May 7, 2026 — Leads & Copy — enGene Therapeutics Inc. (Nasdaq: ENGN) announced additional interim results from the pivotal cohort of its Phase 2 LEGEND trial of detalimogene voraplasmid 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.
The trial enrolled 125 patients. Data as of April 21, 2026, showed 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 experiencing a treatment-related adverse event, mostly mild (Grade 1 and 2).
Ron Cooper, President and Chief Executive Officer of enGene, stated that the updated data 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. He noted that the low rate of progression to muscle-invasive disease leaves patients eligible for other bladder-sparing therapies. Cooper added that while durability outcomes to date are not what they hoped, these data are preliminary, and they 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.
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
- Two re-induced patients have not yet had a 6-month assessment
Of the 52 responders at 6 months:
- 37/44 patients who had a 9-month assessment were in CR; an additional 8 patients are pending evaluation
- 13/22 patients who had a 12-month assessment were in CR; an additional 11 patients are pending evaluation
A maximum of 21 patients, including the 2 currently undergoing re-induction, still have the potential to achieve a CR at 12 months. The Kaplan-Meier (KM) estimate of the 12-month duration of response (DoR) is 25% (95% CI: 11%, 41%). The KM estimate for median DoR is 37.3 weeks (range: 31.6-43.9 weeks). The rate of progression to muscle invasive or more advanced disease was 3.2%.
Safety overview:
- 55% of patients experienced a treatment-related adverse event (TRAE)
- Among patients with any TRAE, 91% experienced Grade 1-2 TRAEs
- Grade ≥3 TRAEs were reported in 6 patients (4.8%)
- Low percentage of patients experienced TRAEs leading to treatment interruption (2.4%) and treatment discontinuation (2.4%)
Among the 32 patients who had their first disease assessment after the last data analysis (October 24, 2025, reported November 11, 2025), CR rates were lower than previously reported results. The CR rate at any time was 39% and at 6 months was 32% for these patients. A preliminary subgroup analysis has not revealed any material differences in demographics or key disease characteristics. A more comprehensive analysis of these patients, including potential contributing factors, is ongoing.
enGene has completed the required FDA manufacturing validation batches and submitted a Statistical Analysis Plan (SAP) to the agency. The Company plans further engagement with the FDA as it approaches a potential Biologics License Application (BLA) filing and plans to provide an update in the second half of 2026.
The Company plans to share these data with the broader medical community at a Plenary Presentation at the upcoming American Urological Association meeting on May 15, 2026.
The overall tolerability profile associated with detalimogene is favorable. Of the 125 patients assessed for safety in Cohort 1, 69 patients (55%) experienced at least one TRAE, which were mainly Grade 1/2 in severity. The most common TRAEs were fatigue (22%), dysuria (14%), micturition urgency (12%), pollakiuria (12%), and bladder spasm (11%). Six patients experienced Grade ≥3 TRAEs, including one Grade 4 TRAE, which has resolved. There were no Grade 5 TRAEs reported. TRAEs leading to dose discontinuations (2.4%) and dose interruptions (2.4%) were rare.
enGene will host a conference call and live webcast at 8:00 a.m. ET today, May 7, 2026. Individuals interested in listening to the conference call may do so by clicking the link available at the “Investors” section of the Company’s website.
Non-muscle invasive bladder cancer (NMIBC) occurs when cancer cells grow in the tissues that line the interior of the bladder, but the cancer has not yet penetrated the muscle of the bladder wall. About 75%-80% of new bladder cancer diagnoses are NMIBC. Patients suffering from high-risk NMIBC who are unresponsive to the standard of care, Bacillus Calmette-Guérin (BCG), face high rates of disease recurrence (50%-70%) and are potentially subject to full removal of the bladder (cystectomy) as a curative but life-altering next step.
Detalimogene is a novel, investigational, non-viral gene therapy for patients with high-risk NMIBC, including Bacillus Calmette-Guérin (BCG)-unresponsive disease. It is designed to be instilled in the bladder and elicit a localized anti-tumor immune response. Detalimogene was developed using the Company’s Dually Derivatized Oligochitosan® (DDX) platform.
Detalimogene has received Regenerative Medicine Advanced Therapy (RMAT) and Fast Track designations from the U.S. Food and Drug Administration (FDA). Detalimogene has also been selected for the FDA’s Chemistry, Manufacturing, and Controls (CMC) Development and Readiness Pilot (CDRP) program.
Detalimogene is being evaluated in the ongoing Phase 2 LEGEND trial to establish its safety and efficacy in high-risk NMIBC. LEGEND’s pivotal cohort (Cohort 1) consists of 125 patients with high-risk, BCG-unresponsive NMIBC with CIS and is designed to serve as the basis of the Company’s planned Biologics License Application (BLA) filing. LEGEND includes three additional cohorts.
enGene is a clinical-stage biotechnology company mainstreaming non-viral genetic medicine through the delivery of therapeutics to mucosal tissues and other organs. enGene’s lead program is detalimogene voraplasmid for patients with non-muscle invasive bladder cancer (NMIBC).
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Source: enGene
