Collection of Peripheral Blood Stem Cells in Patients with Multiple Myeloma after Stem Cell Transplant: A Single Institution Experience

Background

Autologous stem cell transplant is the standard of care for eligible multiple myeloma patients. However, many patients relapse with passage of time. These patients often do not have any or have inadequate numbers of previously harvested stem cells. The question still comes up frequently whether peripheral blood stem cells can be successfully collected from patients with history of prior transplant and what is the best approach. Herein, we report the results from our institution.

Patients and Methods

Records of patients with multiple myeloma who received transplant at our institute between 03/01/12 -07/09/15 dates were reviewed. Recorded data included disease stage, prior transplant and chemotherapies, stem cell mobilization strategies and time to engraftment. Student T-test was performed on reviewed data.

Results

A total number of 21 patients (7 male and 14 female) with multiple myeloma and prior transplant underwent peripheral blood stem cell collection. Median age at diagnosis was 52.1 years (range 36-71 years). Each patient had at least 2 prior rounds of chemotherapy with a median of 4 prior lines of chemotherapies (range 2-6).

One patient had a prior history of allotransplant and remainder had at least one prior autotransplant. ISS staging at diagnosis included 5 patients with Stage 1, 2 patients with Stage 2, 5 patients with Stage 3 and stage was not available for 8 patients. One patient had plasma cell leukemia. Disease subtypes included two patients with IgA kappa, one with IgA lambda, nine with IgG kappa, two with IgG lambda, five with kappa light chain, one with lambda light chain and one with non-secretory disease. 33% of patients had high risk cytogenetics at time of stem cell collection.

The total number of prior transplants before stem cell collection was 25 with a median of 1 transplant (range 1-2). Median age at the time of collection was 59.3 years (range 43-81). Disease status at time of salvage transplant included complete response in 5 patients, very good partial response in 2, partial response in 9 and stable disease in 5 patients.

Filgrastim with plerixafor was used for mobilization in 15 patients, filgrastim, plerixafor and pegfilgrastim in 5 patients and filgrastim with pegfilgrastim in 1 patient. A median number of 3 doses of plerixafor (range 0-5) were used. Median stem cell collection dose was 9.75 X 10⁶/kg CD34 cells (range 3.29-24.8 X 10⁶/kg) and median number of collection days was 3 (range 1-5). All patients received salvage transplants. Engraftment occurred at a median of 12 days (range 10-27). The 21 patients received a total number of 30 transplants after collection with a median of 1 transplant (range 1-2). Prior to collection, D-PACE was administered to 10 patients, VDT-PACE to 2 patients, VCD to 1 patient and growth factors only to 8 patients. 5/8 patients who were mobilized with only growth factors had baseline platelet count of < 130,000. Patients receiving D-PACE had a median collection of 13.55 X 10⁶ cells as compared to 5.70 X 10⁶ cells without it (p<0.004).

Conclusions

Our experience shows that collecting peripheral blood stem cells after prior transplantation in patients with multiple myeloma is very feasible even in patients with multiple lines of chemotherapies. Addition of D-PACE as chemo-mobilization strategy has proved to be effective if platelet count is normal at baseline.