Centocor reported one year data from a phase III trial of ustekinumab (CNTO-1275), a monoclonal antibody against the p40 subunit of IL-12 and IL-23 for the treatment of moderate to severe plaque psoriasis. This randomized, double-blind, placebo-controlled trial, dubbed PHOENIX-1, enrolled 766 subjects.

The subjects received subcutaneously administered ustekinumab (45 mg or 90 mg) at Weeks 0 and 4 followed by the same dose every 12 weeks, or placebo. Following the double blind phase, the subjects in the placebo group crossed over to receive either 45 mg or 90 mg doses of ustekinumab at Weeks 12 and 16 and every 12 weeks thereafter.

The primary endpoint was the proportion of subjects achieving at least a 75% improvement on the Psoriasis Area and Severity Index (PASI 75) at Week 12. The endpoint was reached; after two doses of ustekinumab 67% of subjects receiving the 45 mg dose and 66% of subjects receiving the 90 mg dose achieved PASI 75 compared with 3% of subjects receiving placebo (p

In addition, 42% of subjects in the 45 mg ustekinumab dosing group and 37% of subjects in the 90 mg ustekinumab dosing group achieved PASI 90, compared with 2% of subjects receiving placebo (p

Of those subjects who continued treatment with ustekinumab 45 mg and 90 mg, 87% and 91%, respectively, had a sustained PASI 75 response compared with 64% and 62% of subjects switched to placebo (p less than or equal to 0.001 for 45 mg comparison;

Also at Week 40, 66% and 73% of subjects achieved PASI 90 after receiving either 45 mg ustekinumab or 90 mg ustekinumab, respectively, and response rates remained stable through Week 52 with continued treatment, compared with 37% and 38% of subjects switched to placebo. The adverse events profile was comparable between the treatment arms.

Johnson & Johnson subsidiary Centocor and Janssen-Cilag are developing ustekinumab. A Biologic License Application (BLA) is currently under review by the U.S. Food and Drug Administration (FDA).