enGene Therapeutics (ENGN) Study update summary

Trial design and population

• Phase II LEGEND Cohort 1 enrolled 125 patients with BCG-unresponsive high-risk NMIBC with CIS; 120 were efficacy-evaluable through the Oct. 29, 2026 data cutoff.

• Intravesical detalimogene (0.8 mg/mL, 50 mL) is given with a 60-minute dwell; induction is on weeks 1, 2, 5 and 6 of 12-week cycles, with reinduction and maintenance for eligible responders, including q12-week maintenance in years 2–3.

• The cohort included 40% with concomitant papillary disease and 26% previously treated beyond BCG; more than 30% declined cystectomy rather than being medically ineligible.

LEGEND pivotal cohort efficacy

• CR at any time was 56% (95% CI: 47%–65%; n=120), versus 54% in April 2026; 91% of CRs occurred at the first disease assessment.

• Kaplan-Meier estimated DOR of at least 12 months rose to 43% (95% CI: 30%–55%) from 25%; median DOR was 10.1 months, with responder median follow-up of 12.0 months.

• Twelve-month landmark CR was 24% (95% CI: 16%–33%; n=110), versus 13% in April 2026; one patient awaited assessment.

• 100% of responders remained free from progression to T2 or greater disease and 96% remained cystectomy-free; among efficacy-evaluable patients, 97% were progression-free and 86% cystectomy-free.

• Efficacy and durability gains reflected longer follow-up of the same patients; no change to CR or durability calculations was described.

Safety and tolerability

• At least one treatment-related adverse event occurred in 59%; 93% of affected patients had Grade 1–2 events, which were mainly localized and brief.

• Grade 3 treatment-related events occurred in 4%, serious events in 2%; no Grade 4 or 5 events were reported. Median time to resolution was 6 days.

• Treatment-related events led to dose interruption in 4% and discontinuation in 1%; common events included fatigue, dysuria, pollakiuria, bladder spasm, urgency and urinary tract infection.