Enrolment into a major international drug trial was halted last week (18 January) following the finding that HIV/AIDS progresses much faster if patients do not take drugs continuously.
The study, by the US National Institute of Allergy and Infectious Diseases (NIAID), was designed to see if an alternative called 'episodic' therapy would reduce side effects and costs of HIV treatment.
But the recruitment of study participants was halted last week after an independent data and safety monitoring board found that patients receiving episodic therapy were twice as likely to die or develop full-blown AIDS than those taking drugs continuously.
A press release from NIAID says there was also an increase in major complications such as cardiovascular, kidney and liver diseases in these participants.
HIV-positive volunteers were randomly assigned to either receive drugs continuously or only when their levels of key 'CD4+' immune cells dropped below a certain limit.
Wafaa El-Sadr, one of the principal investigators for the trial, says they were "surprised to learn that in the short term, episodic antiretroviral therapy carries such an increased risk" without sparing patients known side effects.
The trial, which began in 2002, included more than 5,000 participants in Argentina, Australia, Brazil, Canada, Chile, Japan, Morocco, New Zealand, Peru, Russia, South Africa, Thailand, the United States, Uruguay and 17 European countries.
"[It] reached a conclusion much earlier than we expected," says James Neaton, another principal investigator. "That is the significant value and potential power of conducting such a large trial."