Pan African Clinical Trials Registry
South African Medical Research Council, South African Cochrane Centre
PO Box 19070, Tygerberg, 7505, South Africa
Telephone: +27 21 938 0835 or +27 21 938 0967
Email: pactradmin@mrc.ac.za Website: pactr.samrc.ac.za
Trial no.: PACTR202607857642772 Date of Registration: 28/07/2026
Trial Status: Retrospective registration - This trial was registered after enrolment of the first participant
TRIAL DESCRIPTION
Public title Testing primaquine to see if it helps reduce malaria transmission from human to mosquitoes patients treated at a health clinic in Vom,
Official scientific title The effect of primaquine on gametocyte development and clearance in patients treated for uncomplicated falciparum malaria with dihydroartemisinin-piperaquine in a primary health care facility in Vom, Plateau state, Nigeria
Brief summary describing the background and objectives of the trial Malaria remains a major public health challenge, particularly in Nigeria and other Sub-Saharan African countries, despite global control efforts. Artemisinin-based combination therapies (ACTs) are effective but often leave residual gametocytes, which sustain transmission and may signal emerging drug resistance. Primaquine (PQ), the only drug proven to clear mature gametocytes, could strengthen malaria control when added to ACTs. However, data on PQ’s efficacy in endemic regions like Nigeria are limited. This study therefore aimed to evaluate PQ’s effect on gametocyte carriage and clearance in patients treated with dihydroartemisinin-piperaquine, with the goal of informing policy on its use as an adjunct to ACTs in line with WHO recommendations.
Type of trial RCT
Acronym (If the trial has an acronym then please provide)
Disease(s) or condition(s) being studied Infections and Infestations
Sub-Disease(s) or condition(s) being studied Malaria
Purpose of the trial Treatment: Drugs
Anticipated trial start date 15/03/2015
Actual trial start date 15/07/2015
Anticipated date of last follow up 29/09/2015
Actual Last follow-up date 30/09/2015
Anticipated target sample size (number of participants) 168
Actual target sample size (number of participants) 181
Recruitment status Completed
Publication URL
Secondary Ids Issuing authority/Trial register
JUTHDCSADM127XIX5959 JOS UNIVERSITY TEACHING HOSPITAL ETHICS COMMITEE
STUDY DESIGN
Intervention assignment Allocation to intervention If randomised, describe how the allocation sequence was generated Describe how the allocation sequence/code was concealed from the person allocating the participants to the intervention arms Masking If masking / blinding was used
Parallel: different groups receive different interventions at same time during study Randomised Simple randomization using a randomization table created by a computer software program Sealed opaque envelopes Masking/blinding used Outcome Assessors
INTERVENTIONS
Intervention type Intervention name Dose Duration Intervention description Group size Nature of control
Experimental Group dihydroartemisinin and piperaquine plus primaquine Weight-adjusted regimen of DHP tablets (40 mg/320 mg). Dosing was: 3 tablets for ≥41 kg, 2 tablets for 31–40 kg, 1 tablet for 18–30 kg, and ½ tablet for 10–17 kg. This provided total exposures of 4–10.9 mg/kg dihydroartemisinin and 32–87.3 mg/kg piperaquine on Days 1, 2 and 3 Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg. The intervention period was 3 days, from Day 1 to Day 3. All participants received a 3-day, weight-adjusted regimen of dihydroartemisinin-piperaquine [DHP] tablets [40 mg/320 mg]. Dosing was: 3 tablets for ≥41 kg, 2 tablets for 31–40 kg, 1 tablet for 18–30 kg, and ½ tablet for 10–17 kg. This provided total exposures of 4–10.9 mg/kg dihydroartemisinin and 32–87.3 mg/kg piperaquine. Participants were randomized in a 1:1 ratio to: Control arm: DHP alone for 3 days Intervention arm: DHP for 3 days plus a single dose of primaquine [PQ] on Day 3, targeting 0.75 mg/kg The first and third doses were directly observed at the study site. The second dose was taken at home with instructions. If vomiting occurred within 30 minutes of dosing, the full dose was repeated; if between 30 and 60 minutes, half a dose was repeated. Participants who refused repeat dosing were given alternative antimalarial treatment per national guidelines and withdrawn from the