A Phase 2 interventional study of 2,3-dimercapto-1-propanesulfonic acid and marimastat in Snakebite, sponsored by Liverpool School of Tropical Medicine. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-12.
Sponsored by Liverpool School of Tropical Medicine · Phase 2, Interventional, and Treatment
Bites by venomous snakes can cause disability and can be life-threatening. We are doing research in adult patients to try and find medications that can be administered orally and can help to reduce disability and death due to snakebite. We do not know whether the drugs in this study work in humans and we aim to discover this.
In Stage A, we will provide a new drug or placebo (inactive medication) in community locations, such as rural health clinics, in Brazil and Ghana. Neither the patient nor the clinical team will know which treatment option has been allocated. If a drug were to show signs of working as a treatment during Stage A, it will progress to Stage B. In Stage B, we will provide the drug or antivenom (the current approved treatment for snakebite) in a hospital setting. During Stage B, the patient and the clinician will know which treatment has been received. The purpose of Stage B is to discover whether the drug might hold promise as an alternative treatment to antivenom in the future. Participants will be monitored closely during Stage B and 'rescue antivenom' will be given if they become unwell.
The medications being considered were developed for other health conditions, like cancer, so have been given to patients across the world before. The medications may prove effective at inhibiting the damaging effects of snake venom. Each of the trial drugs could be taken by mouth (oral) in community clinics and ambulances, much sooner than the current treatment for snakebite injuries (antivenom), which is only given within hospitals. They may have other advantages too, like reduced cost and less chance of side effects, including severe allergic reaction. Before a medication is included in the trial it will be reviewed and approved by a group of experts. Before a medication is included in Stage B of the trial it will be reviewed for whether it is safe and effective enough (from Stage A results) to be compared against antivenom.
Stage A Participants will be recruited in the field when they attend a community clinic or ambulance. They will be randomly assigned to receive either a study drug or a placebo. When they arrive at hospital, all participants will receive standard of care antivenom. Participants will continue to take study medication (or matching placebo) for 24 hours, and have frequent blood samples collected during their treatment. Once 20 participants have received the drug and twenty have received the placebo, recruitment for this drug will cease. The difference in the improvement in blood clotting studies (how long it takes to clot) will be compared between the participants receiving the drug and the placebo. If the drug shows an improvement in the clotting studies, then it will proceed to Stage B. If the drug fails to improve the clotting studies, or if it is found to cause unsafe side effects, then it will be rejected from progressing to Stage B.
Stage B Participants will be recruited upon arrival at the hospital site and randomly assigned to receive either a study drug shown to be effective in Stage A or standard-of-care antivenom. Study drugs will be administered for 24 hours, during which all participants will undergo frequent blood sampling. Recruitment for each study drug will stop once 48 participants have received the drug and 48 have received antivenom. The primary comparison will be the improvement in blood clotting parameters between the intervention and control groups. If the study drug is safe and achieves a similar improvement to antivenom - allowing for up to a three-hour delay in effect due to oral absorption compared with intravenous antivenom - it will be considered a promising alternative therapy.
Following a planned 3-day stay in hospital, all participants from Stage A and B will be followed up at 2 and 6 weeks. These follow-up visits can be conducted by telephone, outpatient hospital visit, or home visit, depending on what is most suitable for that individual. The end of study visit will take place at the 6-week visit.
38 studies on the registry are indexed under Snake Bites; 11 are open to participants now.
This study's planned enrollment of 504 is above the median of 70 across 18 interventional studies indexed under Snake Bites.
Browse Snake Bites studies →Liverpool School of Tropical Medicine is the lead sponsor of 57 studies on the registry; 23 are open to participants now.
Counted across the registry records on this site, refreshed daily.
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:
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.
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.
Drug: Oral placebo capsules
Drug: Antivenom Snakes
Drug: 2,3-dimercapto-1-propanesulfonic acid
Drug: marimastat
Drug: marimastat
Oral administration
Also known as: unithiol, DMPS
oral administration
Oral placebo
Standard of care IV antivenom recommended in country
Mean time until lab INR is less than 50% of the baseline value (efficacy)
Stage A and B - The mean time until the lab INR is \<50% of the baseline value (or less than 1.4 if the baseline value is \<2.8) on two consecutive measurements per treatment arm. Time is measured starting from randomisation. Time is measured until the first of the two consecutive measurements being \<50% or \<1.4. Baseline INR sample is defined as blood collected day 0 post-consent and prior to treatment administration.
Time frame: From randomisation until end of admission
Incidence (cumulative) of safety events (safety)
Stage A and B- Incidence (cumulative) of any AE, non-serious AE, SAE, SAR, SUSAR. Cumulative incidence is calculated as the number (%) of participants who experience at least one AE in the pre-specified groups.
Time frame: From informed consent until 42 days after randomisation
Stage A- Assess the effect of pre-hospital treatment on INR improvement based on travel time to hospital.
Stage A- Assess the effect of pre-hospital treatment on INR improvement based on travel time to hospital. Amongst participants with baseline INR ≥1.4, the log change in INR, from pre-hospital baseline to hospital arrival, will be analysed using a linear regression model with treatment group, travel time, and their interaction
Time frame: Day 0 clinic and hospital
Stage A- Assess the effect of pre-hospital treatment on fibrinogen improvement based on travel time to hospital.
