Outcomes of Patients With Multiple Myeloma With deletion 1p Following Autologous Stem Cell Transplant

Background: Several studies have suggested that a deletion in the short arm of chromosome 1 (del(1p)) is an independent adverse prognostic factor in patients with multiple myeloma (MM). However, its impact on outcomes of patients undergoing autologous hematopoietic cell transplantation (autoHCT) and receiving contemporary anti-myeloma therapy remains unclear. Study design: A retrospective, single-center analysis of newly diagnosed MM (NDMM) patients with del(1p) who underwent upfront autoHCT between 2010 and 2021. The primary endpoints were progression-free survival (PFS) and overall survival (OS). Propensity-matched comparisons were performed between del(1p) patients and a control group without del(1p) and with standard-risk cytogenetics. Results: 55 patients were included in our analysis. With a median follow-up of 24.0 months (range 3.8-79.5), the median PFS was 30.2 months (95% CI 18.0-not reached [NR]) and the median OS was not reached (95% CI 41.1-NR). In multivariable analysis, female patients (hazard ratio [95% CI] 2.81 [1.14, 6.91], P = .025) and those with R2-ISS stage IV (compared with stage II 4.85 [1.01, 23.34], P = .049) had worse PFS, whereas patients who achieved CR as the best post-transplant response had better PFS (0.38 [0.16, 0.91], P = .029). Concomitant del(17p) was associated with a significantly worse OS (4.47 [1.18, 17.02], P = .028). Propensity score matching showed no significant differences in PFS (1.63 [0.86, 3.10], P = .13) or OS (1.77 [0.73, 4.32], P = .21) between del(1p) and control patients. Conclusions: In NDMM patients undergoing upfront autoHCT, del(1p) alone was not significantly associated with inferior outcomes. However, concurrent del(17p) and del(1p) was associated with worse survival.