The Finland-based drug major Orion Corporation has filed a lawsuit in the United States against domestic drug major Wockhardt for challenging the patents on its brand Stalevo, used for the treatment of Parkinson's disease.

The suit is in response to an Abbreviated New Drug Application filed by Wockhardt with the US Food and Drug Administration seeking to sell a generic version of the drug.

The challenge is specifically for 12.5, 200, 50-mg strength of the drug, which is a combination of three drugs carbidopa, entacapone and levodopa. "Stalevo is an enhanced levodopa treatment originated by Orion Corporation and marketed in the United States by its exclusive licensee Novartis," Orion said in a statement.

Earlier, Orion had sued Sun Pharmaceutical for seeking marketing approval for its generic version of Stalevo. Orion had also sued Wockhardt and Sun for challenging the patent on Comtan, another drug for treating Parkinson's disease. Such suits, meant to delay the entry of generic medicines, are common in the US.

According to the US laws, any suit filed against such applications for drug marketing approvals (called Para IV challenges) within 45 days will automatically trigger a 30-month stay on such approvals.