Pfizer's aim of extending the use of its rheumatoid arthritis drug Xeljanz into new indications has been buoyed by two positive trials in ulcerative colitis.
The two trials - OCTAVE Induction 1 and 2 - showed that the orally-active JAK inhibitor was able to bring patients with moderate-to-severe active UC into remission more effectively than placebo.
Xeljanz is a key growth product for Pfizer and was the first JAK inhibitor to be approved for marketing in 2012, with expectations that it could provide an oral alternative to biologic therapies for RA.
Since then, the drug has grown steadily to reach sales of $523m last year - a 70% increase on 2014 - but Pfizer needs to expand the drug's use if it is achieve its predicted blockbuster sales potential.
Efforts to expand Xeljanz' indications beyond RA hit a hurdle last October however when the FDA turned down a marketing application in psoriasis, asking for additional information. The company is scheduled to meet with the FDA to discuss the reasons for the rejection.
The positive trials in UC - presented at the European Crohn's and Colitis Organisation (ECCO) meeting in Amsterdam last week - are a boost for the company's ambitions for Xeljanz.
In one study, 18.5% of patients on a twice-daily dose of Xeljanz went into remission after eight weeks' treatment, compared to 8% of the placebo group. The results for the other trial were consistent with remission rates of 16.6% and 3.6%, respectively, and patients taking Pfizer's drug in both trials experienced greater rates of mucosal healing than placebo.
Pfizer's president of R&D, Mikael Dolsten, noted that the company is now waiting for the results of two other trials of Xeljanz as a maintenance treatment for UC before submitting the drug for approval in the new indication.
The company is also developing the drug for psoriatic arthritis and is expecting results from its pivotal phase III trials programme for this use in the first half of this year. It is also testing Xeljanz in a head-to-head comparison with AbbVie's TNF inhibitor Humira (adalaimumab).
Pfizer has said it intends to position Xeljanz for psoriatic arthritis patients in whom non-biologic disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate have limited success, as well as those with inadequate responses to anti-TNF therapy.
A once-daily formulation of the drug is currently under review at the FDA and Pfizer is also gearing up to re-file its marketing application in the EU, where it has so far failed to secure approval because of concerns over safety.