Immune responses to COVID‐19 booster vaccinations in intensively anti‐CD38 antibody treated patients with ultra‐high‐risk multiple myeloma: results from the Myeloma UK (MUK) nine OPTIMUM trial.

Summary: Multiple myeloma (MM) and anti‐MM therapy cause profound immunosuppression, leaving patients vulnerable to coronavirus disease 2019 (COVID‐19) and other infections. We investigated anti‐severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) antibodies longitudinally in ultra‐high‐risk patients with MM receiving risk‐adapted, intensive anti‐CD38 combined therapy in the Myeloma UK (MUK) nine trial. Despite continuous intensive therapy, seroconversion was achieved in all patients, but required a greater number of vaccinations compared to healthy individuals, highlighting the importance of booster vaccinations in this population. Reassuringly, high antibody cross‐reactivity was found with current variants of concern, prior to Omicron subvariant adapted boostering. Multiple booster vaccine doses can provide effective protection from COVID‐19, even with intensive anti‐CD38 therapy for high‐risk MM. [ABSTRACT FROM AUTHOR]