Abstract: Introduction: The 2-part phase 3 CASSIOPEIA study (NCT02541383) investigated the combination of DARA with VTd (D-VTd) in transplant-eligible NDMM pts. D-VTd induction/consolidation (ind/cons) led to increased rates of MRD negativity and prolonged progression-free survival (PFS) compared with VTd (Moreau P, et al. Lancet. 2019;394(10192):29-38). In Part 2, DARA as post-autologous stem cell therapy (ASCT) maintenance significantly improved PFS in pts who received VTd ind/cons. Most common (≥2.5%) grade 3/4 adverse events included pneumonia (DARA: 2.5%; observation [OBS]: 1.4%), lymphopenia (3.6%; 1.8%), and hypertension (3.0%; 1.6%; Moreau P, et al. J Clin Oncol. 2021;39(no. 15_suppl):8004). Here, we present results from a detailed analysis of MRD negativity. Methods: Eligible pts were 18-65 years of age, had NDMM and were ASCT eligible. Pts were randomized 1:1 to 4 (28-day) cycles of pre-ASCT induction and 2 (28-day) cycles of post-ASCT consolidation with D-VTd or VTd (bortezomib, 1.3 mg/m 2 SC on Days 1, 4, 8, 11; thalidomide, 100 mg PO daily; dexamethasone, 20-40 mg IV/PO; ± DARA, 16 mg/kg IV weekly (QW) in Cycles 1-2, Q2W in Cycles 3-6). Pts who completed consolidation and achieved partial response or better were re-randomized 1:1 to maintenance DARA at reduced intensity (DARA, 16 mg/kg Q8W) for a maximum of 2 years, or OBS. Samples were collected for MRD analysis at predefined timepoints from all pts regardless of response to ind/cons and in pts with very good partial response or better during maintenance. The primary MRD assessment methodology was multiparametric flow cytometry during ind/cons and next-generation sequencing during maintenance, each at the 10 -5 threshold. MRD negativity is reported here for pts who achieved complete response or better. Results: 1,085 pts were randomized to ind/cons (D-VTd, n=543 or VTd, n=542) and 886 pts were re-randomized for post-ASCT maintenance (DARA, n=442 or OBS, n=444). The rate of MRD negativity was higher with D-VTd than with VTd following induction (9.2% vs 5.4%; odds ratio [OR], 1.79; P= 0.0150) and consolidation (33.7% vs 19.9%; OR, 2.06; P & lt;0.0001). Sustained MRD-negativity was higher in the D-VTd group compared to VTd at 1-year (50.1% vs 30.1%; OR, 2.37; P & lt;0.0001) and at 2 years (35.5% vs 18.8%; OR, 2.41; P & lt;0.0001). Among pts who were at risk of progression 1 or 2 years after induction, those who achieved, respectively, 1- or 2-years sustained MRD negativity from post-induction, showed improved PFS over pts who did not, regardless of treatment (1yr sustained: HR, 0.20; P & lt;0.0001; 2yr sustained: HR, 0.08; P & lt;0.0001). D-VTd pts at risk who achieved 1- or 2-years sustained MRD negativity from post-induction showed improved PFS over D-VTd pts who did not (1yr sustained: HR, 0.20; P & lt;0.0001; 2yr sustained: HR, 0.04; P & lt;0.0001). VTd pts at risk who achieved 1- or 2-years sustained MRD negativity from post-induction showed improved PFS over VTd pts who did not (1yr sustained: HR, 0.40; P=0.0030; 2yr sustained: HR, 0.22; P & lt;0.0046; Figure). During maintenance, the rate of MRD negativity significantly favored DARA over OBS (58.6% vs 47.1%; OR, 1.80; P=0.0001). In pts who received D-VTd ind/cons, the MRD-negativity rates with DARA and OBS were 64.2% and 57.6% respectively (OR, 1.43; P=0.1037). In contrast, pts who had received VTd ind/cons showed significantly higher MRD-negativity rates during DARA maintenance vs OBS (52.6% vs 35.8%; OR, 2.26; P=0.0002). The rates of sustained MRD negativity in the D-VTd group were not significantly different with DARA vs OBS (1yr sustained: 48.5% vs 41.0%; OR, 1.41; P=0.0885; 2yr sustained: 28.8% vs 21.8%; OR, 1.47; P=0.0789). In the VTd group, the 1-year sustained MRD-negativity rate was significantly higher with DARA vs OBS (35.7% vs 21.4%; OR, 2.22; P=0.0006) but no difference was observed in the 2-year sustained MRD rate (11.3% vs 13.0%; OR, 0.83; P=0.5481). Conclusion: In CASSIOPEIA, the highest and most durable rates of MRD negativity were achieved after D-VTd ind/ASCT/cons and DARA maintenance. Reduced intensity (Q8W) DARA maintenance did not significantly improve MRD negativity compared to OBS in patients treated with D-VTd. In patients treated with VTd, DARA maintenance did improve MRD negativity, but this effect was not long lasting. Longer follow-up is required to assess the potential long-term benefits of sustained MRD negativity for DARA vs OBS after D-VTd. Figure 1 Figure 1. Disclosures Sonneveld: Karyopharm: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; SkylineDx: Honoraria, Research Funding; Celgene/BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. Moreau: Amgen: Honoraria; Janssen: Honoraria; Celgene BMS: Honoraria; Sanofi: Honoraria; Abbvie: Honoraria; Oncopeptides: Honoraria. van der Velden: Janssen: Other: Service Level Agreement; BD Biosciences: Other: Service Level Agreement; Navigate: Other: Service Level Agreement; Agilent: Research Funding; EuroFlow: Other: Service Level Agreement, Patents & Royalties: for network, not personally. Hulin: abbvie: Honoraria; Sanofi: Honoraria; Celgene/BMS: Honoraria; Janssen: Honoraria; Takeda: Honoraria. Arnulf: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees. Mohty: Sanofi: Honoraria, Research Funding; Pfizer: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Jazz: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Celgene: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Astellas: Honoraria; Amgen: Honoraria; Adaptive Biotechnologies: Honoraria. Karlin: Janssen: Honoraria, Other: member of advisory board, travel support; Abbvie: Honoraria; Amgen: Honoraria, Other: travel support and advisory board ; Sanofi: Honoraria; Takeda: Honoraria, Other: member of advisory board; Celgene-BMS: Honoraria, Other: member of advisory board; GSK: Honoraria, Other: member of advisory board; oncopeptide: Honoraria. Macro: Sanofi: Honoraria; GSK: Honoraria; Takeda: Honoraria, Other: Travel accomodation, Research Funding; Janssen: Honoraria, Other: Travel accomodation, Research Funding; Celgen/BMS: Honoraria. Perrot: GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria; Sanofi: Honoraria, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Levin: Roche, Janssen, Abbvie: Other: Travel Expenses, Ad-Board. