Opisthorchis ViverriniPhase 2ADORA-VINCT07262814
Efficacy and Safety of Ascending Doses of Arpraziquantel in Children Infected With Opisthorchis Viverrini
A Phase 2 study testing Apraziquantel in people with Opisthorchis Viverrini, run by Jennifer Keiser at 1 site in Laos.
Trial summary
This study aims to assess the efficacy, safety and acceptability of ascending doses of arpraziquantel in children infected with Opisthorchis viverrini. The primary objective is to determine the dose-response relationship in terms of cure rate. This study will involve children aged 6-7 years, since O. Read more about this study
- Who is it for?
- Ages 6 to 7 years
- Conditions the study is for
- Opisthorchis Viverrini
- What is being tested?
- Apraziquantel
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 125 participants
- Where
- 1 siteLaos
- Study dates
- 22 Jul 2026to Oct 2026
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 6 to 7 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- Aged 6 to 7 years (i.e., 72 to 95 months).
- Written informed consent signed by parents/caregivers (signature or thumbprint).
- Agree to comply with study procedures, including provision of two stool samples at baseline and at follow-up assessment 21-28 days after treatment, respectively.
- Willing to be examined by a study physician prior to treatment.
- At least two slides of the quadruple Kato-Katz thick smears positive for O. viverrini.
Who cannot join
- Presence or signs of major systemic illness, e.g. severe anaemia (haemoglobin level of < 80 g/L according to WHO) upon initial clinical assessment.
- Known or suspected infection with Taenia solium (cysticercosis).
- Known or suspected acute schistosomiasis.
- Abnormal liver and kidney function.
- Use of anthelminthic drugs within 4 weeks before or during study period.
- Known allergy to study medications (i.e. praziquantel or any of the excipients).
- Being prescribed or taking concomitantly medication with known contraindication or drug interactions with the study medication.
- Concurrent participation in other clinical trials.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Laos1 site, 1 recruiting
- Recruiting
Lao Tropical and Public Health Institute (Lao TPHI)
Vientiane
Somphou Sayasone, PhD, +856 20 556 79 603, somphou.sayasone@yahoo.com
About this study
Official title: Efficacy, Safety and Acceptability of Ascending Doses of Arpraziquantel for Opisthorchis Viverrini Infections in Children Aged 6-7 Years: A Single-blind Randomized Dose-ranging Trial
This study aims to assess the efficacy, safety and acceptability of ascending doses of arpraziquantel in children infected with Opisthorchis viverrini. The primary objective is to determine the dose-response relationship in terms of cure rate. This study will involve children aged 6-7 years, since O. viverrini infections often occur in pre-school and school-aged children, and this group is largely left untreated in current public health programs.
- Conditions
- Opisthorchis Viverrini
- Being tested
- Apraziquantel
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ApraziquantelDrug
Tablets (dispersible) containing 150 mg arpraziquantel
| Study group | Role | What they receive |
|---|---|---|
| Arpraziquantel 30 mg/kg | Experimental | Treatment with a single dose arpraziquantel: 30 mg/kg, orally administered Receives: Drug: Apraziquantel |
| Arpraziquantel 40 mg/kg | Experimental | Treatment with a single dose arpraziquantel: 40 mg/kg, orally administered Receives: Drug: Apraziquantel |
| Arpraziquantel 50 mg/kg | Experimental | Treatment with a single dose arpraziquantel: 50 mg/kg, orally administered Receives: Drug: Apraziquantel |
| Arpraziquantel 60 mg/kg | Experimental | Treatment with a single dose arpraziquantel: 60 mg/kg, orally administered Receives: Drug: Apraziquantel |
| Arpraziquantel 20 mg/kg | Experimental | Treatment with a single dose arpraziquantel: 20 mg/kg, orally administered Receives: Drug: Apraziquantel |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cure rate (CR) of arpraziquantel against O. viverrini
CRs will be calculated as the percentage of O. viverrini egg-positive participants at baseline who become egg-negative after treatment.
Measured: 21-28 days after treatment
Secondary outcomes (2)
Egg reduction rates (ERR) of arpraziquantel against O. viverrini
Eggs per gram of stool (EPG) will be assessed by calculating the mean egg counts from the quadruplicate Kato-Katz thick smears and multiplying this number by a factor of 24. Geometric and arithmetic mean egg counts will be calculated for the different treatment arms before and after treatment to assess the corresponding ERRs.
Measured: 21-28 days after treatment
Safety and tolerability of the different arpraziquantel dosing regimens, and compared to placebo
Participants will be monitored at the site for 3 hours following treatment for any acute adverse events (AEs). Participants will be interviewed 3 hours and 24 hours after treatment, as well as 21-28 days and 42 days after treatment administration about the occurrence of AEs. AEs will be evaluated descriptively as the difference of proportion reported AEs before and after treatment.
