Motixafortide, a novel cyclic-peptide CXCR4 inhibitor with extended in vivo activity , appears to increase the number of stem cells that can be harvested from transplant candidates, thereby increasing the likelihood of successful transplant, the authors reported.
An application for a new drug approval is currently under review by the Food and Drug Administration.
In the prospective, international, phase 3 GENESIS clinical trial , motixafortide plus granulocyte colony-stimulating factor (G-CSF) – the standard therapy for mobilizing stem cells – significantly increased the number stem cells harvested, when compared with standard therapy plus placebo. After one collection procedure, the combination approach allowed for harvesting of an optimal number of cells in 88% versus 9% of patients who received G-CSF plus placebo. After two collections, optimal collection occurred in 92% versus 26% of patients in the groups, respectively, first author Zachary D. Crees, MD, and colleagues found.
Motixafortide plus G-CSF was also associated with a tenfold increase in the number of primitive stem cells that could be collected. These stem cells are particularly effective for reconstituting red blood cells, white blood cells, and platelets, which all are important for patients’ recovery, they noted.
Stem cells mobilized by motixafortide were also associated with increased expression of genes and genetic pathways involved in self-renewal and regeneration, which are also of benefit for increasing the effectiveness of stem cell transplantation.
The findings were published in Nature Medicine.
“Stem cell transplantation is central to the treatment of multiple myeloma, but some patients don’t see as much benefit because standard therapies can’t harvest enough stem cells for the transplant to be effective, senior author John F. DiPersio, MD, PhD, stated in a news release . “This study suggests motixafortide works extremely well in combination with [G-CSF] in mobilizing stem cells in patients with multiple myeloma.
“The study also found that the combination worked rapidly and was generally well tolerated by patients,” added Dr. DiPersio, the Virginia E. & Sam J. Goldman Professor of Medicine at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University.
Dr. DiPersio is the lead author of another study investigating therapies beyond stem cell transplants. He and his colleagues recently reported the first comprehensive genomic and protein-based analysis of bone marrow samples from patients with multiple myeloma in an effort to identify targets for immunotherapies.
That study, published online in Cancer Research, identified 53 genes that could be targets, including 38 that are responsible for creating abnormal proteins on the surface of multiple myeloma cells; 11 of the 38 had not been previously identified as potential targets.
Dr. DiPersio and Dr. Crees, an assistant professor of medicine and the assistant clinical director of the Washington University Center for Gene and Cellular Immunotherapy, are also evaluating motixafortide’s potential for mobilizing stem cells to support “the genetic correction of the inherited disease sickle cell anemia.”
“This work is of particular importance because patients with sickle cell disease can’t be treated with G-CSF … due to dangerous side effects,” the news release stated. “The hope is that development of a novel, effective, and well-tolerated stem cell mobilizing regimen for a viral-based gene therapy approach using CRISPR-based gene editing will lead to improved outcomes for patients with sickle cell disease.”
The study published in Nature Medicine was supported by the National Institutes of Health and BioLineRx, which makes motixafortide. The study published in Cancer Research was supported by the Paula C. And Rodger O. Riney Blood Cancer Research Fund and the National Cancer Institute.
Dr. Crees reported research funding from BioLineRx. Dr. DiPersio reported relationships with Magenta Therapeutics, WUGEN, Incyte, RiverVest Venture Partners, Cellworks Group, Amphivena Therapeutics, NeoImmune Tech, Macrogenics, and BioLineRx.
Correction, 4/26/23: The headline on an earlier version of this article mischaracterized the study findings.