Estimation of the Antirelapse Efficacy of Tafenoquine, Using Plasmodium vivax Genotyping.
Prevention of relapse of Plasmodium vivax infection is a key treatment goal in malaria. Use of P. vivax genotyping in a multicenter, double-blind, randomized, placebo-controlled phase 2b study in Peru, India, Thailand, and Brazil allowed determination of genetically heterologous or homologous P. vivax infection recurrence following receipt of chloroquine plus one of 4 doses of tafenoquine (50, 100, 300, or 600 mg) or chloroquine plus primaquine, compared with receipt of chloroquine alone. The antihypnozoite efficacy of tafenoquine was evident as a reduction in homologous recurrences of P. vivax infection as drug doses were increased. No clear dose-response pattern was evident for heterologous recurrences of P. vivax infection. Rates of homologous recurrence of P. vivax infection appear to be clinically useful for comparing drug efficacy for the prevention of P. vivax infection relapse.


BACKGROUND
NCT01376167.
Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel.
Hans-Peter
HP
Beck
Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel.
Rahel
R
Wampfler
GlaxoSmithKline Research and Development, Middlesex, United Kingdom.
Nick
N
Carter
GlaxoSmithKline Research and Development, Middlesex, United Kingdom.
Gavin
G
Koh
School of Public Health, Universidad del Valle, Cali, Colombia.
Lyda
L
Osorio
Mae-Sot General Hospital, Tak Province.
Ronnatrai
R
Rueangweerayut
Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Srivcha
S
Krudsood
Fundação de Medicina Tropical Doutor Heitor Vieira Amazonas Dourado, Manaus, Brazil.
Marcus V
MV
Lacerda
Instituto de Medicina Tropical Alexander von Humboldt School of Public Health, Universidad Peruana Cayetano Heredia, Lima, Peru.
Alejandro
A
Llanos-Cuentas
Medicines for Malaria Venture, Geneva, Switzerland.
Stephan
S
Duparc
GlaxoSmithKline Research and Development, Middlesex, United Kingdom.
Justin P
JP
Rubio
GlaxoSmithKline Research and Development, Middlesex, United Kingdom.
Justin A
JA
Green
D000634:Aminoquinolines / Q000008:administration & dosage / Q000627:therapeutic use*; D000962:Antimalarials / Q000008:administration & dosage / Q000627:therapeutic use*; D002738:Chloroquine / Q000008:administration & dosage / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005838:Genotype; D006801:Humans; D016780:Malaria, Vivax / Q000188:drug therapy*; D010966:Plasmodium vivax / Q000235:genetics*; D011319:Primaquine / Q000008:administration & dosage / Q000627:therapeutic use; D055502:Secondary Prevention
D000634:Aminoquinolines; D000962:Antimalarials; C055852:tafenoquine; D002738:Chloroquine; D011319:Primaquine
Plasmodium vivax; antihypnozoite; efficacy; genotyping; tafenoquine