 In these analyses, the efficacy of rifapentine was exposure-dependent. Using maximum inhibitory effect Emax in a time-to-event model, a highly significant rifapentine exposure-response relationship was observed. With rifapentine AUC0-24 350 μghmL, the percentage of participants with culture conversion of sputa from positive to negative in liquid media at 2 months of rifapentine treatment was modeled to be 74 and with rifapentine AUC0-24 300 μghmL low rifapentine AUC to be 55. In summary, adequately high rifapentine exposure resulted in better responses, and large cavity size in poorer responses. 