The FDA has approved motixafortide in combination with filgrastim to mobilize hematopoietic stem cells in multiple myeloma transplantation, based on findings from the phase 3 GENESIS trial.
The FDA has approved motixafortide (Aphexda) in combination with filgrastim (Neupogen; G-CSF) to prompt the mobilization of hematopoietic stem cells in patients with multiple myeloma who are undergoing transplantation.1
The regulatory decision is supported by findings from the 2-part, phase 3 GENESIS trial (NCT03246529). This randomized, double-blind, placebo-controlled study compared the efficacy and safety profile of motixafortide plus filgrastim (n = 92) against placebo plus filgrastim (n = 42). Ultimately, among those who received motixafortide plus filgrastim, 67.5% reached the stem cell collection goal of ≥ 6 × 106 CD34+ cells/kg within 2 apheresis sessions, compared with 9.5% of patients receiving the placebo-based regimen, according to the central laboratory measurements (P < .0001).
According to local laboratory measurements, 92.5% of patients in the experimental arm and 21.4% of patients in the placebo arm received the stem cell collection goal.
Of note, 5.4% of patients enrolled on the trial experienced a serious adverse event (AE) with motixafortide plus filgrastim. Serious AEs included vomiting, injection site reaction, hypersensitivity reaction, injection site cellulitis, hypokalemia, and hypoxia. Comparatively, the most common any grade AEs reported during the trial included injection site reactions (pain, erythema and pruritus), pruritus, flushing, and back pain.
“Greater numbers of patients with multiple myeloma are candidates for autologous stem cell therapy; however, achieving target collection goals can be difficult in some patients given modern barriers, including the treatment of older patients and use of contemporary induction regimens,” said John DiPersio, MD, PhD, primary investigator for the GENESIS trial, professor of medicine, pathology and immunology, and director of the Center for Gene and Cellular Immunotherapy at Washington University School of Medicine in St. Louis, said in a press release.
Autologous stem cell transplantation (ASCT) is considered standard of care for patients with multiple myeloma and is associated with prolonged survival for these patients. However, adequate stem cell mobilization is necessary for ASCT to be successful.
Historically, 37% of patient who underwent ASCT have had difficulty collecting sufficient target numbers of hematopoietic stem cells after 1 apheresis session. Patients who are older, as well as those who have already been exposed to lenalidomide (Revlimid)-containing regimens, are more likely to experience impaired stem cell mobilization.
The American Society for Transplantation and Cellular Therapy (ASTCT) recommends the following target for stem cell collection: 3-5 x 106 CD34+ cells/kg. If necessary, conducting 2 transplantations to ensure that enough stem cells are collected is recommended.
In part 1 of the GENESIS trial, 12 patients received motixafortide. This information was used to determine the appropriate dose. In part 2, 122 patients were randomly assigned 2:1 to receive either motixafortide plus filgrastim or placebo plus filgrastim. Investigators sought to represent the typical multiple myeloma population in this trial: the median age was 63 years and approximately 70% of patients in both arms had received lenalidomide-containing induction therapy.
According to the manufacturers, this FDA approval is the first innovation in stem cell mobilization for multiple myeloma in the United States in over a decade, emphasizing that 1 dose of motixafortide allowed most patients to achieve the collection goal of at least 6 million hematopoietic stem cells.
Motixafortide is a CXCR4 antagonist with longer receptor occupancy. It is approved as a subcutaneous injection and associated with the following warnings and precautions: anaphylactic shock and hypersensitivity reactions, injection site reactions, tumor cell mobilization, leukocytosis, and embryo-fetal toxicity.
“Innovation in this area of medicine has been needed, and today’s approval of [motixafortide] addresses the demand for new therapies that can meet today’s challenges by delivering more reliability in stem cell mobilization, versus filgrastim alone, with fewer days of apheresis sessions and fewer doses of filgrastim for people living with this cancer,” DiPersio said.