Efficacy and Safety of Dimethyl Fumarate in Patients with Moderate-to-Severe Plaque Psoriasis: Results from a 52-Week Open-Label Phase IV Clinical Trial (DIMESKIN 1)

Introduction Although dimethyl fumarate (DMF) has been approved since 2017 for treatment of moderate-to-severe plaque psoriasis, limited data on its safety and efficacy are available in clinical practice. The objective was to assess the efficacy and safety of DMF in patients with moderate-to-severe plaque psoriasis through 52 weeks in conditions close to real clinical practice. Methods DIMESKIN 1 was a 52-week, open-label, phase IV clinical trial conducted at 36 Spanish sites. Adults with diagnosis of moderate-to-severe plaque psoriasis, treated with DMF as per its summary of product characteristics and with ≥ 1 post-baseline Psoriasis Area and Severity Index (PASI) value were included [intention-to-treat (ITT) population]. Efficacy analyses were performed for ITT population and are based on multiple imputation. Results Overall, 282 and 274 patients were included in the safety and ITT populations, respectively. At week 24, 46.0%/24.8%/10.9% of patients achieved PASI 75/90/100 response, respectively. At week 52, these percentages were 46.0%/21.9%/10.9%, respectively. Mean body surface area affected decreased from 17.4% to 6.9%/7.3% after 24/52 weeks ( p < 0.001, both). A total of 42.9%/49.4% of patients had a Physician’s Global Assessment 0–1 at week 24/52, respectively. Mean pruritus visual analogue scale (VAS) significantly decreased after 24 and 52 weeks ( p < 0.001, both), with 56.5% and 67.6% of patients, respectively, rating a pruritus VAS < 3. At week 24/52, 61.3%/73.4% patients had a Dermatology Life Quality Index (DLQI) ≤ 5 and 34.7%/32.1% had a DLQI 0-1. The most frequent adverse events were gastrointestinal disorders (mainly diarrhea/abdominal pain in 50.0%/35.1% of patients, respectively), flushing (28.0%), and lymphopenia (31.2%), mostly mild/moderate. Conclusions DMF significantly improves main severity and extension indexes and rates, as well as patient-reported outcomes such as pruritus and quality of life in patients with moderate-to-severe psoriasis after 24 weeks of treatment. These improvements are sustained through 52 weeks. The safety profile of DMF is similar to that previously described for fumarates. EudraCT number 2017-00136840.