study. Follow-up and outcome assessments Assessments were done at pre-intervention baseline [Day 0], at the end of intervention [Day 3], and during post-intervention follow-up [Days 7, 14, 21, and 28]. At each visit, participants underwent clinical review and finger-prick haemoglobin measurement using the HemoCue Hb 301 system [HemoCue AB, Ängelholm, Sweden]. Venous blood was collected into K₂EDTA tubes and analyzed within 30 min. Giemsa-stained thick and thin blood films were prepared and read by two independent microscopists; discordant results were resolved by a third microscopist. Adverse events were recorded at each visit. Outcomes The primary outcome was the mean absolute change in haemoglobin from pre-intervention baseline [Day 0] to post-intervention Day 28, assessed against a non-inferiority margin of 0.5 g/dL. Secondary outcomes measured during post-intervention follow-up [Days 3, 7, 14, 21, 28] were: 1) the proportion of participants with a haemoglobin reduction >2 g/dL from baseline at any visit; 2) the proportion with haemoglobin <7 g/dL at any visit; and 3) the occurrence of severe haemolysis, defined as haemoglobin <5 g/dL or the need for transfusion. 93
Control Group dihydroartemisinin and piperaquine only The daily DHP regimen was based on weight (≥41 kg: 3 tablets; 31 - 40 kg: 2 tablets; 18 - 30 kg: 1 tablet; 10 - 17 kg: 1/2 tablet). The total dose of Dihydroartemisinin ranged 4 - 10.9 mg/kg, and Piperaquine ranged 32 - 87.3 mg/kg. 3 days, once daily day1, day 2 and day 3 The first daily dose for both study groups was administered at the study center supervised by the study physician or an assistant, the second dose the following day by the patient at home and the third (last) dose at the study center. 88 Active-Treatment of Control Group
ELIGIBILITY CRITERIA
List inclusion criteria List exclusion criteria Age Category Minimum age Maximum age Gender
(a) Adults and children aged one year and above or weight ≥10kg (b) Plasmodium parasite density in the range of 1000 asexual parasites per µl and above (c) Presence of fever or axillary temperature ≥ 37.50 c ,or positive history of fever in the preceding 24hrs (d) Normal glucose-6-phosphate dehydrogenase (G6PD) enzyme levels based on a qualitative test (e) Haemoglobin level of 8g/dL and above (f) Residence in study area and or ability to come for the stipulated follow - up visits (g) Ability to take oral medications (h) Informed consent of participant or parent/guardian of participant a) General danger signs or symptoms and signs of severe malaria (b) Febrile conditions caused by diseases other than malaria; will not respond to anti-malaria (c) Allergy to any of the drug components, or had used any of the component drugs within 28 days of enrollment, to avoid complications to therapy and masking effects of previous drug use. (d) Serious concomitant medical illness; or any medical illness not compatible with the study objectives; epilepsy or affective disorders may not understand trial protocol and give informed consent (e) Pregnancy detected clinically or by urine bHCG or lactating mother, drug safety in pregnancy and breastfeeding not ascertained (f) Refusal to sign informed consent Adolescent: 13 Year(s)-17 Year(s),Adult: 18 Year(s)-44 Year(s),Child: 6 Year-12 Year,Infant: 13 Month(s)-24 Month(s),Middle Aged: 45 Year(s)-64 Year(s),Preschool Child: 2 Year-5 Year 1 Year(s) 64 Year(s) Both
ETHICS APPROVAL
Has the study received appropriate ethics committee approval Date the study will be submitted for approval Date of approval Name of the ethics committee
Yes 19/06/2014 Jos University Teaching Hospital Research Ethical Committee
Ethics Committee Address
Street address City Postal code Country
Katon Rikkos, Lamingo Jos Plateau State 930105 Nigeria
OUTCOMES
Type of outcome Outcome Timepoint(s) at which outcome measured
Primary Outcome The primary outcome measure was the effect of the standard single dose of Primaquine in addition to the completed 3-day treatment with DHP on gametocyte carriage. This was done by comparing the overall risk of gametocyte carriages on day 7 and then weekly till day 28, to measure the combined effect on gametocyte development and clearance (primary endpoint). Day 0 was pre-intervention baseline. Day 3 was the end of intervention. Days 7, 14, 21, and 28 were post-intervention follow-up visits.
