Mumbai-based drug maker USV Ltd. scored a decisive win in a recent legal appeal, winning exclusive US rights to a new drug salt.

The new drug salt, donepezil oxalate, is effective in treating Alzheimer's disease. USV applied to patent this compound in 2004. USV's patent application described its invention as a "Composition of matter," the legal term used in the US patent statute. Surprisingly, the US Patent Office then refused to issue USV's patent application, arguing that the phrase "composition of matter," which appears in the patent statute itself, is too vague to support proper patent rights.

An appeals board in Washington disagreed. Rather, The Board of Patent Appeals and Interferences noted that a 1980 Supreme Court ruling involving another Indian inventor, Sidney A. Diamond v. Ananda Mohan Chakrabarty, concluded that the phrase "composition of matter" is perfectly acceptable. The appeals board thus concluded, in Ex parte Venkatasubraminarian Radhakrishnan Tarur et al., Appeal No. 2007-4478, that USV is entitled to its patent.

Mark Pohl, patent attorney with Pharmaceutical Patent Attorneys LLC of Morristown, New Jersey, argued on behalf of USV Limited; Celia C. Chang of Arlington, Virginia argued on behalf of the United States Patent Office.

Talking about the new patent on donepezil oxalate, USV Ltd's managing director Prashant Tewari said, "The patent on our novel drug salt donepezil oxalate is very important for us. That is why when US patent office rejected our case we went for the appeal".

The company's R&D head Radhakrishnan said that donepezil oxalate is a novel salt for making the donepezil hydrochloride which is the final API product. It is very essential for us for meeting the international quality in our products. "There were several questions from the US Patent office regarding the product. We explained them all their doubts that is why we have received the patent now", Radhakrishnan said.