Atovaquone-proguanil versus chloroquine-proguanil for malaria prophylaxis in nonimmune pediatric travelers: results of an international, randomized, open-label study.

Atovaquone-proguanil has been shown to be effective and well tolerated for malaria prophylaxis in residents of countries of endemicity and in nonimmune adult travelers, but data about traveling children are limited. In a randomized, open-label, multicenter prophylaxis trial, 221 nonimmune pediatric travelers (age, 2-17 years) received either atovaquone-proguanil or chloroquine-proguanil. Safety and clinical outcome were evaluated 7, 28, and 60 days after travel. By posttravel day 7, a total of 39 (35%) of 110 atovaquone-proguanil and 41 (37%) of 111 chloroquine-proguanil recipients reported > or =1 adverse event. The data indicate that, over the course of treatment, fewer atovaquone-proguanil recipients had treatment-related adverse events (8% vs. 14%), including gastrointestinal complaints (5% vs. 10%). Two subjects discontinued prophylaxis because of drug-related adverse events; both had received chloroquine-proguanil. Observed compliance with prophylaxis was similar before and during travel, but it was higher for atovaquone-proguanil in the posttravel period. No study participant developed malaria. Atovaquone-proguanil was well tolerated and is an important addition to the limited arsenal of prophylactic agents available to children.

Efficacy of atovaquone/proguanil for malaria prophylaxis in children and its effect on the immunogenicity of live oral typhoid and cholera vaccines.

A double-blind, placebo-controlled study was conducted to measure the impact of malaria prophylaxis with atovaquone/proguanil (A-P) on the immunogenicity of vaccines against typhoid fever and cholera, Salmonella serotype Typhi Ty21a and Vibrio cholerae CVD103-HgR, respectively. A total of 330 Gabonese schoolchildren were assigned to receive either A-P or placebo for 12 weeks. Vaccination occurred 3 weeks after the start of prophylaxis, and immunogenicity was assessed 4 weeks after vaccination. The protective efficacy of A-P against Plasmodium falciparum malaria was of 97% (95% confidence interval, 79%-100%). The 2 treatment groups did not differ significantly with regard to changes in antibody titers after vaccination (P=.96 for anti-S. Typhi IgG antibodies, P=.07 for anti-S. Typhi IgA antibodies, and P=.64 for vibriocidal antibodies). The A-P combination was highly effective for malaria prophylaxis, without interfering with the in vivo immunogenicity of CVD103-HgR and Ty21a vaccines, and it could therefore be simultaneously administered with these vaccines.

Atovaquone/proguanil therapy for Plasmodium falciparum and Plasmodium vivax malaria in Indonesians who lack clinical immunity.

Thirty-eight of 295 subjects participating in a randomized, double-blind, placebo-controlled trial of the efficacy of daily administration of atovaquone/proguanil for malaria prevention developed malaria at some time during the 20-week prophylaxis period. These subjects (3 atovaquone/proguanil recipients and 35 placebo recipients) were treated with 4 tablets of atovaquone/proguanil per day for 3 days. Atovaquone/proguanil provided safe, well-tolerated, and effective therapy for uncomplicated malaria in nonimmune Indonesians.

Randomized, placebo-controlled trial of atovaquone/proguanil for the prevention of Plasmodium falciparum or Plasmodium vivax malaria among migrants to Papua, Indonesia.

The increasing prevalence of resistance to antimalarial drugs reduces options for malaria prophylaxis. Atovaquone/proguanil (Malarone; GlaxoSmithKline) has been >95% effective in preventing Plasmodium falciparum malaria in lifelong residents of areas of holoendemicity, but data from persons without clinical immunity or who are at risk for Plasmodium vivax malaria have not been described. We conducted a randomized, double-blinded study involving 297 people from areas of nonendemicity in Indonesia who migrated to Papua (where malaria is endemic) < or =26 months before the study period. Subjects received prophylaxis with 1 Malarone tablet (250 mg of atovaquone and 100 mg of proguanil hydrochloride; n=148) or placebo (n=149) per day for 20 weeks. Hematologic and clinical chemistry values did not change significantly. The protective efficacy of atovaquone/proguanil was 84% (95% confidence interval [CI], 44%-95%) for P. vivax malaria, 96% (95% CI, 72%-99%) for P. falciparum malaria, and 93% (95% CI, 77%-98%) overall. Atovaquone/proguanil was well tolerated, safe, and effective for the prevention of drug-resistant P. vivax and P. falciparum malaria in individuals without prior malaria exposure who migrated to Papua, Indonesia.