Results of a phase II trial presented at this years meeting of the American Society of Clinical Oncology (ASCO) suggest that daniplestim, a novel hematopoietic growth factor, may increase the reliability of stem-cell collection for transplantation following ablation of bone marrow by high-dose chemotherapy.
Investigators found that when daniplestim was administered in combination with granulocyte colony-stimulating factor (G-CSF [Neupogen]), it boosted the number of peripheral blood stem cells (PBSCs) and provided for more productive stern-cell harvesting than did G-CSF alone.
To help bone marrow recover quickly from the toxicity of high-dose chemotherapy, we need to collect and refine large amounts of stem cells. This may require multiple stem cell collection procedures, and some patients may never generate the optimal number of cells, said John DiPersio, MD, PhD, lead investigator and Chief, Division of Bone Marrow Transplantation and Stem Cell Biology, Washington University School of Medicine. If the results presented here are confirmed by phase III studies, adding daniplestim to G-CSF therapy could result in more consistent collection of significantly greater numbers of stem cells for transplantation.
The trial involved 22 breast cancer patients who received either daniplestim plus G-CSF or G-CSF alone. Leukapheresis was initiated on Day 5 of growth-factor therapy. Results showed that 12 (75%) of 16 patients achieved 2.5 million stem cells per kilogram with daniplestim plus G-CSF, compared with only 1 of 6 (17%) patients who received G-CSF alone. The threshold of 2.5 million stem cells per kilogram is an important predictor of rapid bone marrow recovery. In addition, this target was achieved with fewer leukaphereses in the daniplestim plus G-CSF group.
The trial also included 24 lymphoma patients. Unlike the breast cancer cohort, the lymphoma patients did not demonstrate a significant benefit with daniplestim. The reason for this are still under investigation, but may be related to the relatively poor marrow function of lymphoma patients.
Daniplestim was well tolerated with premedication. The most common side effects reported were mild-to-moderate flu-like symptoms. A phase III trial is now underway focusing on stem-cell mobilization in preparation for high-dose chemotherapy.