Mechanism of Action

Calcipotriene is a synthetic vitamin D3 analog that has a similar receptor binding affinity as natural vitamin D3. However, the exact mechanism of action contributing to the clinical efficacy in the treatment of psoriasis is unknown.

Pharmacodynamics

The pharmacodynamics of SORILUX (calcipotriene foam) Foam are unknown.

Pharmacokinetics

The systemic absorption of calcipotriene in psoriatic subjects was evaluated at steady state following application of SORILUX Foam or calcipotriene ointment. In the SORILUX Foam treatment group, 15 out of 16 subjects showed calcipotriene plasma concentrations below the limit of quantitation (10 pg/mL), while in the calcipotriene ointment treated group, 5 out of 16 subjects had measurable calcipotriene plasma concentrations at various time points. All measurable plasma calcipotriene concentrations were below 25 pg/mL.

The systemic disposition of calcipotriene is expected to be similar to that of the naturally occurring vitamin D. Absorbed calcipotriene is known to be converted to inactive metabolites within 24 hours of application and the metabolism occurs via a similar pathway to the natural hormone.

Clinical Studies

In two multi-center, randomized, double-blind, vehicle-controlled clinical studies a total of 659 subjects with psoriasis were randomized 2:1 to SORILUX (calcipotriene foam) Foam or vehicle; subjects applied the assigned medication twice daily for 8 weeks. Baseline disease severity was graded using a 5-point Investigator Static Global Assessment scale (ISGA), on which subjects scored either "mild" or "moderate" as shown in Table 1.

Table 1: Investigator Static Global Assessment (ISGA) Scale

Efficacy evaluation was carried out at Week 8 with treatment success being defined as a score of "clear" (grade 0) or "almost clear" (grade 1) and at least 2 grade improvement from the baseline score. Approximately 30% of enrolled subjects were graded as "mild" on the ISGA scale. The study population ranged in age from 12 to 89 years with 10 subjects less than 18 years of age at baseline. The subjects were 54% male and 88% Caucasian. Table 2 presents the efficacy results for each study.

Table 2: Number and Percent of Subjects Achieving Success at Week 8 in Each Study

In one study, subjects graded as "mild" at baseline showed a greater response to vehicle than SORILUX (calcipotriene foam) Foam.

Table 3 presents the success rates by disease severity at baseline for each study.

Table 3: Number and Percent of Subjects Achieving Success by Baseline ISGA Score and by Study

The contribution to efficacy of individual components of the vehicle has not been established.

Last reviewed on RxList: 11/2/2010
This monograph has been modified to include the generic and brand name in many instances.