Vivet Therapeutics (“Vivet”), a clinical-stage biotechnology company, and Pfizer Inc. (NYSE: PFE) today announced the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to VTX-801, Vivet’s clinical-stage gene therapy for the treatment of Wilson Disease – a rare, genetic disorder that reduces the ability of the liver and other tissues to regulate copper levels, causing severe hepatic damage, neurological symptoms, and potentially death. The FDA’s Fast Track program is designed to facilitate the development, and expedite the review of, novel potential therapies that are designed to treat serious conditions and fill unmet medical need. 

VTX-801 is a novel investigational gene therapy to be evaluated in a Phase 1/2 clinical trial to determine the safety, tolerability, and pharmacological activity of a single intravenous infusion in adult patients with Wilson Disease. Pfizer is collaborating  with Vivet on the clinical supply of VTX-801 for the Phase 1/2 clinical trial. 

“The FDA’s decision to grant VTX-801 Fast Track designation underscores the urgent need for new therapeutic options to address this devastating disease, which, if left untreated, can be fatal,” said Seng Cheng, Senior Vice President and Chief Scientific Officer of Pfizer’s Rare Disease Research Unit. “We are pleased to collaborate with Vivet on this important development program, which we believe, if successful, could make a meaningful difference in the lives of patients living with Wilson Disease.”

Dr. Michael Schilsky, Principal Investigator at Yale University School of Medicine (Connecticut, United States), said, “We are proud to participate in this important clinical trial. If VTX-801 is successfully developed, it has the potential to be a truly innovative medicine with the ability to restore copper metabolism after a single injection, addressing significant unmet medical needs for patients with Wilson Disease.”

“With the FDA’s authorization of the IND application for VTX-801 – combined with Pfizer’s state-of-the-art gene therapy manufacturing capabilities – we are well-positioned to rapidly advance development of this potential therapy,” concluded Jean-Philippe Combal, CEO and co-founder of Vivet. 

About Fast Track designation

Fast Track is a process designed to facilitate the development, and expedite the review of, drugs to treat serious conditions that address an unmet medical need, by providing a therapy where none exists or providing a therapy which may be potentially better and shows some advantage over available therapy. Fast Track designation includes opportunities for more frequent meetings with the FDA to discuss trial design, development plans, data needed to support drug approval, submission of a New Drug Application (NDA) on a rolling basis, and eligibility for accelerated approval and priority review, if relevant criteria are met.

About VTX-801

VTX-801 is a novel investigational gene therapy for Wilson Disease, which has been granted Orphan Drug Designation (ODD) by the Food and Drug Administration (FDA) and the European Commission (EC) and Fast Track designation by the FDA. Wilson Disease, a rare genetic disorder, is caused by mutations in the gene encoding the ATP7B protein, which reduces the ability of the liver and other tissues to regulate copper levels, causing severe hepatic damage, neurologic symptoms and potentially death.
VTX-801 is a novel, investigational rAAV-based gene therapy vector designed to deliver a miniaturized ATP7B transgene encoding, a functional protein that has been shown to restore copper homeostasis, reverse liver pathology and reduce copper accumulation in the brain of a mouse model of Wilson Disease. VTX-801’s rAAV serotype was selected based on its demonstrated tropism for transducing human liver cells.

About GATEWAY - Phase 1/2 Clinical Trial of VTX-801 in Wilson Disease

The GATEWAY trial (NCT04537377) is a multi-center, non-randomized, open-label, Phase 1/2 clinical trial designed to assess the safety, tolerability, and pharmacological activity of a single intravenous infusion of VTX-801 in adult patients with Wilson Disease, prior to and following background WD therapy withdrawal. 

Six leading centers in the United States and Europe are expected to participate in the GATEWAY Phase 1/2 trial. The trial is expected to enroll up to sixteen adult patients with Wilson Disease and will evaluate up to three doses of VTX-801. Patients will participate in a pre-dosing observational period and will be administered a prophylactic steroid regimen. 

The primary endpoint of the GATEWAY trial is to assess the safety and tolerability of VTX-801 at 52 weeks after a single infusion. Additional endpoints include changes in disease-related biomarkers, including free serum copper and serum ceruloplasmin activity, as well as radiocopper-related parameters and VTX-801 responder status to allow standard-of-care withdrawal.