Tavneos Side Effects Linked to Severe Liver Injuries, FDA Warns

Postmarketing data has identified 76 cases of Tavneos-related liver injuries, including 54 hospitalizations and eight deaths.

Federal regulators warn that side effects of the drug Tavneos (avacopan) may increase the risk of serious and potentially life-threatening liver injuries, following new reports identifying cases of severe harm among patients using the medication for treatment of a rare autoimmune disease.

The U.S. Food and Drug Administration issued a drug safety communication on March 31, indicating it has identified cases of severe liver damage, including liver failure and death, in patients taking Tavneos. 

While the agency has not established a specific mechanism explaining how the Tavneos side effects may cause liver injury, it says clinical trial data and post-marketing reports suggest a potential pattern of drug-induced liver damage.

Tavneos, developed by Amgen, is prescribed for adults with severe active anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, a rare autoimmune disease that causes inflammation in small blood vessels and can lead to organ damage, particularly affecting the kidneys and lungs. 

The drug works by blocking the complement 5a receptor, a key driver of inflammation in the disease, and was introduced as a targeted alternative to long-term steroid use. The condition affects an estimated 200 to 400 people per million worldwide, and more than 7,000 patients have used Tavneos since its approval in 2021.

According to the FDA, reported Tavneos liver injury cases involved elevated liver enzymes, jaundice and other signs of acute liver damage, with some patients requiring hospitalization and others experiencing fatal outcomes.

Tavneos Liver Injury Risks 

After reviewing postmarketing safety data, medical literature and adverse event reports through October 9, 2024, federal regulators identified a series of serious liver injuries among patients treated with Tavneos.

According to the FDA’s analysis, a total of 76 cases of drug-induced liver injury (DILI) were identified with a reasonable causal association to Tavneos use. The majority of these cases involved severe outcomes:

• 74 cases involved serious complications
• 54 patients required hospitalization
• 8 deaths were reported

Among the reports that included sufficient clinical data, regulators found that liver injury most commonly followed a cholestatic or mixed pattern, meaning the liver was either struggling to properly move bile, a digestive fluid, or experiencing a combination of bile flow problems and direct liver cell damage. This can cause toxic substances to build up in the body instead of being filtered out.

These cases were often marked by significant elevations in liver enzymes and bilirubin, which are key indicators of liver function. Elevated liver enzymes suggest that liver cells are inflamed or damaged and leaking into the bloodstream, while high bilirubin levels can lead to jaundice, a yellowing of the skin and eyes, and signal that the liver is no longer processing waste effectively.

Timing data also showed that symptoms frequently developed early in treatment:

• Median time to onset was 46 days
• Reported onset ranged from 22 to 140 days after starting the drug

The FDA also identified a subset of particularly severe cases involving vanishing bile duct syndrome (VBDS), a rare but serious condition marked by progressive destruction of the liver’s bile ducts. Among these cases:

• 7 patients had biopsy-confirmed VBDS
• All 7 required hospitalization
• 3 cases resulted in death

These findings raise concerns about early-onset liver toxicity, particularly given that many cases developed within the first few months of treatment.

The FDA warns that patients taking Tavneos should be closely monitored for signs of liver injury, particularly during the early stages of treatment. Symptoms may include fatigue, nausea, abdominal pain, dark urine and yellowing of the skin or eyes, which could indicate worsening liver function.

Health officials are advising clinicians to conduct liver function tests before starting treatment with Tavneos and periodically during therapy. Doctors should also consider discontinuing the medication if signs of liver injury develop. The agency recommends avoiding use in patients with severe liver impairment. Regulators are continuing to evaluate whether additional warnings or label changes are necessary.

Patients currently taking Tavneos are urged to consult their healthcare providers before making any changes to treatment and seek immediate medical attention if symptoms of liver injury occur. Adverse events should be reported to the FDA through the MedWatch Safety Information and Adverse Event Reporting Program, either online, by regular mail or by fax at 1-800-FDA-0178.

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