Bedaquiline is a diarylquinoline antimycobacterial drug that inhibits the proton pump of mycobacterial ATP (adenosine 5'-triphosphate) synthase, an enzyme that is essential for the generation of energy in Mycobacterium tuberculosis. Bacterial death occurs as a result of bedaquiline.
Bedaquiline is primarily subjected to oxidative metabolism leading to the formation of N-monodesmethyl metabolite (M2). M2 is not thought to contribute significantly to clinical efficacy given its lower average exposure (23% to 31%) in humans and lower antimycobacterial activity (4 to 6-fold lower) compared to the parent compound. M2 concentrations appeared to correlate with QT prolongation. Bedaquiline inhibits mycobacterial TB at a minimal inhibitory concentration (MIC) from 0.002-0.06 μg/ml and with a MIC50 of 0.03 μg/ml. Furthermore, bacteria that have smaller ATP stores (usually in dormant, nonreplicating bacilli) are more susceptible to bedaquiline.
Bedaquiline is hepatically metabolized. The main enzyme involved is CYP3A4 which metabolizes bedaquiline into the N-monodesmethyl metabolite (M2). This metabolite is 4 to 6-times less active in terms of antimycobacterial potency.
The most common adverse reactions reported in ≥10% of patients treated with bedaquiline are nausea, arthralgia, and headache.