Measurable Residual Disease Testing in Multiple Myeloma Following T-Cell Redirecting Therapies.

Simple Summary: Multiple myeloma (MM) is a blood cancer which classically has a prolonged course of remissions and relapses. Several new highly efficacious medications have been developed for MM in recent years, including some that utilize the body's own immune cells to control the cancer. Alongside the development of these new medications has been the evolution of tests to track small amounts of (measurable) residual disease (MRD). Several MRD tests can now find and track as little as 1 residual cancer cell in 1 million in certain cases. Having no detectable MRD has been independently associated with improved cancer control and longer survival—here, we review how these tests might be used as a companion to new immune therapies for MM. Several novel T-cell-based therapies have recently become available for multiple myeloma (MM). These T-cell redirecting therapies (TRTs) include chimeric antigen receptor T-cells (CAR-T) and bispecific antibodies (BiAbs). In both clinical trial and real-world data, these therapies have demonstrated high rates of deep clinical response, and some are now approved for second-line treatment for relapsed MM. The deep and sustained clinical responses these therapies are capable of inducing will require sophisticated response monitoring to provide meaningful information for patient care. Obtaining measurable residual disease (MRD) negativity has been validated as an independent positive prognostic marker for progression-free survival (PFS) and overall survival (OS) in both newly diagnosed and relapsed refractory patients with multiple myeloma. Assessment for MRD negativity was performed in all of the trials for FDA-approved TRT. Here, we summarize pertinent data for MRD assessment following TRT in MM and provide a rationale and structured framework for conducting MRD testing post TRT. [ABSTRACT FROM AUTHOR]