Tavneos Lawsuit [2026 Investigation]

What Is Tavneos (Avacopan)?

Tavneos is the brand name for avacopan, an oral prescription medication approved for adults with severe active anti-neutrophil cytoplasmic autoantibody (ANCA) associated vasculitis, including granulomatosis with polyangiitis and microscopic polyangiitis.

The medication is used with other therapies, including glucocorticoids, and is not approved as a replacement for steroid treatment.

Tavneos works by blocking the C5a receptor, a part of the complement immune pathway involved in neutrophil activation and blood-vessel inflammation.

The recommended dose is 30 mg twice daily with food, taken as three 10 mg capsules per dose.

Tavneos came to market after premarket clinical trials evaluating whether avacopan could help control active vasculitis while reducing reliance on glucocorticoid-based treatment.

Regulatory and safety developments related to Tavneos include:

• 2021: The FDA approved Tavneos for adults with severe active ANCA-associated vasculitis.
• 2022: Amgen acquired ChemoCentryx, the company that developed Tavneos.
• 2024: The Tavneos label continued to list hepatotoxicity as a warning and included liver-test monitoring recommendations.
• March 31, 2026: FDA identifies cases of serious liver injury in patients taking Tavneos, including 76 drug-induced liver injury cases and fatal outcomes.
• April 27, 2026: FDA’s Center for Drug Evaluation and Research proposed to withdraw approval of Tavneos, citing effectiveness concerns, alleged material misstatements in the application, and new safety concerns.

Health care professionals have been advised to monitor liver panels closely in patients taking Tavneos, especially during the first several months of treatment.

FDA’s recent communications place Tavneos under renewed scrutiny because the reported liver injuries include severe outcomes such as hospitalization, vanishing bile duct syndrome, and death.

Tavneos remains central to an active safety and legal review because the drug’s approved use, clinical-trial history, and postmarketing liver-injury reports now overlap in a developing regulatory record.

FDA Warning on Tavneos Liver Injury Risk

In March 2026, the FDA issued a safety communication after identifying serious liver injuries in patients taking Tavneos.

The agency reported 76 cases of drug induced liver injury with reasonable evidence of a causal association with avacopan use.

Most of those reports involved serious outcomes, including 54 hospitalizations and 8 deaths.

FDA records also identified cases of vanishing bile duct syndrome, a rare bile-duct injury that can impair bile flow and lead to permanent liver damage.

The agency stated that VBDS and DILI cases with fatal outcomes represent new safety concerns, even though hepatotoxicity had already appeared in premarket clinical trials and Tavneos prescribing information.

The FDA findings point to a specific liver-injury pattern.

In 60 cases with enough laboratory data to classify the initial injury, 38 involved cholestatic or mixed-pattern liver injury.

Those cases were often marked by substantial elevations in alkaline phosphatase and total bilirubin, blood tests that can reflect impaired bile flow and liver dysfunction.

The median time to onset was 46 days after Tavneos started, with cases reported between 22 and 140 days.

Patients were advised to seek medical attention for unusual fatigue, nausea, vomiting, itching, pale stools, jaundice, dark urine, abdominal swelling, or right upper abdominal pain.

The FDA warning included several findings that are central to the Tavneos lawsuit investigation:

• Drug induced liver injury: FDA identified 76 DILI cases with evidence linking the injuries to Tavneos use.
• Serious outcomes: 74 cases involved serious medical outcomes, including hospitalization or death.
• Fatal reports: FDA identified 8 deaths among the DILI cases.
• VBDS cases: Seven cases involved biopsy-confirmed vanishing bile duct syndrome.
• Fatal VBDS cases: Three patients with VBDS died.
• Timing: The median onset of liver injury was 46 days after starting Tavneos.
• Injury pattern: Most classifiable cases involved cholestatic or mixed-pattern liver injury.
• Patient symptoms: Warning signs included jaundice, itching, pale stools, dark urine, abdominal swelling, and right upper abdominal pain.
• Monitoring: FDA advised health care professionals to order frequent liver panel blood tests during the first six months of treatment.

The safety communication also gave health care professionals stronger monitoring and discontinuation guidance.

FDA advised liver panel testing every two weeks during the first month, monthly for the next five months, and as clinically indicated after that.

The agency also advised prompt discontinuation and evaluation if liver markers rise or if a patient develops signs of cholestasis, including jaundice or pruritus.

This guidance makes the warning more than a passive label update; it identifies a postmarketing safety signal with severe outcomes, a defined onset window, and specific laboratory patterns tied to serious liver problems.

Types of Liver Injuries Potentially Linked to Tavneos

Liver injuries reported in patients taking Tavneos involve disruption of normal liver function, bile production, and bile flow.

