Plerixafor Salvage Is Safe and Effective in Hard-to-Mobilize Patients Undergoing Chemotherapy and Filgrastim-Based Peripheral Blood Progenitor Cell Mobilization

The combination of filgrastim (G-CSF) and plerixafor is currently approved for mobilizing peripheral blood progenitor cells in patients with non-Hodgkin lymphoma and multiple myeloma undergoing autologous peripheral blood hematopoietic cell transplantation. However, chemotherapy and G-CSF-based mobilization remains a widely used strategy for peripheral blood progenitor cell collection. In this paper we describe our experience from two North American transplant centers in a series of patients who received salvage plerixafor while failing chemotherapy and G-CSF mobilization. Patients received a median of two doses of plerixafor salvage upon failure to mobilize adequate number of peripheral blood progenitor cells at neutrophil recovery. The use of plerixafor was associated with a 2.4-fold increase in peripheral blood CD34+ cell count and 3.9-fold increase in total CD34+ cell yield. All patients were able to collect ≥2 × 106 CD34+ cells/kg with this approach. These results were more pronounced in patients with a higher CD34+ cell count at the time of the first plerixafor dose. Interestingly, peripheral blood white blood cell count was not shown to correlate with a response to plerixafor. Our results provide safety and efficacy data for the use of plerixafor in patients who are destined to fail chemomobilization

Evaluation of Extended Interval Dosing Aminoglycosides in the Morbidly Obese Population

Aminoglycoside dosing has been studied in the obese population, typically recommending an adjusted weight utilizing a 40% dosing weight correction factor (IBW + 0.4 × (TBW–IBW)). These studies included limited numbers of morbidly obese patients and were not done in the era of extended interval aminoglycoside dosing. Here, we report a retrospective evaluation of morbidly obese patients receiving gentamicin or tobramycin at our hospital. The objective of this study was to evaluate the accuracy of the commonly recommended adjusted weight for weight-based dosing. There were 31 morbidly obese patients who received gentamicin or tobramycin 5–7 mg/kg every 24 hours using a 40% dosing weight correction factor. Our institution utilizes 16-hour postdose concentrations to monitor extended interval aminoglycosides. Twenty-two of the 31 patients (71%) achieved an appropriate serum drug concentration. Four patients (13%) were found to be supratherapeutic and 5 patients (16%) subtherapeutic. The only variable that correlated with supratherapeutic levels was older age (P=0.0378). Our study helps to validate the current dosing weight correction factor (40%) in the morbidly obese population. We recommend caution when dosing aminoglycosides in morbidly obese patients who are of older age

Outcomes of Six-Dose High-Dose Cytarabine as a Salvage Regimen for Patients with Relapsed/Refractory Acute Myeloid Leukemia

Relapsed/refractory acute myeloid leukemia (RR-AML) is associated with poor prognosis and long-term disease-free survival requires allogeneic hematopoietic cell transplantation (allo-HCT). Limited data exists, regarding the optimal regimen to obtain remission prior to allo-HCT. Single agent high-dose cytarabine (10–12 doses administered every 12 hours) has been previously used as induction therapy. Six-dose high-dose cytarabine (HiDAC-6), commonly used as a consolidation regimen, has never been evaluated as induction therapy. We present a retrospective review of 26 consecutive patients with RR-AML receiving single agent cytarabine 3 g/m2 intravenously every 12 hours on days 1, 3, and 5 for a total of six doses (HiDAC-6). Median follow-up for surviving patients was 10.4 months (range 1.6–112.2 months). Complete remission was obtained in 62% (54% CR and 8% CRi) of the patients. The median relapse-free survival (RFS) was 22.3 months (range 0.7–112 months), event-free survival (EFS) was 4.7 months (range 0.5–112 months), and the overall survival (OS) was 9.6 months (range 1–112 months). Thirty-five percent of patients were able to subsequently proceed to allo-HCT. Treatment-related toxicities included neutropenic fever (38%), infection (35%), neurotoxicity (8%), and skin toxicity (8%). This is the first study to demonstrate HiDAC-6 as an active treatment option for younger patients with RR-AML which can effectively serve as a bridge to allo-HCT without significant toxicity

Higher infused CD34+ cell dose and overall survival in patients undergoing in vivo T-cell depleted, but not t-cell repleted, allogeneic peripheral blood hematopoietic cell transplantation

BACKGROUND AND OBJECTIVESUnderstanding the effect of cellular graft composition on allogeneic hematopoietic cell transplantation (AHCT) outcomes is an area of great interest. The objective of the study was to analyze the correlation between transplant-related outcomes and administered CD34+, CD3+, CD4+ and CD8+ cell doses in patients who had undergone peripheral blood, AHCT and received either in vivo T-cell depleted or T-cell replete allografts.DESIGN AND SETTINGComparison of consecutive patients who underwent peripheral blood AHCT in our institution between January 2003 and December 2009.PATIENTS AND METHODSThe cohort of 149 patients was divided into two groups; non T-cell depleted (NTCD) (n=54) and T-cell depleted (TCD) (n=95). Study endpoints were overall survival (OS), progression free survival (PFS), engraftment kinetics (neutrophil and platelet recovery), incidence of acute graft versus host disease (acute GVHD), chronic GVHD, non relapse mortality (NRM) and disease relapse.RESULTSMultivariate analysis showed that higher infused CD34+ cell dose improved OS (relative risk 0.58, 95% CI 0.34-0.98, P=.04), PFS (relative risk 0.59, 95% CI 0.35-1.00, P=.05) and NRM (relative risk 0.49, 95% CI 0.24-0.99, P=.048) in the TCD group. By multivariate analysis, there was no difference in engraftment, grades II-IV acute GVHD, extensive chronic GVHD and relapse in the two groups relative to the infused cell doses. There was a trend towards improved OS (relative risk 0.54, 95% CI 0.29-1.01, P=.05) with higher CD3+ cell dose in the TCD group.CONCLUSIONOur findings suggest that higher CD34+ cell dose imparts survival benefit only to in vivo TCD peripheral blood AHCT recipients