Mortality from Multiple Myeloma Within One Year Following Autologous Stem Cell Transplantation: Defining an Ultra-high Risk Population.

Despite improvements in therapy, approximately 5% of patients who undergo autologous stem cell transplantation (ASCT) experience early mortality (EM), death within 1 year of transplant (EM post-ASCT). Such patients tend to have few comorbidities suggesting their EM is owing to aggressive underlying disease. We sought to characterize this ultra-high risk population through a retrospective review of patients with newly diagnosed multiple myeloma (MM) treated with first-line ASCT. Patients who died within 1 year of ASCT were matched for age, sex, and year of transplant in a 1:2 fashion with a control group. Of 962 transplants performed between January 1, 2007, and May 1, 2019, 41 patients (4.3%) died within 1 year of ASCT from MM-related causes. In a multivariate analysis, anemia, hypercalcemia, high-risk cytogenetics, and elevated lactate dehydrogenase were associated with EM post-ASCT. Forty patients (97.6%) received at least 1 novel agent. Most patients with EM post-ASCT received second-line chemotherapy (80.5%), although survival from initiation of second-line chemotherapy was only 2.1 months. The primary reason for not receiving second-line therapy was rapid relapse. Clinical parameters reflecting disease burden, as well as high-risk cytogenetics, are associated with EM post-ASCT. These patients have a dismal overall survival despite significant advances in treatment of patients with relapsed or refractory myeloma. Further study of these ultra-high risk patients is required to improve disease management and may give further insights into the biology of relapse and resistance in myeloma.