PURPOSE Assessing measurable residual disease (MRD) has become standard with many tumors, but the clinical meaning of MRD in multiple myeloma (MM) remains uncertain, particularly when assessed by next-generation flow (NGF) cytometry. Thus, we aimed to determine the applicability and sensitivity of the flow MRD-negative criterion defined by the International Myeloma Working Group (IMWG). PATIENTS AND METHODS In the PETHEMA/GEM2012MENOS65 trial, 458 patients with newly diagnosed MM had longitudinal assessment of MRD after six induction cycles with bortezomib, lenalidomide, and dexamethasone (VRD), autologous transplantation, and two consolidation courses with VRD. MRD was assessed in 1,100 bone marrow samples from 397 patients; the 61 patients without MRD data discontinued treatment during induction and were considered MRD positive for intent-to-treat analysis. The median limit of detection achieved by NGF was 2.9 × 10−6. Patients received maintenance (lenalidomide ± ixazomib) according to the companion PETHEMA/GEM2014MAIN trial. RESULTS Overall, 205 (45%) of 458 patients had undetectable MRD after consolidation, and only 14 of them (7%) have experienced progression thus far; seven of these 14 displayed extraosseous plasmacytomas at diagnosis and/or relapse. Using time-dependent analysis, patients with undetectable MRD had an 82% reduction in the risk of progression or death (hazard ratio, 0.18; 95% CI, 0.11 to 0.30; P < .001) and an 88% reduction in the risk of death (hazard ratio, 0.12; 95% CI, 0.05 to 0.29; P < .001). Timing of undetectable MRD (after induction v intensification) had no impact on patient survival. Attaining undetectable MRD overcame poor prognostic features at diagnosis, including high-risk cytogenetics. By contrast, patients with Revised International Staging System III status and positive MRD had dismal progression-free and overall survivals (median, 14 and 17 months, respectively). Maintenance increased the rate of undetectable MRD by 17%. CONCLUSION The IMWG flow MRD-negative response criterion is highly applicable and sensitive to evaluate treatment efficacy in MM.

Quality of response post-transplantation, notably CR, is significantly associated with EFS and OS prolongation in newly diagnosed patients with MM. There were trends toward similar associations with pretransplantation response status.

Key PointsVRD was effective and well tolerated before ASCT; 33.4% complete response/28.8% minimal residual disease–negative after 6 induction cycles. Responses deepened with VRD throughout induction and over the course of treatment with few discontinuations due to toxicity.

PURPOSE Patients with multiple myeloma (MM) may show patchy bone marrow (BM) infiltration and extramedullary disease. Notwithstanding, quantification of plasma cells (PCs) continues to be performed in BM since the clinical translation of circulating tumor cells (CTCs) remains undefined.PATIENTS AND METHODS CTCs were measured in peripheral blood (PB) of 374 patients with newly diagnosed MM enrolled in the GEM2012MENOS65 and GEM2014MAIN trials. Treatment included bortezomib, lenalidomide, and dexamethasone induction followed by autologous transplant, consolidation, and maintenance. Next-generation flow cytometry was used to evaluate CTCs in PB at diagnosis and measurable residual disease (MRD) in BM throughout treatment.RESULTS CTCs were detected in 92% (344 of 374) of patients with newly diagnosed MM. The correlation between the percentages of CTCs and BM PCs was modest. Increasing logarithmic percentages of CTCs were associated with inferior progression-free survival (PFS). A cutoff of 0.01% CTCs showed an independent prognostic value (hazard ratio: 2.02; 95% CI, 1.3 to 3.1; P 5 .001) in multivariable PFS analysis including the International Staging System, lactate dehydrogenase levels, and cytogenetics. The combination of the four prognostic factors significantly improved risk stratification. Outcomes according to the percentage of CTCs and depth of response to treatment showed that patients with undetectable CTCs had exceptional PFS regardless of complete remission and MRD status. In all other cases with detectable CTCs, only achieving MRD negativity (and not complete remission) demonstrated a statistically significant increase in PFS.CONCLUSION Evaluation of CTCs in PB outperformed quantification of BM PCs. The detection of $ 0.01% CTCs could be a new risk factor in novel staging systems for patients with transplant-eligible MM.