These injuries can progress beyond abnormal blood tests into conditions that affect how the liver processes toxins, produces bile, and supports overall metabolic function.

In more severe cases, patients may require hospitalization, discontinuation of the drug, supportive care, or evaluation by a hepatology specialist.

Some forms of liver injury can become chronic or irreversible, particularly when bile ducts are damaged or lost.

Tavneos prescribing information also identifies serious infections and serious hypersensitivity reactions as additional safety risks, but the injuries below focus on the liver conditions associated with drug induced toxicity.

Specific liver injuries and related conditions include:

• Drug induced liver injury (DILI): DILI occurs when a medication damages liver cells or interferes with liver function. Clinical evaluation often involves blood tests measuring liver enzymes such as ALT, AST, alkaline phosphatase, and bilirubin. DILI can present in different patterns, including hepatocellular, cholestatic, or mixed injury, and may range from mild enzyme elevations to liver failure.
• Cholestatic liver injury: Cholestasis occurs when bile flow from the liver is reduced or blocked. Medical sources such as the Mayo Clinic describe cholestatic injury as a condition where bile cannot move normally through the liver and biliary system, leading to symptoms such as jaundice, itching, dark urine, and pale stools. This type of injury is often associated with elevated alkaline phosphatase and bilirubin on blood tests.
• Mixed-pattern liver injury: Mixed liver injury includes features of both hepatocellular and cholestatic damage. This means that patients may have elevated liver enzymes alongside signs of impaired bile flow. Mixed injury can complicate diagnosis because it does not follow a single pattern and may evolve over time based on the patient’s response to the drug.
• Vanishing bile duct syndrome (VBDS): VBDS is a rare but severe condition involving the progressive destruction and loss of small bile ducts within the liver. As bile ducts disappear, bile cannot be transported properly, leading to ongoing cholestasis and liver damage. Medical literature describes VBDS as a condition that can result in long-term liver dysfunction, cirrhosis, or the need for liver transplantation in severe cases.
• Hepatocellular liver injury: Hepatocellular injury primarily affects liver cells rather than bile flow. It is typically identified through elevated ALT and AST levels on blood tests. This type of injury may occur earlier in the disease process before progressing to more complex patterns involving bile-duct damage.
• Acute liver failure and advanced liver disease: Severe cases of drug induced liver injury can progress to acute liver failure, a condition in which the liver rapidly loses its ability to function. This may require intensive medical care, transplant evaluation, or result in fatal outcomes. Patients with underlying liver disease may face a higher risk of severe complications.

These injury patterns are identified through a combination of blood tests, imaging, and, in some cases, liver biopsy.

The way the injury presents, including timing, symptom progression, and laboratory findings, can help distinguish drug induced liver injury from other causes of liver disease.

In cases where Tavneos is suspected, clinicians evaluate medication history, rule out other conditions, and monitor whether liver function improves after the drug is stopped.

How Tavneos May Affect the Liver

The exact mechanism behind Tavneos-related liver injury has not been fully established, but available scientific sources describe it as likely idiosyncratic and immune mediated rather than a predictable dose-dependent toxicity.

Avacopan is metabolized in the liver primarily through CYP3A4, and its main route of clearance is metabolism followed by biliary excretion of metabolites into feces.

That pathway places the drug and its metabolites in direct contact with the hepatobiliary system, including the bile-transport structures implicated in cholestatic injury.

In drug induced liver injury, idiosyncratic reactions may involve immune activation, direct cellular stress, impaired bile-acid transport, mitochondrial injury, or genetic susceptibility, depending on the drug and patient.

Drug-induced vanishing bile duct syndrome is thought to involve progressive injury to cholangiocytes, the cells lining bile ducts, through immune-mediated damage, direct toxicity from drugs or metabolites in bile, or sustained exposure to toxic bile salts.

When small intrahepatic bile ducts are damaged or lost, bile can accumulate inside the liver, leading to cholestasis, jaundice, itching, elevated alkaline phosphatase, elevated bilirubin, and progressive liver dysfunction.

For Tavneos, the suspected mechanism is best described as an incompletely understood hepatobiliary injury process involving liver metabolism, biliary excretion, and possible idiosyncratic immune-mediated damage rather than a single confirmed toxic pathway.

Symptoms Patients Reported Before Diagnosis

Tavneos-related liver injury may begin with unexplained symptoms before blood tests confirm serious liver problems.

Some symptoms point directly to impaired bile flow or liver dysfunction, while others may overlap with serious infections, serious hypersensitivity reactions, hepatitis B reactivation, active infection, or the underlying vasculitis being treated.

FDA advised patients taking Tavneos to contact a health care professional promptly if symptoms of liver injury appear, especially jaundice, dark urine, pale stools, itching, abdominal swelling, or pain in the right upper abdomen.

