A Retrospective Study on Safety, Efficacy and Cost of the Chemo-Mobilization for Patients Planned to Undergo Autologous Hematopoietic Stem Cell Transplant: The Secom Study

Introduction: Failure of hematopoietic stem cell (HSC) mobilization occurs in 5 to 30% patients planning for high dose chemotherapy and autologous HSC transplantation worldwide. It has adverse impact on patient outcomes and significantly increases health care burden. Data regarding HSC mobilization based on chemotherapy + granulocyte colony stimulating factor (G-CSF) in Asia are currently limited.

Objective: The primary objective was to determine the safety and efficacy of HSC chemo-mobilization protocols in Asia for patients with non-Hodgkin lymphoma (NHL) or multiple myeloma (MM) planning for autologous HSCT. The secondary objective was to provide an estimate of the cost of chemo-mobilization in Asian countries

Study Design: This was a multicenter, multinational retrospective observational study. Patients with NHL or MM undergoing chemo-mobilization for planned autologous HSCT between 1 Jan 2009 to 31 Dec 2012 in five Asian countries including Thailand, Singapore, Malaysia, Hong Kong and Taiwan, were retrospectively included in the study. Patient demographics, disease diagnoses, previous treatment history as well as complete blood counts prior to chemo-mobilization and apheresis, were collected.

Results: A total of 526 patients (male/female = 207/219) were analyzed (diagnoses: NHL=257; MM=269). 160 patients were recruited from Thailand, 98 from Malaysia, 161 from Taiwan, 59 from Singapore and 48 from HK. Median age for the overall group was 53 years (range: 15-82). The most common mobilization regimen was cyclophosphamide + G-CSF; 235 (87.4%) in MM and 72 (28%) in NHL patients. 448 (85.2%) patients had reached at least HSC yield of 2 x 10⁶CD 34+ cells/kg in 1 or 2 apheresis days. During chemo-mobilization, 108 (20.5%) patients were without negative clinical events (grade 3/4 neutropenia, febrile neutropenia, prolonged hospitalization, bone pain, fever, gastrointestinal, line infections or others). Grade 3/4 neutropenia and febrile neutropenia occurred in 401 (76.2%) and 72 (13.7%) patients, respectively. Median number of apheresis sessions was 2 (range: 1-5). Median cost of mobilization was 6,200USD (9,000-48,000). The respective median costs in USD (range) was; 3,500 (1,500-28,500) in Thailand, 6,900 (2,300-29,600) in Malaysia, 7,700 (3,400-48,000) in Taiwan and 9,200 (900-45,400) in Singapore. 436 (82.9%) patients proceeded to receive high dose chemotherapy and HSCT but 94 (17.87%) patients did not, due to insufficient HSC yield (n=26, 4.94 %), progression of disease (n=18, 3.42 %), patient not fit/ withdrawal from study (n=19, 3.61 %), patient expiry (n=11, 2.09 %) and other reasons (n=20, 3.80 %).

Conclusion: Cyclophosphamide and G-CSF is the most common mobilization regimen used in Asian countries. Current chemo mobilization regimens are associated with a satisfactory rate of successful stem cell collection but with a high rate of significant toxicity. More than three-quarter of patients suffered from grade 3/4 toxicity during chemo-mobilization, however, only 20% of them had febrile neutropenia. Variations exist in the cost of chemo-mobilization in Asia, both among and within countries.