Response to hydroxychloroquine in Japanese patients with lupus-related skin disease using the cutaneous lupus erythematosus disease area and severity index (CLASI)

Background: Hydroxychloroquine (HCQ) is not available in Japan. To design a clinical trial of HCQ, we evaluated the response to HCQ in Japanese patients with lupusrelated skin disease using the cutaneous lupus erythematosus disease area and severity index (CLASI). Methods: Twenty-seven patients with lupus-related skin disease who started HCQ at four hospitals were included. Patients were categorized into responders by the CLASI response criteria. The points and the rate of improvement in the CLASI activity score after 16 weeks of treatment were analyzed, focusing on six parameters: systemic lupus erythematosus (SLE), skin manifestations, disease duration, prednisolone, smoking, and severity. Results: Twenty-seven patients, including 17 with SLE (6 with SLE/Sjögren's syndrome), were analyzed retrospectively. Twenty-three patients (85 %) were categorized as responders. The mean CLASI activity score improved from 10.1 to 4.5 (p<0.0001). The improvement rate did not differ in these parameters except for that of annular erythema (81.6 versus 34.3 %, p = 0.036). On multivariate analysis, the baseline CLASI activity score (CLASI ≥9) correlated with the greatest decrease in CLASI activity score (F = 69.7, p<0.0001). Conclusions: CLASI is a reliable indicator to evaluate the efficacy of the drug, and HCQ is an effective treatment for Japanese patients with lupus-related skin disease.