Coherus Oncology Inc American Stock Offering Prospectus (Version as of February 13, 2026)

Common Stock We are offering 28,600,000 of shares of our common stock. Our common stock is listed on The NasdaqGlobal Market under the symbol “CHRS.” The last reported sale price of our common stock on the Nasdaq Global Market on February 11, 2026was $2.04 per share. (1)See “Underwriting” for additional disclosure regarding underwriting discounts, commissions andestimated offering expenses. We have granted the underwriters an option for a period of 30days from the date of this prospectussupplement to purchase up to 4,290,000 of additional shares of our common stock from us at the public Investing in our common stock involves a high degree of risk. See “Risk Factors” on pageS-7of thisprospectus supplement and in the documents incorporated by reference in this prospectus supplement Neither the Securities and Exchange Commission nor any state securities commission has approved ordisapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement. Any The underwriters expect to deliver the shares of common stock to purchasers on or about February17,2026. Oppenheimer & Co. Guggenheim Securities TD Cowen The date of this prospectus supplement is February12, 2026 TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus are part of a “shelf” registrationstatement on Form S-3 (File No. 333-291520). This document is in two parts. The first part is this prospectus supplement, which describes the terms ofthis offering of common stock and also adds to and updates information contained in the accompanyingprospectus and the documents incorporated by reference into this prospectus supplement and theaccompanying prospectus. The second part is the accompanying prospectus dated December8, 2025, alongwith the documents incorporated by reference therein, which provides more general information about ourcommon stock. Generally, when we refer to the prospectus, we are referring to this prospectus supplementand the accompanying prospectus combined. To the extent there is a conflict between the information Neither we nor the underwriters have authorized anyone to provide you with information that isdifferent from that contained in this prospectus supplement, the accompanying prospectus, the documentsincorporated by reference herein or in any free writing prospectus we may authorize to be delivered or madeavailable to you. We take no responsibility for, and can provide no assurance as to the reliability of, anyother information that others may give you. We and the underwriters are offering to sell shares of common When we refer to “Coherus,” “we,” “our,” “us” and the “Company,” we mean Coherus Oncology, Inc.,unless otherwise specified. When we refer to “you,” we mean the holders of common stock of the Company. Coherus Oncology™ and our logo are some of our trademarks used in this prospectus supplement. Thisprospectus supplement, the accompanying prospectus and the documents incorporated by reference hereinalso include trademarks, tradenames and service marks that are the property of other organizations. Solely for convenience, our trademarks and tradenames referred to in this prospectus supplement appear withouttheand ™ symbols, but those references are not intended to indicate, in any way, that we will not assert,to the fullest extent under applicable law, our rights or the right of the applicable licensor to these® This prospectus supplement and the documents incorporated by reference herein contain industry andmarket data obtained from periodic industry publications, third-party surveys and studies, and governmentand industry sources. Industry publications and surveys generally state that the information containedtherein has been obtained from sources believed to be reliable. Although we believe the industry and marketdata to be reliable as of the date of this prospectus supplement, this information could prove to beinaccurate. Industry and market data could be wrong because of the method by which sources obtained theirdata and because information cannot always be verified with complete certainty due to the limits on the PROSPECTUS SUPPLEMENT SUMMARY This summary highlights certain information about us, this offering and selected information containedelsewhere in or incorporated by reference in this prospectus supplement or the accompanying prospectus.This summary provides an overview of selected information and does not contain all of the information youshould consider before buying our common stock. Therefore, you should read the entire prospectus supplement, the section titled Risk Factors in ourAnnual Report on Form 10-K for the year endedDecember31, 2024and in our Quarterly Reports on Form 10-Q for the quarters endedMarch31, 2025,June30, 2025andSeptember30, 2025, each of which are incorporated by reference herein, and the Our Company We are a fully integrated commercial-stage innovative oncol