Daratumumab-based regimens produced higher rates of minimal residual disease (MRD) negativity when compared with standard of care in patients with relapsed/refractory multiple myeloma (RRMM), according to an analysis of data from the POLLUX and CASTOR trials published in the Journal of Clinical Oncology.
“Achieving durable MRD negativity may predict long-term outcomes, as durable MRD negativity improves [progression-free survival] and increases the time between treatment relapses for RRMM,” the authors wrote.
In the POLLUX study (ClinicalTrials.gov Identifier: NCT02076009), researchers compared the combination of daratumumab, lenalidomide, and dexamethasone (D-Rd) with lenalidomide and dexamethasone only.
In the CASTOR trial (ClinicalTrials.gov Identifier: NCT02136134), researchers compared the combination of daratumumab, bortezomib, and dexamethasone (D-Vd) with bortezomib and dexamethasone only.
In POLLUX, the researchers assessed MRD status at the time of suspected complete response (CR), 3 months and 6 months after confirmed CR, and every 12 months after confirmed CR. In the CASTOR trial, MRD status was assessed at 6 months and 12 months after the first dose as well as every 12 months after CR.
The median follow-up was 54.8 months in POLLUX and 50.2 months in CASTOR.
In the intention-to-treat population, the MRD-negativity rates were 32.5% for D-Rd and 6.7% for lenalidomide and dexamethasone only (P <.0001). MRD-negativity rates were 15.1% for D-Vd and 1.6% for bortezomib and dexamethasone only (P <.0001).
Significantly higher rates of MRD negativity were achieved in patients who had a CR or better in both trials.
Researchers conducted a post hoc analysis of combined data from patients in both trials who achieved MRD negativity and CR or better, compared with patients who were MRD positive or who had a response worse than a CR. Patients with the deepest responses had improved progression-free survival (hazard ratio=0.20; 95% CI, 0.15-0.27; P <.0001).
Disclosures: This research was supported by Janssen Research and Development, LLC. Please see the original reference for a full list of authors’ disclosures.
Avet-Loiseau H, San-Miguel J, Casneuf T, et al. Evaluation of sustained minimal residual disease negativity with daratumumab-combination regimens in relapsed and/or refractory multiple myeloma: analysis of POLLUX and CASTOR. J Clin Oncol. 2021;39(10):1139-1149. doi:10.1200/JCO.20.01814