INTRODUCTION: Multiple Myeloma (MM) is an incurable hematologic cancer characterized by multiple recurrences. With each recurrence, patients have a lower probability of response and duration of response is shorter. Therefore, there is an unmet need to improve outcomes in relapsed/refractory multiple myeloma (RRMM). There is a shortage of data describing clinical features and outcomes in these patients in real-world practice, particularly with regard to differences in outcomes by baseline cytogenetic risk. To help address this information gap, this study analyzed data from a cohort of RRMM patients in France.
METHODS: A retrospective observational review of medical records was conducted in a cohort of 200 patients with RRMM in France. Patients were selected (based on randomly generated first letter of last name) from the caseloads of 40 hematology/oncology providers across France practicing mainly in academic hospitals. Inclusion criteria were: ≥18 years of age at initial MM diagnosis; first determined to have RRMM between January 1, 2009 and December 31, 2011, where RRMM was defined by (1) first-line (induction) regimen of chemotherapy with or without stem cell transplant (SCT) and with or without other post-induction/SCT therapy and (2) disease progression while on or at any time after completion of first-line therapy. Patients could be alive or deceased at the time of record abstraction. Baseline cytogenetic risk was defined as follows: high-risk: cytogenetic abnormalities del(17p), t(4:14), or t(14;16); unknown/unassessed risk: patients for whom cytogenetics were unavailable; or standard-risk: all patients with known cytogenetics not classified as high-risk. Patients were assessed for treatment response, overall survival (OS) and progression-free survival (PFS) from date of first relapse (study index date). All analyses were descriptive. Survival was assessed using the Kaplan-Meier (K-M) method.
RESULTS: Demographic and clinical characteristics of the study sample are presented in Table 1. A total of 55 high-risk and 113 standard-risk patients were identified; risk category was unknown or unassessed for 32 patients. Among all patients, mean (SD) age at RRMM diagnosis was 66.3 (8.9) years and 62% of the sample was male. Lenalidomide + dexamethasone was the most common second-line systemic regimen initiated (50% of high-risk patients, 59.5% of standard-risk patients receiving second-line treatment). A total of 114 patients (57%) initiated a third-line treatment. Despite clinical response in second-line treatment occurring sooner in high-risk patients (median: 106 days) than in standard-risk patients (median: 237 days), physician-assessed overall response rate (ORR) was lower in high-risk patients (63%: 17% complete response, 46% partial response) than standard-risk patients (91%: 26% complete response, 65% partial response) across all second-line treatments combined (Table 2).. For third-line treatment, ORR was lower in high-risk patients (54%: 12% complete response, 42% partial response) than standard-risk patients (74%: 9% complete response, 65% partial response). Among patients who initiated a second-line treatment (n = 192), 47.4% were deceased at the time of data collection. From second-line initiation, K-M estimates of 1- to 5-year OS and PFS were substantially lower for high-risk patients versus standard-risk. Specifically, the proportions of patients still alive 1, 3, and 5 years after second-line treatment initiation were 73%, 51%, and 36%, respectively, for high-risk patients and 94%, 73%, and 61% for standard-risk patients. The proportions of patients without disease progression at 1, 3, and 5 years after second-line initiation were 48%, 13.5%, and 5% for high-risk patients and 82%, 42%, and 14% for standard-risk patients.
CONCLUSIONS: The importance of cytogenetic risk classification as a prognostic factor in RRMM was apparent in this retrospective review, in which patients with high-risk cytogenetics had less favorable outcomes in terms of ORR, OS, and PFS than standard-risk patients. Decreased response rate and lower PFS and OS was documented among patients with high-risk cytogenetics, which is in contrast to shorter time needed to achieve best clinical response in this subgroup. Results from this real-world study provide further confirmation of the unmet medical need presented by RRMM, especially for patients with high-risk cytogenetics.
