Three years after the last patient had been enrolled, the primary endpoint – the incidence rate of first diagnosis of active TB, TB death, or death from an unknown cause – had occurred in 32 patients on the 1HP regimen, and 33 on 9-month isoniazid.
Events included confirmed active TB in 18 patients on 1HP and 14 on isoniazid, probable active TB in 11 and 10 patients, respectively, death related to TB in 2 patients on 9-month isoniazid (none in the 1HP group) and death from unknown causes in 3 and 7 patients, respectively.
The incidence of events per 100 person-years of follow-up was 0.65 for the 1HP regimen and 0.67 for 9 months of isoniazid, a difference that was not statistically significant.
There were two cases of isoniazid resistance and one of rifampin resistance in the 1HP arm vs. one each in the 9-month isoniazid arm. There were no cases of multidrug resistance in either arm.