Phase II study of dose-attenuated bortezomib, cyclophosphamide and dexamethasone ("VCD-Lite") in very old or otherwise toxicity-vulnerable adults with newly diagnosed multiple myeloma

Abstract

Objectives: Multiple myeloma (MM) primarily strikes older adults, but full-dose chemotherapy such as bortezomib (Velcade), cyclophosphamide and dexamethasone (VCD) is often excessively toxic to very old or frail adults and those with substantial comorbidities. We piloted dose-attenuated VCD ("VCD-Lite") in such vulnerable adults with newly diagnosed MM (NDMM).

Materials and methods: Subjects with NDMM and a high risk of therapy-related toxicity due to factors above received bortezomib 1.3mg/m² subcutaneously, cyclophosphamide 300mg/m² and dexamethasone 40mg orally, all on days 1, 8, and 15 of a 28day cycle for eight cycles, followed by indefinite, alternating bortezomib and lenalidomide maintenance. Toxicity, overall response rate (ORR), progression-free and overall survival (PFS and OS) were determined. The Cancer and Aging Research Group geriatric assessment (CARG GA) was administered at baseline in an exploratory manner as a predictor of severe toxicity.

Results: 14 patients went on the study, which was closed early due to slow accrual. Intention-to-treat ORR was 64%. 64% of patients experienced grade ≥3 adverse events, the majority of which were unlikely therapy-related. Median PFS was 24.2months and OS 29.7months, with 14%, 36% and 29% of patients discontinuing study drugs due to toxicity, MM progression and other reasons respectively. Baseline CARG GA was successfully completed by all subjects but one.

Conclusion: VCD-Lite is a viable option for vulnerable adults with NDMM. CARG GA is feasible. Further studies to optimize therapy and to explore CARG GA as a toxicity predictor are vital.

Keywords: Chemotherapy; Elderly; Frail; Geriatric assessment; Myeloma; Senior; Toxicity.