Effective new malaria drug to be approved by FDA

January 12th, 2009 - 12:24 pm ICT by IANS  

Washington, Jan 12 (IANS) The US Food and Drug Administration (FDA) is likely to approve a new malaria drug with artemisinin, a wormwood derivative from China that has proven effective for the infection in Africa and Asia. Although only about 1,500 reported cases of malaria are treated in US annually, the drug would also be made available to the military and to Americans planning to go abroad.

However, worldwide malaria is still one of the most serious infectious diseases, claiming two million lives and affecting two to three billion people every year.

Named Coartem, the drug is made by Swiss company Novartis. It combines artemether, an artemesinin derivative, with lumefantrine, a drug developed by Chinese scientists, which does not kill parasites as quickly but lingers in the blood a while longer.

By mopping up parasites that artemisinin misses, lumefantrine helps prevent resistance that would defeat the drug, as has occurred with other therapies like chloroquine.

University of Pennsylvania pharmacologist Doron Greenbaum, said although the exact mechanism by which artemisinin kills parasites is still open to considerable debate, the drug likely acts against one or more protein targets that may make it susceptible to resistance that has developed to most other drugs.

Drug resistance to artemisinin has already been shown to occur in the lab, and reports have already surfaced about potential resistance in malaria endemic regions like southeast Asia.

Thus the potential success of Coartem treatment for malaria should be greeted with cautious optimism knowing that resistance is likely to arise and that other new drugs will need to be developed quickly.

Greenbaum recently reported that small molecule defensin-mimetic compounds discovered by Radnor, Pennsylvania-based biopharmaceutical company PolyMedix, irreversibly kill P. falciparum while sparing human red blood cells.

Plasmodium species are responsible for the nearly 500 million cases of malaria worldwide and as many as two million deaths, most of them in children.

As with antimicrobial agents, first-line malaria agents are losing effectiveness due to development of resistance to drugs by the target organisms.

Greenbaum demonstrated that PolyMedix’s compounds kill P. falciparum irreversibly, meaning the cells do not recover when the agent is depleted.

Irreversible killing distinguishes a “cidal”, or true killing mechanism, from a “static” mechanism that holds the infectious agent at bay while the body’s immune system fights off the infection, said a Pennsylvania release.

“If we treat for 10 hours and remove the compound, the parasites never recover,” notes Greenbaum. Many antimicrobial and antifungal drugs are of the static variety.

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