KRD-PACE Mobilization for Multiple Myeloma Patients with Significant Residual Disease Prior to Autologous Stem Cell Transplantation

Abstract Background Bortezomib has been incorporated into DT-PACE (thalidomide, dexamethasone, cisplatin, doxorubicin, cyclophosphamide and etoposide) as an intensive regimen (VTD-PACE) prior to autologous stem cell transplantation for multiple myeloma (MM). We examined MM patients at our center who received chemomobilization with a regimen that substituted carfilzomib and lenalidomide for bortezomib and thalidomide (KRD-PACE). Methods This was a retrospective study of 27 MM patients who received KRD-PACE for chemomobilization. Our analysis included patients who had circulating plasma cells (CPCs) by flow cytometry, ≥ 10% bone marrow plasma cells (BMPC), a monoclonal protein ≥ 1 g/dL, or an involved serum free light chain ≥ 10 mg/dL. Results The most common indication for KRD-PACE was BMPC ≥ 10% in 16 patients (60%), followed by CPCs in 11 (41%). The median age was 61 years (range, 35- 69), and the median BMPC prior to treatment was 10% (range, 5 – 47%). The overall response rate was 43%, and a median of 20.24 x 106 CD34+ cells/kg (range, 8.08 – 69.88) were collected. CPC clearance rate was 50%, and the median reduction in BMPC was 75%. Two patients had sinus bradycardia, and neutropenic fever in 5 (19%). Discussion KRD-PACE is an effective therapy to mobilize peripheral blood stem cells in MM patients with residual disease burden. This regimen was successful at clearing CPCs and reducing BMPC burden, with an overall response rate of 43%. Despite theoretical concern regarding the combination of three cardiotoxic agents, we observed a low frequency of cardiac issues.