MIAMI – In an ongoing drive to identify an alternative to the mainstay treatment of psoriasis with topical corticosteroids, researchers evaluated a fixed-dose combination of halobetasol propionate 0.01% and tazarotene 0.045% lotion compared to its monads and vehicle in 212 people with moderate to severe psoriasis.
After 8 weeks of once-daily applications, combination therapy yielded significantly greater reductions in erythema, plaque elevation, and scaling at the target lesion, compared with the other groups in the phase II trial. The investigators also reported at safety profile consistent with halobetasol propionate or tazarotene monotherapy, meaning no new safety concerns emerged with the combination.
Dr. Linda Stein Gold
Participants were randomized to the combination, halobetasol propionate alone, tazarotene monotherapy, or vehicle in the multicenter, double blind study.
Efficacy evaluation
At 8 weeks, 53% of the combination group achieved treatment success, defined as at least a 2-point gain in Investigator’s Global Assessment of Disease Severity and a score of “clear” or “almost clear.” In contrast, 33% of the halobetasol propionate group, 19% in the tazarotene, and 10% of the vehicle only group achieved those endpoints in the intent-to-treat-analysis. The difference in efficacy between the combination group and vehicle was statistically significant (P less than .001).
On individual clinical efficacy measures, more than half of the patients in the combination treatment group achieved at least a 2-point improvement from baseline: 54% for erythema, 68% for plaque elevation, 65% for scaling. Each of these outcomes was significantly superior compared to the tazarotene or vehicle group (P less than or equal to .001).
“I was not surprised by the findings as the drugs work by complimentary mechanisms of action – so combination therapy should be effective,” Dr. Stein Gold said.
At baseline, IGA severity score of 3 was most common in each group and for each psoriasis sign at the target lesions. In each group, the mean age of participants ranged from 48 to 56 years; the proportion of men ranged from 59% to 68%; and 87% to 95% were white. The median target lesion sizes ranged from 25 to 32 cm2.
Safety outcomes
One patient in the vehicle-only group died. Three other participants experienced serious adverse events – one in each of the noncombination groups. None of these events were related to the study medications, the investigators noted. Application site reactions were the most common treatment-associated adverse events. Some skin atrophy was reported.
“These results show that the fixed combination of halobetasol propionate and tazarotene was effective and well tolerated,” said Dr. Stein Gold, who serves as division head of dermatology at Henry Ford Health System, West Bloomfield, Mich. “This would be a nice addition to our treatment armamentarium for patients with plaque psoriasis.”
Dr. Stein Gold is a speaker, consultant, and study investigator for Valeant Pharmaceuticals, which supported the study.