Xeljanz (tofacitinib) is a prescription drug first approved by the FDA in 2012 for patients suffering from rheumatoid arthritis (RA). A number of side effects have been known for some time: diarrhea, headaches, and minor sinus and upper respiratory tract infections similar to bronchitis and the common cold are among the more common ones.
Prior to human clinical trials, Xeljanz was linked to certain cancers, genetic mutations, and sterility in laboratory animals. For these reasons, it was rejected by the European Medicines Agency. In February 2019, a safety study found that taking Xeljanz increases the risk of a patient suffering from pulmonary embolism and deep vein thrombosis. The FDA now requires the prescribing information to include a black box warning about the danger of blood clots.
The recent safety study was a condition placed on the drug's manufacturer, Pfizer, when the FDA granted approval. That mandatory post-marketing study involved RA patients aged 50 and older and had at least one risk factor for cardiovascular disease. An independent safety monitoring committee found that patients who took Xeljanz at a 10-milligram dosage twice a day in combination with Trexall or Rheumatrex (which is commonly done) were more likely to suffer from a fatal pulmonary embolism than those taking it at a lower dose.
Since 2010, the FDA has received 109 reports of patients suffering from a pulmonary embolism and 63 who wound up with deep vein thrombosis. Among those cases, nineteen were fatal. Because this particular danger was not publicly known prior to the announcement in February, it is possible that many cases have gone unreported.
The question now is: was Pfizer aware of this danger, and if so, why wasn't it made known to the medical community before now?
If allegations against Pfizer are true and the drug manufacturer deliberately withheld information about blood clotting, it is not difficult to understand why. Although only 132,000 prescriptions were written for Xeljanz between 2013 and 2018, the drug carries an outrageous price tag. In the US, patients or their insurers pay nearly $4,700 for a one-month supply. Last year, Xeljanz netted a tidy $1.7 billion in sales for Pfizer.
Incredibly, Pfizer is looking to expand the market for this dangerous drug. Currently, it is being studied for the treatment of inflammatory bowel disease, psoriasis, vitiligo (loss of skin pigment), ankylosing spondylitis (spinal inflammation), and alopecia.