Chemo-Mobilization of Autologous Hematopoietic Progenitor Cells (HPCs) with a Single Dose of Pegfilgrastim and Supplemental Filgrastim in Patients with Multiple Myeloma and Lymphoma: A Practical Schema

Hematopoietic Progenitor Cell (HPC) mobilization should take into consideration efficacy, predictability, convenience and cost. Despite many different schemas available, the optimal growth factor regimen for chemo-mobilization is still debatable.  The standard growth factor used in HPC mobilization is filgrastim (G-CSF) 10mcg/kg/day, administered subcutaneously.  Patients usually receive daily G-CSF injections after chemotherapy in average of 10 days before starting apheresis. Medicare patients have to go to hospital or clinic every day to have their G-CSF injections given. We retrospectively evaluated our experience with pegylated-filgrastim given in conjunction with a subsequent short course G-CSF in 15 patients (8F/7M) with multiple myeloma (n=6) and lymphoma (n=9) who underwent chemo-growth factor HPC mobilization for high-dose chemotherapy and autologous stem cell transplantation. Median age was 68 (52-78). Chemotherapy regimen used for mobilization was at the discretion of the transplant physician and included cyclophosphamide (n=2), DV-PACE (n=5), DHAP (n=2), ESHAP (n=2), EPOCH (n=2), ICE (n=1), mostly combined with Rituximab.  We planned ahead of time that chemotherapy is completed by the end of the week so that the patient could spend the weekend at home and receive pegfilgrastim at a single fixed dose (6 mg) subcutaneously in the following week with a median 3 (2-4) days after the last day of chemotherapy. At the time of recovery when median WBC was 0.6/mcL (0.1-3.8), daily G-CSF, at a median dose of 6 mcg/kg/day (5 -12) was initiated in 5 (4-7) days after the dose of pegfilgrastim. Five patients (33%) received additional Plerixafor. HPC collection was started based on peripheral CD34 count in a median 3 days (1-6) after the initiation of G-CSF and in 16 days (11-18) after the initial chemotherapy administration.  After 2 days (1-3) of apheresis, all patients but one had adequate (>2 x 10⁶) CD34+ cells/kg in HPC product. Median CD34+ cell count on peripheral blood on day+1 apheresis was 32 (4.6-407) x 10⁶/kg. All patients had full myeloid recovery and median time to ANC>500 x 3 consecutive days was 11 days (10-18) days. No graft failure was observed. All patients tolerated the mobilization regimen well with no serious side effects. Our preliminary data suggest that single dose pegfilgrastim in conjunction with low dose short course G-CSF can provide satisfactory HPC mobilization and be considered an alternative convenient growth factor regimen for select patients. A prospective study is currently underway in our institution.