Dihydroartemisinin-piperaquine Resistance in Plasmodium Falciparum Malaria in Cambodia: A Multisite Prospective Cohort Study

Lancet Infect Dis. 2016 Mar;16(3):357-65. doi: 10.1016/S1473-3099(15)00487-9. Epub 2016 Jan 8.

Abstract

Background: Artemisinin resistance in Plasmodium falciparum threatens to reduce the efficacy of artemisinin combination therapies (ACTs), thus compromising global efforts to eliminate malaria. Recent treatment failures with dihydroartemisinin-piperaquine, the current first-line ACT in Cambodia, suggest that piperaquine resistance may be emerging in this country. We explored the relation between artemisinin resistance and dihydroartemisinin-piperaquine failures, and sought to confirm the presence of piperaquine-resistant P falciparum infections in Cambodia.

Methods: In this prospective cohort study, we enrolled patients aged 2-65 years with uncomplicated P falciparum malaria in three Cambodian provinces: Pursat, Preah Vihear, and Ratanakiri. Participants were given standard 3-day courses of dihydroartemisinin-piperaquine. Peripheral blood parasite densities were measured until parasites cleared and then weekly to 63 days. The primary outcome was recrudescent P falciparum parasitaemia within 63 days. We measured piperaquine plasma concentrations at baseline, 7 days, and day of recrudescence. We assessed phenotypic and genotypic markers of drug resistance in parasite isolates. The study is registered with ClinicalTrials.gov, number NCT01736319.

Findings: Between Sept 4, 2012, and Dec 31, 2013, we enrolled 241 participants. In Pursat, where artemisinin resistance is entrenched, 37 (46%) of 81 patients had parasite recrudescence. In Preah Vihear, where artemisinin resistance is emerging, ten (16%) of 63 patients had recrudescence and in Ratanakiri, where artemisinin resistance is rare, one (2%) of 60 patients did. Patients with recrudescent P falciparum infections were more likely to have detectable piperaquine plasma concentrations at baseline compared with non-recrudescent patients, but did not differ significantly in age, initial parasite density, or piperaquine plasma concentrations at 7 days. Recrudescent parasites had a higher prevalence of kelch13 mutations, higher piperaquine 50% inhibitory concentration (IC50) values, and lower mefloquine IC50 values; none had multiple pfmdr1 copies, a genetic marker of mefloquine resistance.

Interpretation: Dihydroartemisinin-piperaquine failures are caused by both artemisinin and piperaquine resistance, and commonly occur in places where dihydroartemisinin-piperaquine has been used in the private sector. In Cambodia, artesunate plus mefloquine may be a viable option to treat dihydroartemisinin-piperaquine failures, and a more effective first-line ACT in areas where dihydroartemisinin-piperaquine failures are common. The use of single low-dose primaquine to eliminate circulating gametocytes is needed in areas where artemisinin and ACT resistance is prevalent.

Funding: National Institute of Allergy and Infectious Diseases.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antimalarials / pharmacology*
  • Artemisinins / administration & dosage
  • Artemisinins / pharmacology*
  • Cambodia / epidemiology
  • Child
  • Child, Preschool
  • Cohort Studies
  • Drug Resistance*
  • Drug Therapy, Combination
  • Female
  • Genotype
  • Humans
  • Inhibitory Concentration 50
  • Malaria, Falciparum / drug therapy
  • Malaria, Falciparum / epidemiology
  • Malaria, Falciparum / parasitology*
  • Male
  • Middle Aged
  • Plasmodium falciparum / drug effects*
  • Prospective Studies
  • Quinolines / administration & dosage
  • Quinolines / pharmacology*
  • Young Adult

Substances

  • Antimalarials
  • Artemisinins
  • Quinolines
  • dihydroartemisinin
  • piperaquine

Associated data

  • ClinicalTrials.gov/NCT01736319