This is a prospective, double-blind, double-dummy, multicenter, comparative study. A total of 300 subjects will be randomized to treatment on Day 1, of which a minimum of 50 female subjects must be enrolled that display moderate glucose-6-phosphate dehydrogenase (G6PD) deficiency (\>=40% - \<70% of the site median G6PD value). Subjects must have a blood smear that is positive for P. vivax at entry. Subjects will be randomized 2:1 to receive tafenoquine (TQ)/chloroquine(CQ) or the active comparator primaquine (PQ)/CQ. All subjects will receive CQ on Days 1 to 3, followed by TQ or PQ and matching placebo beginning on Day 1 or 2. Tafenoquine, or matching placebo, will be given as a single, 300mg dose. Subjects will receive PQ (15mg once daily) or matching placebo for 14 days. The duration of the study is 180 days, including screening and randomization to treatment (Day 1), three in-hospital days (Days 1-3), four out-patient visits while on treatment with study medication (Days 5, 8, 11 and 15) and seven follow-up visits (Days 22, 29, 60, 90, 120, 150 and 180). The primary safety data collected in this study will help to understand the hemolysis risk to both G6PD-normal and G6PD-deficient subjects. The efficacy data produced from this study will support the results for sister study TAF112582, the pivotal phase III efficacy and safety study of the TQ program.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
251
Tafenoquine will be supplied as a dark pink, capsule-shaped, film-coated tablet that is plain on both sides. Each tablet will contain 150mg TQ.
Placebo TQ tablets will be supplied as a dark pink, capsule-shaped, film-coated tablet that is plain on both sides, with common excipients of appropriate quality.
One of two formulations of commercially available generic chloroquine may be utilized in this study: 1. tablets containing 500 mg chloroquine phosphate (equivalent to 300 mg chloroquine free base); or, 2. tablets containing 250 mg chloroquine phosphate (equivalent to 155 mg chloroquine free base).
Commercially available primaquine containing primaquine phosphate united states pharmacopeia (USP), 26.3 mg (equivalent to primaquine base 15 mg) will be utilized in this study. Primaquine, a pink film-coated tablet imprinted W on one side and P97 on the other side. The PQ tablets for this study have been over-encapsulated in a Swedish orange size B supro capsule.
Placebo to match PQ will be supplied as Swedish orange size B supro capsules with common excipients of appropriate quality.
GSK Investigational Site
Manaus, Amazonas, Brazil
GSK Investigational Site
Cali, Colombia
GSK Investigational Site
Montería, Colombia
GSK Investigational Site
Gonder, Ethiopia
GSK Investigational Site
Jimma, Ethiopia
GSK Investigational Site
Iquitos, Loreto, Peru
GSK Investigational Site
Bangkok, Thailand
GSK Investigational Site
Mae Sot, Thailand
GSK Investigational Site
Tak, Thailand
GSK Investigational Site
Ho Chi Minh City, Vietnam
Percentage of Participants With Clinically Relevant Hemolysis.
Clinically relevant hemolysis is defined as a decrease in hemoglobin of \>=30% or \>3 grams per deciliter (g/dL) from Baseline; or, an overall drop in hemoglobin below 6.0 g/dL at any visit after the first dose of study medication. The percentage of participants with clinically relevant hemolysis has been summarized. Safety Population comprised of all randomized participants who received at least one dose of blinded study medication.
Time frame: Up to Day 180
Percentage of Female Participants With Moderate Glucose-6 Phosphate Dehydrogenase (G6PD) Deficiency Experiencing Clinically Relevant Hemolysis.
Clinically relevant hemolysis is defined as a decrease in hemoglobin of \>=30% or \>3 g/dL from Baseline; or, an overall drop in hemoglobin below 6.0 g/dL at any visit after the first dose of study medication. Despite additional efforts, no females with moderate G6PD-deficiency were enrolled that experienced clinically-significant hemolysis during the study; hence, the end point could not be estimated.
