HIV/AIDS drugs may also be effective against malaria

Jun 2 2005

Researchers at The Queensland Institute of Medical Research (QIMR) have found that drugs used to treat HIV Aids may also be effective against the biggest killer in the world - malaria.

Malaria is a parasitic disease transmitted by mosquitoes and affecting 300-500 million people annually, mainly in sub-Saharan Africa. The most lethal type of malaria is caused by the parasite Plasmodium falciparum and an estimated 1-2 million people die as a result of infection with this parasite each year. Unfortunately, there is currently no vaccine to protect people against malaria, and existing antimalarial drugs, such as chloroquine, are becoming less effective due the development of parasite resistance. New drugs that act on essential parasite processes are essential to combat drug resistant parasites.

"Like malaria, HIV/AIDS is a major infectious disease, particularly in developing countries where malaria is also endemic. Thus, people who are infected with both the malaria parasite and HIV may be treated with both anti-malarial and HIV drugs. This prompted us to explore the effect of HIV drugs on malaria parasite growth. Of the HIV drugs tested, we found protease inhibitors were the most effective. Five of seven HIV protease inhibitors were able to kill malaria parasites grown under laboratory conditions," said QIMR researcher Dr Kathy Andrews, who has been nominated for a Premier's Award for Medical Research in the Senior Post-Doctoral Category.

"Importantly, these drugs are effective against malaria at clinically relevant concentrations. We have confirmed these laboratory findings in vivo using mice infected with mouse malaria. The most significant results were obtained using protease inhibitor combinations of ritonavir with either saquinavir or lopinavir. These drug combinations are the same as those used to treat HIV/AIDS patients in clinical settings," said Dr Andrews.

The observed inhibitory activity of antiretroviral protease inhibitors against malarial parasites raises the prospect of their use as antimalarial drugs. They have the advantage over new experimental antimalarial agents in development as they are already clinically available drugs that are widely prescribed for HIV/AIDS. The QIMR findings have important implications for treatment strategies in co-endemic settings and suggest that appropriate choice of HIV drug combinations may also have an important role to play on malaria disease outcome.

Dr Kathy Andrews and other finalists for the Premier's Awards for Medical Research will be acknowledged at the official Medical Research Week dinner being held on Friday June3 at the Marriott Hotel. The awards are to recognise world-class research as part of Medical Research Week from June 3 - June 12 which is organised by The Australian Society for Medical Research.