Rocket boosted as FDA alignment on pivotal gene therapy trial design sends stock skyward

Rocket Pharmaceuticals has reached alignment with the FDA on the design of a pivotal phase 2 rare disease trial, positioning it to run a 12-patient study that could support accelerated approval of a gene therapy.

New Jersey-based Rocket held an end-of-phase 1 meeting with the FDA late last year. After the meeting, the biotech told investors the regulator “expressed an openness to considering a biomarker-based composite endpoint” and acknowledged the challenges of running a randomized controlled trial in the indication, Danon disease. Rocket outlined plans to start the initial component of the study in the first half of 2023. 

However, the wait for alignment with the FDA dragged on throughout the year. Rocket has now cleared the impasse with a trial design that puts it on the same page as the regulator, sending its share price up 30% to $20 in premarket trading Wednesday.  

“We believe this milestone sets us on the most efficient and rapid path to delivering this potentially transformative therapy to Danon disease patients who would otherwise progress to heart transplantation or death,” Rocket CEO Gaurav Shah, M.D., said in a statement.

The single-arm, open-label study will enroll 12 patients to receive RP-A501, an AAV9 gene therapy that is designed to restore heart function by inserting a gene that is mutated in people with Danon. Rocket and the FDA have agreed to use LAMP2 protein expression and left ventricular mass change from baseline as the co-primary endpoints. The endpoints look at protein expression and a measure of heart health.

Rocket will assess the co-primary endpoints at 12 months and continue tracking patients on secondary endpoints such as event-free survival to 24 months. The biotech plans to file to start the study in Europe in the third quarter. Enrollment in a two-patient pediatric safety run-in is already underway.

Capitalizing on the jump in its stock price, Rocket quickly filed to sell shares. The biotech initially aimed to raise $150 million but ultimately went past that target, hitting a price that will enable it to gross $175 million. Rocket ended June with $307 million, a sum it said would fund operations into 2025.