India has granted a patent to US pharmaceutical giant Gilead for a blockbuster Hepatitis C drug, in a U-turn activists said could potentially stop affordable copies reaching millions of people in other countries.
The drug, Sovaldi, which costs $1,000 (£690) a pill in the United States, was rejected for a patent in January 2015 following opposition by health activists who said the science was not sufficiently new.
But after an appeal by Gilead, the Indian Patent Office on Monday granted its application for the drug, chemically known as sofosbuvir, saying it found the "compounds novel, inventive and patentable".
"This decision underlines the scientific innovation involved in the development of this breakthrough treatment for chronic Hepatitis C," Gilead spokesman Nick Francis said in a statement.
The ruling will not immediately affect patients in India, where several firms are licensed by Gilead to produce low-cost versions of sofosbuvir for sale in developing countries.
But drug access campaigners slammed the decision, saying it could prevent the export of raw materials to other countries seeking to make the drug that some have hailed as a miracle cure.
"We know there are millions of people in other countries who now won't have affordable access because of this decision," said Leena Menghaney, South Asia head of the Medecins Sans Frontieres' Access Campaign.
"It will block a sustainable supply of key raw materials needed to produce the drug in countries like Egypt, Bangladesh and Pakistan, and hence affect production by new suppliers," she said.
Tahir Amin, co-founder of the group Intellectual Property, Initiative for Medicines, Access & Knowledge said the patent office's decision was "flawed".
"(It) ignores the scientific facts and fails to uphold the standards of Indian patent law to ensure only new inventions are patented," he said.
India earned a nickname as the pharmacy to the developing world for its tough stance on patents, taking a view that they should be granted only for major innovations, not updates to existing compounds.
More than 130 million people live with chronic Hepatitis C worldwide, according to the World Health Organization, and 500,000 die each year from related liver diseases.