Results from the Prognostic Immunophenotyping in Myeloma Response (PRIMeR) study, reported in the Journal of Clinical Oncology by Marcelo C. Pasquini, MD, MS, and colleagues, found that undetectable measurable residual disease (MRD) status at 1 year after autologous hematopoietic cell transplantation (autoHCT) and lenalidomide maintenance therapy was associated with improved progression-free and overall survival in patients with multiple myeloma.
Marcelo C. Pasquini, MD, MS
Study Details
PRIMeR was an ancillary study assessing MRD via next-generation multiparameter flow cytometry in a subgroup of patients from the three-arm randomized STaMINA trial. MRD was measured at baseline/pre-autoHCT, pre–maintenance therapy, and 1 year after autoHCT with a sensitivity of 10-5 to 10-6. The primary objective of the trial was to assess undetectable MRD status at 1 year after autoHCT, as well as its impact on progression-free and overall survival.
Key Findings
A total of 435 patients (PRIMeR population, out of 758 total in STaMINA) consented to MRD panel testing. At a median follow-up of 70 months, no significant differences in survival outcomes by treatment group were observed in the PRIMeR population or the STaMINA population.
At all three time points, patients with undetectable MRD status had significantly improved progression-free survival vs those with detectable MRD status. For patients with vs without undetectable MRD status at 1 year, the 3-year progression-free survival was 66% vs 34% (P < .001). For patients with vs without undetectable MRD status at 1 year, the 5-year overall survival was 84% vs 59% (P < .001).
In a multivariate analysis adjusting for disease risk and treatment arm, hazard ratios for progression-free survival in detectable-MRD vs undetectable-MRD patients were 1.55 (P = .0074), 1.83 (P = .0007), and 3.61 (P < .0001) at baseline, pre–maintenance therapy, and year 1, respectively; respective hazard ratios for overall survival were 1.19 (P = .48), 0.88 (P = .68), and 3.36 (P < .001).
Patients with sustained undetectable MRD status or with conversion to undetectable MRD status by year 1 had similar progression-free and overall survival outcomes.
The investigators concluded: “To our knowledge, this first, prospective U.S. cooperative group multicenter study demonstrates that MRD-negative status at year 1 after autoHCT with lenalidomide maintenance is prognostic for improved [long-term] progression-free survival and overall survival. Serial MRD measurements may direct trials to test how further therapy may improve long-term progression-free survival and overall survival.”
Dr. Pasquini, of the Medical College of Wisconsin, Milwaukee, is the corresponding author of the Journal of Clinical Oncology article.
Disclosure: The study was supported by the National Heart, Lung, and Blood Institute; National Cancer Institute; and others. For full disclosures of the study authors, visit ascopubs.org.
