Assessment Of Tumor Depletion Following Tandem Mobilization In Multiple Myeloma Patients Receiving Autologous Stem Cell Transplantation

Background: The majority of multiple myeloma (MM) patients receiving autografts ultimately relapse, and tumor cell contamination of autografts may be a contributing factor. A clinical trial to assess tandem chemo-mobilization with the goal of reducing the myeloma cell burden in the patient and in the apheresis product was conducted and outcomes were previously reported (Chen et al., Bone Marrow Transplant 2012). The effect of myeloma cell depletion using tandem mobilization has not been previously quantified; however, clinical outcomes are comparable with other autotransplant regimens. Here we utilize a sequencing-based minimal residual disease (MRD) technology, termed the LymphoSIGHT™ platform, to assess the effect of tandem chemo-mobilization on myeloma cell contamination in apheresis collections. This sequencing-based method has a sensitivity to detect one tumor-associated immune receptor gene rearrangement molecule per million leukocytes and can be used for MRD quantification in lymphoid neoplasms (Faham et al., Blood 2012; Martinez-Lopez et al., Blood 2014). We analyzed cryopreserved apheresis samples from 19 MM patients to quantify the clonotypicmyeloma cell burden in tandem mobilized apheresis products.