One cohort 2 patient who received four VLX1570 cycles (one cycle at 0.30 mg/kg and three cycles at 0.60 mg/kg) after developing rapid progression of an IgA kappa MM on standard therapy prior to study entry experienced improved overall functionality and constitutional symptoms, as well as modest decrements of several MM parameters compared to pretreatment baseline, including serum M protein (0.80 to 0.60 mg/dL), 24-h urine M protein excretion (184 to 81 mg); urine kappa free light chain (FLC) (114 to 91 mg/L), and kappa/lambda FLC ratio (51 to 18), consistent with stable disease. Here, CD79A is linked to Miyoshi myopathy.