Filsuvez (Oleogel-S10, AP101) is a topical gel that Amryt Pharma developed to treat wounds in epidermolysis bullosa (EB).

The European Union approved the treatment in 2016 under the brand name Episalvan for the treatment of partial-thickness skin wounds where the top layers of the skin have been lost.

How does Filsuvez work?

Researchers don’t know the exact mechanism of how Filsuvez works. The active ingredient in the gel is an extract from birch tree bark. It contains a group of chemicals called triterpenes and includes betulin, betulinic acid, lupeol, oleanolic acid, and erythrodiol, which have pharmacological effects. Scientists have proposed that the triterpene extract compounds may help control the inflammatory response at the wound and enhance the movement, growth, and differentiation of special skin cells called keratinocytes, which make up most of the epidermis (the outer layer of skin).

Filsuvez in clinical trials

Researchers investigated Filsuvez in a Phase 2 clinical trial (NCT01294241), called BEB-10. The open-label, controlled trial recruited 10 patients with EB. On each patient, researchers chose one large wound (between 10 cm² and 200 cm²) and split it in half. Alternatively, they chose two similar smaller wounds (greater than 5 cm²). They then covered the wounds with non-adhesive bandages. They changed the bandages every 24 to 48 hours. On one half of the wound (or on one of the smaller wounds), they applied Filsuvez. On the other half/smaller wound they applied nothing. They took photos of each wound at the beginning, periodically during bandage changes, and either 14 or 28 days later. They gave the photos to two wound-care specialists and asked to review the healing in the wounds. The wound-care specialists were not told which treatment the patient received.

The results showed that the experts identified a statistically significant difference in healing times between Filsuvez and no treatment. The secondary outcomes of the percentage of wound healing at seven days and 14 days also showed a trend toward faster closing for the treated wound. However, the  results were not statistically significant.

Researchers also tested Filsuvez in a double-blind, randomized Phase 3 clinical trial (NCT03068780). The trial, called EASE, recruited 223 adults and children with either junctional EB, dystrophic EB, or Kindler syndrome across 28 countries. Researchers excluded patients with EB simplex from the trial.

The trial comprised two phases. In the first three-month phase, researchers divided the patients evenly into two groups. The treatment group received Filsuvez and the placebo group received a gel that matched the appearance of Filsuvez. After the first phase, all patients received Filsuvez in a 24-month open-label phase. The primary goal of the study was to observe the proportion of patients with a complete closure of their wound within 45 days of treatment. The secondary goal was the time to first closure of the wounds with a maximum of 90 days of treatment.

Amryt released topline results from the trial showing that it was able to reach its primary goal with a statistically higher proportion of patients in the treatment group achieving wound closures within 45 days compared to the placebo. The secondary goal did not reach statistical significance.

Other information

Amryt announced it will complete the analysis of the data from the EASE trial and that they intend to file regulatory submissions for approval to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) by the end of the first quarter of 2021.

The FDA awarded Filsuvez rare pediatric disease designation in July 2018 and fast-track designation in September 2019. These designations are used to incentivize companies to work on rare diseases and help speed the availability of new treatments, respectively.

Filsuvez also received orphan drug designation from the FDA and the EMA for the treatment of EB. This designation provides benefits to companies to recoup the costs of research and development on a treatment with a small target population.


Last updated: Sept. 18, 2020


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