Safety and Efficacy of Replacing Vindesine with Vincristine in R-ACVBP Protocol for the Treatment of High-Grade B Cell Lymphoma

Background: Intensified immunochemotherapy with rituximab, doxorubicin, cyclophosphamide, vindesine, bleomycin, and prednisone (R-ACVBP) has been shown to improve outcomes in younger adults with high-grade B-cell lymphomas (hg-BCL) when compared to standard therapy with R-CHOP (Cyclophosphamide-Adriamycin-Vincristine-Prednisone) (Recher C. Lancet 2011). Due to unavailability of vindesine at our institution, we primarily aimed at assessing the safety and efficacy of replacing vindesine with vincristine in a modified R-ACVBP protocol (mR-ACVBP). Secondary endpoints included progression-free survival (PFS), and overall survival (OS).

Methods: This is a retrospective study performed at the American University of Beirut Medical Center (AUBMC), Lebanon, including all consecutive adult patients (pts) with newly diagnosed hg-BCL who received first-line mR-ACVBP from 10/2014 to 10/2019. mR-ACVBP protocol was similar to published original protocol with the exception of vindesine being replaced by vincristine 1.5 mg intravenously on days 1 and 5 of each cycle (initial protocol included vincristine 2 mg on days 1 and 5, later adjusted for toxicity). Pts were assessed for response after 4 cycles of mR-ACVBP. Responders continued with consolidation consisting of 2 cycles of high-dose methotrexate followed by 4 cycles of Rituximab-Ifosfamide-Etoposide then low-dose cytarabine x2. Pts with inadequate response on interim imaging were offered consolidative autologous stem cell transplantation (ASCT). Incomplete responders after 4 cycles (CR defined as delta SUVmax more than 70%) were shifted to salvage therapy including R-ICE (Rituximab, Ifosfamide, Cytarabine, Etoposide), or R-DHAP (Rituximab, Dexamethasone, Cytarabine, Cisplatin). Pts with age-adjusted IPI ≥ 2 could receive consolidative ASCT at the physician’s discretion.

Results: We identified 56 pts with hg-BCL, with a median age of 41 years [range: 21-67]. 64% of patients were males. 45 (80%) pts had advanced stage (III/IV), and 37 (66%) pts had an age-adjusted-IPI score >1. Fifty-one pts were evaluable for response after 4 cycles by PET CT scan. The overall response rate was achieved in 46 (90%) pts; complete response (CR) in 41 (80%), partial response (PR) in 5 (10%), 2 of which considered to have inadequate response as per delta SUVmax. 12 (27%) pts received consolidative ASCT, 27 (61%) continued consolidation chemotherapy, and 5 (11%) pts received subsequent salvage treatment. The most common reported treatment emergent adverse events, encountered during induction mR-ACVBP, were anemia (n=51, 91%), followed by febrile neutropenia (n=36, 64%, grade 4 in 26 (46%) pts, of whom four required intensive care monitoring), thrombocytopenia (n=22, 39%), and mucositis (n=12, 21%). Peripheral neuropathy was encountered in 7 (12%) pts (grade 1, n=2, grade 2, n=4, grade 3, n =1). Two deaths were attributed to treatment due to febrile neutropenia and septic shock during first and third cycle of mR-ACVBP in patients who had an aaIPI of 3.

After a median follow up of 17 months [range, 0.5-55], a total of 4/44 (9%) pts progressed, 3 while on treatment after high-dose methotrexate, 1 after therapy completion. The median PFS and OS were not reached. The 2-year PFS and OS were 86% and 87% respectively. At last follow up, 47 pts were alive (44 (94%) pts were in continuous CR, 1 (2%) pt in PR and 2 (4%) pts progressive disease), 6 pts died, and 3 were lost to follow up.

Conclusion: The use of vincristine in mR-ACVBP instead of vindesine seems to be feasible, with acceptable manageable adverse events. Despite higher risk disease, survival rates seem to be comparable to published data of the original R-ACVBP protocol.