4,945,055 Ordinary Shares We are offering 4,945,055 ordinary shares, nominal value €0.05 per share, pursuant to this prospectussupplement and the accompanying prospectus. Our ordinary shares are listed on The Nasdaq Global Select Market, or Nasdaq, under the symbol“QURE.” On June 23, 2026, the last reported sale price of our ordinary shares on Nasdaq was $49.04 perordinary share. Investing in our ordinary shares involves significant risks. See “Risk Factors” beginning on pageS-7of thisprospectus supplement as well as the documents incorporated by reference into this prospectus supplement andthe accompanying prospectus for a discussion of the factors you should consider before deciding to purchase oursecurities. 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-25of this prospectus supplement for additional informationregarding total underwriting compensation. Delivery of our ordinary shares is expected to be made on or about June 25, 2026. We have granted theunderwriters an option for a period of 30days to purchase up to an additional 741,758 ordinary shares at thepublic offering price less the underwriting discounts and commissions. Joint Bookrunning Managers Leerink PartnersStifel GuggenheimSecurities RBC Capital Markets Lead Manager H.C. Wainwright & Co. The date of this prospectus supplement is June 23, 2026. 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-11DIVIDEND POLICYS-12DILUTIONS-13MATERIAL DUTCH AND U.S. FEDERAL INCOME TAX CONSIDERATIONSS-15UNDERWRITINGS-25LEGAL MATTERSS-31EXPERTSS-32WHERE YOU CAN FIND MORE INFORMATIONS-33INCORPORATION OF CERTAIN INFORMATION BY REFERENCES-34 PROSPECTUS ABOUT 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. Before buying any of the ordinary shares that we are offering, we urge you to carefully read thisprospectus supplement and the accompanying prospectus, together with the information incorporated byreference herein and therein, including as described under the headings “Where You Can Find MoreInformation” and “Incorporation of Certain Information by Reference” in this prospectus supplement. Thesedocuments contain important information 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 control. If any statement in one of these documents isinconsistent with a statement in another document having a later date - for example, a documentincorporated by reference into the accompanying prospectus - the statement in the document having the laterdate modifies or supersedes the earlier statement. This prospectus supplement and the accompanying prospectus are part of a registration statement thatwe filed with the SEC, utilizing a “shelf” registration process as a “well-known seasoned issuer” as definedin Rule405 under the Securities Act of 1933, as amended, or the Securities Act. Under this shelf registrationprocess, we may offer fro