A Phase 4 interventional study of primaquine and chloroquine + primaquine in Malaria, Vivax and G6PD Deficiency, sponsored by PATH. Terminated at 1 site in Thailand. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-11-12.
Sponsored by PATH · Phase 4, Interventional, and Treatment
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Among 26 studies testing primaquine in Malaria, Vivax — 2 open to participants now, 2 under way, 2 of them phase 3. Primaquine · Malaria, Vivax.
Among the 26 studies testing primaquine in Malaria, Vivax, this one is the 23rd largest by enrollment, is one of 3 that started in 2018, is one of 12 in phase 4, and was the 14th registered.
124 studies on the registry are indexed under Malaria, Vivax; 20 are open to participants now.
Browse Malaria, Vivax studies →2 of the 26 studies testing primaquine in Malaria, Vivax are open now, in 4 countries. Recruiting first, the newest first:
Menzies School of Health Research · Sites in Brazil, Ethiopia, Indonesia and 1 more country
Ages 18+
Curtin University · Sites in Papua New Guinea
Ages 18+ · Women only · Healthy volunteers
By country, each count listing its studies:
Primaquine: first FDA approval 1952 (PRIMAQUINE). What it is approved for, and how studies give it, is on its page →
Of the 9 Malaria, Vivax studies recruiting now, 6 set no upper age limit and 3 stop at 75 or younger; 5 take children under 18; 2 take healthy volunteers.
This study: 18 Years and older · all sexes · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
26 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 1 · Phase 2 3 · Phase 3 7 · Phase 4 12
First in 2001; this study’s year is marked. 3 started in 2018.
This study's enrollment of 54 is below the median of 150 across 104 interventional studies indexed under Malaria, Vivax.
Median enrollment 206 across the 26 interventional studies. Of the 21 that completed or were terminated, 4 (19%) have results posted.
This tab as a report to print or save as PDF → With an account.
1 of 26 have an industry lead sponsor. The 10 most frequent:
PATH is the lead sponsor of 113 studies on the registry; 7 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 10 (100%) have results posted.
PATH has 1 study filed under Malaria, Vivax — fewer than ten, so there is no comparison to draw.
2 of the studies testing primaquine in Malaria, Vivax that are under way reach primary completion within a year, 2 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07060404Phase 3Curtin UniversityPostpartum 8-aminoquinoline Breast Milk Study | 2026-12 |
| NCT06148792Phase 3Menzies School of Health ResearchA Revised Tafenoquine Dose to Improve Radical Cure for Vivax Malaria | 2027-03-01 |
Add all 2 to your calendar (.ics) → With an account.
Among the 26 studies testing primaquine in Malaria, Vivax, from their registry updates:
Nothing recorded among them since 2026-09-25.
This tab as a report to print or save as PDF → With an account.
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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
All participants:
Female participants only:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Twelve males hemizygous for wildtype G6PD, 12 females homozygous for wildtype G6PD, and 12 females heterozygous for G6PD deficiency will be randomized to arm 1A. Participants in arm 1A will receive primaquine for 14 days at 0.5 mg/Kg. Drug administration will be directly observed.
Drug: primaquine
Twelve males hemizygous for wildtype G6PD, 12 females homozygous for wildtype G6PD, and 12 females heterozygous for G6PD deficiency will be randomized to arm 1B. Participants will receive chloroquine for 3 days concomitant with primaquine for 14 days at 0.5 mg/Kg. Drug administration will be directly observed.
Drug: chloroquine + primaquine
Participants receive primaquine for 14 days at 0.5 mg/Kg. Drug administration will be directly observed.
Drug pages: Chloroquine · Primaquine
Participants will receive chloroquine for 3 days concomitant with primaquine for 14 days at 0.5 mg/Kg. Drug administration will be directly observed.
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
| Milestone | 1A: Primaquine | 1B: Chloroquine + Primaquine |
|---|---|---|
| Started | 24 | 24 |
| Completed | 13 | 13 |
| Not completed | 11 | 11 |
| Withdrew: Physician decision | 1 | 0 |
| Withdrew: Lost to follow-up | 1 | 3 |
| Withdrew: Adverse event | 3 | 1 |
| Withdrew: Stopped drug dosing due to study halt | 6 | 7 |
The change in haemoglobin from baseline on exposure to primaquine for P.vivax treatment over treatment course to hemoglobin level at day 28.
| g/dL | 1A: Primaquine | 1B: Chloroquine + Primaquine |
|---|---|---|
| Change in Haemoglobin | -1.1 (-4.1 to 0) | -1.05 (-4.5 to 0) |
The haemoglobin-related change in G6PD concentration, as determined by spectrometer, over treatment course. Change is determined from baseline to day 28
| IU/g Hb | 1A: Primaquine | 1B: Chloroquine + Primaquine |
|---|---|---|
| Change in G6PD Concentration | -1.23 (-2.99 to -0.34) | -1.94 (-6.09 to -0.39) |
relevance of Dextromethorphan assay results to risk of haemolysis models
No measurements were reported for this outcome.
