Efficacy and safety of atovaquone–proguanil in treating imported malaria in Japan: The second report from the research group

Malaria remains an important health risk among travelers to tropical/subtropical regions. However, in Japan, only 2 antimalarials are licensed for clinical use — oral quinine and mefloquine. The Research Group on Chemotherapy of Tropical Diseases introduced atovaquone–proguanil in 1999, and reported on its excellent antimalarial efficacy and safety for treating non-immune patients with uncomplicated Plasmodium falciparum malaria (20 adult and 3 pediatric cases) in 2006. In the present study, additional cases of malaria were analyzed to confirm the efficacy and safety of this antimalarial drug. Fourteen adult and 2 pediatric cases of P. falciparum malaria and 13 adult cases and 1 pediatric case of P. vivax/ovale malaria were successfully treated with atovaquone–proguanil, including 3 P. falciparum cases in which the antecedent treatment failed. Two patients with P. vivax malaria were treated twice due to primaquine treatment failure as opposed to atovaquone–proguanil treatment failure. Except for 1 patient with P. falciparum malaria who developed a moderate liver function disturbance, no significant adverse effects were observed. Despite the intrinsic limitations of this study, which was not a formal clinical trial, the data showed that atovaquone–proguanil was an effective and well-tolerated therapeutic option; licensure of this drug in Japan could greatly contribute to individually appropriate treatment options.

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► The research group in Japan import nationally unlicensed medicines for tropical diseases.
► Cases of imported malaria that are treated with atovaquone–proguanil are analyzed.
► This medicine is effective and well tolerated in P. falciparum and P. vivax/ovale malaria cases.
► Its national licensure would greatly contribute to individually appropriate treatment options.