Pfizer is moving rheumatoid arthritis patients to a lower dose of its blockbuster inflammatory diseases pill Xeljanz in a clinical study after a safety signal emerged in the trial of patients at high risk of cardiovascular events. A Janus kinase inhibitor class drug, Pfizer has produced Xeljanz as an oral alternative to injected anti-TNF class drugs such as AbbVie’s Humira (adalimumab) and others, which are approved in a range of inflammatory diseases. Global sales were nearly $1.8 billion in the full year for 2018, up 32% compared with the previous year, making Xeljanz an important driver of sales growth for Pfizer.
The US pharma said the signal had emerged in the study A3921133, which was required by the FDA as a post-marketing requirement for Xeljanz (tofacitinib). It is taking action after the study’s Data Safety Monitoring Board warned of a safety signal in a study arm where patients received a twice-daily dose at 10mg. The board noted that in patients treated at the higher dose there was a “statistically and clinically important” difference in the occurrence of pulmonary embolism, compared with patients in a control group treated with tumor necrosis factor inhibitor (anti-TNF) drugs.