The efficacy of calcipotriol + acitretin combination therapy for psoriasis: comparison with acitretin monotherapy.

BACKGROUND: Although the use of an oral retinoid as monotherapy is an effective treatment for psoriasis, it is usually used in combination with other topical or systemic therapies including topical corticosteroids, UVB phototherapy, psoralens + UVA (PUVA) chemotherapy and cyclosporine mainly in an effort to reduce or avoid adverse effects.

AIM: To compare the efficacy of the calcipotriol + acitretin combination treatment with acitretin alone over a long period in Korean patients with psoriasis.

METHODS: A randomized, bilateral paired comparison was conducted involving 40 patients with psoriasis who received calcipotriol + acitretin combination therapy and 20 psoriasis patients who received acitretin alone. The initial dose of acitretin was 10 or 20 mg/day. The dose was adjusted at each visit (2, 4 and 6 weeks) in steps of 10mg according to patient responsiveness and adverse effects. The maximum dose was 40 mg/day. The treatment duration for all patients ranged from 4-52 weeks. After 12 weeks, the efficacy of therapy, according to Psoriasis Area and Severity Index scores, was assessed. At the end of the study (52 weeks), we selected patients who had achieved complete clearance and compared the duration of treatment and total dose of acitretin used in both groups.

RESULTS: After 12 weeks, 16 patients (40%) achieved complete clearance in the calcipotriol + acitretin group and 3 patients (15%) in the acitretin monotherapy group (p < 0.05). After 52 weeks, 24 patients (60%) in the calcipotriol + acitretin group and 8 patients (40%) in the acitretin monotherapy group achieved complete clearance. The duration of treatment and total dose of retinoid required to achieve clearance were slightly lower in the calcipotriol + acitretin combination group, however, this was not statistically significant. With the exception of liver enzyme elevation (which affected more patients in the acitretin monotherapy group than in the combination group), adverse effects were not significantly different.

DISCUSSION: Our results showed that calcipotriol might enhance the clinical outcome of systemic acitretin therapy. More large, well-controlled, long-term studies need to be conducted to determine whether there is indeed a beneficial effect of the addition of calcipotriol to acitretin treatment and whether this effect is maintained over long-term periods.