View clinical trials related to Malaria, Vivax.
Filter by:Historically, Plasmodium vivax has been termed "benign" due to its non-life threatening clinical course and since the 1800's this view has been cultivated as demonstrated by the use of the term "benign tertian malaria" to describe the infection.However over the last 15 years, more severe P. vivax malaria is being reported, causing concern that severe P. vivax malaria is under diagnosed. The definition of severe P. vivax malaria borrows from P. falciparum and is primarily one of exclusion. Species PCR (polymerase chain reaction) is the only way to prove P. vivax mono-infection but is expensive and requires skilled staff and technology. In resource constrained settings, diagnostic testing is not available for detection of most non-malarial infections further affecting the ability to determine whether severe symptoms are due to P. vivax malarial infection or a concomitant one. Retrospective studies from India, Pakistan, Indonesia, Papua New Guinea and Sudan support the existence of severe P. vivax malaria. However, inconsistent methodologies, definitions of severity, and use of diagnostic tests to exclude concomitant infection do not allow for standardised assessments for severe P. vivax infection across studies. A review by Baird, highlighted that the risk of being classed as suffering from severe illness was only minimally higher in P. falciparum than in P. vivax, but was unable to combine the data as a meta-analysis. The primary reported symptoms for severe P. vivax included severe anaemia particularly in children, severe thrombocytopaenia, respiratory distress, neurological syndromes (coma or seizures), renal and hepatic failure. Prospective studies have shown similar results. Tjitra et al showed that 23% (675 of 2,937) patients admitted with microscopically diagnosed P. vivax infections in Papua, Indonesia had severe disease and that the risk of severe malaria was significantly higher when admitted with P. vivax than with P. falciparum. In studies from Papua New Guinea, few differences between the clinical presentation of P. falciparum and P. vivax were found in children with severe malaria. This appears to be similar in populations from Sudan, Pakistan and India. In contrast, in Thailand, anecdotal observations note a low prevalence of severe P. vivax infections. The WHO criteria to assess severe P. falciparum have been extrapolated to P. vivax. In the 2015 WHO malaria guidelines some criteria now account for P. vivax, such as removing a minimum parasitaemia when assessing for severe anaemia. Whilst these criteria may not be the most sensitive tool to define severe P. vivax infections, it is used for this purpose. It has been suggested that additional clinical information may be necessary to define truly severe P. vivax cases. In order to describe the characteristics of the severity of P. vivax infections in north-western Thailand, we will perform a retrospective review of annual reports of the outpatient database, the inpatient database and eligible inpatient medical records from 2001 to 2016. The WHO malaria guidelines and additional clinical information will be used to assess the severity of infection and thus, a rate of severe P. vivax can be determined.
Plasmodium vivax can be cause of severe malaria and mortality. There are serious public health implications associated with cases of P. vivax resistant to Chloroquine in the Americas as well there are efforts of many countries to eliminate this disease. In this way, it is critically important to evaluate an alternative radical cure treatment efficient to amazon scenario. The objectives of this trial are to demonstrate the superiority of adequate parasitological response at D42 of Dihydroartemisinin plus Piperaquine (DHA-PQP or Eurartesim®) versus Chloroquine and to evaluate the proportion of failure until D180 considering different starting days of Primaquine (0.50 mg/kg/day) for 14 days. It is an open, 4 arms, randomised, comparative trial. Total of 460 patients are initially planned to be included. To demonstrate the superiority of DHA-PQP compared to Chloroquine, the 95% confidence interval of the difference observed between both treatment success rates will be determined. Each recurrence will be passively and actively detected for 180 days.
