Treatment with 311-nm ultraviolet B enhanced response of psoriatic lesions in ustekinumab-treated patients: a randomized intraindividual trial

Background: Treatment with the interleukin-12/23 antibody ustekinumab produces a satisfactory response [i.e. 75% reduction in Psoriasis Area and Severity Index (PASI) compared with baseline (PASI 75)] in the majority of patients with moderate to severe chronic plaque-type psoriasis.

Objectives: To determine whether concomitant 311-nm ultraviolet (UV) B therapy can further enhance the response in patients with psoriasis treated with ustekinumab.

Methods: Ten patients (five women and five men; mean age 58years, range 48-66) with moderate to severe plaque-type psoriasis were treated with ustekinumab at a standard dosage of 45 or 90mg subcutaneously depending on body weight (below or above 100kg) at weeks 0 and 4. Within 2days after ustekinumab initiation, the minimal erythemal dose (MED) was determined and suberythemal MED 311-nm UVB-based phototherapy was thereafter administered to one randomly selected body half (left or right, excluding the head) three times weekly for 6weeks. Treatment response was monitored weekly in terms of half-body PASI.

Results: Nine patients completed the study. Analysis of their data showed that 311-nm UVB significantly accelerated the therapeutic response. At baseline (i.e. start of 311-nm UVB therapy), the mean PASI was similar in both irradiated and unirradiated body halves (13·6 vs. 13·3). At week 6, however, it was lower on irradiated body halves (2·5 vs. 6·1). This difference of 3·6 (95% confidence interval 1·3-5) was statistically significant and corresponded to an overall mean PASI reduction from baseline of 82% vs. 54%, respectively. At week 6, PASI 75 was achieved significantly more often on UV-irradiated body halves than on unirradiated body halves [7/9 patients (78%) vs. 1/9 (11%)] (McNemar test, P=0·007). At week 12, this synergistic effect of 311-nm UVB was still apparent although not significantly so.

Conclusions: Treatment with 311-nm UVB accelerates the clearance of psoriatic lesions in ustekinumab-treated patients.