Hundreds of people affected by HIV/Aids on Wednesday marched on the Indian parliament to support a legal challenge to a patent application on a key anti- retroviral drug made by US pharmaceutical group Gilead Sciences.

The Indian Network for People Living with HIV/AIDS and the Delhi Network of Positive People this week registered a pre-grant opposition to the patenting of tenofovir disoproxil fumarate (Viread), an important second-generation treatment.