Belinda Beresford
An old drug could have some new tricks up its sleeve with the discovery that the anti-malarial compound chloroquine appears to combat HIV.
Chloroquine has long been used as a prophylaxis against and treatment for malaria. But this old workhorse is now becoming obsolete because of the increasing proportion of malaria parasites which are resistant to it up to 90% in some areas.
Researchers at the University of Turin have found that chloroquine and the related compound hydroxychloroquine appear to curb the HI virus in laboratory settings. Dr Andrea Savarino and his team say that chloroquine affects the production of the envelope around the virus. This means that although the virus may be able to hijack human cells to produce fresh viral genetic material, without the envelope it cannot complete the reproduction cycle.
Chloroquine attacks the part of HIV called glycoprotein120, which is so fundamental to the nature of the virus that it is less likely to be able to mutate and become resistant to the drug.
The drug has been used for decades, and although it does have side effects, these are well understood. The fact that it is widely available and cheap in the developing world, however, may make it less likely that a drug company will be interested in looking at its anti-viral properties.
But even in more developed countries chloroquine could have a crucial role to play.
Since it works at a different stage of the life cycle of HIV, chloroquine could be a potent additive to the cocktail of anti-retroviral drugs used to hold HIV at bay. The drug may also have an impact on HIV/Aids by inhibiting some of the body’s own immune system reponses which the virus uses to ensconce itself in its victim.
In Belgium, meanwhile, Dr Johan Boelaert of Algemeen Ziekenhuis St-Jan suggests that chloroquine may prevent breastfeeding mothers from infecting their infants with HIV. Chloroquine accumulates in breast milk cells, and should theoretically therefore reduce the levels of HIV in the milk.
Boelaert and his team are planning trials in sub-Saharan Africa to look at the impact of chloroquine in real-life settings.