Patients with multiple myeloma (MM) carrying high-risk cytogenetic abnormalities (CA) have inferior outcome despite achieving similar complete response (CR) rates when compared to cases with standard-risk CA. This questions the legitimacy of CR as treatment endpoint for high-risk MM, and represents a biological conundrum regarding the nature of tumor reservoirs persisting after therapy in patients with standard- and high-risk CA. Here, we used next-generation flow (NGF) to evaluate measurable residual disease (MRD) in MM patients with standard- (N=300) vs high-risk CA (N=90) enrolled in the PETHEMA/GEM2012MENOS65 trial (NCT01916252), and to identify mechanisms determining MRD resistance in both patient subgroups (N=40). The 36-month progression-free and overall survival rates were higher than 90% in patients with undetectable MRD, with no significant differences (P≥0.202) between cases having standard- vs high-risk CA. Persistent MRD resulted in median progression-free survival of approximately three and two years in patients with standard- and high-risk CA, respectively (P&lt;0.001). Further use of NGF to isolate MRD followed by whole-exome sequencing of paired diagnostic and MRD tumor cells, revealed greater clonal selection in patients with standard-risk CA, higher genomic instability with acquisition of new mutations in high-risk MM, and no unifying lost or acquired genetic abnormalities driving MRD resistance. Conversely, RNA sequencing of diagnostic and MRD tumor cells uncovered the selection of MRD clones with singular transcriptional programs and ROS-mediated MRD resistance in high-risk MM. Our study supports undetectable MRD as treatment endpoint for MM patients with high-risk CA and proposes characterizing MRD clones to understand and overcome MRD resistance.

The phase III trial GEM05MENOS65 randomized 390 patients 65 years old or younger with newly diagnosed symptomatic multiple myeloma (MM) to receive induction with thalidomide/dexamethasone, bortezomib/thalidomide/dexamethasone and Vincristine, BCNU, melphalan, cyclophosphamide, prednisone/vincristine, BCNU, doxorubicin, dexamethasone bortezomib (VBMCP/VBAD/B) followed by autologous stem cell transplantation (ASCT) with MEL-200. After ASCT, a second randomization was performed to compare thalidomide/bortezomib (TV), thalidomide (T) and alfa-2b interferon (alfa2-IFN). Maintenance treatment consisted of TV (thalidomide 100 mg daily plus one cycle of intravenous bortezomib at 1.3 mg/m on days 1, 4, 8 and 11 every 3 months) versus T (100 mg daily) versus alfa2-IFN (3 MU three times per week) for up to 3 years. A total of 271 patients were randomized (TV: 91; T: 88; alfa2-IFN: 92). The complete response (CR) rate with maintenance was improved by 21% with TV, 11% with T and 17% with alfa2-IFN (P, not significant). After a median follow-up of 58.6 months, the progression-free survival (PFS) was significantly longer with TV compared with T and alfa2-IFN (50.6 vs 40.3 vs 32.5 months, P=0.03). Overall survival was not significantly different among the three arms. Grade 2-3 peripheral neuropathy was observed in 48.8%, 34.4% and 1% of patients treated with TV, T and alfa2-IFN, respectively. In conclusion, bortezomib and thalidomide maintenance resulted in a significantly longer PFS when compared with thalidomide or alfa2-IFN. (no. EUDRA 2005-001110-41).

Praseodymium-doped ZrO 2 photoluminescent (PL) powders have been prepared by a co-precipitation process. Different doping concentrations in the start mixture and annealing temperatures for the precipitated were studied. It is observed that the crystalline structure and the crystallinity of the powders depend on the annealing temperature. For temperatures higher than 750˚C, the material presents the monoclinic phase with an average crystalline grain size of 100 nm. Measurements on photoluminescence show excitation and emission spectra. For an excitation wavelength of 294 nm, all the PL emission spectra show the peaks located at 490

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