Yang and colleagues presented results of a multicenter retrospective analysis that evaluated the impact of cumulative bortezomib dose and dose intensity on survival outcomes in previously untreated patients with multiple myeloma (MM) who were treated with bortezomib-based induction therapies in 3 Chinese centers.1 The study population of 579 previously untreated patients had received a median cumulative bortezomib dose of 28 mg after a median of 4 cycles. Following a landmark analysis with a 6-month cut-off, 450 patients were treated with bortezomib-based induction therapy alone and 78 received autologous stem-cell transplantation (ASCT).
The cumulative bortezomib dose was found to significantly predict survival in patients treated with bortezomib-based induction therapy (P <.001); the cutoff value of cumulative bortezomib dose was 20.75 mg with sensitivity of 0.831 and specificity of 0.373. Median overall survival (OS) was significantly higher (51.0 months vs 42.0 months; P = .015) in the high-cumulative-dose (≥20.75 mg) group compared with the low-cumulative-dose (<20.75 mg) group; however, the progression-free survival (PFS) was similar between the 2 groups (P = .994). Overall, 248 (65.3%) patients were treated with a reduced bortezomib fixed dose of 1.75 mg, and 202 (34.7%) patients with the standard 1.3-mg/m2 dose. Bortezomib dose reductions were reported in 50 patients; of these, dose reductions were due to adverse events in 29 (11.7%) patients in the standard dose-intensity group and 2 (1.0%) in the reduced dose-intensity group. There were no significant differences in PFS and OS between the reduced dose- intensity and standard dose-intensity groups. However, treatment with standard-dose intensity and cumulative bortezomib dose of ≥20.75 mg significantly prolonged median OS compared with treatment with reduced-dose intensity and cumulative bortezomib dose of <20.75 mg (57.0 months vs 45.0 months; P = .05). There was no association between bortezomib dose and the survival in the ASCT cohort. Based on these real-world data, the authors recommended administration of a frontline standard bortezomib dose intensity of 1.3 mg/m2 and a cumulative dose of ≥20.75 mg for improved survival outcomes in patients who are not being considered for ASCT.Yang S, et al. ASH 2015. Abstract 4247.