Stage A- Assess the effect of pre-hospital treatment on fibrinogen improvement based on travel time to hospital. Amongst participants with baseline INR ≥1.4, the log change in fibrinogen from pre-hospital baseline to 12 hours after randomisation, will be analysed using a linear regression model with treatment group, travel time, and their interaction.
Time frame: Day 0 clinic and hospital
Stage A and B- To determine the acceptability of the intervention between treatment arms in terms of quality of life.
Stage A and B- to determine the acceptability of the intervention between treatment arms as a patient-reported outcome of functioning. Assessed using the WHO Disability Assessment Schedule 2.0 (WHODAS 2.0), a 12-item validated scale measuring disability across six life domains (cognition, mobility, self-care, interpersonal interaction, life activities, and participation). Scores range from 0 to 48, where higher scores indicate greater disability. Unit of Measure: Units on a scale (0-48)
Time frame: Day 14, Day 42 (Stage A and B)
Stage A and B- To determine the acceptability of the intervention between treatment arms as patient-reported outcomes of functioning.
Assessed using the Patient Specific Functional Scale (PSFS), in which participants rate their ability to perform up to three self-nominated activities on a numerical scale from 0 to 10, where 0 indicates inability to perform the activity and 10 indicates full pre-injury ability. Higher scores indicate better function. Unit of Measure: Units on a scale (0-10).
Time frame: Day 14 and Day 42 post-randomisation (Stage A and B)
Stage A and B- To evaluate the reach of the intervention (Participant refusal rate)
Stage A and B- To evaluate the reach of the intervention. Monitor enrolment data based on % refusal. Measurement: Percentage of eligible patients who decline participation Unit of measure: Percentage (%)
Time frame: Day 0 clinic (Stage A) or hospital (Stage B)
Stage A and B- To evaluate the reach of the intervention (Exclusion rate)
Stage A and B- To evaluate the reach of the intervention. Monitor enrolment data based on % exclusion. Measurement: Percentage of screened patients excluded due to protocol-defined exclusion criteria. Unit of measure: Percentage (%)
Time frame: Day 0 clinic (Stage A) or hospital (Stage B)
Stage A and B- To evaluate the reach of the intervention (Time between bite and treatment received)
Stage A and B- To evaluate the reach of the intervention. Monitor enrolment data based on time between bite and treatment received. Measurement: Time elapsed between reported snakebite and receipt of study treatment. Unit of measure: Hours
Time frame: Day 0 clinic (Stage A) or hospital (Stage B)
Stage A and B-To evaluate the reach of the intervention based on recruitment rate across the study catchment area (Recruitment rate)
Stage A and B- To evaluate the reach of the intervention. Monitor enrolment data based recruitment rate across the study catchment area. Measurement: Rate of participant enrolment across the study catchment area. Unit of measure: Participants per site per month
Time frame: Day 0 clinic (Stage A) or hospital (Stage B)
Stage A and B- Identify benefits of and barriers for future implementation of the intervention.
Stage A and B- Identify benefits of and barriers for future implementation of the intervention. Mixed-methods following the Consolidated Framework Implementation Research interviewing participants and health care providers
Time frame: Day 42
Stage A- To determine differences in resolution of clinically relevant non-serious bleeding events.
Stage A- To determine differences in resolution of clinically relevant non-serious bleeding events. Amongst all participants with non-major bleeding (epistaxis, gingival bleeding, or bleeding from a venepuncture site for \>5 min) at randomisation, proportion with cessation of bleeding on arrival to the hospital site per treatment arm.
Time frame: Day 0 clinic and hospital
Stage B- Assess the effect of time to treatment on INR improvement (based on estimated time from bite until administration of the treatment).
Stage B- Assess the effect of time to treatment on INR improvement (based on estimated time from bite until administration of the treatment). Amongst participants with baseline INR ≥1.4, change in INR from baseline to 6 hours, analysed using a linear regression model with treatment group, estimated time from bite to treatment, and their interaction
Time frame: Day 0 hospital
Stage B- Assess the effect of time to treatment on fibrinogen improvement (based on estimated time from bite until administration of the treatment).
Stage B- Assess the effect of time to treatment on fibrinogen improvement (based on estimated time from bite until administration of the treatment). Amongst participants with baseline INR ≥1.4, change in fibrinogen from baseline to 12 hours, analysed using a linear regression model with treatment group, estimated time from bite to treatment, and their interaction
Time frame: Day 0 hospital
Stage B- To determine differences in resolution of clinically relevant non-serious bleeding events.
Stage B- To determine differences in resolution of clinically relevant non-serious bleeding events. Amongst all participants with non-major bleeding (epistaxis, gingival bleeding, or bleeding from a venepuncture site for \>5 min) at randomisation, proportion with cessation of bleeding at 3 hours after randomisation per treatment arm.
Time frame: Day 0 hospital
No study locations are listed for this record.
Plan to share: Yes — Deidentified IPD and related documents will be shared via a trial repository.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: After primary results have been published and within 12 months of study completion.
Access criteria: Requests will be assessed and shared per the study Data Management Plan.
No publications or documents are linked to this record.
Start is estimated for Jan 2027; primary completion for Oct 2028, 21 months later.
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This study is not yet recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Unithiol · Marimastat
Liverpool School of Tropical Medicine