The Link Between Xeljanz and Liver Damage

Xeljanz can cause liver damage by altering its enzyme levels. Clinical trials by Pfizer, the manufacturer of Xeljanz, revealed these risks and subsequent medical studies have confirmed them. However, Xeljanz's warning label continues to downplay the risks. Numerous Xeljanz lawsuits have been filed over this failure to adequately warn people of the risks of taking Xeljanz, demanding compensation for the victims who have suffered.

The defective drug lawyers at the Shouse Law Office can legally represent victims who have suffered liver damage after taking Xeljanz for their rheumatoid arthritis. With their help, you can file a Xeljanz lawsuit before the statute of limitations has expired. In this article, they discuss:

xeljanz pills

1. What is Xeljanz?

Xeljanz, the brand name for the drug tofacitinib, is a rheumatoid arthritis and ulcerative colitis treatment. It was designed and manufactured by Pfizer, and was approved for use by the U.S. Food and Drug Administration (FDA) in November, 2012.1 It was later approved by the FDA to treat ulcerative colitis in May, 2018.2

Xeljanz works by slowing down Janus kinase enzymes. These enzymes are essential to the process that cells use to replicate, grow, and spread inside the body. However, Janus kinase enzymes can lead to problems if they work too well and cells grow too quickly. In many cases, Janus kinase enzymes can cause tissue to accumulate in the joints. The extra tissue damages the bone and cartilage, effectively hardening over the joint. The body's immune system then attacks the extra tissue in the joint, causing inflammation that worsens the condition of the joint, leading to rheumatoid arthritis.

Janus kinase enzymes are also thought to be behind the medical condition ulcerative colitis, as well, allowing cells to infiltrate the colon and cause a reaction from the immune system.

Since its development and releases in 2012, Xeljanz has become a popular treatment for rheumatoid arthritis because it can be taken orally in pill form. Other rheumatoid arthritis treatments had to be injected.

2. Side effects of Xeljanz

While Xeljanz can treat rheumatoid arthritis and ulcerative colitis, it can also cause numerous side effects, as well:

  • Cold symptoms, including a running or congested nose and a sore throat,
  • Headaches,
  • Fatigue,
  • Neutropenia, or a low white blood cell count,
  • High blood pressure,
  • Sinus infections,
  • Respiratory infections, and
  • Diarrhea.

Additionally, Xeljanz can cause some far more severe side effects, including:

  • Liver damage,
  • Cancer, and
  • Pulmonary embolisms, or blood clots in the lungs.

Some of these conditions can be fatal or extremely debilitating, and are more frequent at high doses of Xeljanz.

human liver

3. Xeljanz and liver damage

One of the severe side effects that Xeljanz can cause is liver damage.3

Clinical trials for Xeljanz found that the participants who were taking Xeljanz were more likely to have elevated levels of a variety of serum enzymes and other chemicals, including:

  • Alanine transaminase, or ALT
  • Aspartate transaminase, or AST, and
  • Bilirubin.

These serum enzymes are used as biomarkers for liver health. Doctors see altered levels as signs that the liver is being strained, damaged, or compromised.

One post hoc analysis looked at 25 different studies that looked at people with rheumatoid or psoriatic arthritis or psoriasis and who took Xeljanz to treat it. The study then compared the liver function and enzyme levels of study participants taking Xeljanz to those in the placebo group. Across the board, people taking Xeljanz were more likely to have elevated levels of liver enzymes than those taking placebos. In some cases, those levels were above three times the upper limit of normal (ULN)4:


Group Taking Xeljanz (8,115)

Group on Placebo (1,841)

ALT Above the ULN



ALT Three Times Above the ULN



AST Above the ULN



AST Three Times Above the ULN



Total Bilirubin Above the ULN



One of the Phase II clinical studies conducted by Pfizer also found elevated levels of liver enzymes in people taking Xeljanz. This clinical study covered 140 participants and was largely in line with the results of the post hoc analysis. The clinical study found that 19% of Xeljanz patients had elevated ALT readings, compared to only 4% of placebo takers. Of those taking Xeljanz, 3% had ALT levels more than three times the upper limit of normal.5

Another clinical study connected the dosage level of Xeljanz as a possible contributor to elevated enzyme readings and liver damage. In that study, participants took Xeljanz in a variety of doses:

  • 3 milligrams, twice per day,
  • 5 milligrams, twice per day,
  • 10 milligrams, twice per day,
  • 15 milligrams, twice per day, and
  • 20 milligrams, once per day.

Patients taking higher doses were progressively more likely to have ALT levels three times higher than the upper limit of normal.6

Medical researchers are still unsure why Xeljanz can cause liver damage. While they do know that Xeljanz gets metabolized in the liver, there is still uncertainty about the chemical process that happens, there.

4. Symptoms of liver damage

The signs of a damaged liver can be difficult to detect. Some of the symptoms to look for include:

  • Itchiness,
  • Swelling in the legs or ankles,
  • Abdominal swelling or pain,
  • Jaundice, or yellow-colored eyes or skin,
  • Dark urine,
  • Lost appetite,
  • Fatigue, or the constant feeling of tiredness,
  • Nausea,
  • Vomiting, and
  • A sudden tendency to bruise easily.

