ASCO 2021: Ixazomib Maintenance After HCT in High-Risk Multiple Myeloma
Posted: Monday, June 7, 2021
Taiga Nishihori, MD, of the Moffitt Cancer Center, Tampa, Florida, and colleagues conducted a phase II multicenter trial to evaluate maintenance ixazomib with reduced-intensity fludarabine/melphalan/bortezomib-based conditioning after allogeneic hematopoietic cell transplantation (HCT) in patients with high-risk multiple myeloma. Presented during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, their results demonstrated similar progression-free and overall survival between ixazomib and a placebo 21 months after randomization (Abstract 7003).
“Allogeneic HCT with reduced-intensity fludarabine/melphalan and a single pre-HCT dose of bortezomib is safe and can produce durable disease control in extremely high-risk patients,” the study authors concluded. “Ixazomib maintenance after allogeneic HCT could not be assessed as intended due to early termination of study, but there was no signal of an impact in outcomes.”
This study focused on 57 patients with either high-risk multiple myeloma or relapse within 24 months after autologous HCT who were 70 years or younger. Participants received a conditioning regimen of fludarabine/melphalan/bortezomib, along with human leukocyte antigen–matched donor peripheral blood grafts. In addition, individuals were randomly assigned to receive 3 mg of ixazomib on days 1, 8, and 15 of a 28-day cycle or a placebo for 12 cycles.
The median patient age was 56, and most patients received allogeneic HCT (91.2%) and proceeded to randomization (82.7%). A total of 33 patients had high-risk multiple myeloma, and 9 had primary plasma cell leukemia. The overall survival and progression-free survival rates were 85% and 52%, respectively, 24 months after allogeneic HCT; the corresponding transplant-related mortality was 11%.
The ixazomib and placebo cohorts had comparable overall survival (95% vs. 87%) and progression-free survival (55.3% vs. 59.1%) rates. Additionally, grade 3 to 4 acute graft-versus-host disease affected 9.5% of patients given ixazomib but none when given the placebo; chronic graft-versus-host disease affected 69% and 64%, respectively.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.