Investigational Drug Could Improve Stem Cell Collection for ASCT

An investigational drug called motixafortide significantly increased the number of stem cells that could be collected for transplantation in patients with multiple myeloma when combined with standard therapy for mobilizing stem cells. The findings, which could potentially improve the stem cell transplantation process for multiple myeloma patients, were published in Nature Medicine.¹

The treatment landscape for multiple myeloma has expanded in recent years, leading to improved outcomes for patients. Autologous hematopoietic stem cell transplantation (ASCT), which involves harvesting a patient’s own stem cells to store and readminister once intensive chemotherapy is complete, has become a standard and central aspect of the multiple myeloma treatment paradigm, the authors noted.

While ASCT has been shown to improve overall survival and event-free survival outcomes, its effectiveness depends partly on the amount of sufficient hematopoietic stem and progenitor cells (HSPCs) that can be collected.

“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, the Virginia E. and Sam J. Golman Professor of Medicine at Washington University School of Medicine, said in a statement.²

The international phase 3 trial aimed to determine the safety and efficacy of adding motixafortide to granulocyte colony stimulating factor (G-CSF)—the standard drug used to mobilize stem cells in patients with multiple myeloma.

A total of 122 patients at 18 sites in 5 countries were randomly assigned to receive either G-CSF plus motixafortide (n = 80) or G-CSF plus a placebo (n = 42) for HSPC mobilization. The primary end point was the collection of sufficient CD34+ HSPCs, defined as a minimum of 6 million cells per kilogram of body weight. The secondary end point was the collection of sufficient cells with just 1 apheresis.

The results demonstrated substantial improvements in HSPC collection with G-CSF plus motixafortide vs G-CSF with a placebo. In the motixafortide cohort, 92.5% of patients met the primary end point of sufficient cell collection vs 26.2% in the placebo group (odds ratio (OR), 53.3; 95% CI, 14.12-201.33; P < .0001).

In the motixafortide plus G-CSF group, 88.8% of patients met the secondary end point of sufficient cell collection with 1 apheresis, compared with 9.5% in the G-CSF with placebo group (OR, 118; 95% CI, 25.36-549.35; P < .0001).

The combination treatment with motixafortide was also found to be well tolerated. The most common treatment-emergent adverse events were grade 1 or 2 injection site reactions, including pain, erythema, and pruritus.

“This study suggests motixafortide works extremely well in combination with the standard drug, granulocyte colony stimulating factor (G-CSF), in mobilizing stem cells in patients with multiple myeloma,” DiPersio said. “The study also found that the combination worked rapidly and was generally well-tolerated by patients. We are hopeful that this investigational drug, if approved, will expand the number of patients who can receive an effective stem cell transplant for multiple myeloma.”

References

1. Crees ZD, Rettig MP, Jayasinghe RG, et al. Motixafortide and G-CSF to mobilize hematopoietic stem cells for autologous transplantation in multiple myeloma: a randomized phase 3 trial. Nat Med. Published online April 17, 2023. doi:10.1038/s41591-023-02273-z

2. Investigational drug may improve stem cell transplantation for multiple myeloma patients. News release. Washington University School of Medicine in St. Louis. April 17, 2023. https://medicine.wustl.edu/news/investigational-drug-may-improve-stem-cell-transplantation-for-multiple-myeloma-patients/