Efficacy and Safety of Fosmidomycin-Piperaquine as Nonartemisinin-Based Combination Therapy for Uncomplicated Falciparum Malaria: A Single-Arm, Age De-escalation Proof-of-Concept Study in Gabon

Background. Fosmidomycin-piperaquine is being developed as nonartemisinin-based combination therapy to meet the challenge of emerging artemisinin resistance. Methods. Te study was a phase 2, single-arm, proof-of-concept study of the efcacy, tolerability, and safety of fosmidomycin-piperaquine for the treatment of uncomplicated Plasmodium falciparum monoinfection in Gabon. Adults and children of both sexes with initial parasite counts between 1000 and 150 000/μ L received oral treatment with fosmidomycin (twice daily doses of 30 mg/kg) and piperaquine (once daily dose of 16 mg/kg) for 3 days and followed-up for 63 days. Te primary efcacy endpoint was the per-protocol polymerase chain reaction (PCR)-corrected day 28 adequate clinical and parasitological response (ACPR). Results. One hundred patients were enrolled. Te PCR-corrected day 28 ACPR rate was 83/83, or 100% (95% confdence interval, 96-100). Fourteen patients had asexual parasitaemia between day 28 and day 63; all were typed by PCR as new infections. Fosmidomycin-piperaquine therapy led to rapid parasite clearance (median, 36 hours; interquartile range [IQR], 6-60) and fever clearance time (median, 12 hours; IQR, 6-48). Te electrocardiogram assessments showed 2 patients with prolonged QT interval >500 msec following study drug administration. Te majority of adverse events affected the gastrointestinal and respiratory tracts and were transient and mild to moderate in severity. Conclusions. Tis is the frst report of the use of the combination fosmidomycin-piperaquine. Te combination appeared to have high efcacy and be safe and well tolerated despite observed transient changes in electrocardiogram with prolongation of the QT interval.