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2 New Drug Approaches Show Promise Against Malaria

A new study from Tanzania shows that standard malaria drugs given to African babies as a precaution is effective in preventing them from getting the disease. A second African study shows that in older children, a combination of two Chinese drugs is the best to way to treat the disease in areas where older malaria drugs no longer work.

Giving intermittent malaria treatment for people who are not yet sick with the disease is gaining momentum as a way to reduce infections. It is already recommended for pregnant women, and now a study of 700 Tanzanian babies shows it works well for them, too.

The first phase of the study in 2001 showed that when the infants got the drug sulfadoxine-pyrimethamine three times by the age of nine months, they came down with 59-percent fewer malaria infections by 10 months of age than babies not given the drug. The drug was administered when the children came in for routine vaccinations for other diseases.

Now, a continuation of the same study shows that the malaria protection continued long after 10 months. By the end of their second year, the infection rate for the infants who received the drug was still 36-percent lower than the other group.

Study leader David Schellenberg of the Ifakara Health Research and Development Center in Dar Es Salaam says he is encouraged that preventive malaria therapy works in infants. "We've managed to achieve these reductions in the amount of malaria by delivering an available and affordable anti-malarial at the time of routine contacts with the health services," he said.

The work is hopeful because a previous strategy of dosing infants with antimalarials weekly or monthly in their first year of life was not long lasting. Dr. Schellenberg says it quelled malaria as long as the drugs were given, but failed to protect when the drugs were withdrawn.

However the less frequent, intermittent approach apparently allows no such malaria rebound, at least through the second year of life. Dr. Schellenberg speculates that giving fewer drug doses requires the infants' immune systems to do some of the work, which strengthens them to fight the disease when drugs are no longer in their system. "It seems to suggest that there may be even more marked public health benefits with this approach to malaria control, although, of course, we need to replicate these findings in different settings where there is either more or less malaria transmission, greater or lesser use of mosquito nets, and so on," he said.

Malaria kills one million people a year, mostly African children. Cheap and effective treatment with one drug is no longer an option for most African nations because of the rapid emergence of drug resistance to standard drugs like the one used in this study.

This problem has led to calls for combination treatments, several containing the Chinese herb Artemisinin. But there is little information on their effectiveness. So another study published in the Lancet compared three drug combinations available in Africa in another group of 1,700 Tanzanian children under five years old.

A team of Tanzanian and British doctors found that the best combination was the Artemisinin derivative artemether used with lumefantrine, a synthetic drug Chinese researchers developed in the 1970s. It is one of the pairings recommended by the World Health Organization. In two weeks, it cleared the malaria parasite from 99-percent of the children who took it. "This outcome is stunning. It is so high and so effective," he said.

This is Peter Gottfried Kremsner, a parasitic diseases expert at the University of Tuebingen, Germany and the Albert Schweitzer Hospital in Lambarene, Gabon. Dr. Kremsner says the finding is especially stunning because the drugs were given to the children without supervision by the study's researchers. Examination of their blood showed that the children sometimes missed doses, yet the drug combination still worked. "That means that there is enough therapeutic range that even if you miss a little bit, it is still so effective, as shown in this trial," he said.

Dr. Kremsner says this indicates that the artemether and lumefantrine combination could be useful in poor areas where there are not enough health care workers to administer the drugs.