A comparative analysis of outcomes following autologous hematopoietic cell transplantation in multiple myeloma patients with CRAB versus SLiM features.

e19518 Background: Multiple Myeloma (MM) is a plasma cell disorder which evolves from neoplastic proliferation of clonal plasma cells. In 2014, International Myeloma Working Group (IMWG) introduced SLiM criteria (60% or more clonal plasma cells in marrow, Involved:Uninvolved Light Chain ratio >= 100 and >1 focal bone lesion (> 5 mm) on MRI) in addition to CRAB criteria (hyperCalcemia, Renal insufficiency, Anemia, Bone lesions) for diagnoses of active MM. Many studies have indicated disease burden as an independent prognostic risk. In this single institution study, we aim to evaluate the outcomes of MM patients diagnosed by SLiM vs CRAB criteria undergoing Autologous-Hematopoietic cell transplantation (Auto-HCT). Methods: This retrospective, single-center study included 103 patients with multiple myeloma (MM) who underwent autologous hematopoietic cell transplantation (Auto-HCT) between January 2019 and December 2024. Patients were divided into two cohorts: 91 patients (88%) in the CRAB cohort and 12 patients (11%) in the SLiM cohort, defined by the presence of SLiM features only. A log-rank test was used to determine overall survival (OS) and progression-free survival (PFS). Results: The median age was 62 years (range: 35–74), with 70 patients (68%) being male and 33 (32%) females. The racial distribution included 12 African Americans (13%), 2 Asians (2%), and 88 Caucasians (85%). R-ISS stage distribution differed between the CRAB and SLiM cohorts: stages III, II, and I were observed in 18% vs. 16%, 47% vs. 66%, and 22% vs. 6%, respectively. Median OS and PFS were not reached, and no statistically significant difference was observed between the two groups. Conclusions: SLiM criteria were proposed by the IMWG a decade ago to treat myeloma before end organ damage (CRAB features) are met. In our single center retrospective study, no differences were noted in either PFS or OS despite higher disease burden in the CRAB cohort. We suggest that Auto-HCT eligible patients diagnosed by either criteria should be treated similarly. A multi-institutional study with a larger sample size is warranted to validate our findings.