March 31 (Reuters) - The U.S. Food and Drug

Administration on Monday said it had identified cases of liver

injury in patients taking Amgen's ( AMGN ) drug for a group of

rare autoimmune diseases and urged healthcare providers to

closely monitor patients and discontinue the treatment promptly

if liver damage is suspected.

The agency said it had identified 76 cases of drug-induced

liver injury with evidence suggesting a causal link to Tavneos,

including seven cases of vanishing bile duct syndrome, a rare

condition that can cause permanent liver damage. Eight deaths

were reported among those cases.

The safety warning adds to mounting regulatory scrutiny of

Tavneos, which is approved to treat anti-neutrophil cytoplasmic

autoantibody (ANCA)-associated vasculitis, a group of rare

autoimmune diseases that cause inflammation in small- to

medium-sized blood vessels.

In January, Amgen ( AMGN ) said the FDA had asked the company to

voluntarily withdraw the drug after concerns emerged during a

re-evaluation of primary endpoint data for nine of the 331

patients enrolled in the late-stage trial supporting its

approval.

Amgen ( AMGN ) declined to withdraw the drug, saying at the time it

was not aware of any issues with the underlying patient data,

remained confident in Tavneos' benefit-risk profile and was

working with the FDA on next steps.

The FDA said the median time to onset of drug-induced liver

injury was 46 days after starting treatment.

While Tavneos labels in Europe and Australia mention

post-marketing cases of vanishing bile duct syndrome, the U.S.

prescribing information does not currently warn of it, according

to the FDA's website.

In January, the European Medicines Agency said it started a

review of Tavneos, "following emerging information that raises

questions regarding the data integrity (of its study)."

The FDA approved Tavneos in 2021.

Amgen ( AMGN ) did not immediately respond to a Reuters request for

comment.