Pfizer has announced plans to lower its Xeljanz trial dosing from 10mg twice-daily to 5mg twice-daily, after pulmonary embolisms were found to be more frequent among patients treated with the higher dose.

The study, which is assessing the drug in patients with rheumatoid arthritis (RA), also found higher rates of death in the 10mg dosed patients compared with patients on TNFi and the lower 5-mg Xeljanz dose.

The drug was approved by the FDA in 2012 for the treatment of patients with moderately to severely active RA, and the study was designed to assess the risk of cardiovascular events in RA patients 50 years of age and older with at least one risk factor.

The company has said it will "continue to evaluate the risk benefit profile of Xeljanz across all indications and we will continue to work with regulators as more data become available."

It also stated: "we will work with the FDA and other regulatory agencies to review the full results upon completion of this study.”

Xeljanz is also approved in the US for the treatment of adults with active psoriatic arthritis and moderate-to-severe ulcerative colitis, in which the drug is given at a dose of 10mg twice daily for at least eight weeks, followed by a dose of 5mg or 10mg twice daily.