This will be a single-arm observational cohort study. Malaria patients with Plasmodium vivax and meeting study inclusion criteria, who give consent to be enrolled in the study, will have their G6PD status measured by the CareStart™ G6DP rapid diagnostic test (G6PD RDT), and primaquine prescribed according to the result. According to the G6PD RDT result, primaquine will be prescribed at 0.25mg/kg/day for 14 days (normal patients) or 0.75mg/kg weekly for eight weeks (deficient patients). All will receive treatment with chloroquine to clear asexual stages of infection. Patients will be reviewed at day 2, day 7 and day 14. At these visits patients will undergo a brief clinical assessment and a small blood sample will be taken for repeat haemoglobin measurement and dried blood spot for carboxyprimaquine measurement (day 7 and day 14 only). In general, antimalarial treatment will be unsupervised to reflect field conditions. However a subset of 25 G6PD normal patients at a single site will have each day of their primaquine treatment administered and observed at the treatment centre. This is to determine a calibration curve for primaquine pharmacokinetic studies. Dried blood spots will be stored appropriately. Day zero samples will be genotyped in Bangkok (MORU, Dr. Mallika Imwong) after DNA extraction. PCR-RFLP will be used to detect the allele associated with the Mediterranean variant of G6PD deficiency. In addition DNA extracts will be sent for more systematic genetic testing for known G6PD variants through existing collaborations with the Wellcome Trust Sanger Institute. The day 7 and 14 dried blood spot samples will be analysed in the MORU pharmacology laboratory for primaquine and carboxyprimaquine concentrations, from which adherence to primaquine can be determined retrospectively, using the subset of 25 patients receiving directly observed therapy to calibrate the results. Funder: WellcomeTrust, Grant reference: 107548/Z/15/Z
Tafenoquine (TQ) is an 8-aminoquinoline anti-malarial drug which is in development as a single-dose treatment for the radical cure of P.vivax malaria when given with standard doses of chloroquine. Currently, the only available drug for radical cure is primaquine (PQ) which requires administration over 14 days, resulting in poor compliance. In Indonesia, chloroquine has been replaced by artemisinin-based combination therapy (i.e. ACTs) due to widespread chloroquine resistance. This study will evaluate the efficacy and safety of a single dose of tafenoquine when co-administered with an ACT (i.e. DHA-PQP). This single-center, double-blind, double-dummy, randomized study will test the superiority of DHA-PQP plus TQ against DHA-PQP alone in the prevention of P. vivax malaria relapse at 6 months. The study will be conducted in male Indonesian soldiers diagnosed with P.vivax malaria on return from deployment to a malarious region of Indonesia. A PQ plus DHA-PQP comparator arm is included to provide an informal comparison against the standard 14 day treatment for P.vivax malaria in Indonesia. Subjects who are glucose-6-phosphate dehydrogenase deficient (G6PD deficient) will be excluded due to the risk of acute hemolysis following dosing with 8-aminoquinolines drugs. Subjects who have a recurrence of P.vivax malaria during the study will be treated with an ACT plus PQ (0.5mg/kg for 14 days), in line with local treatment guidelines. At the end of the 6 month follow up period, any subject who has not relapsed will be given open label PQ (0.5mg/kg daily for 14 days) to minimize the likelihood of relapse after the study. Approximately 200 subjects will be screened to achieve 150 randomized subjects. The total duration of study for each subject will be 180-195 days. This study is being carried out to support registration of TQ in Indonesia and other countries where ACTs are first line therapy.
This study will investigate the effect of Tafenoquine (TQ) 150 mg tablet ageing (dissolution profiles) on human exposure of TQ comparing the relative bioavailability of TQ from tablets exhibiting different dissolution profiles in healthy subjects. This is a single-centre, 2-arm, randomized open-label, parallel-group study in healthy subjects. All subjects will arrive in the unit approximately 24 hours prior to dosing and will be discharged after the 72-hour post-dose assessments are completed. Subjects will return for outpatient visits on Days 7, 14, 21, 28, and 56 after dosing. A total of 14 subjects (n=7 subjects in each arm) are planned to be enrolled. All subjects will receive a single dose of study medication (2x150 mg TQ tablets + 30 mg TQ SIL in solution) and participate through a 56-day post dose follow-up visit. To enable the application of peripheral microsampling in planned paediatric studies, a comparison of the measured pharmacokinetic (PK) exposure via peripheral blood collection (via microsampling) to venous collection will also be performed in this study.
