Siltuximab as a primary treatment for cytokine release syndrome in a patient receiving a bispecific antibody in a clinical trial setting

INTRODUCTION: Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are common toxicities associated with immunotherapies, including T cell redirecting bispecific antibodies. Although cooperative group guidelines recommend the use of tocilizumab or other IL-6/IL-6R inhibitors for the management of CRS and ICANS, reports on the use of siltuximab, an IL-6 inhibitor, for the treatment of CRS are limited. CASE REPORT: We present the case of a 77-year-old male who received T cell redirecting bispecific antibody therapy with talquetamab for relapsed/refractory multiple myeloma (RRMM) and developed CRS with concurrent ICANS after receiving a second dose of talquetamab. MANAGEMENT AND OUTCOME: The patient received an infusion of siltuximab. The patient recovered from CRS within 1 h of siltuximab administration and ICANS within 7 h of siltuximab administration. Patient tolerated the subsequent dose of talquetamab with no evidence of CRS and continued on study. DISCUSSION: This case describes the successful use of siltuximab for the management of CRS in a patient treated with a T cell redirecting bispecific antibody for RRMM.