A Phase 1 interventional study of TBD11 (300 mg) and Placebo in Healthy Adult Participants, sponsored by Gates Medical Research Institute. Recruiting at 1 site in South Africa. Open to participants aged 18 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-22.
Sponsored by Gates Medical Research Institute · Phase 1, Interventional, and Treatment
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This is a Phase 1, randomized, double-blind, placebo-controlled, multiple dose trial of TBD11 in healthy adults. It includes a dedicated open-label cohort in which TBD11 will be administered as a single dose with either a strong cytochrome P450 3A (CYP3A) inhibitor (itraconazole) or a strong CYP3A inducer (rifampicin) in 2 trial periods to evaluate DDI. The trial will consist of 3 cohorts; Cohort 1 will occur prior to Cohort 2 and Cohort 3. Cohort 2 and Cohort 3 will start after completion of Cohort 1 and will run in parallel. Cohort 1 will be double-blind and participants will receive 300 mg TBD11 or placebo once daily for 14 days. Cohort 2 will be the open-label DDI cohort. Cohort 3 will be double-blind and participants will receive TBD11 or placebo once daily for 84 days.
Gates Medical Research Institute is the lead sponsor of 12 studies on the registry; 2 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.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
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.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants randomized 3:1 to receiveTBD11 300 mg or matching placebo once daily for up to 14 days
Drug: TBD11 (300 mg) · Drug: Placebo
Participants receive TBD11 50 mg single dose alone and in combination with itraconazole 200 mg BID loading dose followed by 200 mg QD.
Drug: Itraconazole (200 mg) · Drug: TBD11 (50 mg)
Participants receive TBD11 up to 300 mg single dose alone and in combination with rifampicin 600 mg QD.
Drug: Rifampicin 600mg · Drug: TBD11 (up to 300 mg)
Participants randomized 2:1 to receive TBD11 up to 300 mg or matching placebo once daily for up to 84 days
Drug: Placebo · Drug: TBD11 (up to 300 mg)
TBD11: TBD11 administered orally at 300 mg
Matching placebo administered orally according to the cohort-specific dosing schedule.
Itraconazole 200 mg orally once daily, with a 400 mg loading dose on the first day of administration.
Rifampicin 600 mg orally once daily.
TBD11: TBD11 administered orally at 50 mg
TBD11: TBD11 administered orally at up to 300 mg
Number of Participants With Treatment-Emergent Adverse Events
Number of participants with one or more treatment-emergent adverse events, summarized overall and by severity, Investigator-assessed relationship to trial intervention, System Organ Class, and Preferred Term.
Time frame: Cohort 1: Day 1 through Day 19. Cohort 2 Arm A: Period 1, Day 1 through Day 8; Period 2, Day -4 through Day 16. Cohort 2 Arm B: Period 1, Day 1 through Day 8; Period 2, Day -10 through Day 8. Cohort 3: Day 1 through Day 92.
Number of Participants With Serious Adverse Events
Number of participants with one or more serious adverse events, summarized overall and by severity, Investigator-assessed relationship to trial intervention, System Organ Class, and Preferred Term.
Time frame: Cohort 1: Day 1 through Day 19. Cohort 2 Arm A: Period 1, Day 1 through Day 8; Period 2, Day -4 through Day 16. Cohort 2 Arm B: Period 1, Day 1 through Day 8; Period 2, Day -10 through Day 8. Cohort 3: Day 1 through Day 92.
Number of Participants With Adverse Events Leading to Trial Intervention Interruption
Number of participants with one or more adverse events resulting in temporary interruption of trial intervention, summarized overall and by severity, Investigator-assessed relationship to trial intervention, System Organ Class, and Preferred Term.
Time frame: Cohort 1: Day 1 through Day 19. Cohort 2 Arm A: Period 1, Day 1 through Day 8; Period 2, Day -4 through Day 16. Cohort 2 Arm B: Period 1, Day 1 through Day 8; Period 2, Day -10 through Day 8. Cohort 3: Day 1 through Day 92.
Number of Participants With Adverse Events Leading to Trial Intervention Discontinuation
Number of participants with one or more adverse events resulting in permanent discontinuation of trial intervention, summarized overall and by severity, Investigator-assessed relationship to trial intervention, System Organ Class, and Preferred Term.
Time frame: Cohort 1: Day 1 through Day 19. Cohort 2 Arm A: Period 1, Day 1 through Day 8; Period 2, Day -4 through Day 16. Cohort 2 Arm B: Period 1, Day 1 through Day 8; Period 2, Day -10 through Day 8. Cohort 3: Day 1 through Day 92.
Number of Participants With Treatment-Emergent Clinical Chemistry Abnormalities
Number of participants with treatment-emergent clinical chemistry abnormalities, summarized by visit, worst post-baseline grade, and grade shift from baseline using the protocol-specified toxicity grading criteria.
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Number of Participants With Treatment-Emergent Hematology Abnormalities
Number of participants with treatment-emergent hematology abnormalities, summarized by visit, worst post-baseline grade, and grade shift from baseline using the protocol-specified toxicity grading criteria.
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Number of Participants With Treatment-Emergent Coagulation Abnormalities
Number of participants with treatment-emergent coagulation abnormalities, summarized by visit, worst post-baseline grade, and grade shift from baseline using the protocol-specified toxicity grading criteria.
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Number of Participants With Treatment-Emergent Urinalysis Abnormalities
Number of participants with treatment-emergent urinalysis abnormalities, summarized by visit, worst post-baseline grade, and grade shift from baseline using the protocol-specified toxicity grading criteria.
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Number of Participants With Treatment-Emergent Lipid Profile Abnormalities
Number of Cohort 3 participants with treatment-emergent lipid profile abnormalities, summarized by visit, worst post-baseline grade, and grade shift from baseline.
