enGene Holdings Inc. - 美股招股说明书（2026年3月9日版）

Up to $100,000,000 Common Shares We have entered into a sales agreement with Leerink Partners LLC (“Leerink Partners”) on March 9, 2026 (the “SalesAgreement”), relating to the sale of our common shares, no par value (the “common shares”), from time to time offered by this prospectussupplement and the accompanying base shelf prospectus. In accordance with the terms of the Sales Agreement, under this prospectus Our common shares are listed on the Nasdaq Capital Market (“Nasdaq”) under the symbol “ENGN.” The last reported sale price ofour common shares on Nasdaq on March 5, 2026 was $8.71 per share. Sales of our common shares, if any, under this prospectus supplement may be made by any method permitted that is deemed an “atthe market offering” as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended, or the Securities Act. Leerink Partners is notrequired to sell any specific amount of our common shares, but will act as our sales agent using commercially reasonable efforts, consistent No sales of our common shares under this prospectus supplement will be offered or made in Canada, or knowingly to a personresident in Canada. Leerink Partners will be entitled to compensation at a commission rate of up to 3.0% of the gross sales price of all common sharessold through it under the Sales Agreement. See “Plan of Distribution” beginning on page S-24 for additional information regarding thecompensation to be paid to Leerink Partners. In connection with the sale of the common shares on our behalf, Leerink Partners will bedeemed to be an “underwriter” within the meaning of the Securities Act and the compensation of Leerink Partners will be deemed to be Investing in our common shares involves a high degree of risk. You should carefully read and consider the risk factors described in,and incorporated by reference under, “Risk Factors” beginning on page S-6 of this prospectus supplement and in the documents Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or determined if this prospectus supplement is truthful or complete. Any representation to the contrary is a criminaloffense. Leerink Partners The date of this prospectus supplement is March 9, 2026 ABOUT THIS PROSPECTUS SUPPLEMENT This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering andthe securities offered hereby, and also adds to and updates information contained in the accompanying base shelf prospectus and thedocuments incorporated into each by reference. The second part, the accompanying base shelf prospectus, gives more general information If there is any inconsistency between information in or incorporated by reference into the accompanying base shelf prospectus andinformation in or incorporated by reference into this prospectus supplement, you should rely only on the information contained in orincorporated by reference into this prospectus supplement. This prospectus supplement, the accompanying base shelf prospectus and thedocuments incorporated into each by reference include important information about us, the common shares being offered and other Neither we nor Leerink Partners have authorized anyone to provide any information or to make any representations other than thosecontained in this prospectus supplement and the accompanying base shelf prospectus, the documents incorporated by reference herein ortherein or in any free writing prospectuses prepared by us or on our behalf or to which we have referred you. We are not, and LeerinkPartners is not, making an offer to sell these securities in any jurisdiction where the offer or sale thereof is not permitted. We are not offeringto sell, or seeking offers to buy, common shares in Canada, to anyone known by the sales agent to be a resident of Canada or over or throughthe facilities of any exchange or market in Canada. The distribution of this prospectus and the offering of common shares in certain Unless otherwise indicated in this prospectus supplement and the accompanying base shelf prospectus all dollar amounts andreferences to “$” or “US$” are to U.S. dollars and references to “C$” are to Canadian dollars. In this prospectus supplement and the accompanying base shelf prospectus, unless the context otherwise requires, references to“we,” “us,” “our” or similar terms, as well as references to “enGene” or the “Company,” refer to enGene Holdings Inc., either alone or PROSPECTUS SUPPLEMENT SUMMARY This summary highlights key aspects of this offering and certain information contained elsewhere in this prospectus supplementand the documents incorporated by reference. This summary is not complete and does not contain all of the information that may beimportant to you or that you should consider before investing in our common shares. You should read carefully the other informationincluded and incorporated by reference in this pro