RARE Daily

Rocket, Following Agreement with FDA on Phase 2 Gene Therapy Trial, Prices $175 Million Offering

September 14, 2023

Rare Daily Staff

Rocket Pharmaceuticals, on the heels of an agreement with the U.S. Food and Drug Administration on the phase 2 pivotal trial design of its experimental therapy for the rare and deadly cardiomyopathy Danon disease, priced a $175 million offering.

The underwritten public offering was for 7.8 million shares of its common stock at a public offering price of $16.00 per share and to certain investors, pre-funded warrants to purchase 3.1 million shares of common stock at a price of $15.99 per pre-funded warrant, which represents the per share public offering price for the common stock less the 1 cent per share exercise price for each such pre-funded warrant.

The gross proceeds to Rocket from the offering, before deducting underwriting discounts and commissions and offering expenses, are expected to be approximately $175 million. Rocket has granted the underwriters a 30-day option to purchase up to an additional 1.6 million shares of its common stock.

Danon disease is a rare X-linked inherited disorder caused by mutations in the gene encoding lysosome-associated membrane protein 2 (LAMP-2), an important mediator of autophagy. This results in accumulation of autophagosomes and glycogen, particularly in cardiac muscle and other tissues, which ultimately leads to heart failure, and for male patients, frequent death during adolescence or early adulthood. It is estimated to have a prevalence of 15,000 to 30,000 patients in the United States and Europe. The only available treatment option for Danon dsease is cardiac transplantation, which is associated with substantial complications and is not considered curative. There is a high unmet medical need for patients with Danon disease.

RP-A501 is Rocket’s experimental gene therapy for the treatment of Danon disease and the first gene therapy for a cardiovascular condition to demonstrate safety and efficacy in clinical studies. RP-A501 consists of a recombinant adeno-associated serotype 9 capsid containing a full-length, wild-type version of the human LAMP2B transgene. When inserted into heart cells harboring mutations in the endogenous LAMP2 gene, RP-A501 has the potential to fully restore cardiac function at its root.

RP-A501 represents a single dose treatment and is administered as an intravenous (IV) infusion. In preclinical and clinical studies, AAV9.LAMP2B has been shown to target cardiac cells and deliver the functional LAMP2B gene to heart tissue, which ultimately leads to improved cardiac structure and function in patients.

The global, single-arm, multi-center phase 2 pivotal trial will evaluate the efficacy and safety of RP-A501 in 12 patients with Danon disease, including a pediatric safety run-in, with a natural history comparator. To support accelerated approval, the study will assess the efficacy of RP-A501 as measured by the biomarker-based co-primary endpoint consisting of improvements in LAMP2 protein expression and reductions in left ventricular mass.

Key secondary endpoint is change in troponin. Additional secondary endpoints will include natriuretic peptides, Kansas City Cardiomyopathy Questionnaire, New York Heart Association class, event free survival to 24 months and treatment emergent safety events. These endpoints could support full approval with longer-term follow-up.

A global natural history study will serve as an external comparator and run concurrently to the phase 2 pivotal trial.

In-house manufacturing has been completed with sufficient high-quality drug product produced to fully supply thephase 2 pivotal study. Potency assays have been developed and qualified in accordance with FDA guidance.

“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,” said Gaurav Shah, CEO of Rocket Pharma. “As a one-time potentially curative infusion, RP-A501 has the potential to restore normal cardiac function and provide a lifetime of benefit to patients with Danon isease who have no other viable treatment options.”

Photo: Gaurav Shah, CEO of Rocket Pharma

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