In a study reported in the Journal of Clinical Oncology, Paiva et al examined the applicability of International Myeloma Working Group (IMWG) criteria for next-generation flow cytometry assessment of minimal residual disease (MRD) in multiple myeloma. They found that the IMWG flow MRD-negative response criterion is “highly applicable and sensitive” in this setting.
“The IMWG flow MRD-negative response criterion is highly applicable and sensitive to evaluate treatment efficacy in multiple myeloma.”— Paiva et al
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Study Details
In the study, the IMWG flow cytometry MRD-negative criteria were longitudinally assessed in 1,100 bone marrow samples from 397 patients with newly diagnosed multiple myeloma in the PETHEMA/GEM2012MENOS65 trial. Assessment was performed after six induction cycles with bortezomib, lenalidomide, and dexamethasone (VRD); autologous transplantation; and two consolidation courses with VRD. Patients received maintenance therapy with lenalidomide with or without ixazomib. An additional 61 patients from the trial without MRD data had discontinued treatment during induction and were considered MRD-positive for the intent-to-treat analysis.
Key Findings
In total, 205 (45%) of 458 patients had undetectable MRD after consolidation. At the time of analysis, disease progression had occurred in 14 (7%).
Undetectable MRD was associated with significantly reduced risk vs persistent MRD for progression or death (hazard ratio [HR] = 0.18, P < .001) and for death (HR = 0.12, P < .001). Estimated 36-month rates for progression-free survival were 87% vs 50%; for overall survival, they were 96% vs 88%.
No significant differences in outcomes were observed with undetectable MRD after induction vs after treatment intensification (P = .38 for progression-free survival; P = .17 for overall survival). No significant differences in 36-month progression-free survival in patients with undetectable MRD were observed according to Revised International Staging System (R-ISS)-I (95%), -II (94%), or -III status (88%). In contrast, patients with persistent MRD and ISS-III status had median progression-free and overall survival durations of 14 and 17 months, respectively.
Conversion from positive to negative MRD was observed in 33 (17%) of 190 patients during maintenance treatment.
The investigators concluded, “The IMWG flow MRD-negative response criterion is highly applicable and sensitive to evaluate treatment efficacy in multiple myeloma.”
Jesús F. San-Miguel, MD, PhD, of the Clinica Universidad de Navarra; Centro de Investigacion Medica Aplicada, Pamplona, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by grants from the Centro de Investigacíon Biomédica en Red—Área de Oncología—del Instituto de Salud Carlos III and others. For full disclosures of the study authors, visit ascopubs.org.