Time frame: Up to Day 180
Rate of Relapse-free Efficacy at Six Months Post Dose
A participant was considered to have demonstrated relapse-free efficacy at 6 months if: a) Participant had non-zero P. vivax asexual parasite count at Baseline. b) Participant showed initial clearance of P. vivax parasitemia defined as two negative asexual P. vivax parasite counts, with at least 6 hours between the counts, and no positive counts in the interval. c) Participant had no positive asexual P. vivax parasite count at any assessment prior to or on Study Day 201 following initial parasite clearance. d) Participant did not take a concomitant medication with anti-malarial activity at any point between Study Day 1 and their last parasite assessment. e) Participant is parasite-free at 6 months. The rate of relapse-free efficacy was estimated by Kaplan-Meier methodology. The percentage of participants who were relapse-free at 6 months post dose has been presented along with 95% confidence interval.
Time frame: 6 months post dose
Rate of Relapse-free Efficacy at Four Months Post Dose
A participant was considered to have demonstrated recurrence-free efficacy at 4 months if: a) Participant had non-zero P. vivax asexual parasite count at Baseline. b) Participant showed initial clearance of P. vivax parasitemia. c) Participant had no positive asexual P. vivax parasite count at any assessment prior to or on Study Day 130 following initial parasite clearance. d) Participant did not take a concomitant medication with anti-malarial activity at any point between Study Day 1 and their last parasite assessment after Study Day 109 (up to and including Study Day 130). e) Participant is parasite-free at 4 months. The rate of relapse-free efficacy was estimated by Kaplan-Meier methodology. The percentage of participants who were relapse-free at 4 months post dose has been presented along with 95% confidence interval.
Time frame: 4 months post dose
Time to Relapse of P. Vivax Malaria
Relapse is defined by a positive blood smear with or without vivax symptoms. Relapse is described as any recurrence of malaria that occurred after Day 32 of the study. The time to relapse was analyzed by the Kaplan-Meier method. The median number of days to relapse along with 95% confidence interval has been presented for each treatment group.
Time frame: Up to Day 180
Time to Parasite Clearance
Parasite clearance time is defined as time needed to clear asexual parasite from the blood that is, parasite numbers falling below the limit of detection in the thick blood smear and remaining undetectable after 6 to 12 hours later. The time to achieve parasite clearance was analyzed by Kaplan-Meier methodology. The median parasite clearance time along with 95% confidence interval has been presented for each treatment group.
Time frame: Up to Day 180
Time to Fever Clearance
Fever clearance time is defined as the time from first dose of treatment to the time when body temperature falls to normal within Study Days 1-4 and remains normal for at least 48 hours up to the Day 8 visit. Fever clearance was considered to have been achieved once an initial temperature of more than 37.4 degree Celsius is reduced to a value less than or equal to 37.4 degree Celsius, in the absence of value more than 37.4 degree Celsius in the following 48 hours up to the Day 8 visit. The time taken to achieve fever clearance was analyzed by Kaplan-Meier method.
Time frame: Up to Day 9
Time to Gametocyte Clearance
Gametocyte clearance time is defined as time from first dose until the first slide that was gametocyte negative and remained so at the next slide reading. The time taken to achieve gametocyte clearance was analyzed by Kaplan-Meier method.
Time frame: Up to Day 180
Number of Participants With Recrudescence
Recrudescence is defined as any P. vivax parasitemia occurring on or before Day 32 (that is, blood stage treatment failure). A participant was considered to have had a recrudescence if both of the following were true: a) Participant had a positive P. vivax asexual parasite count at Baseline and demonstrated clearance (that is, did not have two negative asexual P. vivax parasite counts, with at least 6 hours between the counts, and no positive counts in the interval). b) Participant had a positive genetically homologous asexual P. vivax parasite count, after their zero count in Days 1 to 5, but on or before Study Day 32. The number of participants with recrudescence before Study Day 33 has been presented.
