Clinicopathologic features and outcomes associated with induction regimen intensity among older veterans with myeloma.

Abstract

e20054 Background: More than one third of patients diagnosed with multiple myeloma (MM) are 75 years or older. Though registries and clinical trials have conveyed the disease features across myeloma patients and have confirmed improvement in outcomes with increasing number of frontline induction agents, older patients are disproportionately excluded from these studies. We sought to evaluate the disease characteristics and frontline (FL) induction treatment patterns among older Veterans. Methods: The VA’s Corporate Data Warehouse was queried to identify patients who (1) were diagnosed with MM between January 1, 2016 and December 31, 2019, (2) were 75 years or older at the time of diagnosis, and (3) received at least 1 induction regimen within the VA. Each unique record was reviewed in the VA’s Joint Legacy Viewer, an online platform collectivizing Veteran electronic charts nationwide. Data abstraction was performed to ascertain disease type, cytogenetics, stage, and characteristics of treatment regimen(s) by reviewing provider progress notes and treatment notes. Presence of del(17p), t(4;14), t(14;16), t(14;20), or gain 1q by FISH defined high-risk cytogenetics. Median composite progression-free survival (PFS), defined as the interval between date of FL induction initiation and the earliest date of second induction or death, was computed for Veterans based upon number of drugs in their FL induction regimens. Results: A total of 199 Veterans met selection criteria, with a mean age of 83.0 (SD 4.8) years at start of treatment. Of the 84 patients with documented cytogenetics, 44 (52.3%) had high-risk disease, and 6 (7.1%) had 2 or more deleterious cytogenetic findings. The majority (52.8%) of patients received only 1 induction regimen, and only 44 (22.1%) patients received maintenance therapy following frontline induction. 1 patient underwent autologous stem cell transplant, and 1 was referred for chimeric antigen receptor T-cell therapy. Within FL induction regimen, 104 (52.3%) received 2 drugs and 88 (44.2%) received 3 drugs. Induction therapy selection was unrelated to disease stage (p = 0.556) or cytogenetic risk (p = 0.335), but patients 80 years or older were more likely to receive 2-drug therapy (p = 0.012) than those between 75 and 79 years. No difference in median composite PFS was observed between patients receiving 2 drugs (10.1 [4.5 – 21.7] months) and those receiving 3 drugs (10.7 [5.0 – 20.3] months) (p = 0.733) in FL induction regimen. Conclusions: In a real-world study of older Veterans with MM bearing a high rate of high-risk cytogenetics, the median PFS with FL induction is only 10 months, but a more intensive FL 3-drug induction regimen is not more beneficial than a 2-drug. Less intense treatment planning is most reasonable for geriatric patients. Larger investigations evaluating cytogenetic results across Veterans with MM should be considered.