Lenalidomide-based monotherapy versus augmented therapy for maintenance in standard risk multiple myeloma patients with no complete response post autologous hematopoietic cell transplantation.

Abstract

8055 Background: Standard risk (SR) multiple myeloma (MM) is typically characterized by the absence of poor prognostic cytogenetic aberrations, and better outcomes. However, outcomes in SR MM remain far from homogeneous, especially in patients undergoing autologous hematopoietic cell transplant (AHCT). While many patients do well initially, relapse is inevitable. Here, we studied the role of lenalidomide (R) maintenance therapy in determining outcomes in SR MM with no complete response (non-CR) post-AHCT. Methods: We retrospectively reviewed all MM patients who underwent AHCT at the Cleveland Clinic between January 1, 2011 and January 15, 2021. Electronic medical charts were accessed to retrieve data on demographic characteristics, comorbidities, International Scoring System (ISS) staging, cytogenetic risk categorization, serum and bone marrow studies, as well as maintenance therapy. SR MM was considered in patients who did not have t(4;14), t(14;16), t(14;20), del(17p), or gain(1q). Remission status was determined by serum studies at 3 months post-AHCT. The primary endpoint was median time to either progression or death, reported as time to event (TTE) determined by Kaplan Meier analysis. Results: A total of 517 patients were reviewed, of whom 279 were determined as SR MM. Further stratification yielded 100 non-CR SR patients on lenalidomide-based maintenance, of whom 87 were on R monotherapy and 13 on R combination. Comparison between the R-monotherapy and combination groups showed similar age at AHCT (60.5 vs 56 years, P=0.07), time to transplant (23.5 vs 30.8%, P=0.7), albumin levels (<3.5 g/dL 25 vs 25%, P=1), Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI) score (≥3 43.5 vs 30.8%, P=0.5), Male preponderance (58.8 vs 69.2%, P=0.6), ethnicity (White 82.4 vs 76.9%, P=0.7), ISS stages (I 41 vs 45.5%, II 41 vs 36.4%, III 17.9 vs 18.2%, P=0.9), pre-AHCT lines of therapy (≥2 31.8 vs 38.5%, P=0.8), and pre-AHCT bone marrow plasma cells (≥10%:9.5 vs 7.7%, P=1), respectively. The only significant difference between the two groups was in the MM immunoglobulin subtype (IgG 80 vs 50%, P=0.02). Kaplan-Meier analysis for median TTE revealed that the R monotherapy group had a significantly shorter median TTE at 38.1 months versus 68.6 months (P=0.03) for the R combination group. Conclusions: SR MM patients who do not achieve a CR post-AHCT have better outcomes with R-combination rather than monotherapy.