On April 12th RESIST-TB hosted a webinar on two presentations from the 2019 Conference on Retroviruses and Opportunistic Infections (CROI):
EARLY BACTERICIDAL ACTIVITY OF HIGH-DOSE ISONIAZID AGAINST MULTIDRUG-RESISTANT TB
Presented by Kelly Dooley
High-dose isoniazid (INH) may be useful in treating multidrug-resistant tuberculosis (MDR-TB), particularly when INH resistance is mediated by inhA mutations. Although the World Health Organization (WHO) recommends ‘high-dose’ INH as part of the new shorter MDR-TB regimen, the optimal dose and its efficacy are not established.
AIDS Clinical Trials Group (ACTG) A5312 is a Phase 2A randomized, open-label trial in which individuals with smear-positive pulmonary MDR-TB with INH resistance mediated by an inhA mutation (Group 1) were randomized to receive INH doses of 5, 10 or 15 mg/kg daily for 7 days. Controls with drug-sensitive TB (Group 2) received the standard INH dose of 5 mg/kg/day. Sputum cultures were collected daily, beginning at baseline. The early bactericidal activity of INH, estimated as the average daily change in log10 colony forming units (CFU) on solid media (EBACFU0-7) or average daily change in time to positivity (TTP) in hours on liquid media (EBATTP0-7) over 7 days of treatment was estimated using nonlinear mixed effects models. Safety data were collected from study entry through Day 21.
Dr. Dooley’s webinar presentation: INHindsight Trial
QT EFFECTS OF BEDAQUILINE, DELAMANID OR BOTH IN MDR-TB PATIENTS: THE DELIBERATE TRIAL
Presented by Gary Maartens
Bedaquiline and delamanid are the first drugs of new classes approved for tuberculosis (TB) in 40 years. Both are oral, well-tolerated, and recommended for treatment of multidrug resistant (MDR) TB by WHO. However, these drugs and/or their metabolites have long half-lives, and each prolongs the QT interval with maximum effects weeks after drug initiation. The cardiac safety of these drugs given together as part of multidrug therapy has not been established.
AIDS Clinical Trials Group (ACTG) A5343 is a phase 2, open-label trial randomizing adults with MDR-TB receiving multidrug background treatment (MBT) 1:1:1 to receive bedaquiline (BDQ arm), delamanid (DLM arm) or both (BDQ+DLM arm) for 24 weeks. Patients with QTcF >450ms or CD4 count < 100 cells/mm3 were excluded. HIV-infected participants received dolutegravir-based ART. Clofazimine was not allowed, and levofloxacin was given in place of moxifloxacin. Three electrocardiograms (ECG) were performed at baseline, every two weeks for 24 weeks, then week 28. QTcF (in ms) was calculated by a core laboratory blinded to treatment. The mean QTcF change from baseline (averaged over weeks 8-24) was defined in each arm, and the QTcF change in the BDQ+DLM arm was compared to QTcF changes in the BDQ and the DLM arms. Grade 3 QTcF prolongation was defined as >500ms or >480ms with increase from baseline >60ms. Grade 4 was life-threatening dysrhythmia.
Dr. Maarten’s webinar presentation: DELIBERATE Trial
Due to technical complications during the webinar, the event was unable to be recorded.
We apologize for the inconvenience.