PARIS, France and NEW YORK, N.Y. - November 18, 2020 - Vivet Therapeutics (“Vivet”), a privately held gene therapy biotech company dedicated to developing treatments for inherited liver disorders with high unmet medical need, and Pfizer Inc. (NYSE: PFE) announced today that the U.S. Food and Drug Administration (FDA) has cleared Vivet’s Investigational New Drug (IND) application for the GATEWAY study, a Phase 1/2 clinical trial evaluating Vivet’s proprietary, investigational gene therapy vector, VTX- 801, for the potential treatment of Wilson disease (WD), a rare and potentially life-threatening liver disorder. The trial is expected to commence in early 2021.

“We are pleased to announce Vivet’s first IND clearance by the FDA, which is for our GATEWAY Phase 1/2 study for VTX-801,” said Jean-Philippe Combal, CEO and Co-Founder of Vivet. “This is a very important milestone for the Wilson disease community for whom VTX-801 could bring significant potential therapeutic benefit. VTX-801 aims to restore copper homeostasis and the GATEWAY trial will measure relevant biomarkers to evaluate physiological restoration of copper elimination and transport in patients. We look forward to advancing VTX-801 into the clinic in early 2021.”

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.

In March 2019, the companies announced that Pfizer had acquired a minority equity interest in Vivet and secured an exclusive option to acquire all outstanding shares. In September 2020, Vivet and Pfizer announced the signing of an agreement for the manufacture by Pfizer of the VTX-801 vector for the GATEWAY study.

“The FDA clearance of Vivet’s IND marks an important milestone for the VTX-801 program, which we believe has the potential to become a transformational therapy for people with Wilson disease,” said Seng Cheng, Chief Scientific Officer, Rare Disease Research Unit, Pfizer. “Pfizer has begun manufacturing clinical material for the GATEWAY study and look forward to the study’s commencement.”

“This IND is a recognition of the expertise of Vivet’s research team led by our CSO and Co-Founder, Dr. Gloria González-Aseguinolaza, research collaborations, notably with la Fundación para la Investigación Médica Aplicada (FIMA), and experienced development team. We believe that our global development expertise, together with our collaboration with Pfizer, places us in a strong position to rapidly execute and bring this potentially transformational therapy to patients with high unmet medical needs,” added Jean- Philippe Combal.