Risk factors associated with overall survival in patients with multiple myeloma following carfilzomib treatment: A retrospective study from a large claims database in Japan

BACKGROUND: Carfilzomib is a selective proteasome inhibitor approved for treating relapsed or refractory multiple myeloma (RRMM). Carfilzomib improves overall survival (OS) and progression‐free survival (PFS); however, treatment with carfilzomib results in a higher incidence of cardiovascular and renal toxicity. More than 70% of patients with RRMM in clinical practice do not meet the eligibility criteria for randomized clinical trials (RCT). OS and PFS are negatively influenced by complications, concomitant medications and prior treatments. Therefore, we assessed the risk factors influencing the OS and time to next treatment (TTNT) in the real world. TTNT has emerged as a relevant alternative clinical endpoint to PFS. METHODS: A retrospective analysis of a large claims database prepared during the post‐marketing stages in Japan was performed. The patients treated with carfilzomib for the first time were identified. Multivariable Cox proportional hazards regression analysis was performed to evaluate the risk factors influencing OS and TTNT following carfilzomib treatment. RESULTS: A total of 732 patients with RRMM who received carfilzomib‐containing chemotherapy between April 2014 and September 2021 were identified. Multivariable Cox regression analysis for OS and TTNT showed a significantly higher hazard ratio (HR) of 1.48 (95% confidence interval [Cl]: 1.10–2.00; p = 0.010) and 1.38 (95% Cl: 1.15–1.65; p < 0.001), respectively, for patients with renal impairment compared to those without renal impairment. Multivariable Cox regression analysis for OS and TTNT showed a significantly higher HR of 1.80 (95% Cl: 1.27–2.55; p = 0.0010) and 1.38 (95% Cl: 1.14–1.66; p < 0.001), respectively, for patients with prior lenalidomide treatment compared to those without prior lenalidomide treatment. CONCLUSION: Complication of renal impairment and prior lenalidomide treatment could be risk factors influencing OS and TTNT during carfilzomib treatment.