5. Medical complications of liver damage

If untreated, liver damage can get progressively worse until it leads to chronic liver failure, or cirrhosis.

Chronic liver failure can be a fatal condition. It can also cause a wide variety of other severe medical problems, each of which can be debilitating or fatal on its own:

  • Infection, caused by the breakdown of the immune system from liver failure,
  • Spontaneous bacterial peritonitis,
  • Hepatorenal syndrome, or low urine sodium, and
  • Ascites.

6. Xeljanz lawsuits over liver damage

xeljanz lawsuit attorneys
Call us for help at (855) LAW-FIRM

Numerous Xeljanz lawsuits have been filed against Pfizer over the risks of liver damage.

These lawsuits claim that the warning label on Xeljanz is not strong enough to express the potential for liver damage from taking Xeljanz. While clinical trials for the drug and subsequent studies have all found indications that Xeljanz can cause liver damage, the warning label on Xeljanz merely recommends that doctors monitor a patient's liver enzyme levels. There is no mention of liver damage on the warning label.7

When pharmaceutical companies release a drug, they are legally required to make reasonable disclosures about its side effects. The law requires these disclosures because doctors rely on them to make effective prescriptions, and because patients use them to make informed healthcare decisions. However, drug companies know that fully disclosing all of the risks associated with their products could deter patients, and this could cut into their profits.

The Xeljanz lawsuits claim that Pfizer did not make the necessary disclosures because they failed to mention the possibility of suffering liver damage. The lawsuits seek compensatory damages for injuries and other losses associated with Xeljanz, including:

  • Medical expenses,
  • Lost wages,
  • Reduced earning capacity,
  • Pain and suffering, and
  • Loss of consortium.

Many Xeljanz lawsuits are also demanding punitive damages be assessed against Pfizer to punish them for their decision to not disclose the risks of liver damage.

A likely development in these Xeljanz lawsuits is that they get consolidated into a multidistrict litigation, or MDL, to streamline their process through the court system. Mass tort claims like these Xeljanz lawsuits all have hundreds or even thousands of people who suffered similar injuries because of one party's course of conduct – in this case, Pfizer's inadequate warning about Xeljanz's potential to cause liver damage. Because each case would rely on the same pieces of evidence, courts use MDLs to consolidate lawsuits so they can share evidence and speed up the process. However, an MDL for Xeljanz lawsuits has not yet been created.

Legal References:

  1. FDA Approval Letter for Xeljanz (November 6, 2012).

  2. FDA Approval Letter for Xeljanz to Treat Ulcerative Colitis (May 30, 2018).

  3. See generally, Berhan A, “Efficacy, safety and tolerability of tofacitinib in patients with an inadequate response to disease modifying anti-rheumatic drugs: a meta-analysis of randomized double-blind controlled studies,” BMC Musculoskeletal Disorders 14:332 (November 26, 2013).

  4. Soriano ER, Madariaga H, Castañeda O, Citera G, Schneeberger EE, Cardiel MH, Hendrikx T, Graham D, Shi H, Ponce de Leon D, “FRI0099 Liver enzyme abnormalities after tofacitinib treatment in patients with hepatic steatosis from the rheumatoid arthritis, psoriatic arthritis and psoriasis clinical programmes,” Annals of the Rheumatic Diseases 77(2):593-4 (June 15, 2018).

  5. Identifier No. NCT00603512, “Comparison Of 4 CP-690,550 Doses Vs. Placebo, Each Combined With Methotrexate, For The Treatment Of Rheumatoid Arthritis in Japan,” published at Tanaka Y, Suzuki M, Nakamura H, Toyoizumi S, Zwillich SH, “Phase II study of tofacitinib (CP-690,550) combined with methotrexate in patients with rheumatoid arthritis and an inadequate response to methotrexate,” Arthritis Care and Research 63(8):1150-8 (August 2011).

  6. Kremer JM, Cohen S, Wilkinson BE, Connell CA, French JL, Gomez-Reino J, Gruben D, et al., “A phase IIb dose-ranging study of the oral JAK inhibitor tofacitinib (CP-690,550) versus placebo in combination with background methotrexate in patients with active rheumatoid arthritis and an inadequate response to methotrexate alone,” Arthritis and Rheumatism 64(4):970-81 (April 2012).

  7. Xeljanz Warning Label (May 2018).

Free attorney consultations...

The attorneys at Shouse Law Group bring more than 100 years collective experience fighting for individuals. We're ready to fight for you. Call us 24 hours a day, 365 days a year at 855-LAW-FIRM for a free case evaluation.

Regain peace of mind...

Shouse Law Defense Group has multiple locations throughout California. Click Office Locations to find out which office is right for you.

Office Locations

Shouse Law Group has multiple locations all across California, Nevada, and Colorado. Click Office Locations to find out which office is right for you.

Call us 24/7 (855) 396-0370