[Efficacy of different regimens and prognostic factors in patients with first relapsed multiple myeloma treated after front-line bortezomib, cyclophosphamide, and dexamethasone].

Objective: To analyze the efficacy of second-line regimens and prognostic factors in patients with first-relapsed multiple myeloma (MM) treated with bortezomib, cyclophosphamide, and dexamethasone (BCD). Methods: A retrospective cohort study. Clinical data were collected in first-relapsed MM patients after BCD treatment from three tertiary hospitals in north China from July 2009 to October 2022. Patients were classified according to the second-line regimen into the immunotherapy group, single novel agent group [either proteasome inhibitor (PI) or immunomodulatory drug (IMiD)], combination treatment group (both PI+IMiD), and traditional treatment group. Responses to second-line regimens and survival data were analyzed. The Kaplan-Meier method was used for survival analysis and the Cox proportional risk model was used for univariate and multivariate analyses. Results: A total of 217 patients were enrolled including 8.8% (19/217) in the immunotherapy group, 48.4% (105/217) in the PI/IMiD group, 29.9% (65/217) in the PI+IMiD group, and 12.9% (28/217) in the traditional treatment group. The median age was 62 years (range 31-83 years) and 56.2% (122/217) were males. The overall response rates (ORRs) in the four groups were 94.7% (18/19) vs. 56.2% (59/105) vs. 73.8% (48/65) vs. 32.1% (9/28) (χ2=24.55; P<0.001), respectively. The progression-free survival (PFS) of the second-line regimens (2ndPFS) was 17.7 vs. 9.0 vs. 9.2 vs. 4.6 months (χ2=22.74; P<0.001), respectively, among which patients in the PI/IMiD and PI+IMiD groups had comparable 2ndPFS (χ2=1.76; P=0.923). Patients with high-risk cytogenetic abnormalities (HRCAs) achieved the longest 2ndPFS of 22.0 months in the immunotherapy group (χ2=15.03; P=0.002). Multivariate analysis suggested that immunotherapy (HR=0.11, 95%CI 0.05-0.27), achievement of efficacy of partial response or better (HR=0.47, 95%CI 0.34-0.66), and non-aggressive relapse (HR=0.25, 95%CI 0.17-0.37) were independent prognostic factors of 2ndPFS. Conclusion: In this real-world study, immunotherapy was associated with a more favorable efficacy and PFS for first-relapsed MM patients after BCD treatment, with similar outcomes in patients with HRCAs.