Merck & Co's bid to prevent Glenmark Pharmaceuticals from selling copycat forms of its diabetes drugs Januvia and Janumet has suffered a setback in India.

Last week, the US giant sued Glenmark saying it is acting unlawfully by selling generic forms of Januvia (sitagliptin) and Janumet (sitagliptin plus metformin) as the patents protecting them are still valid. The Indian drugmaker says its just-launched drugs, called Zita and Zita Met, do not infringe any of Merck's patents in India,

Now, the high court in Delhi has denied Merck's bid to get an injunction against the Glenmark drugs although it has stated that the former's lawsuit can proceed. Nevertheless, Merck is disappointed and is considering an appeal, according to The Economic Times.

Merck introduced its drugs in India in 2008 at one-fifth of the price charged in the USA, some 1,200 rupees per month (about $22). Zita and Zita Met are 20%-30% cheaper.

This latest move comes in the wake of the landmark decision by the Supreme Court of India to once again firmly reject Novartis' application to patent its cancer drug Glivec (imatinib). Last month, an Indian patent appeals board confirmed its decision to allow Natco's generic version of Bayer's liver and kidney cancer drug Nexavar (sorafenib) to remain on the market, having issued a compulsory licence on the treatment in 2012 and other drugmakers, eg Pfizer and Roche, have seen patents revoked.