(Adds details from court order)
MUMBAI, May 15 (Reuters) - India's Supreme Court has barred Glenmark Pharmaceuticals from making and selling copies of U.S. drugmaker Merck's diabetes drugs Januvia and Janumet, according to a court document released on Friday.
The court has, however, allowed Glenmark to continue to sell existing inventory, according to the document posted on the Supreme Court's website after a hearing.
The decision against Glenmark comes two years after Switzerland's Novartis AG was denied patent protection for its cancer treatment Glivec in a landmark decision by India's Supreme Court that was widely seen as boosting the local generic drugs industry.
Anti-diabetes drugs are the top-selling therapy area in India, where about 65 million people live with the disease and that number is expected to reach 100 million by 2030.
Merck sued Glenmark in 2013 for infringing a patent it has on sitagliptin, the chemical compound in Januvia and Janumet, both of which the company has been selling in India since 2008.
A month's dose of Merck's drugs costs about 1,300 Indian rupees ($20) and 1,900 Indian rupees ($30), respectively. Merck has licensed the drugs to Sun Pharmaceutical Industries Ltd for sale in India.
Glenmark sells the medicines under the brand names Zita and Zita-met at a nearly 30 percent discount to Merck's price.
Glenmark is barred from producing sitagliptin until the next hearing on the case, the order said.
Spokespersons for Glenmark and Merck declined to comment.
"This is an interim sort of measure taken by the court, and the decision on the patent of sitagliptin is subject to final orders," said Ameet Hariani, managing partner at Mumbai-based law firm Hariani & Co. ($1 = 63.6500 Indian rupees) (Reporting by Zeba Siddiqui and Nivedita Bhattacharjee; editing by David Clarke)