Measured: 3 hours, 24 hours, 21-28 days and 42 days after treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Dec 2025
- Study start22 Jul 2026
- Primary completionOct 2026 (estimated)
- Study completionOct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Opisthorchis ViverriniStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 125 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Jennifer Keiser
- Sponsor type
- University, hospital or other
- Collaborators
- Lao Tropical and Public Health Institute
- Responsible party
- Sponsor-investigator, Jennifer Keiser, Swiss Tropical & Public Health Institute
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07262814
- Sponsor's protocol ID
- ADORA-VI
- Acronym
- ADORA-VI
- Status last verified
- Aug 2026
- First submitted
- 20 Nov 2025
- Last updated
- 4 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacy, Safety and Acceptability of Ascending Doses of Arpraziquantel for Opisthorchis Viverrini Infections in Children Aged 6-7 Years: A Single-blind Randomized Dose-ranging Trial
- ClinicalTrials.gov ID
- NCT07262814
- Acronym / sponsor ID
- ADORA-VI / ADORA-VI
- Conditions
- Opisthorchis Viverrini
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 125 participants (estimated)
- Lead sponsor
- Jennifer KeiserUniversity, hospital or other
- Collaborators
- Lao Tropical and Public Health Institute
- Study start
- 22 Jul 2026 (actual)
- Primary completion
- Oct 2026 (estimated)
- Study completion
- Oct 2026 (estimated)
- First posted
- 4 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to assess the efficacy, safety and acceptability of ascending doses of arpraziquantel in children infected with Opisthorchis viverrini. The primary objective is to determine the dose-response relationship in terms of cure rate. This study will involve children aged 6-7 years, since O. viverrini infections often occur in pre-school and school-aged children, and this group is largely left untreated in current public health programs.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 5
| Arm | Type | Receives |
|---|---|---|
| Arpraziquantel 30 mg/kg | Experimental | Drug: ApraziquantelTreatment with a single dose arpraziquantel: 30 mg/kg, orally administered |
| Arpraziquantel 40 mg/kg | Experimental | Drug: ApraziquantelTreatment with a single dose arpraziquantel: 40 mg/kg, orally administered |
| Arpraziquantel 50 mg/kg | Experimental | Drug: ApraziquantelTreatment with a single dose arpraziquantel: 50 mg/kg, orally administered |
| Arpraziquantel 60 mg/kg | Experimental | Drug: ApraziquantelTreatment with a single dose arpraziquantel: 60 mg/kg, orally administered |
| Arpraziquantel 20 mg/kg | Experimental | Drug: ApraziquantelTreatment with a single dose arpraziquantel: 20 mg/kg, orally administered |
Who may qualify
- Ages
- 6 to 7 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- Aged 6 to 7 years (i.e., 72 to 95 months).
- Written informed consent signed by parents/caregivers (signature or thumbprint).
- Agree to comply with study procedures, including provision of two stool samples at baseline and at follow-up assessment 21-28 days after treatment, respectively.
- Willing to be examined by a study physician prior to treatment.
- At least two slides of the quadruple Kato-Katz thick smears positive for O. viverrini.
Key exclusion criteria (8 listed)
- Presence or signs of major systemic illness, e.g. severe anaemia (haemoglobin level of < 80 g/L according to WHO) upon initial clinical assessment.
- Known or suspected infection with Taenia solium (cysticercosis).
- Known or suspected acute schistosomiasis.
- Abnormal liver and kidney function.
- Use of anthelminthic drugs within 4 weeks before or during study period.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ApraziquantelTablets (dispersible) containing 150 mg arpraziquantel | Drug | Arpraziquantel 20 mg/kg, Arpraziquantel 30 mg/kg, Arpraziquantel 40 mg/kg, Arpraziquantel 50 mg/kg, Arpraziquantel 60 mg/kg |
Primary outcome
Cure rate (CR) of arpraziquantel against O. viverrini
Time frame: 21-28 days after treatment
CRs will be calculated as the percentage of O. viverrini egg-positive participants at baseline who become egg-negative after treatment.
2 secondary outcomes
Egg reduction rates (ERR) of arpraziquantel against O. viverrini
Time frame: 21-28 days after treatment
Safety and tolerability of the different arpraziquantel dosing regimens, and compared to placebo
Time frame: 3 hours, 24 hours, 21-28 days and 42 days after treatment
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Aug 2026.
- Individual participant dataSharing planned: No
Related trials for Opisthorchis Viverrini
RecruitingObservational study
Risk Assessment of Community Spread of Multiple Endemic Infectious Diseases in a One Health Perspective
Dengue, Chikungunya
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Apraziquantel in people with Opisthorchis Viverrini, run by Jennifer Keiser at 1 site in Laos.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 4 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Laos. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jennifer Keiser, PhD (+41 61 284 82 18, jennifer.keiser@swisstph.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cure rate (CR) of arpraziquantel against O. viverrini (time frame: 21-28 days after treatment). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Aug 2026.