Clinical Impact of Ibrutinib with R-CHOP in Untreated Non-GCB DLBCL Co-Expressing BCL2 and MYC Genes in the Phase 3 Phoenix Trial
In the phase 3, double-blind, placebo (pbo)-controlled PHOENIX trial (NCT01855750), 838 patients (pts) with non-germinal center B-cell-like (non-GCB) diffuse large B-cell lymphoma (DLBCL) were randomized 1:1 to ibrutinib (IBR; 560 mg/day orally) + rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or pbo + R-CHOP. IBR + R-CHOP did not improve event-free survival (EFS) in the intent-to-treat (ITT) non-GCB population (hazard ratio [HR] 0.934; 95% confidence interval [CI], 0.726-1.200). However, in an exploratory analysis, pts < 60 years benefited from the addition of IBR (HR 0.579; 95% CI, 0.380-0.881 for EFS), whereas pts ≥ 60 years did not (HR 1.228; 95% CI, 0.887-1.699 for EFS) due to increased toxicity and reduced R-CHOP exposure. Based on evidence that co-expression of BCL2 and MYC by immunohistochemistry (IHC) have a worse outcome with R-CHOP, we examined their clinical prognostic effect in the 2 arms of the PHOENIX trial.