Results of employing a plerixafor dosing algorithm to mobilize hematopoietic stem cells in patients with multiple myeloma and lymphoma.

Abstract

6541 Background: High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (HSCT) is standard of care for some patients with multiple myeloma (MM) and non-Hodgkin’s lymphoma (NHL) and its success depends on harvesting an adequate number of CD34+ cells. Mobilization with growth factors alone or with chemotherapy has resulted in reported failure rates of 20-40% (NHL) and 10-20% (MM). Plerixafor (P) enhances the mobilization and subsequent harvesting of CD34+ cells. To ensure its appropriate and fiscally responsible use, we developed a dosing algorithm to be used in select patients thought to potentially be poor mobilizers. The inclusion criteria and dosing decision pathways were determined by a review of the evidence-based literature. Methods: The records of 64 (37M, 27F) pts with MM or NHL mobilized with P Apr 2009-Nov 2010 using our dosing algorithm were reviewed. A comparative group of 93 (58M, 35F) pts with MM and NHL mobilized Apr 2008-Mar 2009 with filgrastim alone (F) or with chemotherapy (FC) were also reviewed. Patient demographics, number of CD34+ cells harvested, number of P doses, apheresis days and number failing to mobilize at least 2x 106 CD 34+/kg cells were recorded. Results: The median ages were: P-62 yrs (22-76), F-52 yrs (20-76) & FC-52 yrs (20-68). P consisted of 31 MM and 33 NHL pts, F-67 MM and 10 NHL pts and FC-14 MM and 2 NHL pts. The median number of (P) doses and (P) apheresis days were: MM 1 (1-2) and 2 (0-3), NHL 2 (1-4) and 2 (0-4), the median number of apheresis days in F- MM 3 (0-5), NHL 2 (0-3) and FC-MM 2 (0-4), NHL 2.5 (2-3). The median number of CD34+ cells harvested was: P-MM 6.47 (0-15.0), NHL 3.53 (0-10.29), F-MM 6.3 (0-16.26), NHL 3.65 (0-8.41) and FC: MM 6.22 (0-12.34), NHL 5.72 (5.33-6.11). The number of patients failing to mobilize at least 2 x 106 CD34+/kg cells was: P-MM 2 (6.5%), NHL 4 (12%), F-MM 8 (11.9%), NHL 3 (33%) and FC-MM 3 (21.4%), NHL 0. Conclusions: The failure rates for MM and NHL pts receiving P were well below reported literature values and that of our own comparative groups. Additionally, P group required a fewer number of apheresis days than either the F or FC group leading to cost savings. These positive results justify P use in select patients