Background  Ustekinumab, a human anti-interleukin-12/23 monoclonal antibody, has been shown to effectively treat moderate-to-severe psoriasis which significantly affects health-related quality of life (HRQoL), including patients’ sexual lives.

Objectives  The aim of this study was to determine if sexual difficulties associated with psoriasis are related to disease severity and whether sexual difficulties improve with skin disease during ustekinumab treatment.

Methods  In phase III PHOENIX 1 and 2 trials, psoriasis patients were randomized to ustekinumab (n = 1334) at weeks 0 and 4 and q12 weeks thereafter or placebo (n = 662) at weeks 0 and 4 with crossover to ustekinumab at week 12. Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) were used to assess psoriasis severity and patient-reported HRQoL respectively. Based on DLQI Question #9, impaired sexual function was defined as ‘very much’ or ‘a lot’ of sexual difficulties.

Results  At baseline, mean DLQI was 12.0, indicating a very large negative effect on patients’ lives. Impaired sexual function was reported by 22.6% (women = 27.1%; men = 20.8%) and was significantly associated with increased psoriasis severity. At week 12, ustekinumab-treated patients had a greater mean improvement in DLQI (−9.13 vs. −0.53 with placebo, P < 0.001) and the proportion of patients with impaired sexual function decreased from 22.4% to 2.7% compared with no change with placebo (P < 0.001). Patients with greater PASI improvement experienced a greater reduction of sexual difficulties due to psoriasis. A similar pattern of improved sexual function was observed at weeks 24–28 in placebo crossover patients.

Conclusions  Ustekinumab treatment is associated with significant improvement in HRQoL and sexual difficulties due to psoriasis.