HONGKONG will continue to use AZT, the most popular anti-AIDS drug, despite an overseas study released yesterday showing that early use of the medicine had no clear benefit. No improvement in survival or in delaying progression to the full symptoms of AIDS was achieved by giving AZT as soon as patients were diagnosed HIV positive, the report said. Organised by the Medical Research Council in Britain and the French National Aids Research Agency, the study involved 1,700 patients of whom half were given AZT immediately on diagnosis, while the other half were not given the drug until they developed full-blown AIDS. Of those given AZT early, eight per cent died within three years, against seven per cent of those whose medication with AZT was delayed. Dr Lo Yim-chong, of the AIDS Counselling and Health Education Service of the Department of Health, said it would continue to use AZT - the first approved drug for HIV carriers in the world. ''There are many studies on a drug. We cannot repudiate one medicine just because of one report,'' she said. However, only patients with apparently low immunity would be given anti-AIDS drugs, she said. ''Not all patients [found to be HIV positive] will be given drugs. We have to balance the risk and benefits. ''Patients might be prescribed with DDI [introduced into Hongkong last year] if they cannot tolerate AZT or it is found to have little effect,'' Dr Lo said. Some users of AZT suffer headaches, vomiting and problems such as bone marrow suppression leading to anemia. The head of the Department of Health's AIDS preventive unit, Dr Lee Shui-shan, said AZT was the first choice drug prescribed for HIV infection. Dr Patrick Li Chung-ki, of the AIDS Foundation, said he was waiting for the release of the full report but doctors would not immediately stop using AZT. He said current treatment also controlled secondary infections and could have better results than a few years ago. A spokesman for the local office of Wellcome, corr the British makers of AZT, said the drug would not be withdrawn from the market. In a three-page statement, the company said the latest results could be ''explained by modifications to the trial design and the methods of analysis''. Four studies of early use of the drug had shown a significant reduction in disease progression, it said. The chairman of AIDS Concern, Ms Lisa Ross, yesterday said patients should seek advice from their doctors. She said more information about AZT meant that doctors should continue to look for different therapies and not just rely on AZT.