Sangamo and Centessa Receive Fast Track Designation for Rare Disease Treatments

Rare Daily Staff

The U.S. Food and Drug Administration granted Fast Track designation to Sangamo Therapeutics’ ST-920 gene therapy candidate for the treatment of Fabry disease, and to Centessa Pharmaceuticals’ SerpinPC, an investigational novel inhibitor of activated protein C for the treatment of hemophilia B, with or without inhibitors.

Fast Track designation aims to facilitate the development and expedite the review of new therapeutics that are intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs. Companies granted this designation are given the opportunity for more frequent interactions with the FDA. These clinical programs may also be eligible to apply for Accelerated Approval and Priority Review if relevant criteria are met.

Fabry disease is a lysosomal storage disorder caused by mutations in the galactosidase alpha gene (GLA), which leads to deficient alpha-galactosidase A (α-Gal A) enzyme activity, which is necessary for metabolizing globotriaosylceramide (Gb3). The buildup of Gb3 in the cells can cause serious damage to vital organs, including the kidney, heart, nerves, eyes, gut, and skin. Symptoms of Fabry disease can include decreased or absent sweat production, heat intolerance, angiokeratoma (skin blemishes), vision problems, kidney disease, heart failure, gastrointestinal disturbance, mood disorders, neuropathic pain and tingling in the extremities.

Sangamo’s ST-920 is currently being evaluated in the phase 1/2 STAAR study, with a total of 20 patients dosed to date. In February 2023, Sangamo reported promising results from the STAAR study showing sustained, elevated expression of alpha-galactosidase A (α-Gal A) activity in the 13 dosed patients as of the data cutoff, 78 percent globotriaosylceramide (Gb3) substrate clearance at 6-months, and 77 percent reduction in urine podocyte loss in one of the first kidney biopsies, and a clinically meaningful and statistically significant increase in mean general health scores, as measured by the SF-36 General Health survey. Sangamo is currently preparing for a potential phase 3 trial and plans to meet with the FDA on the proposed phase 3 study design in the summer, with a trial start anticipated by the end of 2023, depending on regulatory interactions.

“This decision from the FDA underscores the potential for ST-920 to address a serious unmet need and serve as a meaningful therapeutic option for patients with Fabry disease,” said Nathalie Dubois-Stringfellow, senior vice president and chief development officer at Sangamo.

Hemophilia B is a rare, genetic life-threatening degenerative disease. People with the condition are particularly vulnerable to bleeds in their joints, muscles, and internal organs, leading to pain, swelling, and joint damage. Current treatment includes life-long prophylactic infusions of factor IX (FIX) to temporarily replace or supplement low levels of the blood-clotting factor.

Centessa Pharmaceticals’ SerpinPC is a subcutaneously administered novel inhibitor of APC being developed as a potential treatment for hemophilia, regardless of severity or inhibitor status, and which may also be developed to prevent bleeding associated with other bleeding disorders. Centessa is advancing the registrational program for SerpinPC in hemophilia B, which includes a set of clinical studies with multiple components. PRESent-5, initiated in late 2022, is an observational feeder study to collect prospective observational data for minimum defined periods before switching to dosing subjects in the interventional studies. The interventional studies include PRESent-2 (moderately severe to severe hemophilia B without inhibitors, and severe hemophilia A with and without inhibitors) and PRESent-3 (hemophilia B with inhibitors).

“This designation is important recognition of SerpinPC’s novel mechanism of action and underscores the critical need for new treatment options for persons with hemophilia B,” said Saurabh Saha, CEO of Centessa. “We believe SerpinPC has the potential to be a first-in-class subcutaneously administered therapy with a differentiated safety profile for persons with hemophilia B, subject to review and approval.”

Photo: Saurabh Saha, CEO of Centessa