Tuberculosis (TB) kills more people each year than any other infectious disease. Not only the patients, but their nearest and dearest are at risk, as well. They are more likely to acquire latent TB infection and many will progress to active TB.
NIH is launching a study to compare delamanid, a new drug for multidrug-resistant TB (MDR-TB) with isoniazid, the long-time standard. The study hypothesis is that prophylactic delamanid will better protect family and other household members of patients with MDR-TB. Existing treatments for MDR-TB are often highly toxic and poorly tolerated, putting patients at risk while curing them only about half the time. Delamanid is one of the first drugs available specifically to treat people with MDR-TB and the first formulation suitable for children.
“A highly effective preventive TB therapy for vulnerable household members of people with active MDR-TB disease would be a game-changer in TB care,” says Dr. Anneke Hesseling, MD, PhD, one of the study leaders.
The phase 3 trial, Protecting Households on Exposure to Newly Diagnosed Index Multidrug-Resistant Tuberculosis Patients (PHOENIx MDR-TB), will take place at > 27 sites in at ≥ 12 countries. The researchers plan to enroll 2,158 adults being treated for confirmed active MDR-TB and 3,452 members of their households who are at high risk for developing active TB. The household members will be assigned randomly to receive oral delamanid daily for 26 weeks or oral isoniazid plus vitamin B6 daily for 26 weeks. All at-risk members of the same household will receive the same drug regimen.
Every 2 to 12 weeks, participating household contacts will have physical exams and other health assessments. The researchers will follow them for 96 weeks. Final results are expected in 2024.
TB is the leading cause of death among people with HIV. Both delamanid and isoniazid have minimal potential for interacting with antiretroviral drugs. Study participants with HIV who have not yet begun treatment will be referred to local health care providers for antiretroviral treatment.