The Indian Patent Office has rejected patent protection for Gilead Sciences Inc's crystalline form of adefovir dipivoxil, a new form of its Hepatitis B drug Hepsera, in a pre-grant opposition filed by Ranbaxy Laboratories. The decision will benefit the Indian companies including Ranbaxy, Cipla and Sun Pharma, which are already in the market with adefovir products.

The Delhi patent office, in its decision to reject the application no. 712/DEL/2002 filed by Gilead, stated that the company failed to produce comparative data to prove inventive step and concluded that the product is not patentable under section 3(d). The applicant has not provided a comparative data with respect to the amorphous/parent compound of the alleged invention, it noted.

In its pre grant opposition filed under section 25(1) of the Patents Act, 1970 on September 2005, Ranbaxy challenged the application for lack of novelty, lack of inventive step and lack of utility. Further, the company furnished that the application could not have been filed under section 5(2) of the previous Act and no patent can be granted for a new form of a known substance.

Concluding its decision on the pre-grant opposition, the office said, "In view of above findings and the facts on records, the present application 712/del/2002 is hereby refused to proceed for grant of Patent on the grounds 25(1)(e), read with 2(1) j, and 25(1)(f) read with 3(d). The application stands disposed off with no cost to either party."

Gilead received US Patent for the crystal form of adefovir dipivoxil and its preparation in August 2008, which gives patent protection for the form of the drug till November 11, 2023.

The patent exclusivity would have allowed the Gilead to grab a better opportunity in the fast growing Hepatitis B drug market in the country. According to a report published by the global research and advisory firm Decision Resources in August 2008, the Indian hepatitis B virus drug market is expected to grow ten-fold by 2012 from USD 1.7 million in 2007 to USD 17 million in 2012. This growth will be fuelled by a growing awareness of the hepatitis B virus and the growth of individual wealth among India's urban middle and upper class.

The report finds that the number of prevalent cases of chronic hepatitis B virus in India (30.6 million in 2007) is three times that of the United States, France, Germany, Italy, Spain, United Kingdom and Japan combined. However, both diagnosis rates and drug treatment rates in India are extremely low, resulting in a virtually untapped antiviral market for the disease.

Though the adefovir products costs more than twice that of lamivudine, many of the clinicians switched to adefovir as the latter has high risks of drug resistance, according to the study. Cipla's Adsera, Sun Pharma's Adfovir and Ranbaxy's Adheb are the major adefovir products available in the market at present.