Phoenix Tissue Repair, an affiliate company of BridgeBio Pharma, reported positive findings from the Phase II clinical trial of recombinant collagen 7 (rC7) protein replacement therapy, PTR-01, in people with recessive dystrophic epidermolysis bullosa (RDEB).

In 2017, Phoenix obtained global rights to PTR-01, an investigational drug candidate intended to be systemically available through intravenous administration.

The open-label trial analysed the impact of PTR-01 on healing wound and other endpoints.

It also assessed the long-term safety and tolerability of the drug.

According to the trial findings, PTR-01 was demonstrated to be well tolerated when administered once a week for four weeks and followed by every alternative week for 14 weeks.

Furthermore, PTR-01 treatment offered quick, consistent and long-lasting wound healing as observed in decline of wound surface area and clinician-reported analyses.

More than 80% of target wounds showed a 50% or higher decline in wound surface area by day 120 of the treatment versus baseline.

Subject-reported outcomes assessing pain, essential function, mood, daily living activities and impact of disease demonstrated noticeable mean and median decline at the end of the trial versus baseline.

Over the course of treatment with the investigational drug, all subjects who completed the trial had a decline in pain.

At the end of the trial, a 36% mean decline in total pain as assessed on the Instrument for Scoring Clinical Outcomes of Research for Epidermolysis Bullosa (iscorEB) subject reported subdomain scale versus baseline was reported.

In addition, systemic dosing with PTR-01 offered a quick rC7 deposition at the DEJ during the loading phase and was present for up to three months following treatment.

Phoenix Tissue Repair executive chairman Sanuj Ravindran said: “In patients with recessive dystrophic epidermolysis bullosa (RDEB) even minor friction or trauma can cause debilitating blistering, tearing and scarring of the skin, along with severe pain and itching.

“Our data shows that treatment with PTR-01 led to rapid, consistent, and durable wound healing.”

With the latest development, the company has commenced a Phase II extension trial.

In July last year, BridgeBio signed a clinical partnership to evaluate BBP-398 plus Bristol Myers Squibb’s Opdivo (nivolumab) for the treatment of advanced solid tumours with KRAS mutations.