Secondary Outcome The impact of PQ on gametocytes was assessed using the following secondary endpoints: (1) The gametocyte clearance rates by day 28 in patients with gametocytes on day 3. (2) The incidence of gametocyte development by day 28 in patients who were gametocyte-free on day 3. (3) Gametocyte densities between days 3 and 28 inclusive. Day 0, 3, 7, 14, 21, and 28
RECRUITMENT CENTRES
Name of recruitment centre Street address City Postal code Country
Vom Christian Centre Vom Plateau State 930101 Nigeria
FUNDING SOURCES
Name of source Street address City Postal code Country
Ason Benjamin Tsuung Potiskum Road Damaturu 620001 Nigeria
SPONSORS
Sponsor level Name Street address City Postal code Country Nature of sponsor
Primary Sponsor Tsuung Ason Benjamin Potiskum road Damaturu 620001 Nigeria Individual
COLLABORATORS
Name Street address City Postal code Country
CONTACT PEOPLE
Role Name Email Phone Street address
Principal Investigator Ason Benjamin Tsuung ason.tsuung@npmcn.edu.ng +2348166753143 Potiskum road
City Postal code Country Position/Affiliation
Damaturu 620001 Nigeria Department of Family Medicine Yobe State University
Role Name Email Phone Street address
Public Enquiries Simon Pitmang spitmang@gmail.com +2348037217407 Lamingo Road
City Postal code Country Position/Affiliation
Jos Plateau state Nigeria Consultant Family Physician Jos University Teaching Hospital
Role Name Email Phone Street address
Scientific Enquiries Ason Benjamin Tsuung tabcom007@gmail.com +2348166753143 Potiskum road
City Postal code Country Position/Affiliation
Damaturu Nigeria Yobe state University
REPORTING
Share IPD Description Additional Document Types Sharing Time Frame Key Access Criteria
Yes Individual Participant Data will be made available upon reasonable request. De-identified participant data including demographic data, haemoglobin values, gametocyte carriage data, and data dictionary will be shared. Study protocol and statistical analysis plan will also be available. Statistical Analysis Plan,Study Protocol Data will be available 12 months after publication of the main results and for up to 5 years. Requests should be sent to the corresponding author’s institutional email and will be reviewed by the study steering committee. Data will be shared for meta-analysis and secondary research purposes via secure email transfer.
URL Results Available Results Summary Result Posting Date First Journal Publication Date
Yes 28/05/2026 15/06/2018
Result Upload 1: Result Upload 2: Result Upload 3: Result Upload 4: Result Upload 5:
Result - 13/07/2026
Result URL Hyperlinks Link To Protocol
Result URL Hyperlinks
Changes to trial information
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Official scientific title 26/06/2026 Title changed from capital case to sentence case THE EFFECT OF PRIMAQUINE ON GAMETOCYTE DEVELOPMENT AND CLEARANCE IN PATIENTS TREATED FOR UNCOMPLICATED FALCIPARUM MALARIA WITH DIHYDROARTEMISININ-PIPERAQUINE IN A PRIMARY HEALTH CARE FACILITY IN VOM, PLATEAU STATE, NIGERIA. The effect of primaquine on gametocyte development and clearance in patients treated for uncomplicated falciparum malaria with dihydroartemisinin-piperaquine in a primary health care facility in Vom, Plateau state, Nigeria.
