Comparative Efficacy of the Novel Diarylquinoline TBAJ-876 and Bedaquiline against a Resistant Rv0678 Mutant in a Mouse Model of Tuberculosis

• Published in: Antimicrobial agents and chemotherapy Vol. 65; no. 12; p. e0141221
• Main Authors: Almeida, Deepak, Converse, Paul J, Li, Si-Yang, Upton, Anna M, Fotouhi, Nader, Nuermberger, Eric L
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 17.11.2021
• Subjects: Animals; Antitubercular Agents - pharmacology; Antitubercular Agents - therapeutic use; Bacteriology; Diarylquinolines; Disease Models, Animal; Experimental Therapeutics; Extensively Drug-Resistant Tuberculosis - drug therapy; Mice; Mycobacterium tuberculosis - genetics; Tuberculosis, Multidrug-Resistant - drug therapy; TBAJ-876; mouse; linezolid; Mycobacterium tuberculosis; tuberculosis; pretomanid; bedaquiline; resistance
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/AAC.01412-21

Bedaquiline (BDQ, B) is the first-in-class diarylquinoline to be approved for treatment of tuberculosis (TB). Recent guidelines recommend its use in treatment of multidrug- and extensively drug-resistant tuberculosis (MDR/XDR-TB). The newly approved regimen combining BDQ with pretomanid and linezolid is the first 6-month oral regimen proven to be effective against MDR/XDR-TB. However, the emergence of BDQ resistance, primarily due to inactivating mutations in the gene encoding a repressor of the MmpS5-MmpL5 transporter, threatens to undermine the efficacy of new BDQ-containing regimens. Since the shift in MIC due to these mutations is relatively small (2-8×), safer, and more potent, diarylquinoline analogues may be more effective than BDQ. TBAJ-876, which is in phase 1 trials, has more potent activity and a superior pre-clinical safety profile than BDQ. Using a murine model of TB, we evaluated the dose-dependent activity of TBAJ-876 compared to BDQ against the wild-type H37Rv strain and an isogenic loss-of-function mutant. Although the mutation affected the MIC of both drugs, the MIC of TBAJ-876 against the mutant was 10-fold lower than that of BDQ. TBAJ-876 at doses ≥6.25 mg/kg had greater efficacy against both strains compared to BDQ at 25 mg/kg, when administered alone or in combination with pretomanid and linezolid. Likewise, no selective amplification of BDQ-resistant bacteria was observed at TBAJ-876 doses ≥6.25 mg/kg. These results indicate that replacing BDQ with TBAJ-876 may shorten the duration of TB treatment and be more effective in treating and preventing infections caused by mutants.