Phoenix Tissue Repair, Inc. (PTR), an affiliate company of BridgeBio Pharma, Inc. (NASDAQ:BBIO) today announced updates to its ongoing Phase 1/2 study of PTR-01 (BridgeBio designation BBP-589), an intravenously-administered recombinant collagen 7 protein replacement therapy for patients with recessive dystrophic epidermolysis bullosa (RDEB). Cohorts 1 – 3 have completed treatment at escalating dose levels, and an additional fourth cohort to evaluate higher dosing of PTR-01 has begun enrolling patients.
Based on an interim review of data from the first three cohorts of trial participants, PTR-01 has been well tolerated in all nine patients, and there have been no treatment-related serious adverse events at any dose. In addition, as assessed by our investigators, there has been a dose-dependent increase in collagen 7 skin deposition after just three infusions over 28 days.
RDEB is a rare genetic disorder characterized by severe blistering and scarring of the skin caused by even minor friction or trauma, as well as systemic manifestations including esophageal strictures and dysphagia, corneal abrasions, anemia and nutritional deficiencies.
“RDEB is a debilitating disease, and current treatment options are limited to palliative skin care involving daily wound maintenance, protective bandaging, pain and itch management, and treatment of secondary complications such as anemia,” said Anna L. Bruckner, M.D., MSCS, associate professor of dermatology and pediatrics at University of Colorado School of Medicine. “Intravenous collagen 7 replacement therapy with PTR-01 is the only treatment in development designed to provide broad disease-modifying effects for this multisystem disease. In addition to benefiting the skin, this treatment has the potential to improve wounds that affect the eye or internal mucosa surfaces such as the esophagus.”
The ongoing clinical trial is a randomized, saline-controlled, double-blind, repeat dose, dose-escalation, multi-center study. Patients enrolled in the fourth cohort will each be dosed over a 10-week period, with three 3.0 mg/kg doses of PTR-01 and three doses of saline control. The primary objective of the trial is to evaluate the safety and tolerability of PTR-01 in adults with RDEB. Additional endpoints include assessment of biologic activity through skin biopsy evaluation of collagen 7 deposition and clinical assessments including wound healing, pain, itch and quality of life.
After completion of this trial, the company is planning to follow it up with a six-month open-label clinical trial to inform the design of a pivotal clinical trial. To learn more about the PTR-01 Phase 1/2 clinical trial, please visit www.clinicaltrials.gov and search the identifier NCT03752905.