Was There a Lawsuit Against Xeljanz?

Yes, Xeljanz lawsuits were pursued by former users nationwide against Pfizer for failing to warn about the potential side effects of Xeljanz and Xeljanz XR.

Xeljanz (tofacitinib) was introduced in 2012, and was sold as a safe and effective treatment for rheumatoid arthritis, psoriatic arthritis and ulcerative colitis. However, data from post-marketing studies found that users may faced an increased risk of serious and potentially life-threatening injuries that lawsuits alleged were not disclosed to users and the medical community.

Xeljanz class action lawsuits and individual injury claims were previously pursued for three separate categories of legal cases:

  • Xeljanz Cancer Lawsuits: Preliminary data from a study released in February 2021 found an increased incidence of cancer from Xeljanz. As a result of the failure to adequately disclose this information, lawsuits were investigated for various forms of cancer linked to Xeljanz, including: Breast cancer, colon cancer, prostate cancer, pancreatic cancer, lung cancer (among prior non-smokers), non-Hodgkin’s lymphoma and others.
  • Xeljanz Heart Injury Lawsuits: Federal health officials have warned about a potential link between Xeljanz and heart issues, including heart attack, strokes, cardiac arrest and other cardiovascular problems. Potential lawsuits were investigated for any heart problems on Xeljanz, or within 30 days of last use.
  • Xeljanz Blood Clot Lawsuits: Following the addition of a “black box” Xeljanz FDA label warning in July 2019, potential Xeljanz pulmonary embolism lawsuits and deep vein thrombosis lawsuits were pursued for individuals who suffered these blood clotting problems after receiving a Xeljanz 10mg, twice-daily doses.

What are the side effects of taking Xeljanz?

There have been numerous reported side effects of Xelajnz, the most serious being increased risk of heart problems (stroke, cardiac arrest, etc.), cancer (lung, breast, colon, etc.), and blood clots (embolisms, thrombosis, etc.).

Pfizer has aggressively marketed Xeljanz and Xeljanz XR as a safer and more convenient alternative to other treatments, allowing users to take an oral pill instead of receiving an injection. However, mounting evidence suggests that Xeljanz side effects expose users to some of the same serious health risks, and actually increase the risk of other problems not seen following use of these other Xeljanz alternatives.

When Xeljanz FDA approval was granted in 2012, Pfizer was required to conduct post-marketing studies to examine the potential side effects of Xeljanz and Xeljanz XR at different doses. This clinical trial was intended to evaluate the risk of heart problems from Xeljanz, cancers and opportunistic infections.

According to the National Institutes of Health (NIH) summary of this Xeljanz study, the objective was to compare the 5mg and 10mg twice daily doses of Xeljanz to the use of older TNF inhibitor medications among 4,362 individuals with rheumatoid arthritis who were 50 years or older, with at least one cardiovascular risk. In the U.S. and Canada, this involved comparing Xeljanz and Humira. In other countries researchers compared Xeljanz and Enbrel.

In January 2019, while the study was still on-going, early data revealed a potential risk of Xeljanz blood clot side effects among users receiving the 10mg twice-daily dose. As a result of these findings, a new “black box” Xeljanz FDA label warning was added in July 2019.

The clinical trial “wrapped” in July 2020, and preliminary results were released in early 2021, identifying a potential link between Xeljanz and cancer risks, as well as serious Xeljanz heart problems that were not previously disclosed by the drug makers.

Can Xeljanz Cause Heart Problems?

Side effects of Xeljanz may also be linked to an increased risk of major cardiovascular problems compared to users of older TNF inhibitor medications. This could include a number of different types of heart problems caused by Xeljanz, including:

  • Heart Attack or Myocardial Infarction
  • Stroke
  • Cardiac Arrest
  • Congestive Heart Failure
  • Coronary Heart Failure
  • Coronary revascularization
  • Cardiovascular Death

Prior to FDA approval in 2012, heart risks from Xeljanz were a serious concern among drug experts. This was part of the reason the FDA required Pfizer to conduct a post-marketing, known as A3921133, which was designed to assess the risk of cardiovascular events.

According to preliminary data released in early 2021, out of 4,362 participants who received either Xeljanz or an alternative treatment known as TNF inhibitor, there were 135 major adverse cardiovascular events (MACE):

  • Xeljanz heart side effects were linked to 98 of the reported cardiovascular problems, compared to 37 among users of TNF inhibitors
  • The most frequently reported heart problems were myocardial infarctions or heart attacks from Xeljanz;
  • Data suggests there was more than 30% increased incidence of Xeljanz causing heart problems.

