A clinical study designed to develop and inform an individual risk of hemolysis model based on individual red blood cell G6PD levels. Volunteers who are eligible to treatment with primaquine as per national guidelines and with confirmed normal G6PD levels as per the fluorescent spot test will be exposed to treatment regimens of either primaquine alone for 14 days or 3 day chloroquine with concomitant primaquine for 14 days. The volunteers will be followed intensively during treatment and for 14 days after treatment for haematologic measures, G6PD quantification, and drug level assays.
Open label, randomized trial with 72 total participants assigned to one of two treatment arms. Each arm will have 36 participants comprised of 12 males hemizygous for wildtype G6PD, 12 females homozygous for wildtype G6PD, and 12 females heterozygous for G6PD with a normal fluorescent spot test (FST) (G6PD genotype abnormal with G6PD activity ≥40% and ≤80% of normal). Arm 1a will receive primaquine for 14 days, and Arm 1b will receive chloroquine for 3 days and concomitant primaquine for 14 days. All participants will be healthy volunteers without severe G6PD deficiency who will be followed for two weeks after completing their study drug dosing. Pregnant women and those breastfeeding will be excluded. Venous blood samples will be taken at regular intervals for haematologic measures, G6PD quantification, and drug level assays. G6PD levels will be measured both by spectrophotometry to provide whole blood G6PD levels normalized for hemoglobin, as well by flow cytometry to to provide red blood cell G6PD distributions throughout the treatment and post treatment. Changes in the G6PD distributions will be modeled, incorporating other critical haematological indicators collected throughout the study too.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
54
Participants receive primaquine for 14 days at 0.5 mg/Kg. Drug administration will be directly observed.
Participants will receive chloroquine for 3 days concomitant with primaquine for 14 days at 0.5 mg/Kg. Drug administration will be directly observed.
Shoklo Malaria Research Unit (SMRU)
Mae Sot, Thailand
Change in Haemoglobin
The change in haemoglobin from baseline on exposure to primaquine for P.vivax treatment over treatment course to hemoglobin level at day 28.
Time frame: 28 days after enrollment
Change in G6PD Concentration
The haemoglobin-related change in G6PD concentration, as determined by spectrometer, over treatment course. Change is determined from baseline to day 28
Time frame: 28 days after enrollment
Significance of CYP2D6
relevance of Dextromethorphan assay results to risk of haemolysis models
Time frame: 28 days after enrollment
Association of Drug Levels
Association of chloroquine and primaquine drug levels at the time of sampling for haematological and G6PD profiles.
Time frame: Days 1,2,3,5,7,9,11,14,17,21
Serious Adverse Events
frequency of serious adverse events in women heterozygous for G6PD
Time frame: 28 days after enrollment
Significance of Reticulocyte Count
relevance of reticulocyte count to risk of haemolysis models
Time frame: Days 1,2,3,5,7,9,11,14,17,21
Significance of Urobilinogen Levels
relevance of urobilinogen tests to risk of haemolysis models
Time frame: Days 1,2,3,5,7,9,11,14,17,21
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