Last Updated: 2009-10-15 15:17:47 -0400 (Reuters Health)

NEW YORK (Reuters Health) - When plerixafor is added to granulocyte colony-stimulating factor (G-CSF) and given to patients with non-Hodgkin's lymphoma, autologous stem-cell mobilization and transplantation are enhanced, according to a report in the October 1st Journal of Clinical Oncology.

The article, by Dr. John F. DiPersio from Washington University, St. Louis, Missouri, and colleagues, describes a phase III trial in which 298 adults with non-Hodgkin's lymphoma received G-CSF plus either plerixafor or placebo.

The authors explain that plerixafor "is the first in a new class" of drugs that reversibly inhibit the binding of chemokine stromal cell-derived factor to CXC chemokine receptor 4 (CXCR4).

Significantly more patients who were randomized to the plerixafor group (59.3%, vs 19.6% in the placebo group) achieved the primary end point: collection of at least 5 million CD34+ cells/kg in no more than 4 apheresis days. In the plerixafor group, patients needed a median of 3 apheresis days to meet this goal, whereas fewer than half the placebo group met the target within 4 apheresis days.

Results were similar when the end point was collection of at least 2 million CD34+ cells/kg.

All transplanted patients in each group had successful neutrophil engraftment, and 98% had successful platelet engraftment, the report indicates. There was no difference between the groups in median time to engraftment for neutrophils (10 days) or platelets (20 days).

Overall survival through 12 months of follow-up did not differ between the plerixafor-treated patients (88.0%) and the placebo-treated patients (87.2%).

Ten patients from the plerixafor group and 52 from the placebo group failed to achieve the lower cell target and were entered into rescue treatment with plerixafor and G-CSF. After the rescue course, 37 (4 plerixafor, 33 placebo) achieved at least 2 million CD34+ cells/kg in no more than 4 apheresis days.

Times to neutrophil and platelet engraftment after transplant and 12-month survival were similar in rescue-group patients and in patients transplanted without the need for rescue.

The overall incidence of adverse events was similar between the groups in each study period, the investigators say, and all serious adverse events were considered to be related to the transplantation.

"This study paves the way for future studies where the effects of a drug with proven biologic effects can then be compared with and/or combined with other clinically relevant strategies," the authors conclude. "Future studies will help to further evaluate and define the clinical application of plerixafor for peripheral blood stem-cell mobilization."

Two of the ten authors had served as employees or in leadership positions in AnorMED (now Genzyme), and all authors reported compensation for consultant or advisory roles for Genzyme, the sponsor of the study.

J Clin Oncol 2009;27:4767-4773.