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Official scientific title 06/07/2026 This study was conducted from July to September 2015 as a programmatic evaluation of primaquine safety and efficacy. Prospective registration was not standard practice at our institution at the time. We are registering retrospectively to comply with ICMJE requirements for publication and to ensure transparency. The effect of primaquine on gametocyte development and clearance in patients treated for uncomplicated falciparum malaria with dihydroartemisinin-piperaquine in a primary health care facility in Vom, Plateau state, Nigeria. The effect of primaquine on gametocyte development and clearance in patients treated for uncomplicated falciparum malaria with dihydroartemisinin-piperaquine in a primary health care facility in Vom, Plateau state, Nigeria
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 06/07/2026 no loss to follow up Experimental Group, dihydroartemisinin and piperaquine plus primaquine, Weight-adjusted regimen of DHP tablets (40 mg/320 mg). Dosing was: 3 tablets for ≥41 kg, 2 tablets for 31–40 kg, 1 tablet for 18–30 kg, and ½ tablet for 10–17 kg. This provided total exposures of 4–10.9 mg/kg dihydroartemisinin and 32–87.3 mg/kg piperaquine on Days 1, 2 and 3 Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg., Days 1, 3, 7, 14, 21, and 28, Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg., 84, Experimental Group, dihydroartemisinin and piperaquine plus primaquine, Weight-adjusted regimen of DHP tablets (40 mg/320 mg). Dosing was: 3 tablets for ≥41 kg, 2 tablets for 31–40 kg, 1 tablet for 18–30 kg, and ½ tablet for 10–17 kg. This provided total exposures of 4–10.9 mg/kg dihydroartemisinin and 32–87.3 mg/kg piperaquine on Days 1, 2 and 3 Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg., Days 1, 3, 7, 14, 21, and 28, Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg., 93,
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 20/07/2026 no loss to follow up Experimental Group, dihydroartemisinin and piperaquine plus primaquine, Weight-adjusted regimen of DHP tablets (40 mg/320 mg). Dosing was: 3 tablets for ≥41 kg, 2 tablets for 31–40 kg, 1 tablet for 18–30 kg, and ½ tablet for 10–17 kg. This provided total exposures of 4–10.9 mg/kg dihydroartemisinin and 32–87.3 mg/kg piperaquine on Days 1, 2 and 3 Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg., Days 1, 3, 7, 14, 21, and 28, Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg., 93, Experimental Group, dihydroartemisinin and piperaquine plus primaquine, Weight-adjusted regimen of DHP tablets (40 mg/320 mg). Dosing was: 3 tablets for ≥41 kg, 2 tablets for 31–40 kg, 1 tablet for 18–30 kg, and ½ tablet for 10–17 kg. This provided total exposures of 4–10.9 mg/kg dihydroartemisinin and 32–87.3 mg/kg piperaquine on Days 1, 2 and 3 Participants were randomized to receive DHP alone or DHP plus a single dose of PQ on Day 3, targeting 0.75 mg/kg., he intervention period was 3 days, from Day 1 to Day 3. , All participants received a 3-day, weight-adjusted regimen of dihydroartemisinin-piperaquine [DHP] tablets [40 mg/320 mg]. Dosing was: 3 tablets for ≥41 kg, 2 tablets for 31–40 kg, 1 tablet for 18–30 kg, and ½ tablet for 10–17 kg. This provided total exposures of 4–10.9 mg/kg dihydroartemisinin and 32–87.3 mg/kg piperaquine. Participants were randomized in a 1:1 ratio to: Control arm: DHP alone for 3 days Intervention arm: DHP for 3 days plus a single dose of primaquine [PQ] on Day 3, targeting 0.75 mg/kg The first and third doses were directly observed at the study site. The second dose was taken at home with instructions. If vomiting occurred within 30 minutes of dosing, the full dose was repeated; if between 30 and 60 minutes, half a dose was repeated. Participants who refused repeat dosing were given alternative antimalarial treatment per national guidelines and withdrawn from the study. Follow-up and outcome assessments Assessments were done at pre-intervention baseline [Day 0], at the end of intervention [Day 3], and during post-intervention follow-up [Days 7, 14, 21, and 28]. At each visit, participants underwent clinical review and finger-prick haemoglobin measurement using the HemoCue Hb 301 system [HemoCue AB, Ängelholm, Sweden]. Venous blood was collected into K₂EDTA tubes and analyzed within 30 min. Giemsa-stained thick and thin blood films were prepared and read by two independent microscopists; discordant results were resolved by a third microscopist. Adverse events were recorded at each visit. Outcomes The primary outcome was the mean absolute change in haemoglobin from pre-intervention baseline [Day 0] to post-intervention Day 28, assessed against a non-inferiority margin of 0.5 g/dL. Secondary outcomes measured during post-intervention follow-up [Days 3, 7, 14, 21, 28] were: 1) the proportion of participants with a haemoglobin reduction >2 g/dL from baseline at any visit; 2) the proportion with haemoglobin <7 g/dL at any visit; and 3) the occurrence of severe haemolysis, defined as haemoglobin <5 g/dL or the need for transfusion., 93,
