Xeljanz Side Effects May Increase Risk of Cancer, Serious Heart Problems: FDA Alert

Following a mandatory post-marketing safety study designed to examine the side effects of Xeljanz, federal regulatory officials indicate users of Pfizer’s ulcerative colitis drug with underlying heart conditions may be more likely to develop cancer and severe cardiovascular problems.

The U.S. Food and Drug Administration (FDA) issued a Xeljanz safety communication warning on February 4, alerting healthcare professionals and patients to the preliminary results from the new clinical trial, which suggests the arthritis and ulcerative colitis medicine may cause an increased risk of serious heart-related health risks and cancer.

Xeljanz (tofacitinib) was the first Janus kinase inhibitor (jakinib) approved by the FDA in 2012, for treatment of adults with rheumatoid arthritis, which is an autoimmune disorder that causes inflammation of the joints in approximately 1% of the population. In 2018, the drug gained approval from the FDA to treat a serious inflammatory condition called ulcerative colitis.

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Side effects of Xeljanz linked to risk of cancer, heart attacks, pulmonary embolism, deep vein thrombosis, blood clots and death.


This new FDA warning was issued after initial results from a postmarketing clinical trial, which raises serious concerns about the link between Xeljanz and cancer, heart problems and other health risks.

The study was required by federal regulators to examine the Xeljanz risk of pulmonary embolism and death, and interim results announced in 2019 indicated that users taking higher 10 mg twice daily doses were more likely to develop the serious blood clots in the lungs, leading the agency to require a new “black box” warning, which is the strongest label indication that can be placed on a prescription medication.

“The clinical trial is now complete and initial results show a higher occurrence of serious heart-related events and cancer in rheumatoid arthritis (RA) patients treated with both doses of tofacitinib compared to patients treated with a TNF inhibitor,” the FDA warning states. “FDA is awaiting additional results from the trial.”

Additional concerns raised in that initial clinical trial suggested that patients taking Xeljanz were at an increased risk for developing serious infections including tuberculosis, invasive fungal infections and bacterial and viral infections that resulted in hospitalizations and deaths. Pfizer previously announced that if a patients develops an infection while using Xeljanz, treatment should be interrupted until the infection is controlled.

As Xeljanz blood clot injuries emerged, the FDA required Pfizer to conduct post-marketing safety clinical trials to reassess dosing levels and compare the rate of blood clot, cardiovascular disease, cancer development and overall mortality rates to patients taking alternative tumor necrosis factor (TNF) inhibitors.

Since Xeljanz was first introduced into the market in 2012 by Pfizer Pharmaceutical Company, roughly 1% of the population is anticipated to have used or currently be using the medication. The company’s multi-purpose drug has been steadily increasing in sales each year, reaching blockbuster status with sales in excess of $1 billion per year.

New Recommendations For Doctors and Patients

The FDA’s warning outlines the preliminary data of the post -marketing ORAL Surveillance safety study, finding Xeljanz to be associated with a higher rate of major heart attacks and cancer in patients over 50 with underlying cardiovascular risk factors.

The FDA indicates it will continue to work closely with Pfizer to evaluate the clinical trial results to obtain additional information before communicating a final conclusion and recommendation.

Physicians are now being instructed to consider the benefits and risks of Xeljanz when deciding whether to prescribe or continue patients on the medicine, especially those with underlying heart conditions.

Recommendations to patients warns they should not change their recommended dose or stop taking Xeljanz before consulting with their healthcare professional, as doing so could worsen their condition. Patients taking Xeljanz who begin to experience sudden shortness of breath, chest pain, difficulty breathing, coughing up blood, excessive sweating or clammy or bluish colored skin should seek immediate medical help.

The FDA is encouraging health providers and patients to report adverse events related to Xeljanz and Xeljanz XR to the administration’s MedWatch Safety Information and Adverse Event Reporting Program.

Even before the latest cardiovascular and cancer concerns, Pfizer faced a number of Xeljanz lawsuits filed by users of the medication who have suffered a pulmonary embolism, deep vein thrombosis (DVT), stroke or other blood clot injuries, including wrongful deaths.


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