ABSTRACT
BACKGROUND: Lenalidomide and ixazomib maintenance improve long-term outcomes in newly diagnosed multiple myeloma (NDMM) patients. However, there is less evidence to support bortezomib (BTZ) maintenance therapy, and real-life data on maintenance are scarce. We investigated the efficacy and safety of BTZ maintenance therapy in NDMM. PATIENTS AND METHODS: A retrospective multisite study was performed in 6 medical centers in Israel. All consecutive patients with NDMM diagnosed between January 1, 2010, and July 3, 2019, who received a BTZ-based induction, with or without an autologous transplantation, followed by BTZ maintenance therapy, were identified. Maintenance therapy was defined as BTZ (1.3 mg/m2) once every 2 weeks, administered subcutaneously alone or with dexamethasone, or weekly BTZ monotherapy. RESULTS: A total of 105 patients were identified, 58 of whom had received a transplant (transplant eligible) and 47 who had not (not transplant eligible). During BTZ maintenance therapy, 96% had one or more adverse event, 11.5% had grade 3 or higher adverse events, and 11.5% discontinued treatment due to toxicity. Median progression-free survival (PFS) and overall survival were 45 and 91.5 months, respectively; 4-year survival was 88%. Adverse cytogenetics was associated with worse PFS (24 vs. 46 months, P = .001). In subgroup analysis, adverse cytogenetics were associated with worse PFS (P < .001) and OS (P < .001) among transplant-ineligible but not transplant-eligible patients. CONCLUSION: Analysis of multisite real-life data showed that BTZ maintenance therapy is safe, well tolerated, and effective. Median PFS was similar to that reported with alternative maintenance strategies. Our findings further support its use among patients with adverse cytogenetics, it may also be relevant for patients with lenalidomide-intolerant disease.
