The FDA said it will now require a boxed warning on obeticholic acid (Ocaliva) regarding correct dosing in patients with primary biliary cholangitis (PBC), following up on concerns the agency initially expressed last September.

Obeticholic acid is supposed to be given once or twice weekly at 5-10 mg in patients with a prior decompensation event or with PBC of Child-Pugh class B or C — but some patients in these categories have been taking the drug daily with severe adverse consequences, the FDA said. Daily dosing is allowed for patients with non-cirrhotic or compensated Child-Pugh class A PBC.

The agency did not provide updated numbers of adverse events in its announcement Thursday, but the September statement indicated that 19 deaths had been reported with the drug, some of which were clearly associated with higher-than-recommended dosing.

“FDA is adding a new Boxed Warning, FDA’s most prominent warning, to highlight [recommended dosing] in the prescribing information of the drug label,” the agency said. “FDA is also requiring a Medication Guide for patients to inform them about this issue.”

The drug, made by Intercept Pharmaceuticals, was approved in May 2016. The FDA noted that, as a condition of approval, it had required post-marketing studies of obeticholic acid in patients with advanced PBC; results are not expected until 2023, however.