws and, as such,will be subject to reduced public company reporting requirements for this prospectus and future filings. See “Prospectus summary—Implications of being an emerging growth company and a smaller reporting company.” Investing in our common stock involves a high degree of risk. See “Risk factors” beginning on page18 to read about factorsyou should consider before buying shares of our common stock. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities, or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminaloffense. Following the completion of this offering, we will have two classes of common stock: common stock and Class A common stock. We areoffering voting common stock in this offering, and unless otherwise noted, all references in this prospectus to our “common stock” refers toour voting common stock and all references to “Class A common stock” refers to our non-voting common stock. The common stock andClass A common stock will be economically equivalent to each other. The rights of the holders of our common stock and Class A commonstock will be identical, except with respect to voting and conversion. Each share of common stock will be entitled to one vote and will notbe convertible into any other class of our share capital. The shares of Class A common stock will not have associated voting rights, exceptas otherwise expressly provided in our amended and restated certificate of incorporation and as may be required by law. Each share ofClass A common stock may be converted at any time into one share of common stock at the option of its holder, subject to the beneficialownership limitations provided for in our amended and restated certificate of incorporation. See “Description of capital stock—Commonstock” for more information on the rights of the holders of our common stock and Class A common stock. The Class A common stock willnot be listed for trading on any securities exchange. We have granted the underwriters an option for a period of 30 days from the date of this prospectus to purchase up to 2,647,500additional shares of common stock from us at the initial public offering price less the underwriting discount. The underwriters expect to deliver the shares against payment in New York, New York on January 12, 2026. J.P.Morgan BofASecurities Prospectus dated January 8, 2026 Table of Contents Table of contents PageProspectus summary1Risk factors18Special note regarding forward-looking statements106Market and industry data109Use of proceeds110Dividend policy112Capitalization113Dilution115Management’s discussion and analysis of financial condition and results of operations118Business137Management187Executive and director compensation198Certain relationships and related party transactions219Principal stockholders224Description of capital stock227Shares eligible for future sale234Certain material U.S. federal income tax consequences to non-U.S. holders237Underwriting242Legal matters254Experts254Where you can find more information255Index to consolidated financial statementsF-1 Neither we nor the underwriters have authorized anyone to provide any information or to make any representations other than thosecontained in this prospectus or in any free writing prospectus prepared by or on behalf of us or to which we have referred you. We and theunderwriters take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may provideyou. We and the underwriters are not making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. Youshould assume that the information contained in this prospectus or in any applicable free writing prospectus is accurate only as of its dateregardless of its time of delivery or of any sale of our common stock. Our business, financial condition, results of operations and prospectsmay have changed since that date. For investors outside of the United States: neither we nor any of the underwriters have done anything that would permit this offering orpossession or distribution of this prospectus in any jurisdiction where action for that purpose is required, other than the United States.Persons outside of the United States who come into possession of this prospectus must inform themselves about, and observe anyrestrict