Ranbaxy's US arm to face patent infringement suit

US-based Purdue Pharma has filed a patent infringement suit against India's largest drug company, Ranbaxy, after the latter's wholly-owned US subsidiary, Ranbaxy Pharmaceuticals Inc, applied for marketing approval of a low-cost version of Purdue's pain relieving medicine, Oxycodone.

Ranbaxy's application attempts to challenge the validity of three patents on Oxycodone in the US, complains Purdue, which filed the suit on May 5 in a district court of New York. Purdue has also sued generic drug makers Mylan and Actavis on the same patent infringement charge. Oxycodone is derived from opium and given to critical patients with acute pain.

Ranbaxy had attempted to challenge yet another patent on Oxycodone last year. It later withdrew the move, acknowledging the patent rights of the medicine.

While the earlier patent was issued in 1996, the three patents whose protection is being sought by Purdue through the litigation were granted in the US only in March 2010.

According to US laws, a company intending to apply for marketing approval of a patented medicine should notify the patent holder of its action. This gives the innovator an opportunity to file a patent infringement suit against the generic drug firm and also ensure an automatic stay on the marketing approval for a period up to 30 months.

When asked, a Ranbaxy spokesperson here sought more time for its US office to respond to the development.

Ranbaxy, a subsidiary of Japanese drug major Daiichi Sankyo, has of late been moderate on its patent litigation strategy. The company was earlier known for  attempts to challenge several patents on the world's largest selling medicine, the cholesterol-lowering drug, Lipitor.