BERLIN — Impaired sexual function is common in the setting of moderate to severe psoriasis, and ustekinumab therapy reduces these problems by 10-fold.
That's a key quality-of-life finding from the ongoing randomized double-blind phase III PHOENIX-1 and -2 clinical trials of this human monoclonal antibody directed against the proinflammatory cytokines interkeukin-12 and -23, Dr. Lyn Guenther reported at the annual congress of the European Academy of Dermatology and Venereology.
The marked reduction in sexual difficulties was paralleled by a sharp improvement in overall quality of life in the ustekinumab-treated patients in the PHOENIX studies. Their mean baseline score on the Dermatology Life Quality Index (DLQI) was 12, reflecting a very large negative impact on quality of life. Twelve weeks into the studies, the average DLQI had dropped by 9.13 points for ustekinumab patients, compared with a 0.53-point dip in the placebo arm, according to Dr. Guenther, medical director of the Guenther Dermatology Research Centre and professor of dermatology at the University of Western Ontario, London.
The DLQI is scored on a 0-30 scale. A 5-point or greater improvement is considered clinically significant.
The PHOENIX trials include 1,996 adults with moderate to severe psoriasis who were randomized 2:1 to ustekinumab (Stelara) at 45 mg or 90 mg at weeks 0, 4, 12, and every 12 weeks thereafter or to placebo. After 12 weeks, subjects in the placebo group were crossed over to ustekinumab.
The mean age of participants at entry was 46 years. Sixty-nine percent are men. Their average baseline Psoriasis Area and Severity Index (PASI) score was 20, with 26% of their body surface area being affected and an average disease duration of 20 years. Twenty-eight percent had psoriatic arthritis.
Question 9 on the DLQI is designed to explore sexual problems. Here's the phrasing: “Over the last week, how much has your skin caused any sexual difficulties?”
The response options are “not at all,” “a little,” “a lot,” “very much,” or “not relevant.” A reply of “a lot” or “very much” was interpreted as indicating sexual difficulties.
The prevalence of impaired sexual function by this measure went from 22% at baseline—27% in women and 29% in men—to 3% after 12 weeks on ustekinumab. There was no change at 12 weeks in the placebo group, but they showed markedly improved overall quality of life and sexual function upon repeat DLQI testing at 24-28 weeks—3 months after having been switched to ustekinumab.
DLQI scores did not differ between 90 mg as opposed to 45 mg of ustekinumab.
Sexual dysfunction is an aspect of psoriasis that doesn't get enough attention, Dr. Guenther commented.
Based upon the PHOENIX findings, further studies of ustekinumab's impact in this domain are warranted using more detailed tools for assessing sexual dysfunction, she said. The studies are funded by Centocor. Dr. Guenther is a consultant to the company.