Depomed Inc. said Tuesday that Sun Pharmaceutical Industries is challenging patents on the diabetes drug Glumetza.
Sun asked the Food and Drug Administration to approve a generic version of the drug, which is made by Depomed. Sun is claiming that five patents that expire between 2016 and 2025 will not be infringed by Sun's generic version, or the patents are invalid and unenforceable.
Depomed said it has 45 days to file a patent infringement lawsuit, which would then automatically bar the FDA from approving Sun's application for 30 months or until a court rules on the case.
Depomed is already suing Lupin Ltd. for patent infringement for its plans to sell a generic version of Glumetza.
Shares of Depomed rose 21 cents, or 2.5 percent, to $8.76 in afternoon trading.