Real-world characteristics and outcomes of patients with high-risk and non-high-risk smoldering multiple myeloma using the Flatiron Health database.

This study aimed to provide real-world evidence on progression risk in patients with high-risk smoldering multiple myeloma (SMM). This retrospective, observational study leveraged data from the Flatiron Health database. Eligible patients had SMM and relevant measures to apply Mayo 2018, International Myeloma Working Group (IMWG) 2020, and AQUILA trial risk criteria. Time to progression to active MM (TTP), progression or death (PFS), and death or progression on first-line MM therapy (PFS2) were evaluated using Kaplan-Meier methods and multivariate Cox regression models adjusted for age, Charlson Comorbidity Index, and time from SMM diagnosis to risk classification date. Across the three risk models (Mayo 2018, IMWG 2020, and AQUILA trial), high-risk patients with SMM had 3.0-4.0 times the risk of TTP, 2.1-3.5 times the risk of PFS, and 1.7-3.2 times the risk of PFS2 versus non-high-risk patients (p < 0.001 for all comparisons). Similar results were observed when patients with early treatment, early progression, and/or bone disease were excluded. This study demonstrates that high-risk patients with SMM have worse prognoses than non-high-risk patients, regardless of the criteria used, and highlights a need for early intervention testing.