Clinical trials to test the effectiveness of two prescription drugs for the debilitating skin condition psoriasis have revealed significant differences that should help inform physicians treating patients with the condition.
Researchers at The University of Manchester compared the drugs etanercept and ustekinumab -- relatively new biological therapies that have proved effective in the management of moderate to severe psoriasis.
Little research has been done to test the benefit-risk profiles of these new biological agents or compare their relative effectiveness. The Manchester-led international study tested the two drugs on 903 patients with moderate to severe psoriasis over a 12-week period.
The team, headed by world-renowned dermatologist and psoriasis expert Professor Chris Griffiths, found that there was at least a 75% improvement in the severity of psoriasis symptoms in 56.8% of patients who received twice-weekly 50mg sub-cutaneous injections of etanercept after 12 weeks.
Ustekinumab was given to patients in two doses -- 45mg and 90mg -- and involved just two sub-cutaneous injections over the 12-week period. A 75% improvement in symptoms was observed in 67.5% of patients taking the 45mg dose and 73.8% receiving the 90mg dose.
"Our findings show that the efficacy of ustekinumab at either dosage was superior to that of high-dose etanercept using the 75% improvement measure over a 12-week period," said Professor Griffiths, who is based at Salford Royal Hospital, Greater Manchester.
"Similarly, a higher proportion of patients using ustekinumab were reported to have no or minimal disease symptoms after 12 weeks than those given etanercept -- 70.6% at 90mg ustekinumab compared to 49.0% receiving etanercept."
About one in 50 people are afflicted by psoriasis. The condition is currently incurable and causes significant impairment in the sufferer's quality of life. In severe cases more than 20% of the skin's surface area can be affected. Therapeutic agents used for the management of the condition commonly target the underlying inflammation.
Immunosupressive agents, such as methotrexate and cyclosporin, have proved effective in treating psoriasis but new biological agents that block selective stages of the body's inflammatory process now provide alternative therapies. Etanercept and ustekinumab are two such agents.
Etanercept, marketed as Enbrel by Amgen / Wyeth, works by blocking the actions of a chemical signal called TNF-∝ that is involved in the body's immune response. Ustekinumab, a drug marketed as Stelara by Centocor Research and Development, a subsidiary of Johnson & Johnson, targets two chemical signals involved in the immune system's response, called cytokines.
The research, published in the New England Journal of Medicine, also charted the number and type of adverse reactions for both drugs.
Professor Griffiths said: "The safety of ustekinumab and etanercept, including the rates and types of adverse events and laboratory abnormalities, appeared to be generally similar with short-term treatment.
"There were, however, more injection-site reactions with etanercept but this may be accounted for by the fact patients received more injections of this drug than ustekinumab."
He added: "The results of this study could have implications for determining the optimal approach to the treatment of psoriasis and, in particular, the need for therapeutic strategies targeting the body's immune system to provide the greatest benefit and safety."
- Griffiths et al. Comparison of Ustekinumab and Etanercept for Moderate-to-Severe Psoriasis. New England Journal of Medicine, 2010; 362 (2): 118 DOI: 10.1056/NEJMoa0810652
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