P-173: Novel drug induction followed with autologous hematopoietic stem cell transplantation plus maintenance therapy improves survival of myeloma patients harboring 1p32 and overcomes its adverse prognosis

Introduction: The prognostic significance of 1p32 deletion in newly diagnosed multiple myeloma (NDMM) remains a subject of debate. Although identified as a high-risk cytogenetic abnormality, studies have produced conflicting results regarding its impact, and it is currently not recognized by the International Myeloma Working Group (IMWG) in the risk stratification for MM. This study evaluated the prognostic influence of 1p32 deletion and assessed the response to treatment in NDMM patients harboring this deletion.

Methods: In the retrospective cohort of 298 NDMM patients, 172 underwent autologous stem cell transplantation (ASCT), while 126 received non-transplant therapy. We compared the clinical characteristics and survival outcomes between patients with and without the del(1p32) mutation to elucidate its prognostic relevance.

Results: Of the 298 NDMM patients, 24 (8.05%) exhibited del(1p32). Median progression-free survival (PFS) was 49.0 months for del(1p32) positive patients versus 57 months for those without the deletion (p = 0.019). Median overall survival (OS) was 59.0 months versus not reached (p = 0.001), respectively. Multivariate analysis confirmed del(1p32) as an independent prognostic factor, significantly associated with a higher risk of disease progression (HR = 1.290, p = 0.041) and mortality (HR = 2.347, p = 0.022). In the non-transplant cohort, median PFS was 24.0 months for del(1p32) positive patients compared to 40.0 months for negative patients (p = 0.019), with median OS at 54 months and not reached (p = 0.014), respectively. ASCT patients showed no significant difference in median PFS and OS when stratified by del(1p32) status. However, the median PFS for del(1p32) positive patients increased from 24 months in the non-transplant group to 71 months post-ASCT (P = 0.006), with median OS improving from 54 to 86 months (p = 0.120).

Conclusions: Del(1p32) is an independent adverse prognostic marker in NDMM. Treatment strategies incorporating novel drugs followed by ASCT and maintenance therapy appear to ameliorate the negative impact of 1p32 deletion, suggesting a potential pathway to improve outcomes for this high-risk group.