GENEVA – Tapinarof cream, a first-in-class topical nonsteroidal anti-inflammatory agent, successfully met its primary and secondary efficacy endpoints in a large international, phase 2, dose-ranging study and is moving on to a phase 3 trial for atopic dermatitis.
Tapinarof is a naturally derived compound whose therapeutic mechanism of action has recently been shown to involve activation of the aryl hydrocarbon receptor, Johnny Peppers, PhD, said at the annual congress of the European Academy of Dermatology and Venereology.
GlaxoSmithKline is also developing tapinarof cream for mild to moderate plaque psoriasis, a disease that hasn’t seen a novel nonsteroidal topical therapy approved in more than 25 years. After a strong showing in a phase 2 study, a phase 3 trial in psoriasis is now scheduled.
Dr. Peppers presented a phase 2, double-blind, vehicle-controlled randomized trial including 247 adolescent and adult patients with mild, moderate, or severe atopic dermatitis. The six study arms were tapinarof cream at 1% or 0.5% or vehicle, self-administered at a frequency of either once or twice daily. Participants had a mean baseline Investigator’s Global Assessment (IGA) score of 3.1 on a 5-point scale, an (EASI) score of 9.8-13.1 in the various study arms, and a 5.1-5.8 score on an 11-point self-rated itch severity score recorded weekly.
“The 1% tapinarof arm showed higher efficacy and had a quicker onset of action than the 0.5% arm or vehicle,” he reported.
Indeed, the 1% tapinarof cream groups separated from controls in terms of the efficacy endpoints as early as week 1, with the maximum treatment effect seen at weeks 8-12, Dr. Peppers added.
The primary endpoint was a composite requiring both an IGA of 0 or 1, meaning clear or almost clear, at 12 weeks, along with a minimum 2-point improvement on the IGA from baseline to week 12. This was achieved in 46% of patients on tapinarof cream 1% applied once daily, 53% of those on tapinarof cream 1% twice a day, and in about 25% of controls on vehicle.
Eighty percent of subjects who achieved the primary endpoint maintained that level of treatment effect 2 weeks post treatment, and 70% still held their treatment response 4 weeks after they stopped using the medication.
There were two secondary endpoints. One was achievement of a 75% improvement from baseline on EASI scores (EASI-75) response. This was seen in 51% of the tapinarof 1% once-daily group, 60% on twice a day therapy, and 26% and 25% of controls. Onset of action was fastest with tapinarof cream 1% once daily.
The other secondary endpoint was at least a 3-point improvement from baseline to week 4 on the 11-point self-rated itch scale. This was achieved by 37% and 33% of patients on tapinarof cream 1% once daily and twice daily, respectively, a success rate twice that seen in controls.
Four percent of patients on tapinarof cream and 7% on vehicle discontinued the trial because of treatment-emergent adverse events. There were no serious treatment-related adverse events. The most frequent adverse events associated with tapinarof were folliculitis and contact dermatitis. The phase 3 trial will incorporate patch testing for contact dermatitis.
“We are very excited about this program. This will be the first topical therapy – if we’re able to achieve treatment success and ultimately regulatory approval – that would be able to treat both psoriasis and atopic dermatitis since topical steroids,” Dr. Peppers said.
The study was funded by GlaxoSmithKline and presented by a company employee.