Efficacy of Praziquantel for Treatment of Plasmodium falciparum Infection in Asymptomatic Gabonese Adults: A Double-Blind Placebo-Controlled Randomized Trial.

Abstract

Schistosomiasis and malaria are major poverty-related parasitic infectious diseases. They are often coendemic and affect similar target populations. Mass drug administration and intermittent preventive treatment programs are commonly used for their control. From a programmatic perspective the establishment of preventive treatment programs targeting both diseases simultaneously would be a great advantage. While there is preliminary evidence that certain antimalarial drugs exert a clinically important effect on Schistosomes, little is known on whether praziquantel (PZQ), the only licensed drug to treat schistosomiasis, has activity against Plasmodium parasites. Therefore, the CORMA-MAL study was conducted to evaluate antimalarial activity of PZQ. This double-blinded, randomized, placebo-controlled phase 2b trial was conducted in Lambaréné, Gabon and recruited semi-immune adults with an asymptomatic Plasmodium falciparum parasitemia. Participants were randomized (1:1) to receive placebo or 40 mg/kg PZQ once daily for 3 days and followed up for a total of 7 days. Forty-four participants were recruited. Analytical models indicated a highly significant hourly reduction of microscopically determined parasitemia in the PZQ arm and a nonsignificant decreasing trend in the placebo group (regression slopes of log10-transformed parasitemia: β=-0.006 [P < .001] and β=-0.0013 [P = .3], respectively). However, in total only 9 of 22 (41%) in the PZQ arm compared to 6 of 22 (27%) in the placebo arm reached parasite clearance by day 7. Findings demonstrate a statistically significant antimalarial activity of PZQ; however, the observed effect is only moderate compared to current first-line antimalarial treatments. Future research should investigate the synergistic potential of combining PZQ and antimalarial drugs in malaria and schistosomiasis control. Clinical Trials Registration.Pan African Clinical Trials Registry, PACTR202206584817951, 10 June 2022 (https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=22586).