Treatment with presented as a late-breaker at the virtual annual congress of the European Academy of Dermatology and Venereology.
The drug has several unique features with meaningful clinical differences from other topical psoriasis therapies, according to Linda Stein Gold, MD, director of dermatology clinical research, Henry Ford Health System, Detroit.
“The currently available nonsteroidal topical therapies are typically associated with significant irritation. We did not see that with tapinarof,” said Dr. Stein Gold. This is one of several reasons she believes this drug will be a valuable addition if it receives regulatory approval.
Tapinarof is a small-molecule aryl hydrocarbon receptor (AhR) modulating agent. AhR is widely expressed in immune cells, including macrophages, mast cells, and antigen-presenting cells. It is believed that modulation of AhR signaling by tapinarof reverses immune dysregulation that is involved in the formation of psoriatic lesions.
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The newly presented PSOARING 3 data with tapinarof 1% build on the data from the 12-week PSOARING 1 and PSOARING 2 trials, which were released in August 2020 but have yet to be published.
The primary endpoint in both of the 12-week trials, each of which enrolled about 500 patients with plaque psoriasis, was a Physician Global Assessment (PGA) score of 0 (clear) or 1 (almost clear). Relative to a placebo response rate of about 6% in both trials, the proportion of patients who achieved scores of 0/1 with tapinarof 1% was 35.4% and 40.2% in the PSOARING 1 and PSOARING 2 trials, respectively (P < .0001 vs. placebo in both studies).
For the key secondary endpoint of at least 75% improvement in the Psoriasis Area and Severity Index (PASI 75), the relative advantage for tapinarof over placebo was similar. The results were highly statistically significant (P < .0001) in both of the 12-week trials.
More than 90% of the patients who participated in PSOARING 1 and PSOARING 2 and were eligible for the open-label PSOARING 3 extension trial, according to Dr. Stein Gold.
For the 79 patients with a score of 0 at the time of enrollment, tapinarof 1% was reapplied only if the PGA score reached at least 2 during the course of the study. For the 680 patients who entered with a PGA score of at least 1, once-daily applications of tapinarof 1% cream were maintained until a PGA score of 0 was achieved.
In the outcome analysis, response was defined as the proportion of patients with an initial PGA score of at least2 who achieved PGA 0. A remittive effect was defined as duration of a PGA score of 0 or 1 while off therapy after achieving a PGA score of 0. Durability of response was defined as the proportion of patients who achieved a PGA sore of 0 or 1 at least once during the study while on therapy. This last outcome provided a test of tachyphylaxis.
“Overall, 40.9% of patients achieved complete disease clearance at least once during the trial, and 58.2% who entered the study with a PGA score of 2 or higher achieved a PGA score of 0 or 1,” Dr. Stein Gold reported.
For the 79 patients who entered PSOARING 3 with a PGA score of 0 and were off treatment, the median duration of a remittive effect was 115 days. For the patients who entered the trial with a higher PGA score but who achieved a score of 0 during the study (312 patients), the mean remittive effect after discontinuing therapy was 130 days.
There was no evidence of tachyphylaxis. Rather, “there was no loss of effect despite intermittent therapy observed over the course of the trial,” Dr. Stein Gold reported.
The most common treatment-emergent adverse events in PSOARING 3, as in the previous PSOARING studies, were folliculitis, which was observed in 24.0% of patients; contact dermatitis, which occurred in 5.9% of patients; and headache, which was reported in 2%. Rates of study drug discontinuations for folliculitis and contact dermatitis were 1.2% and 1.4%, respectively. Headache did not lead to any study discontinuations.
Calling tapinarof a “first-in-class nonsteroidal,” Dr. Stein Gold suggested that this is likely to be a useful adjunctive therapy for psoriasis control. It avoids the adverse events associated with long-term topical steroid use, and its tolerability might be particularly attractive for use in sensitive areas.
“This is likely to be very useful in patients who are looking for a topical therapy for skin folds or the face, where there is a need for well-tolerated topical treatments,” Dr. Stein Gold said.
There are a lot of reasons to be positive about a new, well-tolerated topical agent for psoriasis, particularly as an alternative to topical steroids, agreed Adam Friedman, MD, director of translational research and professor and chair of the department of dermatology at George Washington University, Washington. He considers the data with tapinarof promising in general, but he also likes any new, effective topical psoriasis therapy.
“Patients and physicians are always hungry for new options, especially psoriasis patients, given many have ‘been there and done that’ with topical steroids,” Dr. Friedman said.
“Topical steroids are not irritating, but long-term use beyond recommended dosing can lead to skin thinning, lightening, tachyphylaxis, and, if really abused, HPA [hypothalamic-pituitary-adrenal] axis suppression and adrenal insufficiency,” he observed.
A topical therapy with a durable effect is particularly intriguing.
“The other issue with topical steroids is that psoriatic plaques return rather easily after stopping. The data I have seen with tapinarof show more sustainability after cessation, owing to its mechanism of action,” Dr. Friedman said. Rather than its potential for application to sensitive areas, such as the face, the durability “to me is more interesting.”
He suspects that, owing to “the incurable steroid phobia that haunts many of our patients,” an effective nonsteroidal topical option is also likely to lead to better compliance with topical treatment over time.
“A well-tolerated nonsteroidal topical drug will probably find an important place in the future management of chronic inflammatory diseases,” Marius-Anton Ionescu, MD, PhD, a dermatologist at the Hôpital Saint Louis, Paris, said in an interview. He referred to the positive effects of treatment with tapinarof in clinical trials in adults with atopic dermatitis, in addition to psoriasis.
Tapinarof 1% is also being investigated in a phase 3 study involving patients with moderate to severe atopic dermatitis. In that study, patients are as young as age 2 years. The drug is under review at the Food and Drug Administration for the plaque psoriasis indication in adults.
Dr. Stein Gold has financial relationships with Arcutis, Amgen, Bristol-Myers Squibb, Eli Lilly, Leo Pharma Ortho Dermatologic, UCB, and Dermavant Sciences, which is developing tapinarof and is provided funding for the PSOARING 3 trial. Dr. Friedman reported financial relationships with Amgen, Biogen, Encore, Galderma, GlaxoSmithKline, IntraDerm, Johnson & Johnson, Nerium, Novartis, Oculus, Onset, Pfizer, Sanova, and Valeant Pharmaceuticals. Dr. Ionescu has been a speaker or investigator (honoraria) for Celgene, Novartis, Lilly, and Uriage Cosmetics.
A version of this article first appeared on Medscape.com.