Abstract
In this post hoc subgroup analysis of 200 patients enrolled in China from the phase III PHOENIX trial (N = 838, NCT01855750), addition of ibrutinib to rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) did not improve event-free survival (EFS) versus placebo+R-CHOP in the intent-to-treat (ITT; n = 200, hazard ratio [HR] = 0.83, 95% confidence interval [CI]: 0·509-1.349; p = 0.4495) or activated B-cell-like (ABC; n = 141 [based on available gene-expression profiling data], HR = 0.86, 95% CI: 0.467-1.570; p = 0.6160) subpopulations. However, ibrutinib+R-CHOP improved EFS (HR = 0·50, 95% CI: 0.251-1.003) and progression-free survival (PFS; HR = 0.48, 95% CI: 0.228-1.009) versus placebo+R-CHOP in patients aged <60 but not ≥60 years. Grade ≥3 serious treatment-emergent adverse events occurred more with ibrutinib+R-CHOP (45·6% vs. 31·3%). The percentage of patients receiving ≥6 cycles of R-CHOP was similar across treatment arms in those <60 years. A numerical trend was seen towards improved EFS and PFS with ibrutinib+R-CHOP versus placebo+R-CHOP in patients with MYC-high/BCL2-high co-expression. In this slightly younger Chinese subgroup, ibrutinib+R-CHOP did not improve EFS in the ITT and ABC subpopulations but improved outcomes with manageable safety in patients <60 years, consistent with overall PHOENIX study outcomes.