Characteristics and outcomes of patients with relapsed/refractory multiple myeloma after exposure to lenalidomide in first line of therapy: a single center database review in greece

Background The increasing use of lenalidomide (Len) in first-line (1L) therapy of multiple myeloma (MM) has led to a significant proportion of patients becoming Len-refractory following 1L treatment. However, there are limited real-world data on treatment strategies and outcomes of patients who become Len-refractory following 1L therapy. Patients and Methods This real-world retrospective cohort study analysed Len-refractory and non-Len-refractory patients who received 1L Len and initiated second-line (2L) therapy at a Greek MM centre. The Len-exposed cohort (n=249) included 55.4% Len-refractory patients after 1L. Results Compared to non-Len-refractory patients, Len-refractory patients more frequently had high-risk cytogenetics and Revised-International Staging System-3 disease stage at diagnosis, and had shorter progression-free survival (PFS) following 1L therapy. Len-refractory versus non-Len-refractory patients more frequently received triplets (59% vs 40%), anti-CD38 agents (20% vs 9%) and pomalidomide (22% vs 13%). The overall response rate was 53% for Len-refractory patients and 64% for non-Len-refractory patients in 2L therapy; median PFS was 10.7 vs 18.3 months, respectively. Median overall survival (OS) was shorter for Len-refractory patients vs non-Len-refractory patients (23.8 vs 53.6 months). Len refractoriness was an independent prognostic factor for both PFS and OS in Len-exposed patients. Conclusion In this real-world Len-exposed cohort, Len-refractory patients receiving 1L Len experienced poorer survival outcomes than non-Len-refractory patients, highlighting the unmet need in this patient population which has driven the development of novel therapies. MicroAbstract Limited real-world data exist to guide second-line (2L) treatment strategies for multiple myeloma patients who become refractory to lenalidomide (Len) in first-line therapy. This Greek MM centre study reports poor 2L survival outcomes in Len-refractory patients versus patients non-refractory to Len. Proteasome inhibitor-based and triplet regimens were frequently used in Len-refractory patients and yielded longer survival rates than other regimens.