The Swiss pharmaceutical giant Novartis is in court in India this week challenging the country's patent laws.
The drug company is attempting to overturn the Indian government's rejection of its attempt to patent a new version of leukemia drug Gleevec which is known in Europe and India as Glivec.
AIDS activists say if Novartis wins the civil suit, it will have ramifications which could leave millions without access to affordable medicine, in particular AIDS drugs.
If Novartis is successful Indian firms will be banned from making generic versions of the drug and activists say this will set a precedent for other pharmaceutical companies seeking patent protection for essential medicines - including AIDS drugs - currently made cheaply in places like India.
The advent of generic drugs has meant the price of antiretroviral drugs (ARVs) treatment for AIDS for example has dropped from about $12,000 a year per person to as low as $70 per patient annually.
The number of people now on ARVs has increased from very few up to more than 1.6 million as of June 2006.
But despite this the United Nations estimates only 24 percent of people who need the drugs get them, and AIDS activists say any threat to Indian generics would hit hardest in sub-Saharan Africa, which has two-thirds of the world's 40 million HIV-positive people live.
India's patent law effective since 2005, allows patents for products that represent new inventions after 1995 or for an updated drug that shows greater efficacy.
Novartis says that its improved drug is more easily absorbed by the body but Indian drug companies and aid groups say Gleevec is a new form of an old drug invented before 1995.
Generic copies of Gleevec are already being produced by a number of Indian pharmaceutical companies and sell for a fraction of the cost charged by the Swiss company and the same applies to many other generic drugs produced in India, making them available at a much cheaper cost throughout the developing world, where the need for affordable medicines is crucial.