Gel from tree bark: First effective treatment for epidermolysis bullosa

A topical gel treatment derived from birch bark significantly speeds up wound healing compared with standard care in patients with epidermolysis bullosa (EB) lesions, according to the EASE trial presented at the EADV 2020 Conference — representing the first-ever treatment to show positive results for the rare skin disorder.

EB is a chronic genetic skin fragility disorder characterized by recurring healing and breaking down of wounds, with long-lasting wounds in one-third of patients who never saw their wounds healed, explained presenting author Dr Dedee Murrell from the University of New South Wales in Kensington, Australia.

“There are no approved treatment options and care is based on palliation of symptoms and management of complications,” said Murrell, who noted that the current treatments are nonspecific and thus, “there is a high unmet need for these patients.”

Oleogel-S10 is a topical gel made from triterpene extract of birch bark combined with sunflower oil.

In the global, phase III, prospective trial, 223 patients (median age 12 years) were randomized 1:1 to received Oleogel-S10 or control gel, both in addition to standard-of-care dressing; applied during dressing change for their wounds at least every 4 days.

Analyses were stratified according to EB subtypes and wound thickness. EB subtypes included junctional EB (JEB), dystrophic EB (DEB), or Kindler syndrome. Stratified subgroups were as follow: DEB 10 to <20 cm²; DEB 20 to <30 cm²; DEB 30–50 cm²; JEB/Kindler 10 to <20 cm²; JEB/Kindler 20 to <30 cm²; JEB/Kindler 30 to 50 cm².

Overall, significantly more patients treated with Oleogel-S10 met the primary endpoint of target wound closure by day 45 than those on standard care alone (41.3 percent vs 28.9 percent; odds ratio [OR], 1.84; p=0.013). The target wound must meet the criteria of having a partial thickness of 10–50 cm² in size and lasted between 21 days to 9 months in duration.

In particular, healing rate at 45 days was higher among patients with smaller target DEB wounds (10–20 cm²; 54.8 percent vs 39.4 percent), in favour of Oleogel-S10.

When stratified by EB subtype, the recessive DEB subgroup saw a greater benefit with Oleogel-S10 vs control gel (44.0 percent vs 26.2 percent; nominal p=0.008) relative to the overall population.

On the other hand, patients with dominant DEB had similar healing rate of 50 percent, regardless of whether they were treated with Oleogel-S10 or control gel.

In contrast, the healing rate was greater with the control gel over Oleogel-S10 (26.7 percent vs 18.2 percent; p=0.522) in the subgroup with JEB or Kindler syndrome, although the difference between treatments were not statistically significant.

There was also no significant difference in time to wound healing by 90 days between the two treatment groups (p=0.302). Wound healing rates were 50.5 percent with Oleogel-S10 group compared with 43.9 percent with control gel at 90 days (p=0.296).

Other secondary endpoints such as pain reduction and disease severity improved in favour of Oleogel-S10, although the differences were not significant.

“Oleogel-S10 had a reassuring safety profile and was well tolerated when compared with control gel,” reported Murrell.

The incidence of adverse events (AEs) was similar between the two groups (81.7 percent vs 80.7 percent). The most common AEs were wound complications (61.5 percent vs 53.5 percent), pyrexia (8.3 percent vs 13.2 percent), and wound infection (7.3 percent vs 8.8 percent). Nonetheless, most of the AEs were mild to moderate in severity, Murrell stated.

“Oleogel-S10 represents a potentially important advancement for patients and families living with this intractable skin disease,” she concluded.