Pfizer Inc. (PFE) presented top-line data from two phase III studies evaluating Xeljanz (tofacitinib) for the treatment of adults with moderate-to-severe chronic plaque psoriasis.
Data was presented from the OPT Compare (A3921080) and OPT Retreatment (A3921111) studies which are a part of the five studies being conducted under Pfizer’s phase III Oral Psoriasis Treatment (:OPT) program.
OPT Compare, a 12-week, non-inferiority study, was conducted to compare Xeljanz' (5 and 10 mg twice-daily) efficacy and safety to that of Amgen’s (AMGN) high-dose Enbrel (50 mg twice-weekly), the approved starting dose for Enbrel for the first twelve weeks, and placebo.
Results from this study were mixed with Xeljanz (10 mg) meeting the primary endpoint of non-inferiority to Enbrel but failing to meet the non-inferiority criteria to Enbrel at the 5 mg dose.
Meanwhile, Pfizer said that the primary efficacy endpoint for both doses of Xeljanz were met in the OPT Retreatment study. The 56-week OPT Retreatment study compared the efficacy and safety of withdrawal and retreatment with Xeljanz (5 and 10 mg twice-daily) to placebo. It was found that a higher number of patients who continued Xeljanz treatment maintained their response during the treatment withdrawal phase compared to patients who switched to placebo. Moreover, several patients who had lost an adequate response were able to recapture their response upon retreatment with Xeljanz.
Xeljanz is available in the U.S. for the treatment of moderately to severely active rheumatoid arthritis (:RA) in adult patients who have not responded adequately to or cannot tolerate methotrexate (MTX). Xeljanz is the first oral treatment to gain approval in a new class of medicines known as Janus kinase (:JAK) inhibitors. The product represents a new treatment option for patients who respond inadequately to or are unable to tolerate MTX. Xeljanz sales were $33 million in the first half of 2013.
Results from the two phase III studies were mixed with Xeljanz failing to show non-inferiority to Enbrel at the 5mg dose. With Xeljanz currently being available only at this dose, Pfizer will need to gain approval for a higher dose (10mg) in order to be able to take share from existing products once approved for the psoriasis indication.
Top-line results from two other studies being conducted under the OPT program - OPT Pivotal 1 and OPT Pivotal 2 - will be available in the second quarter of 2014. Results from these studies in addition to the OPT Compare and OPT Retreatment studies plus a long-term extension study would allow Pfizer to seek approval for expanding Xeljanz’ label.