Association of chloroquine and primaquine drug levels at the time of sampling for haematological and G6PD profiles.
No measurements were reported for this outcome.
frequency of serious adverse events in women heterozygous for G6PD
| Participants | 1A: Primaquine | 1B: Chloroquine + Primaquine |
|---|---|---|
| Serious Adverse Events | 3 | 1 |
relevance of reticulocyte count to risk of haemolysis models
No measurements were reported for this outcome.
relevance of urobilinogen tests to risk of haemolysis models
No measurements were reported for this outcome.
Collected over 28 days after enrollment. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| 1A: Primaquine | 0/24 (0%) | 3/24 (12.5%) | 8/24 (33.3%) |
| 1B: Chloroquine + Primaquine | 0/24 (0%) | 1/24 (4.2%) | 17/24 (70.8%) |
| Event | 1A: Primaquine | 1B: Chloroquine + Primaquine |
|---|---|---|
| HemolysisBlood and lymphatic system disorders | 3/24 | 1/24 |
| Event | 1A: Primaquine | 1B: Chloroquine + Primaquine |
|---|---|---|
| DizzinessGeneral disorders | 1/24 | 11/24 |
| Blurred visionEye disorders | 1/24 | 6/24 |
| Decreased appetiteGastrointestinal disorders | 2/24 | 5/24 |
| Difficulty sleepingGeneral disorders | 2/24 | 5/24 |
| FatigueGeneral disorders | 2/24 | 4/24 |
| HeadacheGeneral disorders | 4/24 | 3/24 |
| AnemiaBlood and lymphatic system disorders | 3/24 | 0/24 |
| DiarrheaGastrointestinal disorders | 0/24 | 3/24 |
| Common coldRespiratory, thoracic and mediastinal disorders | 2/24 | 2/24 |
| HemolysisBlood and lymphatic system disorders | 0/24 | 2/24 |
Participants randomized to a treatment arm.
| Age, Continuous(years) | 1A: Primaquine | 1B: Chloroquine + Primaquine | Total |
|---|---|---|---|
| Median | 33.5 (19 to 63) | 38.5 (19 to 64) | 36 (19 to 64) |
| Sex: Female, Male(Participants) | 1A: Primaquine | 1B: Chloroquine + Primaquine | Total |
|---|---|---|---|
| Female | 16 | 16 | 32 |
| Male | 8 | 8 | 16 |
| Race and Ethnicity Not Collected(Participants) | 1A: Primaquine | 1B: Chloroquine + Primaquine | Total |
|---|---|---|---|
| Count of participants | — | — | 0 |
| Region of Enrollment(participants) | 1A: Primaquine | 1B: Chloroquine + Primaquine | Total |
|---|---|---|---|
| Thailand | 24 | 24 | 48 |
| G6PD Status(Participants) | 1A: Primaquine | 1B: Chloroquine + Primaquine | Total |
|---|---|---|---|
| Heterozygous Female | 5 | 4 | 9 |
| Homozygous Female | 11 | 12 | 23 |
| Hemizygous Male | 8 | 8 | 16 |
| Hemoglobin(g/dL) | 1A: Primaquine | 1B: Chloroquine + Primaquine | Total |
|---|---|---|---|
| Median | 13.2 (10.1 to 17.1) | 12.65 (9.6 to 15.7) | 12.9 (9.6 to 17.1) |
| G6PD Concentration(IU/g Hb) | 1A: Primaquine | 1B: Chloroquine + Primaquine | Total |
|---|---|---|---|
| Median | 7.66 (2.94 to 11.08) | 7.515 (3.55 to 12.66) | 7.58 (2.94 to 12.66) |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Undecided — Individual participant data sharing plan will be completed by the time of completion of the study
Ran from May 2018 to primary completion in Aug 2018, 3 months.
Results were first posted in Nov 2021, 3 years 2 months after primary completion.
How these figures are worked out, and which studies are left out of them.
This study is terminated, as verified in May 2019. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Primaquine · Chloroquine