Ordinary SharesPre-Funded Warrants to Purchase Ordinary Shares We are offeringordinary shares, nominal value €0.05 per share, and, in lieu of ordinary shares tocertain investors, pre-funded warrants to purchaseordinary shares pursuant to this prospectussupplement and the accompanying prospectus. The purchase price of each pre-funded warrant will equal theprice per ordinary share at which our ordinary shares are being sold to the public in this offering, minus$0.0001, which is the exercise price of each pre-funded warrant. This prospectus supplement also relates tothe offering of our ordinary shares issuable upon exercise of the pre-funded warrants. Our ordinary shares are listed on The Nasdaq Global Select Market, or Nasdaq, under the symbol“QURE.” On June 22, 2026, the last reported sale price of our ordinary shares on Nasdaq was $44.39 perordinary share. We do not intend to list the pre-funded warrants on Nasdaq, any other national securitiesexchange or any other nationally recognized trading system. Investing in our ordinary shares or pre-funded warrants involves significant risks. See “Risk Factors”beginning on pageS-7of this prospectus supplement as well as the documents incorporated by reference intothis prospectus supplement and the accompanying prospectus for a discussion of the factors you should considerbefore deciding to purchase our securities. Neither the Securities and Exchange Commission nor any state securities commission has approved ordisapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or theaccompanying prospectus. Any representation to the contrary is a criminal offense. (1)See “Underwriting” beginning on pageS-29of this prospectus supplement for additional informationregarding total underwriting compensation. Delivery of our ordinary shares and pre-funded warrants is expected to be made on or about June,2026. We have granted the underwriters an option for a period of 30days to purchase up to anadditionalordinary shares at the public offering price less the underwriting discounts andcommissions. Bookrunning Managers Stifel Leerink Partners TABLE OF CONTENTSPROSPECTUS SUPPLEMENT PageABOUT THIS PROSPECTUS SUPPLEMENTS-iiSPECIAL CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSS-ivENFORCEMENT OF CIVIL LIABILITIESS-viPROSPECTUS SUPPLEMENT SUMMARYS-1THE OFFERINGS-5RISK FACTORSS-7USE OF PROCEEDSS-12DIVIDEND POLICYS-13DILUTIONS-14DESCRIPTION OF PRE-FUNDED WARRANTSS-16MATERIAL DUTCH AND U.S. FEDERAL INCOME TAX CONSIDERATIONSS-18UNDERWRITINGS-29LEGAL MATTERSS-35EXPERTSS-36WHERE YOU CAN FIND MORE INFORMATIONS-37INCORPORATION OF CERTAIN INFORMATION BY REFERENCES-38PROSPECTUSPageABOUT THIS PROSPECTUS1THE COMPANY2RISK FACTORS3SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS4USE OF PROCEEDS6DESCRIPTION OF ORDINARY SHARES AND ARTICLES OF ASSOCIATION7DESCRIPTION OF DEBT SECURITIES13DESCRIPTION OF WARRANTS19DESCRIPTION OF RIGHTS20DESCRIPTION OF UNITS21CONVERTIBLE OR EXCHANGEABLE SECURITIES22FORM, EXCHANGE AND TRANSFER23BOOK-ENTRY PROCEDURES AND SETTLEMENT24PLAN OF DISTRIBUTION26LEGAL MATTERS29EXPERTS30WHERE YOU CAN FIND MORE INFORMATION31INCORPORATION OF CERTAIN INFORMATION BY REFERENCE32 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus relate to an offering of our ordinaryshares and pre-funded warrants to acquire our ordinary shares. Before buying any of the ordinary shares orpre-funded warrants that we are offering, we urge you to carefully read this prospectus supplement and theaccompanying prospectus, together with the information incorporated by reference herein and therein,including as described under the headings “Where You Can Find More Information” and “Incorporation ofCertain Information by Reference” in this prospectus supplement. These documents contain importantinformation that you should consider when making your investment decision. This document is in two parts. The first part is this prospectus supplement, which describes the terms ofthe offering of the securities offered hereby and also adds to, updates and changes the information containedin the accompanying prospectus and the documents incorporated by reference into this prospectussupplement and the accompanying prospectus. The second part is the accompanying prospectus, whichprovides more general information, some of which may not apply to this offering and some of which mayhave been supplemented or superseded by information in this prospectus supplement or documentsincorporated or deemed to be incorporated by reference into this prospectus supplement that we filed withthe Securities and Exchange Commission, or SEC, subsequent to the date of the prospectus. To the extentthe information contained in this prospectus supplement differs from or conflicts with the informationcontained in the accompanying prospectus or any document incorporated by reference herein or therein, theinformation in this prospectus supplement will contro