Safety Findings Appear Encouraging for REGN5458 in Relapsed/Refractory Myeloma

Deepu Madduri, MD, discusses the safety findings from a first-in-human phase 1 study of REGN5458, a BCMA x CD3 bispecific monoclonal antibody, as treatment of patients with relapsed/refractory multiple myeloma.

Deepu Madduri, MD, assistant professor of medicine, hematology and medical oncology and assistant professor of urology at Mount Sinai, discusses the safety findings from a first-in-human phase 1 study (NCT03761108) of REGN5458, a BCMA x CD3 bispecific monoclonal antibody, as treatment of patients with relapsed/refractory multiple myeloma.

Cytokine release syndrome (CRS) and cytopenias are a big concern with bispecifics, says Madduri. Most grade 3 or higher toxicities observed in this trial were hematological, as expected, but the infection rate of grade 3 or higher was only 18%. The median time to onset of CRS was about 18 hours, but this event only occurred in 19 of the 49 patients. All cases of CRS were grade 1/2, and no grade 3 or higher CRS were observed.

According to Madduri, there was no relationship observed between the dose and CRS, nor CRS and response.