Pegfilgrastim and Planned Plerixafor for Autologous Stem Cell Mobilization Is Safer Than and As Effective As Chemo-Mobilization in Patients with Hematological Malignancies

Introduction:

We have previously shown that as compared with chemo-mobilization (CHM) cytokine mobilization (CTM) is associated with a better chance of achieving a target autologous stem cell dose for patients with multiple myeloma (MM). We now review our experience of autologous stem cell mobilization using a similar strategy for all patients referred for an autologous transplant (auto-SCT).

Methods:

We analyzed consecutive patients who received an auto-SCT for hematological malignancies at our center from July 2010 to June 2013. CHM was achieved with cyclophosphamide (4 g/m2), pegfilgrastim (12 mg) and plerixafor (0.24 mg/kg once daily until target dose collected or maximum of 4 days apheresis). CTM was achieved with pegfilgrastim and plerixafor. We recorded the total CD34+ cells/kg collection, number of apheresis days, and if the prescribed dose of CD34+ cells/kg was achieved. The prescribed cell dose in patients with MM is 6.0 x 106/kg, and 3.0 x 106/kg for all other hematological malignancies. We compared the median total CD34+ cells/kg dose collection (Wilcoxon test), the mean number of apheresis days (Poission), and target stem cell dose collection (non-inferiority test on two proportions). We also compared day 1 stem cell collection in the CTM group based on disease (myeloma vs. non-myeloma) (Wilcoxon test). Finally, we analyzed the probability of successful stem cell dose collection if the target collection dose was higher than our own criteria.

Results:

A total of 74 patients were included. Fifty-three patients had a diagnosis of MM and twenty-one patients had other hematological malignancies, non-Hodgkin (n=15) and Hodgkin lymphoma (n=2). There was no statistically significant difference in age, gender, number of prior induction treatment, prior treatment with lenalidomide and time from diagnosis to transplant between the two groups. In the CHM group, 7 (47%) were hospitalized from complications of mobilization regimen, whereas no patients were hospitalized in the CTM group (p<0.001). There was no statistically significant difference in neutrophil or platelet engraftment between CHM and CTM. Multivariate analysis did not reveal predictive factors which lead to >1 apheresis attempts. Table 1 describes the primary outcomes.

Conclusion:

Cytokine-mobilization with pegfilgrastim and planned plerixafor is an effective strategy for stem cell mobilization in patients being considered for autologous transplant.

Table 1.0: Primary Endpoint Analysis
	Chemo-mobilization (N = 19)	Cytokine mobilization (N=55)	p-value
Median total CD34 cells/kg collected (in millions/kg): Myeloma Non-Myeloma	14.9 4.47	8.37 5.03	0.01 0.71
Median number of apheresis days (mean): Myeloma Non-myeloma	1 (1.75) 2 (1.67)	1 (1.76) 1 (1.59)	0.99 0.89
Target dose achieved: Yes No	16 (84.2%) 3 (15.8%)	51 (92.7%) 4 (7.3%)	0.05
Median Day 1 CD34 collection (in millions/kg): Myeloma Non-myeloma	NA NA	6.86 3.67	0.01