Gilead's Sovaldi--Courtesy of Gilead

India's intellectual-property police nixed a key patent on Gilead Sciences' ($GILD) hepatitis C drug Sovaldi, opening the door for cheap generic copies from domestic drugmakers such as Natco Pharma. It's the latest blow to a multinational drugmaker's ambitions in India, which remains one of the fastest-growing drug markets in the world.

The Indian patent office determined that Sovaldi was a "molecule with minor changes" from a previous compound developed by another company, and thus undeserving of patent protection. For Big Pharma, it's the latest example of India failing to recognize innovative treatments hailed elsewhere as breakthroughs. But for Indian health officials and patient advocates, the patent court decision means more people infected with hepatitis C can actually afford to be treated with Gilead's highly effective drug.

Gilead had already said it would sell Sovaldi for $900 per treatment course in India, a vast discount off its U.S. list price of $84,000 for 12 weeks of therapy. It's one of several deals Gilead has struck in emerging markets, where the disease burden is high and health budgets low. The company also licensed the drug to 7 Indian drugmakers, which signed on to manufacture Sovaldi copies for 91 emerging countries, including India.

But patient advocates--including Médecins Sans Frontières--haven't been satisfied with a $900 price in India. They are calling for a hepatitis C treatment drive across the country, where an estimated 12 million people are infected with the disease--and where $900 is still beyond the reach of most Indians' pocketbooks, they say. Citing a production-cost study by Liverpool University researchers, MSF has said that manufacturing Sovaldi costs somewhere between $68 to $136 per 12-week supply.

Natco and the Initiative for Medicines, Access & Knowledge (I-MAK) officially opposed patent protection for Sovaldi in November 2013. Now that the patent office has officially denied the patent, Natco and other Indian drugmakers who didn't sign on to Gilead's licensing deal can roll out their own versions.

"The move to reject Gilead's patent application really opens up the playing field, so we hope to now see many other generic companies starting to produce more affordable versions of this drug," said I-MAK Director Tahir Amin in a statement.

Gilead isn't the only hepatitis C drugmaker drawing fire for its pricing in the developing world. MSF chastised Bristol-Myers Squibb ($BMY) in November after the company announced it would develop a 90-country licensing strategy to make its drug daclatasvir affordable there. MSF maintains that limiting cheap copies to those countries leaves out middle-income countries that are still unable to foot the bill for the expensive brand.

For activists, fighting IP protections is a logical choice, especially in India, where patent officials and courts have been skeptical of the pricing power they convey. Novartis ($NVS) fought for a patent on its blood-cancer treatment Glivec for years, and all the way to the Indian Supreme Court, only to be turned away in the end.

Meanwhile, the Indian government forced Bayer to license its on-patent drug Nexavar to Natco Pharma, which is turning out a discount-priced version. And the Indian patent office has revoked patents on a series of Big Pharma drugs, including Roche's ($RHHBY) hep C treatment Pegasys. The series of decisions against pharma IP coverage has landed Indian officials in hot water with U.S. trade reps.

- here's the release