A Phase 3 interventional study of Delamanid (DLM) and Isoniazid (INH) in Tuberculosis, MDR, sponsored by National Institute of Allergy and Infectious Diseases (NIAID). Active, not recruiting at 31 sites in 13 countries. Per ClinicalTrials.gov, last updated 2026-11-02.
Sponsored by National Institute of Allergy and Infectious Diseases (NIAID) · Phase 3, Interventional, and Prevention
The purpose of this study is to compare the efficacy and safety of 26 weeks of delamanid (DLM) versus 26 weeks of isoniazid (INH) for preventing confirmed or probable active tuberculosis (TB) during 96 weeks of follow-up among high-risk household contacts (HHCs) of adults with multidrug-resistant tuberculosis (MDR-TB) (index cases). High-risk HHCs are those with HIV or non-HIV immunosuppression, latent TB infection, and young children below the age of 5 years.
This study will compare the efficacy and safety of 26 weeks of delamanid (DLM) versus 26 weeks of isoniazid (INH) for preventing confirmed or probable active tuberculosis (TB) during 96 weeks of follow-up among high-risk household contacts (HHCs) of adults with multidrug-resistant tuberculosis (MDR-TB) (index cases). High-risk HHCs are those with HIV or non-HIV immunosuppression, latent TB infection, and young children below the age of 5 years.
If at least one HHC within a household (HH) is found to be eligible, the HH will be randomized to one of the following:
Arm A: DLM daily for adults, adolescents, and children, given for 26 weeks.
Arm B: INH daily for adults, adolescents, and children, given for 26 weeks AND pyridoxine (vitamin B6) daily for adults, adolescents, and children, given for 26 weeks.
All high-risk HHCs in the same HH will receive the same randomized regimen.
All participants will be in the study for 96 weeks. At study entry, index cases will undergo a medical history review and sputum collection. HHCs will have study visits at study entry and at Weeks 2, 4, 8, 12, 16, 20, 26, 36, 48, 60, 72, 84, and 96. Visits may include physical examinations; blood, urine, and sputum collection; electrocardiograms (ECGs); and questionnaires and assessments. Forty HHCs under the age of 5 taking DLM will undergo an intensive PK visit at Week 8.
132 studies on the registry are indexed under Tuberculosis, Multidrug-Resistant; 25 are open to participants now.
This study's enrollment of 5,832 is above the median of 194 across 88 interventional studies indexed under Tuberculosis, Multidrug-Resistant.
Browse Tuberculosis, Multidrug-Resistant studies →National Institute of Allergy and Infectious Diseases (NIAID) is the lead sponsor of 2,446 studies on the registry; 179 are open to participants now.
Of its 405 completed or terminated interventional studies of FDA-regulated products, 302 (75%) have results posted.
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.
INDEX CASE
Pulmonary MDR-TB defined as:
HOUSEHOLD CONTACTS
If any member(s) of the HH is/are not eligible or do not want to participate, all other eligible TB contacts within the HH can still participate.
HHCs must be in one of the following high-risk groups:
The following specific laboratory values for infants, children, and adults obtained within 30 days prior to study entry by any DAIDS-approved non-US laboratory.
For females of , negative serum or urine pregnancy test within 7 days prior to study entry by any DAIDS-approved non-US laboratory that operates in accordance with GCLP and participates in appropriate external quality assurance programs.
Exclusion Criteria:
INDEX CASE
HOUSEHOLD CONTACTS
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.
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.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
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.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
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.
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.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask 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.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
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.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
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.
HHCs will receive delamanid (DLM) for 26 weeks.
Drug: Delamanid (DLM)
HHCs will receive isoniazid (INH) and pyridoxine (vitamin B6) for 26 weeks.
Drug: Isoniazid (INH) · Dietary Supplement: Pyridoxine (vitamin B6)
Adults and children ≥30 kg: delamanid 200 mg orally once daily. Children ≥2.5 kg to \<30 kg: weight-band dosing orally once daily as per the study protocol. As children gain weight, their DLM dose should be adjusted, typically every month or as the visit schedule permits.
Adults and children ≥24 kg: INH 300 mg orally once daily. Children ≥2.5 kg to \<24 kg: INH weight-band dosing orally once daily as per the study protocol. As children gain weight, their INH dose should be adjusted.
All HHCs in Arm B must receive pyridoxine (vitamin B6) with each dose of INH based on the current local dosing guidelines. For children up to 3 years of age and nursing women, pyridoxine will be given as per local standard of care. Pyridoxine is not supplied through the study.
Percent of participants with confirmed or probable active TB at any time between Day 0 and the week 96 study visit
TB diagnoses will be reviewed by the independent outcomes review committee to assess whether the HHC had TB, if it was confirmed or probable TB, and if it was MDR-TB.
Time frame: Measured through Week 96
Percent of participants who permanently discontinue randomized study drug (DLM or INH) due to a treatment-related adverse event
Requiring discontinuation as defined in the protocol, or in the opinion of the site investigator is a treatment-limiting adverse event.
Time frame: Measured through Week 96
Percent of participants with confirmed active MDR-TB at any time between Day 0 and the week 96 study visit
Percent of participants with confirmed active MDR-TB at any time between Day 0 and the week 96 study visit
Time frame: Measured through Week 96
Percent of participants who died from any cause at any time between Day 0 and 96 weeks of follow-up
Deaths will be reviewed by the independent outcomes review committee to assess whether the HHC had TB at the time of death, possibly undiagnosed, and relatedness of the death to TB.
Time frame: Measured through Week 96
Percent of participants who died from any cause at any time between Day 0 and 96 weeks of follow-up, or with confirmed or probable active TB at any time between Day 0 and the week 96 study visit
Deaths and TB diagnoses will be reviewed by the independent outcomes review committee to assess whether the HHC had TB at the time of death, possibly undiagnosed, and relatedness of the death to TB; and whether the HHC had TB, if it was confirmed or probable TB, and if it was MDR-TB.
Time frame: Measured through Week 96
Percent of participants with a Grade 3 or higher adverse event during the period receiving randomized study drug (DLM or INH)
If a HHC has a Grade 3 or higher adverse event prior to starting randomized study drug, then the same event will only be considered during follow-up if the grade worsens.
Time frame: Measured through Week 26
Plan to share: Yes — Individual participant data that underlie results in the publication, after deidentification.
Supporting information: Study protocol, Statistical analysis plan
Time frame: Beginning 3 months following publication and available throughout period of funding of the AIDS Clinical Trials Group by NIH.
Access criteria: With whom? Researchers who provide a methodologically sound proposal for use of the data that is approved by the AIDS Clinical Trials Group. For what types of analyses? To achieve aims in the proposal approved by the AIDS Clinical Trials Group. By what mechanism will data be made available? Researchers may submit a request for access to data using the AIDS Clinical Trials Group "Data Request" form at: https://actgnetwork.org/about-actg/templates-and-forms. Researchers of approved proposals will need to sign an AIDS Clinical Trials Group Data Use Agreement before receiving the data.
No publications or documents are linked to this record.
Started Jun 2019 (actual). Primary completion is estimated for Nov 2026, 89 months after the start.
Since we started tracking on Sep 25, 2026, the dates moved once, on Nov 2, 2026: primary completion Jan 2027 → Nov 2026 and completion Jan 2027 → Nov 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
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 ↗
This study is active, not recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: OPC-67683 · Isoniazid · Pyridoxine
Tuberculosis, Multidrug-Resistant →
National Institute of Allergy and Infectious Diseases (NIAID) →