Time frame: Up to Day 32
Number of Participants With Genetically Homologous and Genetically Heterologous P. Vivax Infections
Two drops of peripheral blood were collected onto pre-printed filter paper for subsequent deoxyribonucleic acid (DNA) extraction and polymerase chain reaction (PCR) analysis of Plasmodium species on all participants at screening (Day 1; pre-dose) and; if necessary, at the time of the first recrudescence/relapse or re-infection. PCR of the P. vivax genes, was used to distinguish between genetically homologous and genetically heterologous infection. The number of participants with genetically homologous and genetically heterologous P. vivax infections has been summarized for each treatment group. Only those participants with an infection occuring on or after Study Day 33 were analyzed.
Time frame: Up to Day 180
Number of Participants With Clinical Chemistry Laboratory Data Outside the Reference Range
Plasma or serum samples were anlalyzed to evaluate clinical chemistry parameters such as alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), bilirubin, creatine kinase, creatinine, glomerular filtration rate (GFR), indirect bilirubin and urea. The number of participants with clinical chemistry laboratory values outside the extended normal range (F3) has been presented. The upper and lower limits for F3 range were defined by multiplying the normal range limits by different factors. High and low indicated that the participants had values flagged as high and low respectively for the particular parameter any time on-treatment. Safety Population consisted of all randomized participants who received at least one dose of blinded study medication.
Time frame: Up to Day 120
Number of Participants With Hematology Laboratory Data Outside the Reference Range
Blood samples were collected for the evaluation of hematology parameters including eosinophils, leukocytes, lymphocytes, neutrophils, platelets, reticulocytes and methemoglobin. The number of participants with hematology laboratory data outside the extended normal range (F3) has been presented. The upper and lower limits for F3 range were defined by multiplying the normal range limits by different factors. High and low indicated that the participants had values flagged as high and low respectively for the particular parameter any time on-treatment. Participants having both High and Low values for Normal Ranges at any post-baseline visits for safety parameters were counted in both the High and Low categories.
Time frame: Up to Day 120
Number of Participants With Abnormal Urinalysis Dipstick Results
Mid-stream urine was collected and analyzed for bilirubin, glucose, ketones, leukocyte esterase (LE), nitrites, occult blood, proteins and urobilinogen by dipstick method. The number of participants with abnormal urinalysis results (Trace, +, ++, +++, ++++) has been presented. Only those participants with data available at the specified data points were analyzed.
Time frame: Up to Day 120
Number of Participants With Treatment Emergent Adverse Events (TEAEs) and Serious TEAEs
An adverse event (AE) is defined as any untoward medical occurrence in a participant under clinical investigation, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Serious adverse event (SAE) is defined as any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/ birth defect, other situations such as important medical events and events of possible drug induced liver injury with hyperbilirubinemia. TEAEs are defined as AEs with an onset date and time on or after that of the start of first dose of study medication (including CQ). Number of participants with TEAEs and serious TEAEs have been presented.
Time frame: Up to Day 180
Number of Participants With Electrocardiogram (ECG) Findings
12 lead ECG was performed with the participant in a semi-supine position having rested in this position for at least 10 minutes. ECG assessments were performed in triplicate at screening followed by single ECGs 12 hours after the first dose of study medication and at Day 29. The number of participants with abnormal-clinically significant ECG findings have been presented. The 12 Hour Post Randomized Treatment (11.5-12.5 Hours) timepoint included all readings taken between 11.5 and 12.5 hours post randomized treatment. The 12 Hour Post Randomized Treatment (8-72 Hours) timepoint is a sensitivity analysis of the 12 Hour post randomized treatment timepoint, including all readings taken between 8 and 72 hours post randomized treatment. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Up to Day 29
Change From Baseline in Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Mean Arterial Pressure (MAP)
Vital signs were measured twice a day on Days 1 through 3, at least 4 hours apart, and immediately prior to pharmacokinetic (PK) measurements. MAP was calculated as the sum of SBP and two times DBP divided by 3. The mean and standard deviation of SBP, DBP and MAP has been presented. The values presented does not include Day 3 assessments for participant number 570. Baseline value is defined as the latest pre-treatment assessment where treatment is their first dose of study medication (CQ/PQ/TQ/Placebo). Change from Baseline is the value at post dose minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Baseline and up to Day 180
Change From Baseline in Pulse Rate
Vital signs were measured twice a day on Days 1 through 3, at least 4 hours apart, and immediately prior to PK measurements. The mean and standard deviation of pulse rate has been presented. The values presented does not include Day 3 assessments for participant number 570. Baseline value is defined as the latest pre-treatment assessment where treatment is their first dose of study medication (CQ/PQ/TQ/Placebo). Change from Baseline is the value at post dose minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Baseline and up to Day 180
