Evaluating the Clinical Efficacy of Increased Granulocyte Colony-Stimulation Factor (GCSF) in Patients Who Fail a Standard Dose Regimen during Peripheral Blood Stem Cell Collection.

Granulocyte Colony-Stimulating Factor (GCSF) at 10 microg/kg (with or without chemotherapy) is the standard dose commonly administered to patients undergoing Peripheral Blood Stem Cell (PBSC) mobilization and collection. Due to various host and disease factors, 10–20% of our patients failed to mobilize sufficient PBSC at this standard dose. At our institution it is common practice to increase GCSF from 10 microg/kg to 16–20 microg/kg during the initial or second mobilization attempt if the patient is able to tolerate the increased dose. To assess the clinical efficacy of increased GCSF administration among patients who fail to mobilize at the standard dose, we performed a retrospective chart review of 112 patients who underwent stem cell mobilization and collection between 01/31/2000 and 11/6/2003. The median age at the start of collection was 51.2 (range: 1.3–72.2); the case-series was made up of 52 men and 60 women. The majority of the cases were Lymphoma patients (Non-Hodgkin’s Lymphoma=52; Hodgkins Disease=15) with the remaining patients classified as Acute Myeloid Leukemia (AML=12), Multiple Myeloma (MM=13), or ‘Other’ (N=20). Initially all 112 patients received 4–10 days of GCSF at 10 microg/kg per day before the first day of PBSC collection. Because these patients failed to collect sufficient daily CD34 cells, the GCSF dose was increased to 16–20 microg/kg. Before increasing the GCSF dose, the median CD34 daily yield was 0.19 (range: 0.03–0.90), and the median peripheral WBC was 27.6 (range: 1.3–61.8). The median number of collection at 10 microg/kg was 4 (range 2–15), and the median number of days from the end of collection at 10 microg/kg to the start of 16–20 microg/kg was 1 (range: 0–53). After increasing the GCSF dose the median peripheral WBC was 37.1 (range: 3.1–70.2), and the median CD34 daily yield was 0.28 (range: 0.03–3.43). The median CD34 total yield was 3.1 (range 0.6–12.3). Ultimately 90 patients (80%) reached a CD34 cell target of 2*10–6/kg (range: 2.0–12.3), and 22 patients (20%) did not reach this target. The overall difference in CD34 counts pre-post increased GCSF administration was statistically significant (Wilcoxon p<0.01). The difference in CD34 counts (pre-post increase GCSF dose) was explained by age only; the patient’s diagnosis and gender had no statistically significant explanatory value. Patients less than 40 years of age were more likely to have successful PBSC collection with an increase dose of GCSF (p=0.02). The mean difference in daily CD34 yield for patients <40 years was 0.38; for patients ≥40 years was 0.11. Based on this analysis we recommend to increase GCSF dose to 16microg to 20 microgram/kg among the younger (<40 years) patients who failed a standard dose regimen at 10microg/kg, while other re-mobilization regimens should be considered for older patients irrespective of their gender or underlying diagnosis.