‘Real life’ clinical studies that quote high failure rates for combination therapy may underestimate its real success, a senior UK doctor told the 6th Glasgow HIV Conference.
Dr Margaret Johnson of London’s Royal Free Hospital said that ‘cohort’ studies of large groups of patients starting HIV therapy often showed that fewer than 50 per cent had achieved, and maintained, an HIV viral load under 50 a year later (for instance, see ‘45 per cent “rebound”’, opposite).
And yet, continued Johnson, an analysis of the Royal Free’s own patients showed that between 1999 and 2001, viral success rates - meaning in this case maintaining viral loads under 400 - improved from 75 per cent to 81 per cent of patients. Only 3.7 per cent of patients a year experienced a direct failure of their drugs to suppress HIV, she said. (Other patients may have ‘failed’ because they had to stop HIV drugs due to side effects).

To put it another way, if you are currently a Royal Free patient on HIV therapy, your drugs are likely to keep on working for the next 13 years on average - as long as you don’t have to stop due to toxicity. And in 13 years time there will be a lot more treatments.
In response to a question, Dr Johnson said she did not think the Royal Free’s figures were exceptional. Researchers have been taught to measure success in studies by the rigorous ‘Intent to Treat’ standard, whereby patients who changed their drugs due to side effects, or because they were incompatible with their lifestyle, were counted as treatment failures.
In a situation where there were very few alternatives to toxic drugs, she said, having to stop treatment due to toxicity would indeed imply clinical failure. But these days there were enough HIV drugs around to try several alternative regimes before doctor and patient found the best ‘fit’.