A randomized controlled trial of narrowband ultraviolet B vs. bath-psoralen plus ultraviolet A photochemotherapy for psoriasis

Background In 1991, consensus guidelines recommended psoralen plus ultraviolet A photochemotherapy (PUVA) for those requiring second-line therapy for psoriasis. Narrowband (TL-01) UVB has since become more widely available, replacing the less effective broadband sources. Objectives To compare the efficacy of TL-01 UVB phototherapy and trimethoxypsoralen (TMP) bath-PUVA for chronic plaque psoriasis. Participants and methods A randomized, observer-masked, intraindividually controlled, paired (half-body) study was done in the Photo (chemo) therapy Unit in Ninewells Hospital and Medical School, Dundee. The study comprised 28 patients (skin phototypes I-III) with chronic plaque psoriasis. Each patient's body halves (sagittal plane) were treated independently, one-half with TL-01 UVB, the other with bath-PUVA. Both treatments were administered according to standard, optimized regimens. Treatment was continued until clearance or minimal residual activity (MRA), or a maximum of 30 treatments. The main outcome measures were treatments and time to clearance/MRA, the proportion reaching clearance/MRA, change in psoriasis severity score (scaling, erythema and induration) and remission durations. Results Of 18 who completed the study, all reached clearance/MRA with TL-01, but three were still not clear after 30 PUVA exposures. TL-01 achieved clearance/MRA a median of 11 (6.5-25; P = 0.001) days more quickly than PUVA, but required a median of 24.5 compared with 19 exposures [95% confidence interval (CI) for difference 1.5-5.5; P = 0.01]. Ten patients were withdrawn (four because of inadequate response of PUVA-treated halves). Analysed on an intention-to-treat basis, 21 of 28 (75%) of all participants reached clearance/MRA with TL-01 compared with 15 of 28 (54%) with PUVA (95% CI for difference 4-37%; P = 0.03). Remission durations did not differ. Conclusions When administered according to these regimens in a skin phototype I-III population, TL-01 UVB is more efficacious than TMP bath-PUVA in the treatment of chronic plaque psoriasis.