Temporal changes in plerixafor administration and hematopoietic stem cell mobilization efficacy: results of a prospective clinical trial in multiple myeloma.

Plerixafor with granulocyte colony-stimulating factor (G-CSF) is effective for hematopoietic stem cell (HSC) mobilization in patients with non-Hodgkin Lymphoma and myeloma; however, labeling requires dosing 11 hours before apheresis. Pharmacodynamic studies show peak blood CD34(+) cell counts at 10 to 14 hours; limited data are available for later time points. To address the effect of afternoon plerixafor dosing on CD34(+) cell yields, we conducted a prospective clinical trial in myeloma patients undergoing stem cell collection. Thirty-one patients received plerixafor 17 hours before apheresis; blood CD34(+) cells were measured before the first plerixafor dose and 1, 3, and 17 ± 1 hours after treatment. The target HSC number (≥10 × 106 CD34(+) cells/kg) was collected from 22 subjects (73%) in 1 day and from all subjects within 3 days. Hematopoietic engraftment after transplantation and adverse events were similar to previous studies. Plerixafor given 17 hours before apheresis yields desired HSC collection efficiencies after induction treatment in myeloma patients.

Effectiveness and cost analysis of "just-in-time" salvage plerixafor administration in autologous transplant patients with poor stem cell mobilization kinetics.

BACKGROUND: Plerixafor is a recently Food and Drug Administration (FDA)-approved CXCR4 antagonist, which is combined with granulocyte-colony-stimulating factor (G-CSF) to facilitate stem cell mobilization of lymphoma and myeloma patients. STUDY DESIGN AND METHODS: To evaluate the effectiveness and the related costs of a "just-in-time" strategy of plerixafor administration, we performed a retrospective cohort study comparing 148 consecutive lymphoma and myeloma patients in whom mobilization was attempted during 2008 before the Food and Drug Administration (FDA) approval of plerixafor with 188 consecutive patients mobilized during 2009 after FDA approval. RESULTS: Plerixafor was administered to 64 of 188 patients considered to be at risk for mobilization failure due to either their medical history ("high risk," n = 23) or the occurrence of peripheral blood CD34+ count of fewer than 15 × 10(6) cells/L with a white blood cell count of greater than 10 × 10(9) cells/L after at least 5 days of G-CSF administration (just-in-time, n = 41). The success rates of collecting a minimum transplant CD34+ cell dose (≥2 × 10(6) cells/kg) or target cell dose (≥5 × 10(6) lymphoma or ≥10 × 10(6) CD34+ cells/kg myeloma) in the just-in-time patients compared favorably with the 36 poor mobilizers collected with G-CSF alone: 93% versus 72% and 42% versus 22%, respectively. CONCLUSIONS: The use of plerixafor in selected high-risk patients and poor mobilizers did not increase the total charges associated with stem cell collection when compared with poor mobilizers treated with G-CSF alone. The targeted use of plerixafor increased the overall success rate of mobilizing a minimum number of CD34+ cells from 93% to 98% in patients with hematologic malignancies scheduled for autotransplant and increased the overall charges associated with stem cell collection in all patients by an average of 17%.

A randomized clinical trial comparing granulocyte-colony-stimulating factor administration sites for mobilization of peripheral blood stem cells for patients with hematologic malignancies undergoing autologous stem cell transplantation.

BACKGROUND: A study was undertaken to investigate whether granulocyte-colony-stimulating factor (G-CSF) injection in lower adipose tissue-containing sites (arms and legs) would result in a lower exposure and reduced stem cell collection efficiency compared with injection into abdominal skin. STUDY DESIGN AND METHODS: We completed a prospective randomized study to determine the efficacy and tolerability of different injection sites for patients with multiple myeloma or lymphoma undergoing stem cell mobilization and apheresis. Primary endpoints were the number of CD34+ cells collected and the number of days of apheresis. Forty patients were randomly assigned to receive cytokine injections in their abdomen (Group A) or extremities (Group B). Randomization was stratified based on diagnosis (myeloma, n=29 vs. lymphoma, n=11), age, and mobilization strategy and balanced across demographic factors and body mass index. RESULTS: Thirty-five subjects were evaluable for the primary endpoint: 18 in Group A and 17 in Group B. One evaluable subject in each group failed to collect a minimum dose of at least 2.0×10(6) CD34+ cells/kg. The mean numbers of CD34+ cells (±SD) collected were not different between Groups A and B (9.15×10(6)±4.7×10(6) /kg vs. 9.85×10(6) ±5×10(6) /kg, respectively; p=NS) after a median of 2 days of apheresis. Adverse events were not different between the two groups. CONCLUSION: The site of G-CSF administration does not affect the number of CD34+ cells collected by apheresis or the duration of apheresis needed to reach the target cell dose.

Receiver operating characteristic curve analysis of circulating blood dendritic cell precursors and T cells predicts response to extracorporeal photopheresis in patients with chronic graft-versus-host disease.

BACKGROUND: One proposed mechanism of extracorporeal photopheresis (ECP) in reducing chronic graft-versus-host disease (cGVHD) is alteration in numbers of circulating dendritic cells (DCs). This hypothesis was tested by correlating numbers of DC precursors and T cells in the blood before and during ECP therapy with response of cGVHD. STUDY DESIGN AND METHODS: Twenty-five patients with cGVHD were treated with ECP. Data were collected with emphasis on blood cellular markers, clinical response to ECP, and overall survival. RESULTS: Fourteen patients (56%) responded and had better 2-year survival than nonresponders (88% vs. 18%, p=0.003). Responders had higher baseline circulating myeloid DC (mDC) and plasmacytoid DC precursors and CD4+ and CD8+ T cells compared with nonresponders. Receiver operating characteristic curve analyses showed that the best baseline cutoff values to predict response to ECP were mDC counts of 3.7 cells/µL (79% sensitivity, 82% specificity) and CD4+ T-cell counts of 104 cells/µL (71% sensitivity, 82% specificity). CD4+ T cells declined in responders over time, but not in nonresponders, and no significant changes were seen in CD8 T-cell or DC numbers over a 12-month period in responder or nonresponder groups. CONCLUSIONS: Higher baseline numbers of circulating DCs and T cells may predict clinical response to ECP in patients with cGVHD.