The nine-year wait for new clinical data on Promore Pharma’s ensereptide has ended in disaster, with the failure of the polypeptide to reduce scarring in a midphase trial wounding the biotech’s share price.
Promore, formerly known as Pergamum, began a phase 2 clinical trial of the candidate in patients who had undergone flexor tendon surgery in 2009 and published the data five years later. Two years ago, Promore outlined a new strategy focused on scar prevention—which it immediately had to defend—and got the green light to start a midstage study late in 2021.
After a delay caused by a shortage of qualified personnel and specialized image analysis equipment, the Swedish biotech has now shared the top-line results of the midphase clinical trial. Worth the wait? Let’s see.
Promore primarily designed the 24-subject study to assess the safety of ensereptide when used to stop the formation of scars associated with surgery or trauma. The candidate passed that test, with Promore seeing no serious adverse events or differences between the treatment and placebo groups. But all eyes were on the secondary efficacy endpoints included to show whether ensereptide can prevent scarring.
Unfortunately for Promore, the story of the safety and efficacy endpoints was the same: There were no differences between treatment and placebo. The study used two clinical rating scales to assess scarring. Ensereptide failed to cause “statistically verifiable” improvements over placebo on either scale.
Histopathological analysis of skin biopsies found “no clear evidence of treatment effect.” The analysis and clinical rating scale data suggest that ensereptide, a drug candidate designed to inhibit the release of pro-inflammatory cytokines, failed to exert the expected biological effects in the clinical trial. Shares in Promore fell 67% to 0.42 ($0.04) Swedish kronor in the hours after the data drop.
Promore CEO Jonas Ekblom made no attempt to duck the negative findings of the study, telling investors in a statement that the study was high quality and provided results that the company thinks are reliable. Based on the data, Ekblom “sees no tangible treatment value of ensereptide in this medical indication,” but the company is still evaluating the situation and determining the next steps for the drug.
If this marks the end of the line for ensereptide, Promore can fall back on another asset, ropocamptide. The second candidate is in development for chronic wound healing and has a distinct mechanism of action from ensereptide.