Characteristics and clinical outcome of high-risk multiple myeloma patients in Korea (KMM 1805).

Optimal treatments for multiple myeloma (MM) patients with high-risk cytogenetics must be determined, but subgroup features are not well-defined. We used real-world data from the Korean Myeloma Registry (KMR) to analyze the characteristics and clinical outcomes of newly diagnosed MM patients with ≥ 1 high-risk cytogenetic abnormality: Group 1: t(4;14) or t(14;16); Group 2: del(17p); Group 3: t(4;14)/del(17p) or t(14;16)/del(17p). Overall, 347 high-risk patients were identified (males, 48.7%; median age, 63 years). Median progression-free survival (PFS) and overall survival (OS) were 19.0 months (95% CI 17.0-20.0) and 50.0 months (95% CI 37.0-61.0), respectively. PFS (p = 0.047) and OS (p = 0.020) differed significantly between groups. After stratification by transplant eligibility, PFS and OS were significantly poorer in Group 3 among transplant-eligible patients, and even poorer in those with gain(1q). Patients stratified by cytogenetic abnormality and revised International Staging System (R-ISS) had significantly different PFS (p < 0.001) and OS (p = 0.003), with the worst survival in R-ISS III/Group 3 (median OS 21.0 months). Higher number of high-risk cytogenetic abnormalities was a negative prognostic marker for PFS and OS (p < 0.001). Real-world KMR data showed that risk factors for poor prognosis of MM patients included del(17p), R-ISS stage, and number of cytogenetic abnormalities.