Outcomes by BCL2 and MYC expression and rearrangements in untreated diffuse large B-cell lymphoma (DLBCL) from the POLARIX trial.

Abstract

7517 Background: Overexpression of BCL2 and MYC, and translocation of MYC, BCL2, and BCL6, are associated with poorer outcomes in patients (pts) with DLBCL (Horn et al. Blood 2013). We previously reported progression-free survival (PFS) from POLARIX in subgroups of pts with DLBCL receiving Pola-R-CHP or R-CHOP, including pts with double expressor lymphoma (DEL; favoring Pola-R-CHP: hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.42–0.97), and double- or triple-hit lymphoma (DHL/THL; favoring R-CHOP: HR 3.81, 95% CI 0.82–17.64) (Tilly et al. NEJM 2022). In this prespecified exploratory analysis, we further analyzed immunohistochemistry (IHC) expression status of BCL2, MYC, and rearrangements (R) of BCL2, BCL6 and MYC as independent prognostic markers. We also explored the prognostic impact of DEL within treatment arms. Methods: BCL2 and MYC protein expression were assessed by IHC and identified as IHC+ (≥50% [BCL2]/≥40% [MYC]) or IHC−; MYC-R, BCL2-R, and BCL6-R were detected by fluorescence in situ hybridization (Tilly et al. NEJM, 2022). Exploratory multivariate Cox regression models were adjusted for treatment, stratification factors (IPI, bulky disease, geographic region), age >60 years, cell of origin, and biomarker evaluated, as appropriate. Results: The prevalence, univariate HR, and 2-year (yr) PFS estimates of BCL2+/MYC+ and BCL2-R/ MYC-R/ BCL6-R subgroups are presented (Table) except for BCL6-R, because all 4 PFS events in this subgroup were with Pola-R-CHP. Multivariate analyses results for Pola-R-CHP vs R-CHOP in pts with BCL2+ (HR 0.60, 95% CI 0.43–0.86) and in pts with MYC+ (HR 0.63, 95% CI 0.45–0.89) were similar to results of univariate analyses. Multivariate analyses of other subgroups were not performed due to the low pt number with BCL2-R/ MYC-R/ BCL6-R. While pts with DEL treated with Pola-R-CHP had improved PFS vs pts treated with R-CHOP (HR 0.64, 0.42–0.97), the prognostic impact of DEL vs non-DEL was more pronounced with R-CHOP (univariate HR 1.53, 95% CI 1.06–2.21; multivariate HR 1.29, 95% CI 0.88–1.91) vs Pola-R-CHP (univariate HR 1.10, 95% CI 0.72–1.69; multivariate HR 1.42, 95% CI 0.89–2.28). Conclusions: Multivariate analyses support the benefit of Pola-R-CHP in pts with BCL2+ and MYC+ DLBCL. The poor prognostic impact associated with DEL appears reduced in Pola-R-CHP- vs R-CHOP-treated pts. Clinical trial information: NCT03274492. [Table: see text]