enGene Announces Updated Interim Results From LEGEND Pivotal Cohort

54% complete response (CR) rate at any time; 43% six month CR rate Low rate of progression to muscle-invasive or higher disease (3.2%) Low percentage of patients experienced treatment-related adverse events (TRAEs) (55%), nearly all of which were mild Low percentage of patients experienced TRAEs leading to treatment interruption (2.4%) or discontinuation (2.4%) Kaplan-Meier estimate of 12-month CR rate is 25% enGene to host webcast to discuss results today, May 7, 2026, at 8:00 a.m. ET BOSTON & MONTREAL – enGene Therapeutics Inc. (Nasdaq: ENGN or “enGene” or the “Company”), a clinical-stage, non-viral genetic medicines company, today reported additional interim results from the pivotal cohort of its ongoing, Phase 2 LEGEND trial of detalimogene voraplasmid (also known as detalimogene) in high-risk, Bacillus Calmette-Guérin (BCG)-unresponsive non-muscle invasive bladder cancer (NMIBC) patients with carcinoma in situ (CIS) with or without concomitant papillary disease, which enrolled 125 patients. These data, as of April 21, 2026, demonstrated that patients treated with detalimogene achieved a 54% complete response (CR) at any time and a 43% CR rate at six months. The progression rate to muscle-invasive or advanced disease was low, at 3.2%. Detalimogene was generally well tolerated with 55% of patients having experienced a treatment-related adverse event, mostly mild (Grade 1 and 2). “These updated data continue to reinforce the favorable safety and tolerability profile of detalimogene and its clinical activity in a heavily pretreated, high-risk NMIBC patient population with limited therapeutic options. Importantly, the low rate of progression to muscle-invasive disease leaves patients eligible for other bladder-sparing therapies,” said Ron Cooper, President and Chief Executive Officer, enGene. “While durability outcomes to date are not what we hoped, these data are preliminary. We are focused on evaluating the totality of the data as it evolves and plan to continue to engage with the FDA and the medical community.” LEGEND Pivotal Cohort Data Update The interim analysis is based on the 125 patients enrolled in Cohort 1. Patients who discontinued without any disease evaluation or who discontinued after a CR were considered not evaluable for subsequent landmark CR analysis. Efficacy overview: 54% (95% CI: 45%, 63%) CR at any time (67/124) 91% of responses occurred at first disease assessment 43% (95% CI: 34%, 52%) CR rate at 6 months (52/121) with 14% (6/43) of patients having successfully converted from non-CR to CR post re-induction

The release as fetched from its publisher. engene.com ↗