Birch Bark Derivative Effective for Epidermolysis Bullosa

A gel derived from birch bark is the first topical medication ever tested in the treatment of epidermolysis bullosa (EB) to heal wounds faster than placebo. The results come from the largest double-blind, randomized trial performed in this patient population.

More than 41% of EB target wounds that were treated with Oleogel-S10 healed within 45 days, compared to about 29% of target wounds treated with placebo, in the EASE phase 3 trial, conducted at 58 sites in 28 countries.

Dr Dedee Murrell

A group of rare genetic disorders, EB “is described as the worst disease you’ve never heard of,” explained lead investigator Dedee Murrell, MD, from St. George Hospital at the University of New South Wales, Sydney, Australia. “It starts in children and is like having burns that heal with scars, and no treatment has been approved for it” by the US Food and Drug Administration (FDA).

“This is the first large clinical trial with placebo of a topical treatment that’s worked for this terrible disease,” Murrell told Medscape Medical News. She noted that standard EB treatment currently consists of applying nonstick dressings to wounds to protect skin from trauma and infection.

Murrell, who has focused her work on EB patients since 1990, presented the findings at the virtual European Academy of Dermatology and Venereology (EADV) Congress 2020.

The trial enrolled 223 patients (average age, 12 years, but ages ranged to 81 years) with three types of EB, including dystrophic and junctional EB and Kindler syndrome. For each participant, a target wound was selected for use as the primary efficacy endpoint. Those wounds had a partial thickness of between 10 cm2 and 50 cm2 and lasted between 21 days and 9 months. Patients were stratified into groups depending on type of EB and size of target wound.

Participants were randomly assigned to receive either Oleogel-S10 (n = 109) or placebo (n = 114). All applied the blinded study gel to all their wounds at least every 4 days at the time dressings were changed.

The primary endpoint was the percentage of patients whose target wounds completely closed within 45 days. Key secondary endpoints included time to wound healing and percentage of target wounds that healed within 90 days of treatment; incidence and severity of target wound infection; change in total body wound burden, as measured by the Epidermolysis Bullosa Disease Activity and Scarring Index skin activity subscore; change in itching, as measured by the Itch Man Scale and the Leuven Itch Scale; and adverse events.

Nearly 92% of patients who were treated with Oleogel-S10 completed the double-blind phase of the trial, compared with nearly 87% who received placebo. As noted, the primary endpoint was met, with 41.3% of Oleogel-S10 patients achieving target wound closure within 45 days, compared to 28.9% of the patients who received placebo (P = .013).

But the difference in time to wound healing by day 90 between the two patient groups was not statistically significant (P = .302), with 50.5% of

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First-Ever Positive Phase III Trial in Epidermolysis Bullosa

A topical treatment derived from tree bark significantly increased healing of epidermolysis bullosa (EB) lesions versus standard care in an international multicenter clinical trial.

After 45 days of treatment, 41.3% of patients randomized to oleogel-S10 (Filsuvez) had complete wound closure as compared with 28.9% of the control group. A subgroup analysis showed that the beneficial effects were limited to patients with recessive dystrophic, which accounted for almost 80% of the study population.

The wound-healing advantage of oleogel-S10 emerged at about 30 days and persisted out to 90 days, when the proportion of patients with healing became similar in the two treatment groups, reported Dedee Murrell, MD, of the University of New South Wales in Kensington, Australia, during the European Academy of Dermatology and Venereology virtual conference.

“The time to event, which is wound healing over 90 days … was not statistically significant overall,” she said. “The wound healing trajectories demonstrated that oleogel-S10 accelerates wound healing in a subset of the wounds. However, as expected, with good wound care, the control group begins to catch up later by 90 days. The difference in the proportion of healed target wounds had narrowed between treatment groups at 90 days, but the control group never overtook the oleogel arm.”

“This is the first time that a phase III trial in EB has met its primary endpoint,” she added.

Background of Development

A rare genetic skin-fragility disorder, EB characteristically emerges as a pattern of recurring healing and break-down wounds, along with chronic slow-healing or nonhealing wounds. The condition has no approved therapy, and standard of care consists of nonadhesive bandages, topical antimicrobial agents, topical steroids, and various unapproved therapies that are not specific for EB, Murrell noted.

The primary active ingredient in oleogel-S10 is betulin, a naturally occurring triterpene found in the bark of certain types of birch trees. Dry betulin extract is mixed with sunflower oil to form a gel, which is applied directly to EB lesions and to the contact surface of bandages. The mechanistic rationale for its use in EB includes evidence that triterpenes help modulate inflammation and are involved in keratinocyte proliferation, migration, and differentiation.

Preliminary clinical research provided evidence of accelerated wound healing in patients with dystrophic EB. The work subsequently led to the international phase III EASE trial. Investigators at 58 sites in 28 countries enrolled 223 patients, primarily with dystrophic EB but also junctional EB or Kindler syndrome. Eligible patients had a partial thickness wound 10-50 cm2 in size, persisting for 21 days to 9 months.

Patients were randomized to oleogel-S10 or control gel, each in addition to standard dressings changed at least once every 4 days. The primary endpoint was the proportion of patients who had a first complete closure of a target wound within 45 days. Secondary endpoints included time to wound healing, proportion of target wounds healed within 90 days, incidence and severity of wound infections, change in total body wound burden, change in itching, and adverse events.

Patients ages 4-12 years accounted for

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