U.S. Markets open in 6 hrs 32 mins

Pfizer's drug shows mixed results in psoriasis trials

Oct 9 (Reuters) - A high dose of Pfizer Inc's drug, tofacitinib, proved as effective as the widely used treatment, Enbrel, in treating adults with moderate-to-severe psoriasis in a late-stage study , while a lower dose of tofacitinib was less effective than Enbrel, the drugmaker said on Wednesday.

The mixed results were seen in a 12-week study, called OPT Compare, which examined the effectiveness of both 5 milligram and 10 milligram twice-daily doses of oral tofacitinib with a placebo and with the approved starting twice-weekly dose of injectable Enbrel.

Pfizer said tofacitinib, already approved to treat rheumatoid arthritis under the brand name Xeljanz, showed similar dose-response trends and similar safety trends as those seen in an earlier mid-stage trial of tofacitinib for treatment of psoriasis.

On Wednesday, Pfizer said tofacitinib met its primary effectiveness goal in a separate Phase III psoriasis study, called OPT Retreatment, which lasted 56 weeks and compared the 5 milligram and 10 milligram doses of tofacitinib to placebo.

That study compared the effectiveness and safety of withdrawal and retreatment with both tofacitinib doses, compared with placebo, in adult patients with moderate to severe psoriasis.

A greater proportion of patients taking tofacitinib maintained symptom relief during the withdrawal of treatment compared with patients who switched to placebo, Pfizer said in a statement.

Enbrel, a blockbuster product sold by Amgen Inc and Pfizer, works by blocking a protein called tumor necrosis factor, that is linked to inflammation.

Tofacitinib is a so-called JAK inhibitor, and blocks an enzyme called Janus kinase, that is also associated with inflammation.