GlaxoSmithKline has filed a lawsuit in a United States court against Dr Reddy's Laboratories alleging infringement of patent rights of a generic version of 'Imitrex' drug, used for the treatment

of migraine.

Dr Reddy's has also filed an Abbreviated New Drug Application with the US Food and Drug Administration for 'Sumatriptan Succinate', the generic variant of 'Imitrex', a Dr Reddy's statement said.