This is a randomized open-label trial to evaluate the efficacy of chloroquine (CQ) alone compared to chloroquine+primaquine (CQ+PQ) in the treatment of uncomplicated malaria caused by Plasmodium vivax infection in a endemic area in the westernmost part of the Amazon Basin of Brazil. The duration of follow up for evaluating CQ efficacy as a schizonticidal drug was 28 days. The duration of complete follow up to detect recurrent P. vivax infections by passive surveillance was six months. All patients in the CQ alone arm received 7 days of PQ treatment (3.5mg/kg total dose) starting on day 28 of the study follow-up.
The study aims to provide evidence of retinal safety to support the use of tafenoquine as a potential single dose radical cure treatment for patients with Plasmodium vivax (P. vivax) malaria (i.e., co-administration of a schizonticidal drug with TQ). The study will be conducted as a single masked, randomized, placebo-controlled, parallel group design. It will assess retinal changes from baseline using spectral domain optical coherence tomography (OCT) and fundus auto fluorescence (FAF) at Month 3 (90 days) post-dose in adult healthy volunteers (participants). A placebo control group will be used to compare the results in the TQ group. Interim analysis will be conducted after completing 100 out of 300 participants in TQ group and 50 out of 150 participants in matched placebo.
This is a prospective, open-label, multicenter, non-comparative, single arm study of pediatric subjects with Plasmodium vivax (P. vivax) malaria, aged 6 months to <16 years of age. A total of 60 subjects will be enrolled. Potential subjects who are slide-positive for P. vivax will be started by the site on chloroquine (CQ) per local/national guidelines. Sites will have up to 48 hours to obtain consent. Once full consent is provided, all subjects will be screened and, if eligible, receive Tafenoquine (TQ), given as a single dose on Day 1. All study medication should be taken with food. After the treatment period, subjects will attend up to 7 follow-up visits through Day 120 (Days 3, 8, 15, 29, 60, 90 and 120). The main cohort will consist of subjects aged >=2 years to <16 years with no restriction on gender. Subjects will be dosed according to four weight bands. Within the total of 60 enrolled pediatric subjects, a second cohort of up to 6 infants aged >=6 months to <2 years (weighing >=5 kilogram [kg]) will be recruited following completion of a planned first interim analysis. An interim analysis will be conducted once sufficient data from 16 subjects is available to assess pharmacokinetic (PK) and safety parameters. If needed, a second interim analysis will be conducted after a total of 32 subjects have enrolled. The primary objective of this PK bridging study is to adequately characterize the systemic TQ exposure in the pediatric population in order to identify appropriate doses that achieve a similar exposure to that of the TQ adult dose of 300 milligram (mg).
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.
This will be a single-centre, 5-cohort, randomized open-label, parallel-group study in healthy volunteer subjects. This study aims to provide sufficient pharmacokinetic (PK) evidence to support the safe usage of Tafenoquine (TQ) in studies and markets where the Artemisinin-based Combination Therapies (ACTs) are the standard of care for patients with Plasmodium vivax malaria (i.e., co administration with TQ). The objective of this study is to assess the pharmacokinetics, safety and tolerability of TQ when co-administered with the chosen ACTs (AL and DHA + PQP), administered concomitantly in healthy subjects. Specifically, the study will evaluate whether there are drug-drug interactions between TQ and each of the ACTs and if these interactions are considered to be clinically significant. The co-primary objectives of this study are to characterize both the effects of a 300 milligram (mg) single dose of TQ on the pharmacokinetics; changes in (area under the concentration-time curve from 0 to time t) AUC (0-t), AUC (0-infinity), and maximum observed concentration (Cmax) of each of the two Artemisinin-based Combination Therapies (ACT) according to their prescribed dose when co-administered as well as the effects of the ACTs on the PK of TQ. A total of 120 subjects (24 subjects in each of 5 cohorts) are planned to be enrolled in order to ensure a target sample size of at least 22 subjects completing the study per cohort. All subjects will arrive in the unit at least 24 hours prior to dosing and be discharged after 72-hour post first dose assessments have been completed. Subjects will return for outpatient visits on Days 7, 14, 21, 28, and 56 after first dose.