Single-dose of experimental malaria drug clears parasites in mice, represents potential new class of drugs to treat malaria in humans

An experimental malaria drug was shown to effectively treat the disease in mice with only a single dose, according to a study published Thursday in the journal Science, Reuters reports (Kelland, 9/2). The new drug, known as NITD609, "represents an entirely new class of medicines to treat malaria ... Human trials, backed by Swiss pharmaceutical giant Novartis AG, could begin later this year," the Wall Street Journal writes (Naik, 9/3).

Thierry Diagana, of the Novartis Institute for Tropical Diseases (NITD), and Elizabeth Winzeler, a grantee of the NIH's National Institute of Allergy and Infectious Diseases (NIAID), who is affiliated with The Scripps Research Institute and the Genomic Institute of the Novartis Research Foundation, led the study, states an NIAID press release (9/2). To identify new compounds that might be effective against malaria, the research team "used robots to screen 12,000 naturally occurring chemicals against plasmodium falciparum, the deadliest malaria parasite. The chemicals were supplied by Novartis, which leads a big effort to develop drugs for tropical diseases," according to the Wall Street Journal (9/3). Novartis collaborated with "several non-profit organizations, U.S. and Singapore government agencies and researchers at universities in the United States, Switzerland, Thailand, and Great Britain" to develop the compound, Agence France-Presse notes.

Researchers then tested the drug "on mice infected with a strain of malaria that typically kills them within a week," AFP writes. "A single large dose of the drug cured all of the five infected mice which received it. Half of the six mice which received a smaller dose were cured and the cure rate rose to 90 percent when mice were given three doses of the smaller amount," the news service reports (9/2). Researchers think the drug could effectively treat malaria in humans because it "killed two species of parasites in their blood-stage form and also was effective against drug-resistant strains" in test-tube experiments, the press release notes (9/2).

Researchers have been hoping to identify new malaria treatments after a 2009 study showed that malaria drugs derived from "artemisinin, the basis of the most effective medicines, were losing power in Cambodia," Bloomberg writes. "New drugs developed over the past 30 years have been variations on previous treatments, leaving them vulnerable to the same weaknesses as their predecessors, [study co-author] Diagana said. Novartis's medicine targets the parasite in a way it hasn't seen before and isn't resistant to," the news service reports. "I would be extremely shocked if someone comes back and tells me that we're not hitting the bug in humans," Diagana said. "When I see the type of potency that we're getting, I'm very excited and very optimistic" (Bennett, 9/2).

Winzeler said the compound "has a lot of encouraging features as a drug candidate, including an attractive safety profile and potential treatment in a single oral dose," AFP writes. "Current treatment methods require patients to take drugs between one and four times daily for three to seven days. Reducing the treatment to a single dose leaves less opportunity for the parasites to develop a resistance to the drug, researchers said" (9/2).

The head of WHO's global malaria program, Robert Newman, said, "We welcome a new class of drug because it could help us stay one step ahead of the parasite," the Wall Street Journal reports. Newman, who was not involved with the NITD609 study, added, "[I]t's a long route to making the drug marketable … many drugs fall by the wayside."

The study also received support from Medicines for Malaria Venture, the Wellcome Trust, and the Keck Foundation, according the newspaper (9/3).