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Pfizer’s Xeljanz and Xeljanz XR (tofacitinib), a popular drug used to treat rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis, has been linked to an increased risk of serious heart problems, cancer, and death, especially in older patients – the largest demographic among Xeljanz users.

A large clinical trial showed a higher rate of serious heart-related events, such as heart attack and stroke, and cancers, including lung cancer and lymphomas, in people treated with Xeljanz compared to an alternative treatment. The FDA and Health Canada have confirmed the findings of the trial and are warning the public of the increased risk of these dangerous side effects.

Xeljanz is an oral medication prescribed for rheumatoid arthritis and ulcerative colitis

Xeljanz is a drug used to treat serious, chronic, and progressive inflammatory conditions, namely rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. Rheumatoid arthritis (RA) is a condition in which the body attacks its own joints, causing pain, swelling, joint damage, and loss of function. Psoriatic arthritis is a type of arthritis linked to psoriasis that causes similar symptoms. Ulcerative colitis is a chronic, inflammatory disease affecting the colon. As the incidence of RA increases with age (over 3% of Canadians aged 70-79 and over 4% of Canadians aged 80+), Xeljanz users tend to be older patients.

Xeljanz is in the class of medications known as janus kinase (JAK) inhibitors, which function by slowing the activity of enzymes that transmit information into the cell nucleus, influencing the immune response. By interfering with the enzymes, Xeljanz decreases the activity of the immune system, inhibiting the production of inflammatory mediators, and suppressing certain genes in joint tissue. This is meant to provide therapeutic benefits for patients suffering inflammation.

Xeljanz has been marketed in Canada since 2014. It is also available as an extended-release tablet (Xeljanz XR). Xeljanz was the first oral medication approved to treat rheumatoid arthritis that was a different class of drug than the standard treatment for RA, methotrexate – a drug which a high percentage of patients have a poor response to. With the Canadian population aging and Xeljanz being easy to administer, Xeljanz’s popularity has increased over time, with over 65,000 prescriptions filled in Canadian pharmacies in 2020.

A large clinical trial has linked Xeljanz to major adverse cardiovascular events and cancers

When US Food and Drug Administration (FDA) first approved tofacitinib in 2012, it required Pfizer to conduct a clinical trial to evaluate the risk of heart-related events, cancer, and other side effects.

The trial was a massive, randomized study of over 4300 patients split into three groups: ones taking a low dose of tofacitinib, ones taking a high dose, and ones taking an alternative treatment. Patients were required to be at least 50 years old and have at least one risk factor for heart disease.

The full results of the trial were finally published earlier this year, and the researchers concluded that Xeljanz poses an increased risk of major adverse cardiovascular events (MACE) and cancers. Notable findings included:

  • the rate of serious heart-related events (such as heart attack and stroke), cancer, blood clots, and death was higher in both groups of patients treated with Xeljanz;
  • a higher rate of lymphomas was specifically observed in patients treated with Xeljanz;
  • a higher rate of lung cancers was also observed in smokers treated with Xeljanz; and
  • current or past smokers also had an additional increased risk of overall cancers.

On September 1, 2021, based on its own review of trial results, the FDA announced that it had independently concluded there is an increased risk of serious heart-related events, such as heart attack or stroke, cancer, blood clots, and death with Xeljanz. On January 12, 2022, Health Canada followed suit and announced that it was also confirming a link between Xeljanz and increased risks of serious heart-related problems and cancer, especially in older patients, patients who are current or past smokers, and patients with cardiovascular or cancer risk factors.

Pfizer’s updated label warns of serious cardiovascular events and cancer

Pfizer’s post-market clinical trial had been ongoing since 2012. However, until very recently, the Canadian product monograph did not provide substantial warnings for patients and doctors of the increased risk of serious heart-related events (such as heart attack or stroke), cancer, blood clots, and death with Xeljanz.

Following their safety review of the final trial results, Health Canada required Pfizer to update the product labels to further strengthen the warnings on the elevated risks of cancer and heart issues.

In December 2021, Pfizer Canada ULC (a subsidiary of multinational pharmaceutical manufacturer Pfizer Inc.) significantly revised the Health Canada Product Monograph, which is intended to provide information about the properties, claims, indications, and conditions of use of the drug, with new warnings about links to serious heart issues and cancer, including:

  • a warning for major adverse cardiovascular events was added to the monograph;
  • new warnings concerning cancers were also added, including specifically detailed warnings addressing increased observations of lung cancers and lymphomas;
  • heart attacks and multiple types of cancers were added among the table outlining all potential serious side effects for patients; and
  • additional cautions were also added for older patients, current or past smokers, and patients with cardiovascular or cancer risk factors.

In May 2022, Pfizer introduced further warnings to the Monograph, including:

  • a warning that bone fractures of multiple types, including osteoporotic fractures, had been observed; and
  • warnings that a dosage of Xeljanz 10mg twice a day was not recommended for the treatment of rheumatoid arthritis or psoriatic arthritis.

Xeljanz and Xeljanz XR (tofacitinib) class action

Siskinds LLP and Siskinds’ Québec-based affiliate, Siskinds, Desmeules, are seeking to recover compensation for Canadians who suffer injuries resulting from their use of prescription Xeljanz. Siskinds Desmeules has filed a class action alleging that the makers of Xeljanz failed to adequately warn users of Xeljanz, and their health care providers, that Xeljanz increases the risk of major adverse cardiovascular events, including death, heart attack, coronary revascularization, stroke, hospitalization for heart failure, and cancer.

If you or someone you know has used Xeljanz and has suffered a major adverse cardiovascular event and/or cancer, Siskinds may be able to help. Contact us for more information or to receive a free consultation. Visit https://www.siskinds.com/class-action/xeljanz-and-xeljanz-xr-tofacitinib/ and complete the form at the bottom of the page or call 1-800-461-6166. Quebec residents should contact Siskinds Desmeules by phone at 418-694-2009 or by email at [email protected].

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