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 21/07/2026 no loss to follow up
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 06/07/2026 no loss to follow Control Group, dihydroartemisinin and piperaquine only, The daily DHP regimen was based on weight (≥41 kg: 3 tablets; 31 - 40 kg: 2 tablets; 18 - 30 kg: 1 tablet; 10 - 17 kg: 1/2 tablet). The total dose of Dihydroartemisinin ranged 4 - 10.9 mg/kg, and Piperaquine ranged 32 - 87.3 mg/kg. , 3 days, The first daily dose for both study groups was administered at the study center supervised by the study physician or an assistant, the second dose the following day by the patient at home and the third (last) dose at the study center., 84, Active-Treatment of Control Group Control Group, dihydroartemisinin and piperaquine only, The daily DHP regimen was based on weight (≥41 kg: 3 tablets; 31 - 40 kg: 2 tablets; 18 - 30 kg: 1 tablet; 10 - 17 kg: 1/2 tablet). The total dose of Dihydroartemisinin ranged 4 - 10.9 mg/kg, and Piperaquine ranged 32 - 87.3 mg/kg. , 3 days, The first daily dose for both study groups was administered at the study center supervised by the study physician or an assistant, the second dose the following day by the patient at home and the third (last) dose at the study center., 88, Active-Treatment of Control Group
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 20/07/2026 Clarification Control Group, dihydroartemisinin and piperaquine only, The daily DHP regimen was based on weight (≥41 kg: 3 tablets; 31 - 40 kg: 2 tablets; 18 - 30 kg: 1 tablet; 10 - 17 kg: 1/2 tablet). The total dose of Dihydroartemisinin ranged 4 - 10.9 mg/kg, and Piperaquine ranged 32 - 87.3 mg/kg. , 3 days, The first daily dose for both study groups was administered at the study center supervised by the study physician or an assistant, the second dose the following day by the patient at home and the third (last) dose at the study center., 88, Active-Treatment of Control Group Control Group, dihydroartemisinin and piperaquine only, The daily DHP regimen was based on weight (≥41 kg: 3 tablets; 31 - 40 kg: 2 tablets; 18 - 30 kg: 1 tablet; 10 - 17 kg: 1/2 tablet). The total dose of Dihydroartemisinin ranged 4 - 10.9 mg/kg, and Piperaquine ranged 32 - 87.3 mg/kg. , 3 days, once daily day1, day 2 and day 3, The first daily dose for both study groups was administered at the study center supervised by the study physician or an assistant, the second dose the following day by the patient at home and the third (last) dose at the study center., 88, Active-Treatment of Control Group
Section Name Field Name Date Reason Old Value Updated Value
Outcome OutCome List 26/06/2026 Typographical error Primary Outcome, The primary outcome measure was the effect of the standard single dose of Primaquine in addition to the completed 3-day treatment with DHP on gametocyte carriage. This was done by comparing the overall risk of gametocyte carriages on day 7 and then weekly till day 28, to measure the combined effect on gametocyte development and clearance (primary endpoint)., Days 7, 14, 21 and 28 Primary Outcome, The primary outcome measure was the effect of the standard single dose of Primaquine in addition to the completed 3-day treatment with DHP on gametocyte carriage. This was done by comparing the overall risk of gametocyte carriages on day 7 and then weekly till day 28, to measure the combined effect on gametocyte development and clearance (primary endpoint)., Days 0, 3, 7, 14, 21 and 28
Section Name Field Name Date Reason Old Value Updated Value
Outcome OutCome List 21/07/2026 Typographical error Primary Outcome, The primary outcome measure was the effect of the standard single dose of Primaquine in addition to the completed 3-day treatment with DHP on gametocyte carriage. This was done by comparing the overall risk of gametocyte carriages on day 7 and then weekly till day 28, to measure the combined effect on gametocyte development and clearance (primary endpoint)., Days 0, 3, 7, 14, 21 and 28 Primary Outcome, The primary outcome measure was the effect of the standard single dose of Primaquine in addition to the completed 3-day treatment with DHP on gametocyte carriage. This was done by comparing the overall risk of gametocyte carriages on day 7 and then weekly till day 28, to measure the combined effect on gametocyte development and clearance (primary endpoint)., Day 0 was pre-intervention baseline. Day 3 was the end of intervention. Days 7, 14, 21, and 28 were post-intervention follow-up visits.
