Autologous hematopoietic stem cell transplantation (auto-HSCT) is the standard treatment option for multiple myeloma (MM) and relapsed non-Hodgkin’s lymphoma (NHL) patients.1, 2, 3 Granulocyte colony stimulating factor (G-CSF) combined with high-dose chemotherapy is a frequently used mobilization approach.2 Chemo-mobilization success depends on the patient’s age, apheresis timing, chemotherapy and immunomodulatory regimens as well as chemotherapy-related adverse events (AEs).3 Mobilization failure leads to remobilization, which negatively impacts clinical outcomes and healthcare costs.4

We retrospectively analyzed 526 patients with MM (n=269) and relapsed NHL (n=257) undergoing stem cell collection after chemo-mobilization, in 14 centers in Asian Pacific countries, during 2009–2012. Among 269 MM patients, 235 (87.4%) received cyclophosphamide (CY) plus G-CSF and 34 (12.6%) were mobilized with other chemotherapeutic drugs (Table 1). Overall 232 MM patients (86.2%) achieved at least 2 × 106 CD34+ cells/kg after 1–2 aphereses at initial mobilization. For MM patients who had received cyclophosphamide as a mobilizing agent, 223 (94.9%) had at least CD34+ 2 × 106 cells/kg and 182 patients (77%) achieved 5 × 106 CD34+ cells/kg or higher (Table 1).

Table 1 Impact of cyclophosphamide and other salvage regimens on mobilization of CD34+ cells
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Among 257 NHL patients, 187 patients (72.8%) received salvage chemotherapy such as ICE (n=20), RICE (n=21), ESHAP (n=21) and RDHAP (n=8), and 70 patients (27.2%) received CY plus G-CSF (Table 1). Only 143 NHL patients (55.6%) achieved at least 2 × 106 CD34+ cells/kg after 1–2 aphereses at initial mobilization. Administration of salvage regimens resulted in mobilizing at least 2 × 106 CD34+ cells/kg in 172 NHL patients (92.0%) (Table 1). In 70 NHL patients, who received CY as a chemo-mobilizing agent, 53 patients (76%) achieved 2 × 106 CD34+ cells/kg (Table 1).

Following chemo-mobilization and apheresis, a total of 242 MM patients (95.3%) and 178 NHL patients (79.1%), who achieved a minimum of 2 × 106 CD34+ cells/kg, underwent HSCT. Overall, a higher population of MM patients was able to mobilize adequate numbers of stem cells for collection. The reasons for MM patients not proceeding to HSCT included patient withdrawal (5), being unfit for procedure (3), death (2) and disease progression (1). It is noteworthy that two patients had more than one reason. Of the 225 NHL patients who achieved at least 2 × 106 CD34+ cells/kg, 5 patients died from a severe adverse event and 41 patients (18.2%) did not proceed to transplant because of patient withdrawal (20), disease progression (14) and being unfit for procedure (7).

This was the first study in an Asian Pacific population regarding the efficacy of chemo-mobilization of stem cells for auto-HSCT in MM and NHL patients. Cyclophosphamide plus G-CSF was the most appropriate combination to mobilize adequate number of stem cells in MM patients. By contrast, salvage chemotherapy plus G-CSF was more efficacious than cyclophosphamide for mobilizing stem cells in NHL patients. The majority of MM patients, mobilized with cyclophosphamide, and NHL patients receiving salvage chemotherapy, underwent auto-HSCT.