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SnakebitePhase 2TOCSINSNCT07500233

Trial of Oral Community SVMP INhibitors for Snakebite

A Phase 2 study testing 2,3-dimercapto-1-propanesulfonic acid, marimastat and Antivenom Snakes in people with Snakebite, run by Liverpool School of Tropical Medicine.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

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. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Snakebite
What is being tested?
2,3-dimercapto-1-propanesulfonic acid, marimastat and Antivenom Snakes
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
504 participants
Where
No sites listed yet
Study dates
Jan 2027to Dec 2028
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 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Snakebite in the preceding 12 hours (Stage A \& B)
  • Aged ≥18-years (Stage A \& B)
  • Residing in the Amazonas region of Brazil or the Upper West region of Ghana (Stage A \& B)
  • Capable of giving informed consent (Stage A \& B)
  • Are eligible for antivenom treatment according to local guidelines (Stage B only)

Who cannot join

  • individual with severe envenoming (defined in the protocol) (Stage A \& B)
  • concomitant anticoagulation (heparins, coumarin anticoagulants such as warfarin, or direct oral anticoagulants such as apixaban) (Stage A \& B)
  • pregnant or breastfeeding (Stage A \& B)

Trial locations and contacts

No sites are listed yet. Contact the study team or a site near you to ask about taking part.

TOCSINS Trial Management contact

+44(0)1517053100

tocsins@lstmed.ac.uk

About this study

Official title: A Phase 2 Randomised Placebo-controlled Platform Trial of Snake Venom Metalloproteinase Inhibitors for Snakebite Envenoming in Brazil and Ghana

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.

Read more

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.

Conditions
Snakebite
Being tested
2,3-dimercapto-1-propanesulfonic acid, marimastat, Oral placebo capsules, Antivenom Snakes
Keywords
envenoming
Medical subject headings
Snake Bites

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 2,3-dimercapto-1-propanesulfonic acidDrug

    Also called unithiol, DMPS

    Oral administration

  • marimastatDrug

    oral administration

  • Oral placebo capsulesDrug

    Oral placebo

  • Antivenom SnakesDrug

    Standard of care IV antivenom recommended in country

Study groups in NCT07500233
Study groupRoleWhat they receive
Oral Placebo Stage APlacebo comparatorNot described
Receives: Drug: Oral placebo capsules
Stage B IV AntivenomActive comparatorNot described
Receives: Drug: Antivenom Snakes
Stage A & B Oral DMPSExperimentalNot described
Receives: Drug: 2,3-dimercapto-1-propanesulfonic acid
Stage A & B Oral MarimastatExperimentalNot described
Receives: Drug: marimastat
Stage B IV MarimastatExperimentalNot described
Receives: Drug: marimastat

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. 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.

    Measured: From randomisation until end of admission

  2. 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.

    Measured: From informed consent until 42 days after randomisation

Secondary outcomes (13)
  1. 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

    Measured: Day 0 clinic and hospital

  2. 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.

    Measured: Day 0 clinic and hospital

  3. 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)

    Measured: Day 14, Day 42 (Stage A and B)

  4. 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).

    Measured: Day 14 and Day 42 post-randomisation (Stage A and B)

  5. 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 (%)

    Measured: Day 0 clinic (Stage A) or hospital (Stage B)

  6. 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 (%)

    Measured: Day 0 clinic (Stage A) or hospital (Stage B)

  7. 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

    Measured: Day 0 clinic (Stage A) or hospital (Stage B)

  8. 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

    Measured: Day 0 clinic (Stage A) or hospital (Stage B)

  9. 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

    Measured: Day 42

  10. 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.

    Measured: Day 0 clinic and hospital

  11. 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

    Measured: Day 0 hospital

  12. 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

    Measured: Day 0 hospital

  13. 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.

    Measured: Day 0 hospital

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted30 Mar 2026
  2. Study startJan 2027 (estimated)
  3. Primary completionOct 2028 (estimated)
  4. Study completionDec 2028 (estimated)

Resources

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
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
504 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07500233
Sponsor's protocol ID
25-033-310
Acronym
TOCSINS
Status last verified
Mar 2026
First submitted
24 Mar 2026
Last updated
12 May 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: Deidentified IPD and related documents will be shared via a trial repository.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing 2,3-dimercapto-1-propanesulfonic acid, marimastat and Antivenom Snakes in people with Snakebite, run by Liverpool School of Tropical Medicine.

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 3 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: opening soon, as of the sponsor's last update on 12 May 2026. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. 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 TOCSINS Trial Management (+44(0)1517053100, tocsins@lstmed.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Mean time until lab INR is less than 50% of the baseline value (efficacy) (time frame: From randomisation until end of admission). The study lists 2 primary outcomes in all. 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 12 May 2026.

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