A Single Center Experience with Using Dose-Adjusted Repoch in Elderly Patients with Large B-Cell Lymphoma

Background: RCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) has been the predominant regimen for treatment of aggressive large B-cell lymphomas (LBCL). In the CALGB 50303 trial, REPOCH (rituximab, etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin) was associated with similar efficacy but increased toxicity compared to RCHOP, however pts with higher risk disease by International Prognostic Index (IPI) had longer progression-free survival (PFS) with REPOCH therapy in the subgroup analysis ( J Clin Oncol, 2019). Providers may be hesitant to use REPOCH therapy in older, frail patients (pts) with high-risk LBCL due to concern for increased toxicity. One study demonstrated that empirically dose-reduced REPOCH (30-50% dose reduction by age group) was effective and well-tolerated in an elderly population ( Ann Hematol, 2018).A separate study showed significantly reduced neuropathy rates without compromised efficacy when vincristine doses in the REPOCH regimen were capped at 0.5 mg/d compared to 0.4 mg/m 2/d ( Leukemia & Lymphoma, 2019). At our institution, vincristine doses are capped at 0.4 mg/d for all pts, and REPOCH dosing is not empirically dose-reduced based for age alone. The aim of this study is to provide additional insights on the safety and efficacy of REPOCH in elderly pts diagnosed with LBCL with a routine vincristine dose cap of 0.4 mg/day (“REPOCH 0.4”). Methods: In this single cohort study, pts with newly diagnosed LBCL that received dose-adjusted REPOCH 0.4 at a single institution from August 2015 to October 2020 were retrospectively reviewed. Pts were excluded if they received fewer than 2 cycles, had CNS disease, transferred to another facility during treatment, or were lost-to-follow-up. Primary endpoints included adverse effects (AEs), overall response rates (ORR) via Lugano staging at end of treatment, 2y PFS, and overall survival (OS). Survival endpoints were estimated via Kaplan-Meier survival analysis. Secondary endpoints included CNS relapse rates and percentage of pts electing for hospice during therapy. Outcomes were descriptively compared to the historical cohort (N=241) in the CALGB 50303 trial receiving R-REPOCH without a vincristine dose cap ( J Clin Oncol, 2019) . Results: Forty-six pts were eligible for analysis (“entire cohort”), 19 of whom were 70 years or older (“70+ cohort”, figure 1). Median age in the entire and 70+ cohort was 67 and 75 years respectively. In the entire cohort, 23.9%