Antimalarial Drug Regains Effectiveness

November 22, 2006 -- A new study indicates that an antimalarial drug which had lost its effectiveness more than a decade ago is now working again. This is a rare event, as researchers are unaware of any other drugs regaining their effectiveness like this.

The antimalarial drug, chloroquine, had been the mainstay of malaria treatment since the end of World War II, but its effectiveness dwindled in recent decades due to the spread of resistant malaria strains. In 1993, Malawi dropped use of the drug entirely due to its inability to treat malaria. But after reports that chloroquine had regained its effectiveness in that nation, researchers tested chloroquine on 105 malaria-infected children in Malawi and reported that 99 percent of the cases were cured. Only one-fifth of the children who received Malawi’s current first-line treatment were cured. Their study appears in the New England Journal of Medicine.

While this is good news, scientists recommend not using chloroquine on its own. Doing so would risk a resurgence of the drug-resistant strain that continues to have a presence in other countries. Instead, researchers recommend incorporating the drug into a combination treatment with other antimalarials. To be effective, however, other countries would need to reduce their current use of chloroquine as a single-drug therapy, as Malawi did in 1993, to allow the resistant strain to diminish.

The National Academies report, Saving Lives, Buying Time: Economics of Malaria Drugs in an Age of Resistance explores the use of antimalarial drugs and recommends combination therapies as a cost-effective long-term strategy to benefit patients and preserve the few highly effective antimalarials now available. The report discusses chloroquine’s loss of effectiveness and the costs associated with using alternatives.

• Saving Lives, Buying Time: Economics of Malaria Drugs in an Age of Resistance (2004)

• CDC