June 16, 2026 —
enGene Therapeutics provided clinical and corporate updates for detalimogene voraplasmid, its investigational non-viral gene therapy for patients with high-risk non-muscle invasive bladder cancer, or NMIBC, including Bacillus Calmette-Guérin-unresponsive disease.
The company expects to report 12-month complete response data from the pivotal Cohort 1 of the LEGEND trial in the second half of 2026 and plans to engage with the FDA about initiating a Biologics License Application submission for detalimogene before year end. enGene also reiterated that initiation of the BLA filing is planned for the second half of 2026.
Detalimogene is designed to be administered directly into the bladder and to generate a localized anti-tumor immune response. The therapy was developed using enGene’s Dually Derivatized Oligochitosan, or DDX, platform, a non-viral genetic medicine delivery technology designed to simplify handling, storage, manufacturing, and administration compared with viral-vector-based gene therapies.
In the pivotal LEGEND Cohort 1, detalimogene is being evaluated without surfactant in patients with high-risk, BCG-unresponsive NMIBC with carcinoma in situ, with or without papillary disease. Interim data presented at the American Urological Association meeting showed a 54% complete response rate at any time among 124 patients, with a low rate of progression to muscle-invasive or more advanced disease at 3.2%.
The safety profile was also described as favorable. Treatment-related adverse events leading to treatment interruption and discontinuation were each reported in 2.4% of patients. As of the April 21, 2026 data cutoff, 21 patients were still pending disease assessments at six, nine, or 12 months.
enGene has also initiated an additional LEGEND cohort evaluating detalimogene plus a surfactant bladder rinse using diluted polidocanol solution. The company believes this approach may further enhance efficacy and durability while preserving detalimogene’s office-based administration profile. In preclinical models, polidocanol pretreatment increased mean IL-12 expression by 10-fold in murine studies and increased nanoparticle distribution throughout the bladder by approximately 50% with a nine-fold increase in IL-12 expression in a large animal model.
The first patients have been enrolled in the surfactant cohort, which may include up to 80 patients globally. enGene said the surfactant strategy could help strengthen detalimogene’s profile while maintaining ease of use and tolerability, features that may be important for community urology practices where many NMIBC patients receive care.
As part of its cash conservation strategy, enGene has stopped enrollment in LEGEND Cohorts 2a, 2b, and 3 and plans to reassess those programs after FDA discussions in the second half of 2026. The company also announced a workforce reduction of approximately 50% to streamline operations and preserve cash as it focuses on completing LEGEND Cohort 1, advancing the surfactant cohort, preparing for BLA initiation, and supporting pre-commercial activities.
As of April 30, 2026, enGene reported $285.2 million in cash, cash equivalents, and marketable securities. The company said it has retained the personnel and resources needed to execute key regulatory, clinical, and pre-commercial milestones, including a potential FDA approval decision and platform designation in 2027.
Detalimogene has received Regenerative Medicine Advanced Therapy and Fast Track designations from the FDA for BCG-unresponsive CIS NMIBC with or without resected papillary tumors in patients unable to undergo cystectomy. It has also been selected for the FDA’s CMC Development and Readiness Pilot program, which is intended to support CMC development for therapies with compressed clinical development timelines.
If successful, detalimogene could provide a non-viral, locally administered genetic medicine option for patients with high-risk NMIBC who have limited treatment options after BCG therapy.
