Halobetasol/tazarotene combination most effective for plaque psoriasis treatment
A fixed combination of halobetasol propionate 0.01% and tazarotene 0.045% lotion provided a synergistic effect over either component on its own for the treatment of plaque psoriasis, according to Leon H. Kircik, MD, of Indiana University, Indianapolis, and his associates.
The investigators performed a post hoc analysis of 212 patients with moderate to severe plaque psoriasis randomized to receive either the halobetasol/tazarotene combination, halobetasol only, tazarotene only, or vehicle only for 8 weeks, with follow-up at 12 weeks. Treatment success was based on the proportion of patients who achieved at least a 2-grade improvement in the Investigator Global Assessment (IGA) score, IGA scores of “clear” or “almost clear,” and percent change from baseline in IGA multiplied by Body Surface Area (BSA) composite score (IGAxBSA). “Synergy was calculated by summing up the contribution of the individual active ingredients (HP and TAZ) to overall efficacy and comparing to the efficacy achieved with HP/TAZ lotion relative to vehicle,” the authors explained.
Relative to vehicle, treatment success for halobetasol/tazarotene after 8 weeks was 42.8%, 23.6% for halobetasol alone, and 9.0% for tazarotene alone. After 12 weeks, the difference was 31.3%, 14.1%, and 5.9%, respectively. The percent change in IGAxBSA scores from baseline after 8 weeks, relative to vehicle, were 51.6%, 37.3%, and 3.3%, respectively. After 12 weeks, the change was 47.3%, 25.7%, and 8.6%, respectively.
After 8 weeks, the synergy ratio for treatment success and IGAxBSA scores for the halobetasol/tazarotene combination was 1.3. After 12 weeks, the synergy ratio for treatment success was 1.6 and the ratio for IGAxBSA scores was 1.4.
“By combining two agents into one once-daily formulation, this novel formulation reduces the number of product applications and may help patient adherence,” the study authors noted.
Dr. Kircik reported serving as a consultant and investigator for Valeant Pharmaceuticals. One study author is an employee of Bausch Health and Ortho Dermatologics, and another is an employee of Dow Pharmaceutical Sciences (a division of Valeant).