Cyllene Therapeutics’ experimental gene therapy EG110A has received US FDA Regenerative Medicine Advanced Therapy (RMAT) designation for neurogenic detrusor overactivity (NDO), a bladder disorder that can cause severe urinary incontinence.

The designation follows early clinical results from an ongoing Phase 1b/2a study in adults with spinal cord injury and NDO. Further results are due to be presented at the International Continence Society (ICS) annual conference in October.

Early results show reduction in incontinence

EG110A is being developed as a one-course treatment for NDO-related urinary incontinence. It uses a non-replicating herpes simplex virus type 1 (HSV-1) vector to deliver a genetic payload to sensory neurons involved in bladder overactivity.

The Phase 1b/2a trial is an open-label, dose-escalation study in adults aged 18 to 75 with spinal cord injury, NDO and urinary incontinence. Participants receive 30 injections into the bladder wall under local anaesthesia and are followed for 52 weeks.

Data from the first four participants showed a reduction in mean weekly urinary incontinence episodes from 26.3 at baseline to 2.7 at week 12, an 88.3% reduction. The effect was sustained at weeks 24 and 36, according to the interim data presented by the study investigators.

Improvements were also reported in urodynamic measures and patient-reported outcomes. The most frequently reported adverse events were nausea and fever, each occurring in two participants during the 24 hours following treatment. Most adverse events were mild.

The results remain early, with only four participants included in the first dose cohort and the study continuing to enrol patients in its second cohort. One participant was lost to follow-up after week eight for a non-medical reason.

FDA designation supports further development

The FDA grants RMAT designation to regenerative medicine therapies intended to treat serious or life-threatening conditions where preliminary clinical evidence indicates the treatment may address an unmet medical need.

For EG110A, the designation provides opportunities for more frequent interaction with the FDA during development, including discussions around clinical trial design and potential approaches to accelerated approval.

Cyllene Therapeutics previously received Fast Track designation for EG110A in October 2025. The company is planning a Phase 2b/3 study in NDO in 2027.

Cyllene co-founder and CEO Philippe Chambon said: “Receiving RMAT designation from the FDA for EG110A is a key milestone in the history of the company. It recognizes the critical need to provide better therapeutic solutions to patients affected by severe urinary incontinence as well as the encouraging initial clinical results we have achieved to date.”

Targeting a difficult-to-treat bladder disorder

NDO is caused by neurological injury or disease and is common among people with spinal cord injury and can also occur in conditions including multiple sclerosis and Parkinson’s disease. The condition can cause involuntary bladder contractions and urinary incontinence and, in some patients, can contribute to damage to the upper urinary tract.

Existing approaches include oral medicines and locally administered botulinum toxin, although treatment can require repeated administration and may have limitations for some patients.

EG110A is designed to act locally on sensory neurons involved in the bladder’s signalling pathway rather than producing a systemic effect. The approach is intended to reduce bladder overactivity while preserving normal bladder function.

Cyllene chief medical officer Cornelia Haag-Molkenteller said: “The clinical data seen to date, demonstrating a marked reduction in urinary episodes, suggests treatment with EG110A could have a profound impact on the daily lives of patients.”

The company expects to present further interim findings at the ICS meeting on 7 October 2026 as development of EG110A continues towards later-stage testing.