From the Journals

All-oral regimen succeeds for rifampin-resistant tuberculosis



A combination oral-only therapy of bedaquiline, pretomanid, and linezolid was significantly more effective than standard care in preventing unfavorable outcomes in patients with treatment-resistant tuberculosis, based on data from more than 500 individuals.

Rifampin-resistant tuberculosis affects approximately 500,000 people worldwide each year, but current treatments are associated with toxicity and limited effectiveness, and data on the use of new and repurposed drug combinations are lacking, wrote Bern-Thomas Nyang’wa, MBBS, of Médecins Sans Frontières, Amsterdam, and colleagues.

In a study known as the TB-PRACTECAL trial, the researchers enrolled 552 pulmonary rifampin-resistant tuberculosis patients aged 15 years and older to examine several new and repurposed drug combinations. The participants were randomized in a 1:1:1:1 ratio to treatment with 36-80 weeks of standard care; 24-week oral bedaquiline, pretomanid, and linezolid (BPaL); BPaL plus clofazimine (BPaLC); or BPaL plus moxifloxacin (BPaLM) . This was followed by stage two of the trial, in which participants were randomized 1:1 to receive standard care or BPaLM. The current study, published in The Lancet Respiratory Medicine, reported the stage two findings; the primary outcome was a composite of unfavorable outcomes at 72 weeks including death, treatment failure, treatment discontinuation, recurrence of tuberculosis, or loss to follow-up.

The modified intent-to-treat population included 138 patients in the BPaLM group and 137 patients in the standard care group. In this population, 56 (41%) of 137 participants in the standard care group and 16 (12%) of 137 participants in the BPaLM group met criteria for the unfavorable outcome at 72 weeks; noninferiority and superiority were significantly greater in the BPaLM group (P < .0001).

Early discontinuation was the main reason patients met the unfavorable outcome criteria (89% of standard care patients and 69% of BPaLM patients); adverse events accounted for 23% of discontinuations in the standard care group and 64% of discontinuations in the BPaLM group.

However, fewer patients in the BPaLM group experienced grade 3 or higher adverse events compared with the standard care group (23% vs. 48%). The most common adverse events included hepatic disorders, cardiac disorders, and anemia.

In addition, all subgroup analyses favored BPaLM over standard care at 72 weeks including subgroups based on sex, age, disease severity, re-treatment status, and smoking status.

The findings were limited by several factors including the changes to standard of care over the course of the study, potential bias because the study was stopped for efficacy, and inclusion of loss to follow-up as part of the composite unfavorable outcome, the researchers noted.

Remaining research questions include the optimal dose of linezolid, whether use of alternative fluoroquinolones would yield similar results, and whether the results would generalize to populations including children, pregnant women, and patients with extrapulmonary tuberculosis, they added.

However, the results support BPaLM as the preferred treatment for adults and adolescents with pulmonary rifampin-resistant TB, the researchers concluded.

BPaLM poised to improve TB care

Before 2020, treatment for rifampin-resistant tuberculosis was 9-20 months in duration, toxic, and inadequately effective, and new treatment regimens are urgently needed, Mary Jo Farmer, MD, a pulmonary and critical care specialist at the University of Massachusetts Baystate Health Regional Campus, Springfield, said in an interview.

“The BPaL-based regimens perform better than the 9- to 20-month standard of care, are shorter in duration, have a lower pill burden, improve quality of life, and are cost-effective,” she said. “The BPaL regimens have the potential to improve outcomes for thousands of patients with rifampin-resistant tuberculosis.”

“The 24-week oral regimen consisting of bedaquiline, pretomanid, linezolid and moxifloxacin is noninferior to standard of care for treatment of patients with pulmonary rifampin-resistant tuberculosis, and this BPaLM regimen was added to the WHO guidance for treatment of this condition in 2022,” said Dr. Farmer, who was not involved in the study. “It remains to be seen if BPaLM will become the preferred regimen for adolescents and adults with pulmonary rifampin-resistant tuberculosis,” she said.

Dr. Farmer agreed with the study authors that the optimal dose of linezolid, optimal duration of treatment, and the role of dose reduction remain unknown, and pharmacokinetic studies are needed to identify these parameters.

The study was supported by Médecins Sans Frontières. TB Alliance donated pretomanid to the study prior to its commercialization. The researchers had no financial conflicts to disclose. Dr. Farmer had no financial conflicts to disclose, but serves on the editorial advisory board of CHEST Physician.

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