The U.S. Patent and Trademark Office has rejected the request from Israeli pharma giant Teva Pharmaceuticals to have its patent protection on Copaxone extended until September 2015, meaning that its patent will only be valid until May 2014. After this period the generic version of Copaxone, a drug used for the treatment of relapsing-remitting multiple sclerosis, will be allowed on the U.S. market. The product generates annual sales of about $3 billion in the United States.

The generic version is being developed by Hyderabad-based Natco Pharma Ltd., in partnership with U.S. generic and specialty pharmaceuticals company Mylan Inc. Previously, the launch of the jointly developed generic version of Copaxone was scheduled for May 2014 but it is expected that this will be pushed further into the future, according to the Indian unit of CNBC.

In a statement, Natco pointed out that the final decision regarding the launch date of the generic version of Copaxone was entirely up to Mylan. The latter will also have the final say on the pricing of the product. Meanwhile, Natco will take all necessary steps to ensure that a safe generic U.S. FDA approved product reaches patients suffering from multiple sclerosis, Natco's statement said.

Mylan issued its own statement in which it welcomed the decision of the U.S. Patent and Trademark Office.