|The following article features coverage from the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting. Click here to read more of Hematology Advisor‘s conference coverage.|
Among patients with high-risk multiple myeloma (MM) who undergo allogeneic hematopoietic stem cell transplantation (alloHCT), maintenance ixazomib does not appear to provide clinical benefit, according to research presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.
It is not yet known what therapies are optimal for maintenance after alloHCT. For this randomized, placebo-controlled phase 2 study (ClinicalTrials.gov Identifier: NCT02440464), researchers evaluated the safety and efficacy of ixazomib maintenance therapy with a reduced-intensity fludarabine, melphalan, and bortezomib combination conditioning regimen among patients with MM undergoing alloHCT.
Overall, 57 patients from 15 centers were enrolled between 2015 and 2018. Among this enrolled cohort, 52 underwent alloHCT, and 43 were randomly assigned to receive maintenance ixazomib (21 patients) or placebo (22 patients).
In the overall cohort, the median age was 56 years (range, 35-65). A total of 33 patients (57.9%) had high-risk MM, while 9 patients (15.8%) had primary plasma cell leukemia.
After 24 months post-alloHCT, the 2-year progression-free survival (PFS) and overall survival (OS) rates were 52% and 85%, respectively, in the entire cohort. Transplant-related mortality occurred in 11% of patients.
At 21 months after study randomization, patients who received ixazomib had a PFS rate and OS rate of 55.3% and 95%, respectively, which did not differ significantly from the placebo group (PFS, 59.1%; OS, 87%; P =.17).
Grade 3-4 acute graft-vs-host disease (GVHD) at 100 days occurred in 9.5% of patients in the experimental group vs 0% in the placebo group, although chronic GVHD rates were similar at 12 months (69% vs 64%, respectively).
The 21-month transplant-related mortality rates, however, were lower in the ixazomib group (0% vs 4.5%).
“AlloHCT 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 authors wrote. “Ixazomib maintenance after alloHCT could not be assessed as intended due to early termination of study, but there was no signal of an impact in outcomes.”
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Read more of Hematology Advisor’s coverage of the 2021 ASCO Annual Meeting by visiting the conference page.
Nishihori T, Bashir Q, Pasquini MC, et al. The results of multicenter phase II, double-blind placebo-controlled trial of maintenance ixazomib after allogeneic hematopoietic cell transplantation (alloHCT) for high-risk multiple myeloma (MM) from the Blood and Marrow Transplant Clinical Trials Network (BMT CTN 1302). J Clin Oncol. 2021;39:(suppl 15; abstr 7003). doi:10.1200/JCO.2021.39.15_suppl.7003