Phase II study of R-CHOP with GM-CSF cytokine support for elderly patients with untreated diffuse large B-cell lymphoma (DLBCL): A Wisconsin Oncology Network study
7566 Background: According to mature data from the GELA study, approximately 55% of elderly patients with DLBCL will be cured with R-CHOP. We hypothesized that sargramostim (GM-CSF), added to R-CHOP may potentiate the efficacy of rituximab by upregulating tumor cell CD20 expression and by augmenting antibody dependent cellular cytotoxicity (ADCC). Methods: Patients > 60 years old with untreated stage I-IV DLBCL were eligible if they had PS ≤ 2, measurable disease, adequate organ function, and provided informed consent. R-CHOP for 6–8 cycles was given every 21 days with GM-CSF given subcutaneously at a dose of 250 mg/m2 days 3–10 of each cycle. The primary endpoint was to estimate the CR/CRu rate. Secondary endpoints included estimates of the ORR, EFS, and OS. Results: Thirty-eight/forty patients have been enrolled to date and data are available for 36. One patient is too early and another was deemed ineligible after centralized pathology review. Baseline characteristics include median age 72 (range 61–86), 25% PS 0, 44% PS 1, 31% PS 2, 80% stage III/IV, 56% elevated LDH, 8% IPI 0–1, 25% IPI 2, 36% IPI 3, 31% IPI 4–5. Thirteen/thirty-six (36%) patients did not complete 6 cycles of protocol therapy, 8 due to intolerance of R-CHOP and 5 due to intolerance of GM-CSF. By intent-to-treat analysis, 17/36 patients achieved CR/CRu (47%) and 9/36 achieved PR (25%) for an ORR of 72%. No patients progressed while on study and all non-responders were deemed so secondary to inability to complete protocol therapy. The median follow-up time for surviving patients is 19 months. Considering inability to complete protocol therapy as an event, the 2-year EFS is 38%, the 2-year PFS is 56%, and the 2-year OS is 74%. Conclusions: Any benefit that may be conferred by GM-CSF is likely to be offset by toxicity and intolerance, with 14% of patients in this series unable to complete GM-CSF therapy. Additionally, R-CHOP is more toxic in elderly patients than is commonly appreciated with, 22% of patients unable to complete 6 cycles. Despite recent advances, DLBCL in the elderly remains a difficult problem and new approaches to therapy must be developed. [Table: see text]