Circulating Tumor Cells Predict Myeloma Outcomes in Patients Treated with Daratumumab, Bortezomib, Lenalidomide, and Dexamethasone.

ABSTRACT:Circulating tumor cells (CTC) represent a high-risk biomarker in newly diagnosed multiple myeloma (NDMM); however, their prognostic value among transplant-eligible (TE) patients receiving daratumumab/bortezomib/lenalidomide/dexamethasone (D-VRd) remains unknown. In this study, we analyzed CTC in the phase 3 PERSEUS/EMN017 trial. TE-NDMM patients were randomized (1:1) to D-VRd with daratumumab/lenalidomide maintenance (D-VRd group) or bortezomib/lenalidomide/dexamethasone (VRd) with lenalidomide maintenance (VRd group), both with transplant. A subset of 451 of 709 patients from PERSEUS (D-VRd, 231/355; VRd, 220/354) had screening blood samples collected for CTC analysis by flow cytometry. CTC were detected in 370 patients (82%; median limit of detection, 0.0004%). CTC were prognostic of progression-free survival (PFS), independent of other factors, as a continuous (hazard ratio [HR], 1.36 [95% confidence interval (CI), 1.15-1.60]; P< .001) and categorical variable (≥0.175% CTC-high, optimal threshold). D-VRd improved PFS vs VRd in CTC-low patients (4-year rates: 88% vs 74%; HR, 0.42 [95% CI, 0.25-0.70]; P = .0013). Regardless of study treatment, minimal residual disease (MRD)-negativity rates were lower in CTC-high vs CTC-low patients (10-5: 52.2% vs 66.2%; 10-6: 34.8% vs 52.4%). D-VRd significantly increased MRD-negativity rates vs VRd among CTC-high (10-5: 69.4% vs 33.3%; 10-6: 47.2% vs 21.2%; both P< .05) and CTC-low patients (10-5: 74.4% vs 57.8%; 10-6: 65.6% vs 38.5%; both P< .001), with similar observations for sustained MRD-negativity. CTC levels are an independent prognostic factor in TE-NDMM treated with standard-of-care frontline quadruplet. D-VRd improved and sustained MRD-negativity rates in CTC-high and CTC-low, and improved PFS for CTC-low with a positive trend in CTC-high patients. This trial was registered at www.clinicaltrials.gov as #NCT03710603.