Approval of Tafenoquine for Malaria Chemoprophylaxis

Am J Trop Med Hyg. 2019 Jun;100(6):1301-1304. doi: 10.4269/ajtmh.19-0001.

Abstract

Malaria chemoprophylaxis has become increasingly prominent now that it is used for vulnerable populations in endemic regions in addition to nonimmune travelers to those regions. The objective would be a drug with > 95% efficacy and that is easily tolerated, including in children and pregnant women. For individuals who prefer weekly rather than daily drug administration, a further objective is a product that is administered weekly. The deficiencies of present agents are parasite resistance to chloroquine, neuropsychiatric liability of mefloquine, the need for daily dosing for atovaquone-proguanil, and daily dosing plus adverse reactions for doxycycline. A primaquine analogue, tafenoquine, has a 17-day half-life and was approved for weekly prophylaxis in the United States and in Australia in 2018. Weekly tafenoquine was equal to mefloquine in efficacy in nonimmunes. The tafenoquine label contains a contraindication for preexisting psychosis, but not for the broad number of other neuropsychiatric disorders which are listed as contraindications in the mefloquine label. As an 8-aminoquinoline, tafenoquine is contraindicated for glucose-6-phosphate dehydrogenase (G6PD)-deficient persons or in pregnancy if the fetus might be G6PD deficient. Other possible significant adverse reactions for tafenoquine are declines in hemoglobin levels reported in some G6PD-normal patients, asymptomatic elevations in methemoglobin, and minor psychiatric events. The lack of broad neuropsychiatric adverse reactions suggests that tafenoquine may have a role as the weekly prophylactic of choice for G6PD-normal persons.

MeSH terms

  • Aminoquinolines / administration & dosage*
  • Aminoquinolines / adverse effects
  • Antimalarials / administration & dosage*
  • Antimalarials / adverse effects
  • Australia
  • Chemoprevention / methods*
  • Child
  • Contraindications, Drug*
  • Drug Administration Schedule
  • Drug Approval / legislation & jurisprudence
  • Female
  • Fetus
  • Glucosephosphate Dehydrogenase Deficiency / blood
  • Glucosephosphate Dehydrogenase Deficiency / diagnosis
  • Hemoglobins / metabolism
  • Humans
  • Malaria, Falciparum / parasitology
  • Malaria, Falciparum / prevention & control*
  • Methemoglobin / metabolism
  • Pregnancy
  • Psychotic Disorders / diagnosis
  • United States

Substances

  • Aminoquinolines
  • Antimalarials
  • Hemoglobins
  • tafenoquine
  • Methemoglobin