Time frame: Baseline and scheduled post-baseline assessments from Day 1 through Day 92 for Cohort 3.
Change From Baseline in Systolic Blood Pressure
Change from baseline in systolic blood pressure, measured in millimeters of mercury (mmHg).
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in Diastolic Blood Pressure
Change from baseline in diastolic blood pressure, measured in millimeters of mercury (mmHg)
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in Heart Rate
Change from baseline in heart rate, measured in beats per minute (bpm)
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in Body Temperature
Change from baseline in body temperature, measured in degrees Celsius (°C)
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in 12-Lead ECG Heart Rate
Change From Baseline in 12-Lead ECG Heart Rate Change from baseline in 12-lead ECG heart rate, measured in beats per minute (bpm)
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in RR Interval
Change From Baseline in RR Interval Change from baseline in RR interval, measured in milliseconds (ms).
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in PR Interval
Change From Baseline in PR Interval Change from baseline in PR interval, measured in milliseconds (ms).
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in QRS Duration
Change From Baseline in QRS Duration Change from baseline in QRS duration, measured in milliseconds (ms).
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in QT Interval
Change From Baseline in QT Interval Change from baseline in QT interval, measured in milliseconds (ms).
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Change From Baseline in QTcF Interval
Change from baseline in QT interval corrected for heart rate using Fridericia's formula (QTcF), measured in milliseconds (ms).
Time frame: Cohort 1, Day 1 through Day 19; Cohort 2 Arm A, Period 1 Day 1 through Day 8 and Period 2 Day -4 through Day 16; Cohort 2 Arm B, Period 1 Day 1 through Day 8 and Period 2 Day -10 through Day 8; Cohort 3, Day 1 through Day 92.
Maximum Observed Plasma Concentration of TBD11
Maximum observed plasma concentration (Cmax) of TBD11 following single-dose and multiple-dose administration, measured in nanograms per milliliter (ng/mL).
Time frame: Cohort 1: Day 1 and Day 14. Cohort 3: Day 1 and Day 84.
Time to Maximum Observed Plasma Concentration of TBD11
Time to reach the maximum observed plasma concentration (Tmax) of TBD11, measured in hours (h).
Time frame: Cohort 1: Day 1 and Day 14. Cohort 3: Day 1 and Day 84.
Area Under the Plasma Concentration-Time Curve From Time Zero to 24 Hours for TBD11
Area under the plasma concentration-time curve from time zero to 24 hours (AUC0-24), measured in hour-nanograms per milliliter (h·ng/mL).
Time frame: Cohort 1: Day 1. Cohort 3: Day 1
Area Under the Plasma Concentration-Time Curve From Time Zero to the Last Quantifiable Concentration for TBD11
Area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUClast), measured in hour-nanograms per milliliter (h·ng/mL).
Time frame: Cohort 1: Day 14. Cohort 3: Day 84.
Minimum Plasma Concentration of TBD11
Minimum plasma concentration (Cmin) of TBD11 after multiple-dose administration, measured in nanograms per milliliter (ng/mL).
Time frame: Cohort 1: Day 14. Cohort 3: Day 84
Accumulation Ratio for TBD11 Based on AUC Over the Dosing Interval
Accumulation ratio calculated as AUCtau following multiple-dose administration divided by AUC0-24 following the Day 1 dose.
Time frame: Cohort 1: Day 14 compared with Day 1. Cohort 3: Day 84 compared with Day 1.
Geometric Mean Ratio of TBD11 Cmax With and Without Itraconazole
Geometric mean ratio and corresponding two-sided 90% confidence interval for TBD11 Cmax, where Test is TBD11 co-administered with itraconazole and Reference is TBD11 administered alone.
Time frame: Cmax derived from plasma PK samples collected from pre-dose through 12 hours after TBD11 administration on Day 1 of Period 1 and Day 1 of Period 2.
Geometric Mean Ratio of TBD11 AUC0-inf With and Without Itraconazole
Geometric mean ratio and corresponding two-sided 90% confidence interval for TBD11 area under the plasma concentration-time curve from time zero extrapolated to infinity, where Test is TBD11 co-administered with itraconazole and Reference is TBD11 administered alone.
Time frame: AUC0-inf derived from plasma PK samples collected from pre-dose through 168 hours after TBD11 administration in Period 1 and through 360 hours after TBD11 administration in Period 2.
Geometric Mean Ratio of TBD11 Cmax With and Without Rifampicin
Geometric mean ratio and corresponding two-sided 90% confidence interval for TBD11 Cmax, where Test is TBD11 co-administered with rifampicin and Reference is TBD11 administered alone.
Time frame: Cmax derived from plasma PK samples collected from pre-dose through 12 hours after TBD11 administration on Day 1 of Period 1 and Day 1 of Period 2.
Geometric Mean Ratio of TBD11 AUC0-inf With and Without Rifampicin
Geometric mean ratio and corresponding two-sided 90% confidence interval for TBD11 area under the plasma concentration-time curve from time zero extrapolated to infinity, where Test is TBD11 co-administered with rifampicin and Reference is TBD11 administered alone.
Time frame: AUC0-inf derived from plasma PK samples collected from pre-dose through 168 hours after TBD11 administration in each treatment period.
Plan to share: Yes
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Time frame: Within 12 months of study completion date.
Access criteria: Anonymized participant-level data may be shared with the external research in accordance with trial participant' written and executed informed consent and applicable local regulations. Qualified research may submit a request along with a research proposal to Gates MRI for review. A data sharing agreement must be in place before any clinical trial data are shared. Additional restrictions may apply due to contractual obligations or regulatory constraints.
No publications or documents are linked to this record.
Started Oct 2026 (actual). Primary completion is estimated for May 2027, 7 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Gates Medical Research Institute