The drug’s prescribing information also lists common and serious adverse reactions that may complicate early diagnosis, including worsening tiredness, high blood pressure, stomach pain, increased blood creatinine, urinary tract infections, and infection-like flu symptoms.

Symptoms and warning signs that may require medical evaluation include:

• Jaundice, or yellowing of the skin or eyes.
• Dark urine, which may reflect elevated bilirubin.
• Pale or light-colored stools, a possible sign of impaired bile flow.
• Itching, especially when paired with jaundice or abnormal liver blood tests.
• Abdominal swelling or fluid retention.
• Right upper abdominal pain, the liver-specific pain pattern identified by FDA.
• Stomach pain or severe abdominal pain, especially if it appears with jaundice, vomiting, or abnormal blood tests.
• Worsening tiredness, unusual fatigue, or weakness.
• Nausea or vomiting that does not resolve.
• Flu symptoms, fever, cough, body aches, or sore throat that may suggest infection.
• Trouble breathing, swelling, rash, or chest pain, which may indicate a serious hypersensitivity reaction or another urgent condition.
• Pain during urination, urinary tract infections, or urine bleeding, which may require evaluation because Tavneos patients may have kidney involvement from ANCA-associated vasculitis or treatment-related complications.
• High blood pressure or increased blood creatinine, both listed in Tavneos safety information and relevant to patients with kidney involvement.
• Signs of hepatitis B virus reactivation, including fatigue, jaundice, dark urine, abdominal pain, or unexplained worsening of liver blood tests.
• Any unexplained symptoms after starting Tavneos, especially during the first several months of treatment.
• Symptoms preceding fatal cases, including jaundice, pruritus, abdominal symptoms, and worsening liver-function markers, should be treated as urgent warning signs rather than routine side effects.

Who May Be Eligible for a Tavneos Lawsuit?

Patients may be eligible for a Tavneos lawsuit if they took Tavneos and later developed drug induced liver injury, vanishing bile duct syndrome, jaundice, liver failure, or another severe liver complication.

Families may also have a potential wrongful death claim if a loved one died after suffering serious liver problems linked to Tavneos use.

Case review will likely focus on the patient’s prescription timeline, liver-related symptoms, blood test results, hospitalization records, biopsy findings, and whether other causes of liver disease were ruled out.

Clinical data, FDA safety findings, and postmarketing reports may help determine whether Tavneos warnings adequately addressed known or emerging patient safety risks.

Stronger claims may involve documented cholestatic or mixed-pattern liver injury, elevated bilirubin or alkaline phosphatase, or a diagnosis of vanishing bile duct syndrome after starting the drug.

TorHoerman Law is reviewing Tavneos cases involving severe liver injury, hospitalization, permanent liver damage, and fatal outcomes.

What to Do if You Experienced Liver Problems After Taking Tavneos

Patients who develop liver-related symptoms while taking Tavneos should seek prompt medical evaluation.

Liver injury can progress quickly, and early testing may help identify abnormal liver function before complications worsen.

Health care professionals may order blood tests, imaging, and other diagnostic evaluations to determine the cause of the injury.

Any suspected drug-related liver injury should be documented clearly in medical records, including the timing of symptoms and medication use.

Steps to take may include:

• Seek immediate medical care if symptoms such as jaundice, severe abdominal pain, dark urine, or itching develop
• Request liver function blood tests, including ALT, AST, alkaline phosphatase, and bilirubin
• Document Tavneos use, including start date, dosage, and when symptoms began
• Follow medical advice regarding discontinuation or monitoring of the medication
• Keep records of hospital visits, diagnoses, and treatment plans
• Ask about additional testing, such as imaging or liver biopsy if recommended
• Avoid alcohol or other substances that may worsen liver function during evaluation
• Consult TorHoerman Law to discuss whether your case should be reviewed

TorHoerman Law: Investigating Tavneos Lawsuit Claims

Tavneos remains under active regulatory and safety review as reports of drug induced liver injury, vanishing bile duct syndrome, and fatal outcomes continue to shape the record.

The FDA’s findings, combined with clinical data and postmarketing reports, have raised ongoing patient safety questions about how these injuries develop and whether risks were fully addressed.

Cases involving liver injury often depend on clear timelines, laboratory findings, and documented progression from symptoms to diagnosis.

A focused review of medical records can determine whether a patient’s injury aligns with the patterns now under investigation.

If you or a loved one took Tavneos and developed drug induced liver injury, vanishing bile duct syndrome, jaundice, liver failure, or fatal liver complications, contact TorHoerman Law for a free consultation.

You can also use the chat feature on this page for a free case evaluation and to get in touch with our attorneys.