The FDA has idled yet another hepatitis drug in the Idenix pipeline. The company said the FDA put a clinical hold on its experimental hepatitis C drug IDX19368. The news follows the August 16 announcement that the FDA put a partial clinical hold on hepatitis C candidate IDX184. Both therapies are nucleotide polymerase inhibitors.

The holds mean different things for the two drugs – for IDX19368, no patients can be recruited or trials commenced until the hold is dismissed; for IDX184, patients were already enrolled in Phase IIb trials, and the partial hold prevents the company from enrolling patients for new trials.

The reason for the hold on IDX368 is an outside force: Bristol Myers-Squibb pulled its experimental nucleotide Friday after one clinical trial patient died and 8 others were hospitalized for reasons linked to heart and kidney toxicity. (Both Idenix agents share the same active metabolite as BMS-986094, although the company says a prodrug approach makes them different in their toxicity profiles.)

“Based on our discussions with the FDA, we understand the clinical hold is a precautionary decision made by the FDA in light of the adverse events seen with BMS-986094,” Ron Renaud, Idenix’s CEO, said in a statement.

The move puts a crimp on the Idenix pipeline, which currently includes the two idled nucleotide inhibitors, and two other experimental hepatitis treatments. The company sells one product, the hepatitis B medication Tyzeka (telbivudine).