Real-world renal function among patients with multiple myeloma in the United States

Abstract

Dear Editor, Multiple myeloma (MM) is the second most common hematologic malignancy and is associated with substantial patient burden. Despite the introduction of newer agents, patients with MM continue to experience relapses and/or become treatment refractory. Renal impairment has been shown to affect up to 50% of patients with MM, and has been reported to be an independent predictor of poor survival outcomes, with a median survival of approximately half that of MM patients without renal impairment. The aims of this analysis were to assess change in renal function by drug class (i.e., proteasome inhibitor [PI], immunomodulatory drug [IMiD], and monoclonal antibody [mAb]) among patients with MM and renal impairment (defined as estimated glomerular filtration rate [eGFR] < 50mL/min/1.73 m using the Modification of Diet in Renal Disease equation [MDRD]) in early treatment lines, and to assess real-world patient outcomes by baseline renal status, renal response, and drug class. This study used the nationwide Flatiron Health electronic health record-derived de-identified database. The Flatiron Health database is a longitudinal database, comprising de-identified patient-level structured and unstructured data, curated via technology-enabled abstraction. During the study period, the de-identified data originated from ~280 cancer clinics (~800 sites of care). The study included 10,389 patients diagnosed with MM from January 1, 2011, to November 30, 2019. After excluding patients with probable missing treatment information, there were 6994 patients who received ≥1 line of MM therapy and had information on race. Another four patients with unlikely creatinine levels (i.e., extremely high or low) were excluded, resulting in 6990 patients (Supplemental Fig. 1). eGFR-MDRD was calculated from creatinine lab values using the following equation: 175 × (creatinine mg/ dL) × (age) × (0.742 if female) × (1.212 if Black/ African American). The distribution of patients was assessed by eGFR-MDRD level (<50 and ≥50 mL/min/ 1.73 m) at the start of first(1 L) and second-line (2 L) therapy. Overall survival (OS) was evaluated by treatment line, stratified by eGFR-MDRD level at the start of the treatment line. Renal response was assessed in patients with eGFR-MDRD < 50mL/min/1.73 m at the start of treatment, who had ≥1 eGFR-MDRD measurement during the treatment line; using International Myeloma Working Group recommendations, patients with complete renal response (CRR) were defined as patients with ≥1 eGFR-MDRD measurement ≥60 mL/min/1.73 m during the treatment line. Logistic regression models were used to examine the association between treatment class and CRR status. These models were adjusted for the following clinically relevant variables, as they were potential confounders of the examined associations: other treatment classes received, age, sex, race, practice type, year of therapy line, and cytogenetic risk. Kaplan–Meier analyses and Cox proportional hazard models were used to examine OS from the start of 1 L therapy and 2 L therapy by baseline renal status and by both treatment class and renal response. Cox proportional hazard models were adjusted, as described above. The data that support the findings of this study have been originated by Flatiron Health, Inc. These de-identified data may be made available upon request, and are subject to a license agreement with Flatiron Health; interested researchers should contact [email protected] to determine licensing terms. Flatiron Health, Inc, did not participate in the analysis of this data.