The supposedly best hope for AIDS sufferers, zidovudine (AZT), has been shown to have no effect in delaying the onset of the disease in healthy HIV positive people and does not improve their chances of survival.

A joint study by the British Medical Research Council and the French National AIDS Research Agency (The Lancet, 3 April 1993) shows that there is no benefit in asymptomatic people taking the drug.

In the trial, 877 people were given zidovudine, and 872 a placebo. "There was no difference in clinical outcome between the two groups. The survival rates at three years were 92 per cent in the treatment group and 93 per cent in the placebo group. In both groups 18 per cent of patients progressed to AIDS or died."

The findings flatly contradict earlier research which concluded that taking the drug did improve survival prospects, although patients were tracked for only a year.

Writing in the BMJ (10 April 1993), Luisa Dillner describes the latest study as "an unpalatable result", but says it will not have come as a shock to "thinking physicians".

The joint study, nicknamed Concorde, has cast further doubt on the benefits of a drug which enjoyed an unprecedented bypassing of the ordinarily rigorous American regulatory process.