Drug-resistant tuberculosis treatment

Bedaquiline use beyond 6 months. It is generally agreed that most patients can be treated with four 
effective agents at the start of the therapy, one of which – usually bedaquiline – can usually be stopped 
at month 6. However, evidence assessed by the GDG in November 2019 supports the safety of using 
bedaquiline beyond 6 months in patients who receive appropriate schedules of baseline and follow-up 
monitoring. The GDG was not able to assess the relative effectiveness of prolonged bedaquiline use, 
owing to the limited evidence and to potential residual confounding in the data. The regimen needs 
to have at least three effective agents if bedaquiline is stopped at 6 months; thus, if another agent 
needs to be stopped because of toxicity, then that medicine would need to be replaced by another 
one.
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The replacement medicine would be chosen from either Group B (unless both clofazimine and 
cycloserine or terizidone are already included) or Group C. The choice from Group C is determined 
by the order in which the medicines are ranked, and the individual circumstances of the patient and 
setting. Starting with five agents instead of four may be preferred in certain situations, to avoid the 
need to replace a medicine after treatment has started. Such situations include the following: two of 
the four agents are likely to be stopped before the end of treatment (e.g. if bedaquiline is stopped 
at month 6 and linezolid is stopped early because of toxicity); reliable DST is not available for one 
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While replacement of one agent by another one because of toxicity may be acceptable, this should not be done if there are signs that 
the patient is not responding (e.g. persistent culture positivity or reversion to positive after culture has become negative). A need to 
replace two or more agents because of toxicity fulfils the definition of treatment failure (41). 

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WHO consolidated 
guidelines 
on
tuberculosis: 
drug-resistant tuberculosis treatment
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or more of the agents on the regimen, but background resistance to the agent is known to be high; 
and the agents included in the regimen are unlikely to cure the patient (e.g. a total of only two of the 
agents from Group A and Group B are included in the regimen).