Section Name Field Name Date Reason Old Value Updated Value
Outcome OutCome List 21/07/2026 Clarification Secondary Outcome, The impact of PQ on gametocytes was assessed using the following secondary endpoints: (1) The gametocyte clearance rates by day 28 in patients with gametocytes on day 3. (2) The incidence of gametocyte development by day 28 in patients who were gametocyte-free on day 3. (3) Gametocyte densities between days 3 and 28 inclusive., Day 28 Secondary Outcome, The impact of PQ on gametocytes was assessed using the following secondary endpoints: (1) The gametocyte clearance rates by day 28 in patients with gametocytes on day 3. (2) The incidence of gametocyte development by day 28 in patients who were gametocyte-free on day 3. (3) Gametocyte densities between days 3 and 28 inclusive., Day 0, 3, 7, 14, 21, and 28
Section Name Field Name Date Reason Old Value Updated Value
Funding Source FundingSources List 26/06/2026 I was not sure of what to write - whether just the Principal investigator or name Principal investigator Tsuung AB, Potiskum Road, Damaturu, 620001, Nigeria, Self Funded, Ason Benjamin Tsuung , Potiskum Road, Damaturu, 620001, Nigeria, Self Funded,
Section Name Field Name Date Reason Old Value Updated Value
Reporting IPD description 13/07/2026 I wrongly assumed it was not applicable for retrospective trial registration Not Applicable as study done before 1January 2019 Individual Participant Data will be made available upon reasonable request. De-identified participant data including demographic data, haemoglobin values, gametocyte carriage data, and data dictionary will be shared. Study protocol and statistical analysis plan will also be available.
Section Name Field Name Date Reason Old Value Updated Value
Reporting IPD-Sharing time frame 13/07/2026 I wrongly assumed it was not applicable for retrospective trial registration Not Applicable as study done before 1January 2019 Data will be available 12 months after publication of the main results and for up to 5 years.
Section Name Field Name Date Reason Old Value Updated Value
Reporting Key access criteria 13/07/2026 I wrongly assumed it was not applicable for retrospective trial registration Not Applicable as study done before 1January 2019 Requests should be sent to the corresponding author’s institutional email and will be reviewed by the study steering committee. Data will be shared for meta-analysis and secondary research purposes via secure email transfer.
Section Name Field Name Date Reason Old Value Updated Value
Reporting Study protocol document 13/07/2026 I wrongly assumed it was not applicable for retrospective trial registration Informed Consent Form Study Protocol, Statistical Analysis Plan
Section Name Field Name Date Reason Old Value Updated Value
Reporting Result Summary Pdf file1 13/07/2026 I wrongly assumed it was not applicable for retrospective trial registration 41407_28584_1045.pdf 41407_28584_1045.pdf
Section Name Field Name Date Reason Old Value Updated Value
Reporting Result Summary Pdf file1 13/07/2026 I wrongly assumed it was not applicable for retrospective trial registration 41407_28584_1045.pdf 41407_28584_1045.pdf