A new gene therapy called detalimogene voraplasmid (also known as detalimogene or EG-70) shows promise in treating a difficult type of bladder cancer.
This therapy is nonviral and being tested for patients with high-risk, nonmuscle-invasive bladder cancer (NMIBC) that does not respond to the standard Bacillus Calmette-Guérin (BCG) treatment. In a recent clinical trial called LEGEND, 62% of patients had a complete response six months after treatment.
The trial results come from 37 patients tested at six months and 62 patients tested at three months. The protocol was updated in late 2024 to better match current medical guidelines. At three months, 56% of patients responded fully.
Overall, 63% had a complete response at some point during the study. Some patients improved after additional treatment, and all five patients assessed at nine months maintained a complete response.
In total, 125 patients have joined the trial. The treatment appeared safe with 42% experiencing side effects related to therapy. Very few patients had to pause or stop treatment due to side effects.
Dr. Suzanne Merrill, a urologic oncologist, said the therapy could be a good option because it helps patients avoid invasive surgery while controlling cancer and maintaining quality of life. The therapy’s ease of use also benefits busy doctors and their patients.
Earlier protocol results showed a 41% complete response at six months. The newer protocol improved this rate to 62%, showing better effectiveness. The company noted that previous results were lower compared to approved treatments for this cancer type.
Dr. Hussein Sweiti, chief medical officer at enGene, stated the improved results and good tolerability make detalimogene a strong candidate for first-line treatment of this bladder cancer.
The study’s main goal has shifted from measuring 12-month response to looking at any complete response during treatment. This change, agreed with the FDA, aligns the trial with other recent studies. enGene expects to provide more data and submit for FDA approval next year.
Ron Cooper, enGene’s CEO, expressed optimism about the treatment’s potential in the market due to its efficacy and ease of use.
The FDA granted detalimogene a special regenerative medicine designation in June 2025, speeding its review process. This decision was based on the strong clinical data from the LEGEND trial.
Cooper said detalimogene offers patients and doctors long-awaited advantages: a nonviral therapy that is safely and easily administered in the bladder, potentially changing how this type of bladder cancer is treated.
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