This trial is in household contacts (HHC) at high risk for developing multidrug resistant tuberculosis (MDR-TB) which is an infection that does not get better with standard treatment for TB.  HHC means any person that  lives with, has lived with, or shared housekeeping duties in a home or the same place with a person (an Index Case) who has pulmonary MDR-TB (a lung infection or pneumonia with TB) and started treatment for MDR-TB within the past 90 days. It is also for people who have spent more than 4 hours indoors with the index case, during the week before they started MDR-TB treatment.

High-risk household contacts are those with HIV or an immune system problem not from HIV like cancer , latent TB infection (a history of TB infection in the past based on testing), and young children below the age of 5 years.

Purpose of this Study: 

Is to compare how safe and effective 26 weeks of Delamanid (DLM), a medicine used to treat TB,  is versus 26 weeks of isoniazid (INH), a standard medicine to treat or prevent TB,  for preventing infection with TB (latent TB) or confirmed or probable active infection with TB among participantshigh risk HHC (see above for description).

Requirements to Enter Study:

The Index Case must be an adult (18 years and older) with pulmonary MDR-TB who has started MDR-TB treatment within the past 90 days, who has one or more household contacts and gives site staff permission to call and visit the household contacts.

The Household contact must be a High-Risk Contact:

  • Children up to 5 years of age regardless of standard tests for TB known as the tuberculin skin test (TST) or the interferon gamma release assay (IGRA), a blood test for TB, or HIV status.
  • Adults, adolescents, and children ≥5 years of age who are TST-positive (defined as a skin test bump ≥5 mm in size) and/or IGRA test-positive and whose HIV status is negative, indeterminate, or unknown and who are not immunosuppressed from another condition besides HIV.
  • Adults, adolescents, and children ≥5 years of age who are HIV-infected or are immunosuppressed without HIV (defined as receiving anti-tumor necrosis factor (TNF) treatment, or in chronic renal failure receiving dialysis, or being solid organ or hematologic transplant recipients), regardless of TST/IGRA


Household contacts will be randomly assigned (like a flip of a coin) one of two groups:

Group A will receive:

DLM daily for adults, adolescents, and children, given for 26 weeks

Group B will receive:

  • INH daily for adults, adolescents, and children, given for 26 weeks
  • 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.

Duration of Study:

All participants will be in this study for 96 weeks.

Document list:


A5300B/I2003B V3 Final Protocol dated March 31, 2020

A5300B/I2003B V3 Manual of Procedures dated May 6, 2022

A5300B/I2003B V3 Lab Processing Chart dated May 3, 2022