While the complete data from this Xeljanz heart study have not been made available, findings reported by the drug maker suggest that users of Xeljanz 5 mg dose faced a 24% increased risk, and those receiving the higher 10mg Xeljanz dose faced a 42% risk. This higher dose response is strong evidence of a causal connection between Xeljanz and heart attacks, stroke, cardiac arrest, heart failure and other problems.

Lawsuits alleged that if earlier warnings and information about the Xeljanz heart side effects had been provided by the drug maker, many users may have avoided serious and often life-threatening injuries. If you or a loved one suffered a heart attack or other cardiac injury, find out if financial compensation may be available.

What types of Cancer Does Xeljanz Cause?

Initial information about the link between Xeljanz and cancer was released by the FDA in a drug safety communication (PDF) on February 4, 2021. Reports suggested that some of the most common Xeljanz cancers may include:

  • Lung Cancer
  • Breast Cancer
  • Colon Cancer
  • Prostate Cancer
  • Pancreatic Cancer
  • Non-Hodgkin’s Lymphoma

In this recently completed post-marketing study, researchers identified 164 cancers, excluding non-melanoma skin cancer, among 4,362 participants:

  • Xeljanz cancer cases accounted for 122 events (4.19%) among users of either dose, compared to 42 cases among users of TNF inhibitors (2.89%);
  • Data suggests a more than 42% increased incidence of cancer following Xeljanz or Xeljanz XR use;

In a press release announcing the findings, the only specific malignancy identified was lung cancer from Xeljanz, which was the most frequently reported and occurred at rates higher than would be expected. Among individuals without a history of heavy smoking, there appears to be strong evidence that Xeljanz may cause lung cancer.

Unfortunately, Pfizer has only provided limited information about the findings of this study, and has not disclosed information about the length of use among those diagnosed with cancer. Concerns have been raised that with longer follow up than was provided through this study, additional cancer cases may be diagnosed.

While prior warnings were provided about the risk of lymphoma, it appears that the drug makers knew or should have known that users face a much greater cancer risk from side effects than was disclosed on the FDA label.

Can Xeljanz Cause Blood Clots?

In July 2019, the FDA required a Xeljanz “black box” warning about the serious blood clot risk with Xeljanz when taken at higher doses, which was not initially included on the Xeljanz warning label. As a result of the failure to provide these important warnings earlier, many users of Xeljanz have been left with serious or fatal injuries.

Types of blood clots that have been linked to Xeljanz side effects may include:

  • Pulmonary Embolism (PE)
  • Pulmonary Thrombosis
  • Deep Vein Thrombosis (DVT)
  • Arterial Thrombosis
  • Cerebrovascular Accident
  • Transient Ischemic Attack
  • Ischemic Stroke

Pulmonary embolism from Xeljanz involves blood clots in the lungs, which constitute a medical emergency and may cause symptoms like:

  • Irregular heartbeat or heart arrhythmias
  • Chest pain
  • Trouble breathing
  • Feeling light headed, dizzy or faint
  • Sweating or fever
  • Coughing up blood

If symptoms are not promptly recognized and treatment is not received, individuals with a pulmonary embolism from Xeljanz may die from this very serious side effect. An estimated 50,000 deaths each year in the United States are caused by a pulmonary embolism.

Deep vein thrombosis (DVT) from Xeljanz involves blood clots in the leg, thigh or pelvis, which may cause symptoms like:

  • Swelling in one leg
  • Throbbing or cramping in the leg, usually in the calf or thigh
  • Warm skin around the painful area
  • Red or darkened skin around the painful area
  • Swollen veins that are hard or sore

Users are now advised to seek immediate medical attention if they experience signs of a blood clot on Xeljanz, and doctors are encouraged to closely monitor patients prescribed the medication. However, it appears that Pfizer knew or should have known about the link between Xeljanz and blood clots much earlier.

Lawsuits alleged that many individuals may have avoided a pulmonary embolism, deep vein thrombosis or other blood clot injury if Xeljanz warnings had been provided when the medication was first introduced.

What Allegations Were Raised in Xeljanz Class Action Lawsuits?

Pfizer had a duty to fully research their new-generation drug, and warn about potential Xeljanz risks, so that consumers and doctors could make an informed decision about whether to use the medication. According to allegations raised in Xeljanz and Xeljanz XR class action lawsuits and individual injury claims, the Pfizer Pharmaceuticals has:

  • Failed to properly research the Xeljanz side effects before introducing the drug;
  • Failed to promptly follow through on studies to investigate the potential Xeljanz cardiovascular risks;
  • Failed to warn about the risk of cancer from Xeljanz;
  • Failed to disclose reports of pulmonary embolism, deep vein thrombosis, stroke and other blood clots on Xeljanz;
  • Failed to issue a Xeljanz recall or safety warnings about the risks users face at certain doses;


Other Xeljanz Lawsuit Frequently Asked Questions


What is Xeljanz?

