CIPLA, India's fourth-largest pharmaceutical manufacturer, will soon market an indigenously developed AZT (azido deoxythymidine) based drug under the brand name Zidovir that will substantially reduce the cost of AIDS treatment.

AZT, developed in the US in the 1960s as an anti-cancer drug, was found effective in delaying the onset of AIDS in people infected by HIV, but it does not cure the disease. It is known to have side effects such as nausea, liver function abnormalities and anaemia.

AZT was licensed to the US pharmaceutical firm Burroughs Wellcome, which now claims a global monopoly on AZT production. A 100-mg capsule of the drug, marketed under the brand name Retrovir, costs about US $ 2.75 and since large doses are required, a year's treatment for a patient can cost up to US $ 10,000. In India, the imported capsule costs about Rs 53 and treatment can cost Rs 1.3 lakh a year.

Spurred by estimates of expected increases in AIDS cases in India, the Indian Institute of Chemical Technology (IICT) in Hyderabad initiated a project in 1988-89 to develop AZT. Using reverse-synthesis -- starting from the finished product -- the scientists produced the drug without replicating the Burroughs Wellcome process. Zidovir will sell for Rs 15 per 100 mg capsule.

The development has raised a great deal of dust. Burroughs Wellcome is fighting a legal suit against a Canadian pharmaceutical concern that produces an AZT drug called Vepotex. The Canadians claim AZT was discovered long before it was patented as an anti-AIDS drug by Burroughs Wellcome. They contend the product patent has run out and it is now a generic drug. Burroughs Wellcome only has a use patent. In India, product patents are not recognised and only process patents are.

The Indian technology has been passed on to Cipla, and other manufacturers like Lupin and Dr Reddy's Laboratories are interested in producing the drug. IICT scientist M K Gujar says, "We view this development as a social obligation and it has been passed on to the company at almost no charge." Lupin will produce the drug in Thailand. Labogen, a pharmaceutical manufacturer in Brazil, has also bought the technology through the National Research Development Corporation (NRDC) for about $ 25,000 and royalties. NRDC managing director N K Sharma said some South Korean firms had also evinced interest in the Indian technology.

Cipla also plans to enter the export market, but director R K Bammi says, "We can't export to countries that have a patent on AZT."