Blood Stem Cell Collection: Factors Influencing the Recovery of Granulocyte-Macrophage Colony Forming Cells

Melphalan, prednisone, and thalidomide vs melphalan, prednisone, and lenalidomide (ECOG E1A06) in untreated multiple myeloma

This phase 3 trial (Eastern Cooperative Oncology Group [ECOG] E1A06) compared melphalan, prednisone, and thalidomide (MPT-T) with melphalan, prednisone, and lenalidomide (mPR-R) in patients with untreated multiple myeloma (MM). A noninferiority design was used, and inferiority was defined as a progression-free survival (PFS) hazard ratio (HR) of MPT-T/mPR-R ≤0.82. A total of 306 patients enrolled, with a median age of 75.7 years. Median follow-up was 40.7 months. Median time on therapy was 12.1 months and 23.1 months for the 46.6% of treated patients who received maintenance, with no differences by arm. Median PFS was 21 months on MPT-T and 18.7 months on mPR-R (HR, 0.84; 95% confidence interval, 0.64-1.09). Overall survival was 52.6 months (MPT-T) vs 47.7 months (mPR-R) (P = .476). Per-protocol response rates were 63.6% (MPT-T) and 59.9% (mPR-R) (P = .557). Grade ≥3 nonhematologic toxicity was 59.5% for MPT-T vs 40.0% for mPR-R (P = .001). Second malignancies were observed in 18 MPT-T patients vs 14 mPR-R patients. Quality-of-life analysis favored mPR-R by induction end (P = .007). Use of MPT-T or mPR-R in elderly patients with untreated MM demonstrates no statistical or clinically relevant differences in response rates, PFS, and OS; however, quality of life at end of induction was improved and lower toxicity reported with mPR-R. This trial was registered at www.clinicaltrials.gov as #NCT00602641.

Effect of prior chemotherapy on hematopoietic stem cell mobilization

A number of studies have suggested that prior chemotherapy correlates negatively with the efficiency of hematopoietic stem cell mobilization. However, little data exist with regard to the relative effects of the specific chemotherapeutic drug classes. We retrospectively reviewed the records of 201 consecutive patients with nonmyeloid malignancies undergoing CD34+ cell mobilization with chemotherapy+granulocyte colony-stimulating factor (G-CSF). The number of prior chemotherapy courses correlated negatively with the peripheral CD34+ cell concentration (pCD34) on the first day of collection (P<0.001). No significant correlation was found for age, gender, tumor primary, mobilization chemotherapy regimen, disease status, marrow involvement, prior radiation therapy, or dose and timing of G-CSF administration. When the number of courses of individual classes of chemotherapeutic agents was correlated with pCD34, only exposures to platinum compounds (P=0.001) and alkylating agents (P=0.01) were found to be independent negative predictive factors for pCD34. Within classes, DNA crosslinking agents and etoposide appeared possibly more damaging than DNA methylating agents and doxorubicin, respectively. None of the drug classes showed evidence of recovery. We conclude that exposure to chemotherapy, especially platinum compounds and alkylating agents, should be minimized prior to mobilization.

Comparison of CD34+ cell collection efficiency on the COBE Spectra and Fenwal CS-3000 Plus

Optimal collections of mobilized CD34+ cells are important in terms of both patient toxicity and cost. The factors that determine CD34+ collection efficiency (CD34eff) of cell separators have not been well studied. In addition, because several cell separators are available, the type of collection device may also be a significant variable. Previous studies comparing the Baxter-Fenwal CS3000 and the COBE Spectra have not yielded consistent conclusions. Therefore, we retrospectively analyzed the collection outcomes of 163 consecutive donors with a peripheral CD34+ cell concentration (pCD34) of > or =5 cells/microl on the first collection that had been harvested on one or the other device. The CS3000 was found to yield a significantly higher CD34eff (50% vs. 39%, P = 0.006). However, donors were not balanced for several prognostic factors, which may contribute to CD34eff including mobilization with G-CSF vs. chemotherapy+G-CSF, average flow rate, and total volume of peripheral blood processed. When appropriate variables were included in a stepwise multiple variable analysis, cell separator type emerged as a significant independent predictive factor for CD34eff (P = 0.018). Our data indicates that the CS3000 will, on average, show a higher absolute CDeff of 8%. Furthermore, since the two devices differ in mechanism, prognostic factors may also differ. Comparisons suggest that peripheral blood WBC and hematocrit may be more important predictors for the CS3000.