Credit: Miltenyi Biotec
The US Food and Drug Administration (FDA) has granted approval for a device system that can prevent graft-vs-host disease (GVHD).
The CliniMACS CD34 Reagent System is intended for use in patients with acute myeloid leukemia who are in first complete remission and undergoing stem cell transplant (SCT) from a matched, related donor.
This in vitro system enriches CD34+ hematopoietic stem cells from a donated apheresis product, while depleting other cells that can cause GVHD.
The system employs a reagent consisting of a CD34 antibody conjugated to an iron-containing nanoparticle. It enriches CD34+ cells by passing the antibody/nanoparticle-labeled cell suspension through a magnetic separation column, which is provided as part of a single-use, disposable tubing set.
Magnetically labeled CD34+ target cells are retained within the separation column, while the unlabeled cells flow through. The CD34+ cells can be recovered by removing the magnetic field and eluting the targeted CD34+ cells into a collection bag.
The FDA’s approval of this system was based on data from a phase 2 study (BMT CTN 0303) conducted by the Blood and Marrow Transplant Clinical Trials Network (Pasquini et al, JCO 2012).
The trial included 128 patients undergoing SCT from a matched, sibling donor. Forty-four patients received grafts that were T-cell depleted (TCD) using the CliniMACS system as the sole form of immune suppression. The other 84 patients received T-cell-replete grafts and pharmacologic immune suppression therapy (IST).
The 2 groups were largely similar, although more patients in the TCD arm received treatment regimens that included radiation—100% vs 50%.
Neutrophil engraftment was similar between the 2 groups. At 28 days, 96% of patients in the IST arm and 100% in the TCD arm had achieved engraftment.
Patients in the TCD arm had a significantly lower rate of chronic GVHD than those in the IST arm. The TCD patients also had a lower rate of acute GVHD, but the difference was not significant.
At 100 days, the rates of grade 2-4, acute GVHD were 39% with IST and 23% with TCD grafts (P=0.07). At 2 years, the rates of chronic GVHD were 19% with TCD grafts and 50% with IST (P<0.001).
There were no significant differences between the 2 groups with regard to graft rejection, leukemia relapse, treatment-related mortality, disease-free survival, or overall survival. However, patients in the TCD arm had a higher rate of GVHD-free survival at 2 years—41% vs 19% (P=0.006).
The CliniMACS CD34 Reagent System is manufactured by Miltenyi Biotec. For more information on the system, see the company’s website.