Change From Baseline in Temperature
Vital signs were performed twice a day on Days 1 through 3, at least 4 hours apart, and immediately prior to PK measurements. The mean and standard deviation of pulse rate has been presented. The values presented does not include Day 3 assessments for participant number 570. Baseline value is defined as the latest pre-treatment assessment where treatment is their first dose of study medication (CQ/PQ/TQ/Placebo). Change from Baseline is the value at post dose minus Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Baseline and up to Day 180
Number of Participants With P. Falciparum
Microscopic blood slides (two thick film and one thin film slide) were prepared and examined for asexual parasite count. The number of participants with positive P. falciparum asexual parasite count post Baseline has been summarized for each treatment arm.
Time frame: Up to Day 180
Number of Participants With Keratopathy
Ophthalmic assessments were carried out at pre-qualified sites prior to randomization and at Days 29 and 90 and at withdrawal follow-up visit. Assessments were carried out at Day 180 (and up to resolution) if the Day 90 assessments showed abnormalities. The last assessment performed on the day of randomization or earlier was considered Baseline. The number of participants displaying keratopathy in each eye has been summarized for each visit. The number of participants with new keratopathy at any time post Baseline is also reported. Ophthalmic Safety Population comprised of all participants in the Safety Population who have results from any eye assessments. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Up to Day 180
Number of Participants With Change in Best Corrected Visual Acuity Test Scores
Ophthalmic assessments were carried out at pre-qualified sites prior to randomization and at Days 29 and 90 and at withdrawal. Assessments were carried out at Day 180 if the Day 90 assessments showed abnormalities. The last assessment performed on the day of randomization or earlier was considered Baseline. Change from Baseline is the value at post dose visit minus the Baseline value. Best corrected visual acuity was assessed individually for each eye. Scores were recorded as a ratio. The values were used to derive a logMAR score for statistical analysis where logMAR=-1x log10 (ratio score). The number of participants with change in Best Corrected Visual Acuity Test Scores from Baseline has been presented where possible change is defined as a change from Baseline \>=0.12 to \<0.3 and definite change is defined as a change from Baseline \>=0.3 logMAR score. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Baseline and up to Day 180
Number of Participants With Retinal Changes From Baseline
Ophthalmic assessments were carried out at pre-qualified sites prior to randomization and at Days 29 and 90 and at withdrawal follow-up. Assessments were carried out at Day 180 (and up to resolution) if the Day 90 assessments showed abnormalities. The last assessment performed on the day of randomization or earlier was considered Baseline. Change from Baseline was calculated as the value at post dose visit minus the Baseline value. The number of participants with definite retinal change and questionable (ques) retinal change from Baseline has been presented. The number of participants with maximum change post-Baseline (definite when absent or questionable at Baseline) has been presented for either eye. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Baseline and up to Day 180
Change From Baseline in Percent Methemoglobin
Methemoglbin is an oxidized and inactive form of hemoglobin. Methemoglobin assessment was made with the aid of a non-invasive signal extraction pulse CO-Oximeter handheld machine. The change from Baseline in percent methemoglobin by treatment, time and sex has been summarized. The latest pre-treatment assessment where treatment is their first dose of study medication (CQ/PQ/TQ/Placebo) was considered as Baseline value. Change from Baseline is the value at post dose visit minus the Baseline value. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Baseline and up to Day 120
Cost Associated With Relapse Episode of P Vivax Malaria
Health outcomes were evaluated based on the total costs spent on treatment, transport, medication and tests. The cost was summarized according to the place at which the participant went to for care (drug shop, trial clinic, other clinic, hospital emergency center, other). The costs associated with a relapse episode of P. vivax malaria has been presented. Participants may be represented in more than one category, so the total number of participants may be less than the number quoted. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Up to Day 180
Cost Associated With a Hemolysis Event
Health outcomes were evaluated based on cost incurred due to clinically relevant hemolysis. The total cost was evaluated based on the amount spent on treatment, transport, medication and test. The costs associated with hemolysis event has been presented. The aim of this outcome measure was to determine the cost to a participant due to an event of hemolysis, regardless of treatment received in the study. It was not expected there would be major cost differences with hemoglobin decrease between the treatment arms. This was pre-specified in the statistical analysis plan.
