Phase I dose escalation study of naive T-cell depleted donor lymphocyte infusion following allogeneic stem cell transplantation.

Prophylactic donor lymphocyte infusions (DLI) are used to augment post-transplant immune recovery to reduce both infectious complications and disease recurrence. Preclinical studies implicate the naive T-cell subset as the primary driver of graft-versus-host disease (GvHD). In this phase I dose escalation study, we assessed the safety of a DLI that was depleted of CD45RA+ naive T cells. Sixteen adult patients received a prophylactic DLI at a median of 113 days (range 76-280 days) following an HLA-identical, non-myeloablative allogeneic hematopoietic stem cell transplantation. Three patients each received the naive T-cell depleted DLI with a CD3+ dose of 1 × 105/kg, 1 × 106/kg, and 5 × 106/kg. The maximum dose of 1 × 107/kg was expanded to 7 patients. No dose-limiting grade III/IV acute GvHD or adverse events attributable to the DLI were observed at any dose level. One patient developed grade 2 acute GvHD of skin and upper intestines, and another developed moderate chronic GvHD of the lungs following the DLI. With a median follow-up of 2.8 years, 2-year progression-free and overall survival is 50.0% and 68.8%, respectively. In conclusion, these data suggest that a DLI that has been depleted of CD45RA+ naive T cells is feasible and carries a low risk of acute or chronic GvHD.

Evaluation of Hematopoietic Stem Cell Mobilization Rates with Early Plerixafor Administration for Adult Stem Cell Transplantation.

The addition of plerixafor to high-dose colony-stimulating growth factor has been shown to improve stem cell mobilization rates in autologous transplant patients with multiple myeloma and non-Hodgkin lymphoma. This study evaluates the change in administration time of plerixafor to determine if cell mobilization rates are similar between the US Food and Drug Administration-approved administration time of 11 hours before apheresis and an earlier administration time of 16 hours before apheresis. Medical records of patients age ≥ 18 years undergoing autologous stem cell transplantation requiring the use of plerixafor after at least 4 days of granulocyte colony-stimulating factor therapy to complete stem cell mobilization from January 1, 2010 through September 30, 2014 were retrospectively reviewed. The primary outcome was CD34+ cell mobilization success rates when plerixafor was administered 11 ± 2 hours (standard administration group) compared with 16 ± 2 hours before cell apheresis (early administration group), as defined as collection of ≥2 × 106 CD34+ cells/kg. Secondary outcomes included the number of plerixafor therapy days required to collect a total of ≥2 × 106 CD34+ cells/kg, the number of apheresis cycles required to achieve ≥2 × 106 CD34+ cells/kg, the median CD34+ cells/kg collected in each apheresis session, and the rates of reported adverse events that occurred in the standard administration time group compared with the early administration time group. Of the 197 patients included, 114 patients received plerixafor 11 ± 2 hours before apheresis and 83 patients received plerixafor 16 hours ± 2 hours before apheresis. Ninety-four percent of patients in the early administration group achieved successful stem cell mobilization compared with 81.6% in the standard administration group (P = .0111). The median number of plerixafor days to reach the collection goal of ≥2 × 106 CD34+ cells/kg was 1 day for each group (P = .323), and the median number of apheresis days to reach the collection goal was 2 days for the standard administration group compared with 1 day for the early administration group (P = .0156). Most adverse events were similar between the 2 groups except for fever, which occurred in 4.8% of the patients in the early administration group and none of the patients in the standard administration group. This study demonstrates plerixafor effectively mobilizes peripheral blood stem cells when given at an early administration time of 16 hours before apheresis compared with standard administration of 11 hours before apheresis. However, further prospective studies could strengthen these results.

Myeloablative conditioning with total body irradiation for AML: Balancing survival and pulmonary toxicity.

PURPOSE: The purpose of this study was to compare leukemia-free survival (LFS) and other clinical outcomes in patients with acute myelogenous leukemia who underwent a myeloablative allogeneic stem cell transplant with and without total body irradiation (TBI). METHODS AND MATERIALS: Adult patients with acute myelogenous leukemia undergoing myeloablative allogeneic stem cell transplant at Duke University Medical Center between 1995 and 2012 were included. The primary endpoint was LFS. Secondary outcomes included overall survival (OS), nonrelapse mortality, and the risk of pulmonary toxicity. Kaplan-Meier survival estimates and Cox proportional hazards multivariate analyses were performed. RESULTS: A total of 206 patients were evaluated: 90 received TBI-based conditioning regimens and 116 received chemotherapy alone. Median follow-up was 36 months. For all patients, 2-year LFS and OS were 36% (95% confidence interval [CI], 29-43) and 39% (95% CI, 32-46), respectively. After adjusting for known prognostic factors using a multivariate analysis, TBI was associated with improved LFS (hazard ratio: 0.63; 95% CI: 0.44-0.91) and OS (hazard ratio: 0.63; 95% CI, 0.43-0.91). There was no difference in nonrelapse mortality between cohorts, but pulmonary toxicity was significantly more common with TBI (2-year incidence 42% vs 12%, P < .001). High-grade pulmonary toxicity predominated with both conditioning strategies (70% and 93% of cases were grade 3-5 with TBI and chemotherapy alone, respectively). CONCLUSIONS: TBI-based regimens were associated with superior LFS and OS but at the cost of increased pulmonary toxicity.