BridgeBio Pharma and Affiliate Phoenix Tissue Repair Announce First Patient Dosing In Phase 2 Trial of Protein Replacement Therapy for the Treatment of Recessive Dystrophic Epidermolysis Bullosa (RDEB)

BridgeBio Pharma, Inc and affiliate Phoenix Tissue Repair today announced that the first patient has been dosed in a Phase 2 study of BBP-589 (also known as PTR-01), an intravenously-administered recombinant collagen 7 (rC7) protein replacement therapy, in patients with recessive dystrophic epidermolysis bullosa (RDEB). RDEB is a rare genetic disorder caused by mutations in the gene encoding collagen type VII (C7).

RDEB is a devastating disease and is one of the most severe forms of epidermolysis bullosa, characterized by severe and painful skin blistering, as well as extreme fragility and scarring of mucous membranes throughout the body. There is currently no cure or effective treatment available for patients suffering from this disease.

Sanuj K. Ravindran, M.D., executive chairman of Phoenix Tissue Repair Said: “BBP-589 is a potentially disease-modifying rC7 replacement therapy that we hope may improve the skin manifestations as well as the systemic symptoms these patients endure. The results observed in the Phase 1 study give us confidence in our approach, and we are excited to continue advancing this therapeutic candidate through the clinic.” 

The Phase 2, open label study is designed to examine the effect of BBP-589 on wound healing and various systemic endpoints and to evaluate the long-term safety and tolerability of the drug candidate. The study plans to enroll six patients who will receive doses of BBP-589 intravenously in two regimens over 18 weeks, followed by 12 weeks of observation after completion of dosing to assess the durability of wound healing and other efficacy endpoints.

About Dystrophic Epidermolysis Bullosa (DEB)

DEB is a rare genetic disorder symptomatic from birth that is caused by mutations in the gene for a protein called collagen type VII (C7). The C7 protein is essential for the formation of anchoring fibrils, structures which connect the epidermis and dermis—the uppermost two layers of the skin. Patients with the recessive form of DEB (RDEB) tend to have particularly severe symptoms due to severe insufficiency of functional C7. Symptoms include extreme skin and mucosal fragility that present as recurrent, painful blistering and scarring of the skin, as well as ulcerations of the mouth, tongue and dental caries. In addition to the cutaneous and oral symptoms, severe forms are associated with erosions and scarring of mucous membranes of the eye, esophagus, genitals and anus. Joint contractures, mutilating deformities of hands and feet, malnutrition, growth retardation, recurrent infections and a significantly increased risk for squamous cell carcinoma are also common. There are currently no approved disease-modifying therapies for any form of DEB, and the standard of care focuses on wound and pain management.  

About Phoenix Tissue Repair and BBP-589

Phoenix Tissue Repair is a Boston-based company that is an affiliate of BridgeBio Pharma and is focused on advancing a novel systemic treatment for recessive dystrophic epidermolysis bullosa (RDEB). BBP-589 is an investigational protein replacement therapy which uses a recombinant collagen type VII (rC7) for the treatment of RDEB. BBP-589 is designed to be systemically available through intravenous delivery. Phoenix Tissue Repair acquired worldwide rights to BBP-589 in 2017. Preclinical studies of BBP-589 have demonstrated C7 staining in basement membranes with de novo anchoring fibril formation and improved survival in models of RDEB.

BBP-589 has been granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency.

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