FDA Approves Chiesi’s Filsuvez Topical Gel for the Treatment of EB

Rare Daily Staff

The U.S. Food and Drug Administration approved Chiesi Global Rare Diseases’ Filsuvez (birch triterpenes) topical gel for the treatment of partial thickness wounds in patients 6 months and older with junctional epidermolysis bullosa and dystrophic epidermolysis bullosa.

Epidermolysis Bullosa (EB) is a rare and devastating group of hereditary disorders of the skin, mucous membranes, and internal epithelial linings characterized by extreme skin fragility and blister development. Patients with severe forms of EB suffer from severe, chronic blistering, ulceration, and scarring of the skin, mutilating scarring of the hands and feet, joint contractures, strictures of the oesophagus and mucous membranes, a high risk of developing aggressive squamous cell carcinomas, infections and risk of premature death. Living with EB entails daily challenges to navigate, including slow-healing wounds at risk of infection and painful dressing changes.

The FDA approval is based on the EASE trial, the largest ever global phase 3 trial conducted in patients with EB, performed across 58 sites in 28 countries. It comprises a 3-month double-blind randomized controlled phase followed by a 24-month open-label, single-arm phase. Patients with EB target wounds of between 10 and 50cm2 in size that were present for > 21 days and < 9 months were randomized in the double-blind phase to study treatment in a 1:1 ratio and wound dressings applied according to the standard of care. 223 patients were enrolled in the trial including 156 pediatric patients. Of those who completed the double-blind phase, 100 percent entered the open-label safety follow-up phase. The primary endpoint of the trial was to compare the efficacy of Filsuvez topical gel versus control gel according to the proportion of patients with complete closure of the target wound within 45 days of treatment. The primary endpoint was achieved with statistical significance. While the key secondary endpoints did not achieve statistical significance, a number of favorable differences were observed.

Filsuvez is the first approved treatment for wounds associated with junctional epidermolysis bullosa (JEB), a rare, moderate-to-severe form of EB with blisters beginning in infancy. Chiesi acquired the drug as part of its acquisition of Amryt Pharma in January 2023. Filsuvez was previously approved in June 2023 by the European Commission for the treatment of skin wounds in adults and children, ages 6 months and older with both JEB and DEB.

Filsuvez (birch triterpenes) topical gel, is a medicine that is used in adults and children aged 6 months or older with epidermolysis bullosa (EB). Filsuvez contains a dry extract from two species of birch bark consisting of naturally occurring substances known as triterpenes, including betulin, betulinic acid, erythrodiol, lupeol and oleanolic acid. Filsuvez is available as a gel that should be applied to the wound surface at a thickness of approximately 1 mm and covered by a wound dressing. The medicine can also be applied directly to the wound dressing. Filsuvez is administered at home, allowing for integration into existing treatment routines.

“The FDA’s decision to approve Filsuvez provides those living with EB a safe and effective treatment option for the most prominent and difficult symptom of EB, open wounds that may not heal,” said Brett Kopelan, executive director, Debra of America. “Today marks an important milestone for those living with junctional EB, as Filsuvez is the first FDA approved treatment for this variant of the disease.”