Mumbai: India’s Intellectual Property Appellate Board (IPAB), which is hearing an appeal filed by Swiss drug maker Novartis AG questioning a 2005 decision of the Chennai patent office to reject its patent application for blood cancer drug Glivec, has asked Novartis to submit relevant documents to support its claims that the drug has enhanced efficacy over a previously known base molecule. The appellate body, which resumed hearing the Novartis plea on Monday after the Union government appointed a special technical member P.C. Chakraborty in the judiciary panel last month, asked the Swiss company’s counsel, Shanti Bhushan, to provide documents to support his explanation of efficacy.

The Novartis counsel said in his argument at the hearing that “the drug, a beta-crystalline form of imatinib mesylate, was 30% more bio-available, thermo-stable at room temperature, and less hygroscopic than other forms of imatinib and imatinib mesylate.”

Bio-availability refers to the fraction of an administered dose of unchanged drug that reaches the body’s circulation and hygroscopicity is the ability of a substance to attract water molecules around it.

Bhushan had also argued that these advantageous properties made the beta-crystalline form more efficacious, claiming that such increase in bio-availability was crucial for cancer drugs that are attendant with serious side effects, as it meant that a greater quantity of the drug could reach the target site with the same or lesser dosage. The Novartis appeal to IPAB follows the denial of a patent for the internationally patented Glivec here in India. The Chennai patent office had rejected the application three years ago saying it doesn’t qualify for such protection as per section 3(d) of the existing patent law that rules out patentability of any pre-1995 drug unless the new form is shown to have enhanced efficacy.

Local drug makers Natco Pharma Ltd, Cipla Ltd, and Ranbaxy Laboratories Ltd, along with Cancer Patients’ Aid Association, had opposed the Novartis patent filing.

Glivec, a modified form of a drug known as imatinib mesylate, and invented before 1995, had been granted patents in several countries, including Switzerland and the US earlier. Novartis also enjoys patent exclusivity for the new form of the drug in several countries, including China.

The appellate board hearing by a special bench will continue till next week.