Newly discovered liver safety problems with high doses of Novartis' diabetes treatment Galvus are expected to delay the European launch of the drug and have raised questions about whether the FDA will back its approval here in the US.
Data showed that patients taking 100 mg doses of Galvus once daily had more frequent liver-enzyme elevation when compared to those taking 50 mg a day or 50 mg twice daily.
Novartis has recommended changing doses to 50 mg once or twice daily rather than the single higher dose.
The company said it plans to discuss the data with regulators.
Galvus has been approved for use in the European Union but analysts predict the new findings could push back its launch there for at least three to six months.
Meanwhile, skin toxicity issues have dogged Galvus' US approval. Novartis aims to resubmit the drug in the US in 2009.
The delays are a further setback for Novartis as Merck's Januvia continues to gain market share as the only DPP-4 inhibitor on the market.
DPP-4s, such as Januvia and Galvus, are designed to enhance the body's own ability to lower elevated blood sugar.
Januvia won US marketing approval in October 2006.