Inovio制药美股招股说明书(2026-01-27版)

This Amendment No.1 to Prospectus Supplement (this “Amendment”) dated January27, 2026, filed by Inovio Pharmaceuticals, Inc. (the “Company”),modifies and supplements certain information contained in the Company’s prospectus supplement, dated July2, 2025 (as amended and supplementedfrom time to time, the “Prospectus”), as part of the Company’s Form S-3 Registration Statement declared effective by the Securities and ExchangeCommission on January31, 2024. This Amendment is not complete without, and may not be delivered or used except in connection with, theProspectus, including all amendments and supplements thereto. The Prospectus, as amended by this Amendment, relates to the offering of an aggregateof 14,285,715 shares of common stock, par value $0.001 per share, of Inovio Pharmaceuticals, Inc., accompanying Series A common stock warrants (the“Series A Warrants”) to purchase up to 14,285,715 shares of our common stock (orpre-fundedwarrants to purchase up to 14,285,715 shares of ourcommon stock in lieu thereof), and accompanying Series B common stock warrants to purchase up to 14,285,715shares of our common stock(orpre-fundedwarrants to purchase up to 14,285,715 shares of our common stock in lieu thereof) and an amendment to the terms of the outstandingSeries A Warrants. On January27, 2026, we entered into amendments to the outstanding Series A Warrants (the “Amendments”) with holders of the outstanding Series AWarrants (the “Holders”) whereby we agreed to amend Series A Warrants to extend the expiration date of the outstanding Series A Warrants to 5:00 pmNew York City time on March31, 2026. As of the date of this prospectus supplement, each outstanding Series A Warrant expires at 5:00pm New YorkCity time on March31, 2026. All other terms of the Series A Warrants remain unchanged. The information in this Amendment modifies and supersedes, in part, the information contained in the Prospectus. Any information that is modified orsuperseded in the Prospectus shall not be deemed to constitute a part of the Prospectus, except as so modified or superseded by this Amendment. Wemay further amend or supplement the Prospectus from time to time by filing additional amendments or supplements as required. You should read theentire Prospectus and any amendments or supplements carefully before you make an investment decision. The Company’s common stock is traded on the Nasdaq Capital Market under the symbol “INO.” On January26, 2026, the closing sale price of theCompany’s common stock was $1.51 per share. We are a “smaller reporting company” under applicable Securities and Exchange Commission, or the SEC, rules and are subject to reduced publiccompany reporting requirements. See “Prospectus Summary—Implications of Being a Smaller Reporting Company” in the Prospectus. Investing in the Company’s securities involves risks. Before making any investment in the Company’s securities, youshould read and carefully consider risks described in the “Risk Factors” section in the Prospectus and in theCompany’s most recent Annual Report on Form 10-K and subsequently filed Quarterly Reports on Form 10-Q. The Securities and Exchange Commission and state securities regulators have not approved or disapproved these securities or determined if theProspectus, or any of the supplements or amendments relating thereto, is truthful or complete. Any representation to the contrary is a criminaloffense. The date of this Amendment No.1 is January27, 2026.