Time frame: Up to Day 180
Cost Incurred With Purchase of Medications Associated With Relapse Episode of P. Vivax Malaria
Health outcomes were evaluated based on the cost of medications purchased. The total medication cost for paracetamol associated with relapse episode of P vivax malaria has been presented. Medications recorded as "Other" and medications without costs are excluded from the analysis. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Up to Day 180
Cost Incurred With Purchase of Medications Associated With Hemolysis Event
Health outcomes were evaluated based on the cost of medications purchased. The total medication cost associated with hemolysis event has been presented. Medications recorded as "Other" and medications without costs are excluded from the analysis. The aim of this outcome measure was to determine the cost to a participant due to an event of hemolysis, regardless of treatment received in the study. It was not expected there would be major cost differences with hemoglobin decrease between the treatment arms. This was pre-specified in the statistical analysis plan.
Time frame: Up to Day 180
Number of Participants or Care Givers Who Had Taken Time Off From Normal Occupation Due to Relapse Episode of Malaria
Health outcomes were evaluated based on total time lost by participants or care givers due to an episode of malaria. The number of participants or care givers who had taken off from their normal occupation due to relapse episode of P vivax malaria has been presented by country. Participants may be represented in more than one category, so the total number of participants may be less than the number quoted. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Up to Day 180
Number of Participants or Care Givers Who Had Taken Time Off From Normal Occupation Due to a Hemolysis Event
Health outcomes were evaluated based on total time lost by participants or care givers due to a hemolysis event. The number of participants or care givers who took days off from work due to a hemolysis event has been presented based on the normal occupation. The aim of this outcome measure was to determine the time taken off by participants due to an event of hemolysis, regardless of treatment received in the study. It was not expected there would be major differences in time taken off by participants with hemoglobin decrease between the treatment arms. This was pre-specified in the statistical analysis plan.
Time frame: Up to Day 180
Number of Participants With Action Taken to Treat Relapse Episode of P. Vivax Malaria
Health outcomes were evaluated based on the actions taken by the participants to treat relapse episode of P vivax malaria. The number of participants with the type of action taken to treat relapse episode of P vivax malaria has been presented by country. Participants may be represented in more than one category, so the total number of participants may be less than the number quoted. Only those participants with data available at the specified data points were analyzed (represented by n=X in category title).
Time frame: Up to Day 180
Number of Participants With Action Taken to Treat a Hemolysis Event
Health outcomes were evaluated based on the actions taken by the participants to treat hemolysis events. The number of participants in Brazil who attended the trial clinic to treat a hemolysis event has been presented. The aim of this outcome measure was to determine the action taken by a participant due to an event of hemolysis, regardless of treatment received in the study. It was not expected there would be major differences in action taken by the participants with hemoglobin decrease between the treatment arms. This was pre-specified in the statistical analysis plan.
Time frame: Up to Day 180
Oral Clearance (CL/F) of TQ
Apparent population oral clearance of TQ
Time frame: Day 2, Day 3, Day 8, Day 15, Day 29, Day 60 and Day 180
Volume of Distribution (Vc/F) of TQ
Apparent population central volume of distribution of TQ
Time frame: Day 2, Day 3, Day 8, Day 15, Day 29, Day 60 and Day 180
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.