Two articles in The Lancet have shown the efficacy of ustekinumab for treating moderate-to-severe psoriasis, and that dosing every 12 weeks maintains efficacy in most patients.
Psoriasis is the most common immune-mediated skin disease in adults, with an estimated prevalence of 2–3%. Interleukins 12 and 23 are believed to have a central role in psoriasis physiology, and agents that block these interleukins have shown promise as drugs for treating psoriasis; however, currently available therapeutic options have left a substantial unmet need for treatments that are convenient, effective, and well tolerated, especially for long-term treatment.
The PHOENIX studies have been carried out by two teams of investigators to determine the efficacy of ustekinumab, a drug which binds to interleukins 12 and 23 and prevents their interaction with their specific receptors on the surface of cells.
The PHOENIX I trial found that 67% of psoriasis patients receiving ustekinumab 45 mg, 66% receiving ustekinumab 90mg, and 3.1% receiving placebo achieved 75% improvement in psoriasis areas and severity index (PASI 75) at week 12. PASI 75 response was better maintained to at least one year in those given maintenance treatment. Rates of adverse events were similar between ustekinumab and placebo groups.
The PHOENIX 2 found that 67% of patients receiving ustekinumab 45mg, 76% receiving ustekinumab 90mg, and 4% of patients receiving placebo achieved PASI 75 at week 12.
The authors conclude: “Although treatment with ustekinumab every 12 weeks is effective for most patients with moderate-to-severe psoriasis, intensification of dosing to once every eight weeks with ustekinumab 90mg might be necessary to elicit a full response in patients who only partially respond to the initial regimen.”
In an accompanying comment, Dr Brenda Bartlett and Professor Stephen Tyring, University of Texas Health Science Center, say: “Not only does ustekinumab compare favourably to the best available therapies for psoriasis, the maintenance of response between injections every three months also provides a more convenient regimen than those currently available.”