6 September 2023
Birch tree extract offers hope for rare skin disorder
Epidermolysis bullosa has a devastating impact on quality of life, with dressings alone taking two to three hours a day.
Results of a phase III clinical study of topical gel made from the extract of a birch tree have brought hope for patients with the rare genetic disease group epidermolysis bullosa.
The trial was conducted across five countries and led by senior investigator Professor Dedee Murrell, head of dermatology at St George Hospital, and conjoint professor at the University of New South Wales.
Professor Murrell presented findings of the two-year analysis of the open-label phase of the EASE study at the World Congress of Dermatology in July. Results were also published in the British Journal of Dermatology in January.
She told Dermatology Republic the gel had been approved for use in the European Union by the European Medical Agency and then in the UK by the National Institute for Health and Care Excellence.
It has also been submitted to the FDA. Professor is hopeful an application to the TGA will lead to the treatment being available in Australia.
“People living with this all types of this disease desperately need treatment – it has a devastating impact on quality of life,” Professor Murrell said.
Oleogel-S10 (Filsuvez, Amryt Pharma) It is the first approved drug treatment for patients with dystrophic epidermolysis bullosa and junctional epidermolysis bullosa. The topical treatment is based on a triterpene-containing dry extract from birch bark.
Epidermolysis bullosa (EB) is a group of rare, genetic, difficult-to-treat, inherited multisystem diseases that cause extremely fragile skin. Main types of the disease including dystrophic EB (DEB), junctional EB (JEB), recessive dystrophic EB (RDEB) and Kindler EB (KEB), a rare form of EB where blistering can occur in multiple levels in the skin. Children with KEB are also at increased risk of developing severe skin cancer.
It is estimated to affect less than one in 20,000 children and there is no cure. Professor Murrell said researchers have been working on gene therapy for specific forms of the disease, but until the discovery of Oleogel-S10, treatment has been limited to wound dressing and supportive care, such as treating and reducing the risk of infections, maintaining nutrition and managing pain.
While blisters are most often found on the feet, elbows, knees and hands, they can also form in other parts of the body, including the face, nappy area and mouth. In severe cases the throat, oesophagus, stomach and bladder may be affected.
Professor Murrell said some children became malnourished, because it was too painful to eat or drink, and were at increased risk of death from skin cancer, infections and other complications.
“Even the friction from a nappy can lead to serious wounds,” she said. “It’s a horrible disease. Dressings alone can take two to three hours a day.”
Oleogel-S10 is a topical treatment based on a triterpene-containing dry extract from birch cork. EASE was the largest phase III randomised controlled study in EB and examined the efficacy and safety of Oleogel-S10 against a control gel.
The study included 223 patients from 26 countries, most of them with severe disease. Of these, 175 patients (78·5%) had a diagnosis of RDEB, 20 patients (9·0%) had dominant DEB (DDEB) and 25 patients (11·7%) had JEB. No patients with KEB were enrolled.
After 90 days, patients treated with Oleogel-S10 had reduced requirements for daily dressing changes, reduced procedural pain, had a sustained reduction in wound burden and wound healing was accelerated.
Professor Murrell said that after 24 months the treatment proved to have a reassuring long-term safety profile, sustained reduction in wound burden and was a well-tolerated topical treatment. Infection rates also reduced for patients treated with Oleogel-S10, she said.
She said the primary endpoint of the study was met – Oleogel-S10 resulted in 41·3% of patients with first complete target wound closure within 45 days, compared with 28·9% in the control gel arm. Adverse events occurred with similar frequency for Oleogel-S10 (81·7%) and the control gel (80·7%). AEs were predominantly of mild-to-moderate intensity, she said.
Professor Murrell said she knew of one patient in Australia who had imported the treatment privately, and she was hopeful Australian children’s hospitals might help patients access the treatment through special access pathways.
“It’s promising,” she said. “It’s not a cure but it’s something that will work across most types of EB.”
