Population-Wide Introduction of Dose-Adjusted EPOCH-R Is Associated with Improved Outcome of High Grade B-Cell Lymphoma with MYC and BCL2 Rearrangements with Diffuse Large B-Cell Lymphoma Morphology

Introduction: High-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (HGBL-DH/TH), colloquially referred to as double- or triple-hit lymphoma, is associated with poor outcomes prompting many centers to use dose-intensive immunochemotherapy. The benefit of treatment intensification in patients with HGBL-DH/TH with diffuse large B-cell lymphoma (DLBCL) morphology, who would otherwise receive standard-of-care rituximab, cyclophosphamide, vincristine and prednisone (R-CHOP), remains unclear because suitably powered randomized clinical trials have not been performed, and earlier studies included patients with high-grade morphology. Furthermore, selection bias due to the restriction of fluorescence in situ hybridization (FISH) testing to diagnose HGBL-DH/TH in patients with high-risk clinical presentation or aggressive tumor morphology confounds historical comparators. Since 2015, de novo DLBCL biopsies in British Columbia (BC) have undergone routine FISH testing in clinical practice. Concurrently, provincial guidelines were introduced recommending treatment with dose-adjusted etoposide, doxorubicin, vincristine, cyclophosphamide, prednisone and rituximab (DA-EPOCH-R) for appropriately fit patients aged 75 years (y) or younger with HGBL-DH/TH harboring BCL2 rearrangements with DLBCL morphology (HGBL-DH/TH-BCL2-DLBCL). A population-based analysis was conducted to assess the impact of the introduction of DA-EPOCH-R on outcomes in HGBL-DH/TH-BCL2-DLBCL.

Methods: Outcomes of HGBL-DH/TH-BCL2-DLBCL patients diagnosed between 2015 to 2020 using clinical FISH performed on de novo DLBCL biopsies (DA-EPOCH-R era) were compared to patients with HGBL-DH/TH-BCL2-DLBCL identified from a historic province-wide cohort of de novo DLBCL diagnosed between 2005-2010 in BC that underwent universal FISH in a research setting (R-CHOP era). Patients with the rarer entity of HGBL-DH/TH harboring MYC and BCL6 rearrangements only (HGBL-DH-BCL6) were excluded and were not part of the original DA-EPOCH-R guideline. Multivariable Cox proportional hazards regression models were used to predict the independent effect of treatment era after controlling for the International Prognostic Index (IPI).

Results: 99 patients with HGBL-DH/TH-BCL2-DLBCL were identified through routine clinical FISH in the DA-EPOCH-R era. Of 1172 de novo DLBCL patients in the historic R-CHOP era, 824 had adequate diagnostic material for evaluation by FISH, 52 of which were HGBL-DH/TH-BCL2-DLBCL. The analysis was restricted to patients aged 75y or younger, yielding 71 and 38 patients in the DA-EPOCH-R and R-CHOP eras, respectively. 7/38 (18%) biopsies in the R-CHOP era had undergone clinical FISH testing at diagnosis with results known to the treating physician. Median (interquartile range) follow-up in living patients was 2.8y (2.0-4.4y) in the DA-EPOCH-R era and 12.2y (11.2-13.4y) in the R-CHOP era. 49/71 (69%) patients received DA-EPOCH-R in the DA-EPOCH-R era, whereas 32/38 patients (84%) received R-CHOP in the R-CHOP era. Both eras had comparable baseline clinical characteristics with no significant difference in IPI risk groups (Table 1). The DA-EPOCH-R era was associated with superior 2-year time to progression (TTP, 73.9% vs 47.4%, p=0.016) and overall survival (OS, 77.7% vs 50.0%, p=0.022, Figure 1). After adjusting for IPI risk groups (low 0-2, high 3-5), the DA-EPOCH-R era was independently associated with superior TTP (hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.21-0.77, p=0.005) and OS (HR 0.39, 95% CI 0.21-0.76, p=0.005). After controlling for individual IPI factors, treatment era remained predictive of TTP (HR 0.38, 95% CI 0.19- 0.76, p=0.006) and OS (HR 0.39, 95% CI 0.19-0.79, p=0.008).

Conclusions: Introduction of a provincial, population-based recommendation to use DA-EPOCH-R for appropriately fit patients aged 75y or younger is associated with improved real-world outcomes of HGBL-DH/TH-BCL2-DLBCL. The similarity between TTP and OS within each era suggests the high failure rate of conventional salvage therapy irrespective of frontline treatment, prompting further investigation of novel second-line therapies in this poor-prognosis population. Targeted capture sequencing to identify MYC translocation partners is underway, and the influence of the MYC partner on outcomes in both eras will be presented.

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