Treatment Pattern, Healthcare Resource Utilization and Symptom Burden Among Patients with Triple Class Exposed Multiple Myeloma: A Population-Based Cohort Study.

PURPOSE: This study aims to describe the treatment patterns, outcomes, health care utilization and symptom burden of triple class exposed (TCE) relapsed/refractory patents with multiple myeloma (MM) receiving a subsequent line of treatment (LOT). METHODS: This is a retrospective observational cohort study using administrative databases in Ontario, Canada. Outcomes were captured for TCE patients receiving a subsequent LOT and included: treatment regimen details, time to next treatment (TTNT), overall survival (OS), health care utilization, palliative care referral, and patient reported symptoms. RESULTS: Of the 16,777 patients diagnosed with MM between 2007-2021 in Ontario, 1358 (8%) patients were classified as TCE. Among the TCE MM patients, 489 (36%) received a subsequent LOT. The two most commonly administered therapies post TCE were carfilzomib/dexamethasone (n = 111, 22%) and pomalidomide/dexamethasone(n = 95, 19%). Median TTNT was 1.7 months (95%CI 1.2-2.4 months) and median OS 12.8 months (95%CI 10.8-16.5). Healthcare utilization was high with 276 (56%) of patients evaluated in an emergency department (ED) or admitted to hospital. There was high symptom burden as reported by patients with moderate-severe impairment in well-being, fatigue, pain and drowsiness noted in greater than 25% of the cohort. Palliative care referrals rates were low with only 10% (n = 48) patients referred to palliative care. Among the patients that died during study follow up, the majority died in hospital (n = 147,44%). CONCLUSION: Our study reports one of the largest series of real-world TCE patients published and demonstrates the poor outcomes of TCE patients receiving a subsequent LOT.

Autologous stem cell boost improves persistent immune effector cell associated hematotoxicity following BCMA directed chimeric antigen receptor T (CAR T) cell therapy in multiple myeloma.

Persistent Immune Effector Cell Associated Hematotoxicity (ICAHT) is a significant side effect of BCMA CAR T-Cell therapy in patients with relapsed multiple myeloma (MM). The use of stem cell boosts in ICAHT has been described, however studies have been limited by small patient numbers and short follow up. Herein, we report on our multi-institutional experience of ICAHT, defined by an absolute neutrophil count (ANC) of ≤ 1000, thrombocytopenia with a platelet count ≤ 50,000 or/and anemia as hemoglobin (hgb) ≤9 g/dL, in patients who received BCMA CAR T therapy, and the effects of subsequent stem cell boost on hematopoietic reconstitution and clinical outcome. In this study, ICAHT was observed in 60% (n = 61/101) of patients at D + 21, and risk factors for its development included history of a prior ASCT, higher number of prior lines of therapy, a decreased platelet count prior to lymphodepletion and history of ICANS. 28% of patients with ICAHT received a stem cell boost at a median of 116 days due to profound and prolonged cytopenias often requiring ongoing transfusion support. Stem cell boost significantly improved cytopenias at 3 and 6 months follow up without any adverse effects on PFS and OS, underscoring the safety of this procedure.