Autologous Stem Cell Collection In Lymphoma and Myeloma Patients: Single Center Analysis With Intention To Successful Mobilization and Collection Under Restricted Permission For Use Of Plerixafor
Authors: Hasbal Baris , Bilgen Hulya , Ozcelik Tulay , Hindilerden Fehmi , Guvenc Serkan , Serefhanoglu Songul , Küçükkaya Reyhan , Arat Mutlu 
Published: October 2019

Abstract
High dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation (HSCT) rescue is a potentially curative&consolidative therapy for advanced hematological malignancies, and it also permits the administration of higher doses of chemotherapy to overcome tumor cell resistance. In this study, our aim is to evaluate 167 consecutive myeloma (MM) and lymphoma (ML) patients referred to our center between August 2010 and May 2013. Patients data are analyzed in intent to successful hematopoietic stem cell (HSC) mobilization and collection. In our country we have limited access to plerixafor, as salvage HSC mobilizing agent, permitted only after a failed mobilization&collection trial of chemotherapy and G-CSF. Our center's policy is to collect HSC with G-CSF in all MM (exception of prolonged revlimide use and prior autologous HSCT), and non-heavily pretreated ML patients. Candidates for poor mobilization underwent first CT and G-CSF, and second line receive plerixafor. Under these circumstances 86 lymphoma patients (31 Hodgkin and 55 NHL) and 81 MM patients (F/M: 57/110, med. age 52, range 18-72) were included in this study. Nearly >15% of the patients received more than 2 cycles of chemotherapy before HSC collection. Mobilization with G-CSF as a single agent resulted in optimal CD34+ cell yield for 121 (72%) patients. In myeloma G-CSF as first line resulted with 92.7% successful HSC mobilization and collection. Overall 17 patients received plerixafor as 2nd or 3rd line, and resulted with sufficient HSC collection in 57.3%. In three cases (MM:1, ML:2) additional support with autologous bone marrow collection necessary. Only in 9 (5.3%) patients all attempts for mobilization failed including plerixafor. After any type of mobilization regimen median count for pCD34+ cells obtained was 18/mcl. Median yield of 3.3 x 106/kg CD34+ cells/kg was collected with range of 0.2-33.9x106/kg in total apheresis sessions. MM patients have significant high levels of preapheresis circulating CD34+ count in comparison to ML patients (29 vs 15, p=0.001). pCD34+ cell did not correlate with body mass index, age, underlying disease and previous treatment cycles. There is a close correlation between pCD34+ cell count and collected CD34+ cells in all types of mobilization regimens as G-CSF, chemotherapy and plerixafor (relatively; p<0.001, p=0.002 and p=0.001). Successful ASCT is achieved in 144 patients transplanted so far. Mobilization is achieved in almost all multiple myeloma patients and most of lymphoma patients with only G-CSF based regimen in our cohort. Half of patients not mobilized with G-CSF were successfully mobilized with chemotherapy and plerixafor as second or third line regimen. The restricted use of plerixafor resulted in time and expense for additional chemotherapy and collection attempt, whereas this inconvenience did not impact the success of stem mobilization and collection in our current policy within 3 years.

Disclosures:
No relevant conflicts of interest to declare.