Natural History and Prognostic Factors at First Relapse in Multiple Myeloma.

The prognosis of multiple myeloma has considerably improved due to the introduction of novel agents in the upfront setting. However, the great majority of patients ultimately relapse, and choosing a salvage treatment at first relapse remains challenging. The natural history of first relapsed disease in the current era is also not well described. We retrospectively studied 300 patients with first relapsed myeloma seen between 2004 and 2019 from two institutes in Singapore. The median duration from diagnosis to first relapse was 22.7 months (1.1-97.0 months). Most patients received novel agent-based induction therapy, and 41.3% underwent autologous stem cell transplant. A very good partial response (VGPR) or better was achieved in 48.6%. Regarding first relapse, 50.5% were symptomatic and 19.0% received newer agent-containing regimens. Nearly a third of patients (31.7%) had a VGPR or better response. The median progression free and overall survival from first relapse was 12.0 and 44.8 months, respectively. Based on a randomized sample splitting, we first identified non-hyperdiploid karyotype at diagnosis, clinical relapse, and treatment sequence as impacting survival independently from a testing cohort, and we then further demonstrated their significance in a validation cohort. This study provides a real-world picture of first relapsed myeloma and highlights the prognostic importance of the treatment sequence.