Evaluating the Efficacy of Chloroquine for the Treatment of Plasmodium Vivax Infections in Central Vietnam
Status:
Unknown status
Trial end date:
2016-12-01
Target enrollment:
Participant gender:
Summary
Understanding the extent and regional distribution of CQR vivax malaria and detecting early
signs of resistance is critical to prevent the spread of resistant strains, optimize
treatment guidelines, and reduce the risk of recurrent and severe malaria. In Vietnam, CQR in
P.vivax has been reported sporadically. One study carried out in Binh Thuan province
(central-south Vietnam) at the end of the 1990s demonstrated early P.vivax recurrences (7%)
by Day 16 after a 3-day CQ treatment. However, in a summary report to World Health
Organization (WHO) including data from 11 sentinel sites, from studies conducted between 2006
and 2011 in central and southern Vietnam (total 350 patients), P.vivax is still considered
sensitive to CQ. More recently in a cohort study conducted in Quang Nam province (Central
Vietnam) in which P.vivax patients were treated radically with CQ and primaquine (10-day at
0.5mg/kg/day) following national guidelines, the 28-day failure rate was measured at 3.45%
and CQ blood concentrations measured at day of recurrence (>100ng/ml) confirmed resistance in
three patients. The current national guidelines for the radical cure regimen of P.vivax
infections recommends 3 days of CQ (total 25 mg/kg body weight (bw)) together with 14 days of
primaquine at 0.25 mg/kg bw/ day.
The current WHO protocol recommends a 28-day follow-up to assess the efficacy of CQ for the
treatment of P.vivax infections. However, recurrence of early stage resistant parasites may
occur after Day 28 in the presence of CQ blood levels above the minimum efficacy
concentration (MEC, ≥100ng/ml) and relapses could occur as early as 36 days after standard CQ
treatment. Therefore, in order to confirm CQR it is recommended to extend the follow-up
period, to Day 42 or 63 and measure whole blood CQ level at Day 28 and at the time of
recurrence. Moreover, it has been shown that emerging drug resistance in P.vivax is
associated with delayed parasite clearance after treatment, i.e. some parasites are still
detectable at Day 3. The aim of the present study is to assess the in vivo and ex vivo
susceptibility of P.vivax to CQ in Central Vietnam following the currently recommended
radical cure regimen and using GMP certified CQ.
Phase:
Phase 4
Details
Lead Sponsor:
National Institute of Malariology, Parasitology and Entomology, Vietnam