PTR-01 Shows Signs of Efficacy in RDEB Patients, Early Trial Data Reveal

Treatment with PTR-01 is well-tolerated and safe, and increases the levels of collagen type VII (C7) in the skin of adults with recessive dystrophic epidermolysis bullosa (RDEB), early data from a Phase 1/2 trial show.

The PTR-01-001 study (NCT03752905) seeks to evaluate PTR-01 treatment in RDEB patients with at least one chronic wound. Enrollment is still ongoing. More information on contacts and the three U.S. clinical sites can be found here.

PTR-01, developed by Phoenix Tissue Repair, is a synthetic version of the human C7 protein, which is faulty in RDEB patients. This potential disease-modifying therapy is administered intravenously (directly into the bloodstream), and works by replacing defective C7 proteins with healthy collagen where it is needed throughout the body. By providing functional C7, PTR-01 is designed to improve the attachment of the two outermost skin layers, called the epidermis and dermis.

“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,” Anna L. Bruckner, MD, associate professor of dermatology and pediatrics at University of Colorado School of Medicine, said in a press release.

“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,” Bruckner added.

The main goal of the double-blind, multi-center trial is to assess the safety and tolerability of PTR-01 in adults with RDEB. Additional goals include testing the biologic activity of PTR-01 through skin biopsies, evaluating collagen VII deposition, and exploring clinical assessments of wound healing, pain, itch, and quality of life.

The trial is divided in three parts: a four-week screening period, a 10-week treatment period, and an eight-week follow-up. 

Nine adults with RDEB were enrolled and divided into three groups, where PTR-01 was given at increasing doses (0.1, 0.3, and 1.0 mg/kg of body weight) every two weeks. A fourth group will receive three 3.0 mg/kg doses of PTR-01 and three doses of saline (control) over 10 weeks.

Early data from the first three groups showed that PTR-01 was well-tolerated in all nine patients, with no reports of treatment-related serious adverse events at any dose.

In addition, a dose-dependent increase in collagen 7 skin deposition was observed after three infusions, over a 28-day period.  

“With safety as a top priority, we are committed to creating the first-ever systemic treatment for RDEB, which targets the genetic root of the disease by replacing the collagen protein that normally helps keep the epidermis from separating from the dermis,” said Sanuj K. Ravindran, MD, executive chairman at Phoenix Tissue Repair.

After completion of the PTR-01-001 trial, the company is planning to follow up with a six-month open-label study (where no control group is used) to inform the design of a pivotal clinical trial. Notably, a pivotal trial is intended to provide support for regulatory approval of a new therapy.

“As the program advances, we look forward to working closely with the epidermolysis bullosa patient community to help raise awareness of this debilitating disease and ensure that we develop our therapy to best address the unmet needs that patients currently face,” Ravindran said.

PTR-01 has been granted orphan drug designation by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency to support treatment development for RDEB. The FDA also granted the therapy fast track designation to speed up its development and review.