Safety and Efficacy of Elranatamab in Patients with Relapsed and/or Refractory immunoglobulin Light-Chain Amyloidosis.

Immunoglobulin light chain (AL) amyloidosis is a plasma cell disorder characterized by progressive organ dysfunction secondary to deposition of organized immunoglobulin light chain aggregates. Achievement of rapid and deep normalization of involved immunoglobulin free light chains is necessary to maximize chances of reversibility of organ dysfunction, which in turn results in improved quality and length of life. There are no FDA-approved therapies for patients with relapsed and/or refractory immunoglobulin light chain (AL) amyloidosis. B cell maturation antigen (BCMA)-targeting bispecific T cell engagers teclistimab and elranatamab have shown high activity and acceptable safety profile in relapsed and/or refractory multiple myeloma patients, leading to their FDA approval. Herein we report on safety and efficacy of elranatamab for patients with relapsed and/or refractory AL amyloidosis. We treated 9 consecutive, advanced-stage AL amyloidosis patients with Elranatamab single agent, observing a 100% overall response and 67% complete response rate, including minimal residual disease (MRD)-negativity, with expected toxicities. Median time to hematological response was 9 days (6-24), with deep suppression in involved free light chains observed within one cycle of therapy, translating in cardiac and renal responses at 3-6 months. These data support prospective studies exploring Elranatamab in relapsed and/or refractory AL amyloidosis patients.