Rocket Pharmaceuticals (RCKT) received FDA clearance to proceed with its Danon disease gene therapy program using a recalibrated dose, the company said Tuesday at a Morgan Stanley conference.
CEO Gaurav Shah confirmed the trial will remain a 12-patient, single-arm study. Three patients have already been dosed under the revised protocol, with nine remaining. Dosing is expected to be completed by mid-2027, across six planned sites—three in the U.S. and three in Europe.
The recalibrated dose is 3.8 × 10^13 vector genomes per kilogram, down from the original 6.7 × 10^13 vg/kg. Shah noted the figure mirrors the earlier Phase I pediatric dose of approximately 4 × 10^13 vg/kg. "Because the safety was so pristine, I believe that they allowed us to continue the trial exactly as it is," he said. The FDA did not expand the trial.
The program's co-primary endpoints are LAMP2 protein expression and at least a 10% reduction in left ventricular mass index. About 80% of male patients remain eligible under the refined criteria, Shah said. A natural history study has enrolled more than 50 patients. Male patients typically become symptomatic in their teens and have a median life expectancy of 19 to 20 years without a transplant.
Shah also provided mechanistic commentary on capillary leak syndrome observed in prior studies. "It is not the C3 inhibitor itself," he said. "It is the C3 plus the AAV—the torrential rain of AAV. The combination basically de-opsonizes the AAV that would have been opsonized with C3b, and the AAV then attacks endothelial cells."
On the commercial side, Rocket highlighted KRESLADI, its approved therapy for severe LAD-I, which launched in Q4 2024 and carries a wholesale acquisition cost of $3.9 million per treatment. The company sold a priority review voucher tied to KRESLADI for $180 million. Annual free cash flow burn is roughly $170 million, with the current ratio at 9.2 and cash runway projected through Q2 2028.
Rocket also touched on its broader pipeline. The PKP2-related arrhythmogenic cardiomyopathy program addresses a market estimated at 50,000 to 140,000 people in the U.S. and Europe, with roughly 80% of U.S. patients relying on implantable cardioverter-defibrillators. The BAG3-related dilated cardiomyopathy program was also referenced. Shah noted that approximately 25 LAD-I patients are born annually in the U.S., two-thirds with severe disease.
Shares fell 4.81% to $3.27 on the day, within a 52-week range of $2.53 to $5.45. Rocket will provide a portfolio update on Oct. 6, 2026, at 4:30 p.m.
