Pfizer has suffered a setback after advisors to the European Medicines Agency recommended against approval of the drug giant's rheumatoid arthritis treatment Xeljanz.

The agency's Committee for Medicinal Products for Human Use (CHMP) has adopted a negative opinion for Xeljanz (tofacitinib) for the treatment of adults with moderate-to-severe active RA. The committee said the drug helps improve the signs and symptoms of RA and the physical function of patients, but "did not believe that a consistent reduction in disease activity and structural damage to joints had been sufficiently demonstrated".

The CHMP also raised questions about the serious infections, gastrointestinal perforations and malignancies observed in Xeljanz trials. As such, it believes Xeljanz does not demonstrate a favourable risk:benefit profile at this time and recommended against marketing authorisation.

Pfizer responded by saying it intends to appeal "and immediately seek a re-examination of the opinion by the CHMP". The data package it had submitted to the EMA, which included 5,000 patients across Phase II and III trials in more than 40 countries, was the same presented to the US Food and Drug Administration which approved Xeljanz in November. Japan and Russia have also given the green light to the drug.

Yvonne Greenstreet, head of the medicines development group for Pfizer Specialty Care, said "we believe our application to the EMA demonstrates that XELJANZ has a favourable risk:benefit profile". She added that the safety profile of the oral Janus kinase (JAK) inhibitor, taken twice-daily, is well-characterised, and the issues raised by the agency "are familiar to rheumatologists who are experienced working with treatments for patients to manage this difficult disease".

Dr Greenstreet said the re-examination process "will enable us to seek to address the CHMP’s questions, and we will continue to work closely with the EMA with the goal of making this medicine available to appropriate patients in Europe".

FDA approval made Xeljanz the first new oral non-biologic disease-modifying antirheumatic drug (DMARD) to be available in over a decade. Many analysts believe it could be a game-changer given that biologics that have come on the market over the past ten years for RA - AbbVie's Humira (adalimumab), Amgen's Enbrel (etanercept) and Johnson & Johnson's Remicade (infliximab) - are injectables.