GH Research PLC 美国招股说明书（2026年4月29日版）

6,527,779 Ordinary Shares GH Research PLC We are offering 6,527,779 ordinary shares, nominal value $0.025 per share. Our ordinary shares are listed on the Nasdaq Global Market, or Nasdaq, under the symbol “GHRS”. OnApril 28, 2026, the last reported sale price of our ordinary shares on Nasdaq was $19.85 per share. Investing in our ordinary shares involves risks. See the section titled “Risk Factors” on page S-6ofthis prospectus supplement and in the documents we incorporate by reference herein. The ordinary shares are expected to be delivered to investors on or about April 30, 2026. Joint Book-Running Managers CantorCo-Lead Managers Stifel TABLE OF CONTENTS TABLE OF CONTENTS ABOUT THIS PROSPECTUS SUPPLEMENT This document consists of two parts. The first part is this prospectus supplement, which describes the specificterms of this offering of ordinary shares. The second part is the accompanying prospectus, which is part of aregistration statement that we filed with the U.S. Securities and Exchange Commission, or the SEC, using a “shelf”registration process. The accompanying prospectus provides you with a general description of the securities that maybe offered by us, some of which may not apply to this offering. This prospectus supplement and the informationincorporated by reference in this prospectus supplement adds to, updates and, where applicable, modifies andsupersedes information contained or incorporated by reference in the accompanying prospectus. Before buying anyof the ordinary shares that we are offering, you should carefully read both this prospectus supplement and the To the extent there is a conflict between the information contained in this prospectus supplement, on the onehand, and the information contained in the accompanying prospectus or in any document incorporated by referencein this prospectus supplement, on the other hand, you should look to the information in this prospectus supplement, Neither the delivery of this prospectus supplement nor any offering made under it implies that there has been nochange in our affairs or that the information in this prospectus supplement, the accompanying prospectus, any freewriting prospectus prepared by us or any documents incorporated by reference is correct as of any date after theirrespective dates. You should not assume that the information in this prospectus supplement, the accompanyingprospectus, any free writing prospectus prepared by us or any documents incorporated by reference is accurate as of Neither we nor the underwriters have authorized anyone to provide you with any information or to represent asto anything different from, or not contained in, or incorporated by reference into, this prospectus supplement, theaccompanying prospectus or in any free writing prospectus that we may authorize to be delivered or made availableto you. Neither we nor the underwriters take any responsibility and can make no assurance as to the reliability of,any other information that others may give you. This prospectus supplement does not constitute an offer to sell or Neither we nor the underwriters have taken any action that would permit the offering or possession ordistribution of this prospectus supplement, the accompanying prospectus or any filed free writing prospectus in anyjurisdiction where other action for that purpose is required, other than in the United States. Persons outside theUnitedStates who come into possession of this prospectus supplement, the accompanying prospectus or any freewriting prospectus filed with the SEC must inform themselves about, and observe any restrictions relating to, the This prospectus supplement is not a prospectus for the purposes of the Irish Companies Act 2014 (asamended), the EU Prospectus Regulation (EU) 2017/1129 (as amended), the European Union (Prospectus)Regulations 2019 of Ireland (as amended) or the Central Bank (Investment Market Conduct) Rules 2019 ofIreland. This prospectus supplement has not been approved by the Central Bank of Ireland, as competentauthority under the Prospectus Regulation, or any equivalent authority in a European Economic Area This prospectus supplement, accompanying prospectus and documents incorporated by reference containindustry, market and competitive position data that are based on general and industry publications, surveys and TABLE OF CONTENTS research. Third-party publications, surveys and studies generally state that they have obtained information fromsources believed to be reliable, but do not guarantee the accuracy and completeness of such information. These datainvolve a number of assumptions and limitations and contain projections and estimates of the future performance ofthe industries in which we operate that are subject to a high degree of uncertainty. We caution you not to give undueweight to such projections, assumptions or estimates. See “Cautionary Statement Regarding Forward-LookingStatements.” While we are not aware of any misstatements regar