Xeljanz and Xeljanz XR are part of a new class of rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis drugs, known as Janus kinase (JAK) inhibitors, which work in a unique way deep inside the cell to disrupt cellular activities.

The drug was first introduced in 2012, as a second-line treatment for adults with severe rheumatoid arthritis. Approval was expanded to include treatment of active psoriatic arthritis (PsA) in 2017 and for treatment of ulcerative colitis in 2018.

Xeljanz is an oral medication, which provides convenience over other injectable drugs used to relieve pain and swelling the joints for treatment of rheumatoid arthritis and psoriatic arthritis, and lowering inflammation to treat ulcerative colitis symptoms.

Amid aggressive marketing by Pfizer, Xeljanz has quickly grown to become a “blockbuster” treatment, generating over $1 billion in annual sales. However, lawsuits alleged that the drug maker knew or should have known about the link between Xeljanz and side effects like cancer, heart attacks, strokes, blood clots and other injuries, yet failed to provide adequate warnings for users and the medical community.

Is Xeljanz safe?

Xeljanz works by decreasing activity of the immune system. An overactive immune system contributes to rheumatoid arthritis, psoriatic arthritis and ulcerative colitis.

Side effects of Xeljanz block the immune system’s production of cytokine, which is a protein involved in the body’s inflammatory response. Individuals with rheumatoid arthritis make more cytokines, which leads to inflammation and pain. Disrupting the cell signals in the janus kinase pathways, Xeljanz reduces the production of new cytokines, reducing swelling and offering relief.

Although the FDA first approved the medication in 2012, there were serious concerns about the safety of Xeljanz at that time. As a result, regulators required Pfizer to conduct post-marketing studies, to evaluate the cardiovascular risks, cancer risks and infection risks associated with the medication.

Preliminary data from these recently completed clinical trials uncovered several Xeljanz safety issues that were not initially included on the drug label, including an increased risk of blood clots, heart attacks, strokes, heart failure and cancer.

If you are concerned about the safety of Xeljanz, speak with your medical provider. Never stop taking Xeljanz or any medication without first consulting with your doctor.

Has a Xeljanz Recall been issued?

There has not been a Xeljanz recall, and the medication remains on the market in the United States.

In July 2019, the FDA required Pfizer to add information to a “black box” Xeljanz warning about the risk of pulmonary embolism, blood clots and death, which is the strongest label warning that can be required for a prescription medication. However, since the agency suggested that risk was limited to users receiving the higher 10mg, twice-daily dose, there was no indication that Xeljanz would be removed from the market.

Experts have indicated that regardless of whether there is a recall for Xeljanz, data makes it clear that biologics should be the first-line treatment and JAK inhibitors like Xeljanz should be avoided unless there are no safer alternatives.

After the FDA completes the drug safety evaluation into the potential cancer and heart problems with Xeljanz, it appears that improved warnings and recommendations to medical providers may minimize the risk. However, if experts conclude that any potential benefits are outweighed by the side effects, it remains possible that the FDA will remove Xeljanz from the market.

Who is the Xeljanz Lawsuit against?

Xeljanz claims were pursued against Pfizer Pharmaceuticals, who was responsible for the development and sale of the drug. Pfizer had a duty to properly research the potential side effects of Xeljanz and provide warnings to users and the medical community about the health risks.

Lawsuits were not pursued against individual doctors who prescribed Xeljanz, as medical providers were also provided with false and misleading information.

If earlier warnings had been provided about the risk of cancer, heart attacks, strokes, cardiac arrest, heart disease and blood clots, doctors could have monitored patients and users could have made an informed decision about whether to use the medication.

History of Xeljanz Side Effect Studies

Pfizer Logo for Xeljanz Lawsuit


FDA approves Xeljanz for treatment of adults with rheumatoid arthritis.


Xeljanz sales rapidly grow to generate a new “blockbuster” drug for Pfizer, reaching $927 million in sales by 2016.

Dec 2017

Expanded approval for treatment of active psoriatic arthritis (PsA).

May 2018

Expanded approval for treatment of moderate to severe active ulcerative colitis.

Feb 19, 2019

Pfizer announces preliminary results of Study A3921133, which was required by FDA to evaluate heart risks.

Feb 25, 2019

FDA Safety Communication warns about risk of blood clots in the lungs when 10mg twice daily dose of Xeljanz used with rheumatoid arthritis.

March 2, 2019

European Medicines Agency (EMA) warns that overall incidence of pulmonary embolism with Xeljanz was 5-fold higher with 10mg twice daily dose, compared to other rheumatoid arthritis drugs.

July 26, 2019

The FDA required a new “Boxed Warning” for Xeljanz, which is the strongest label information a drug maker can be required to add.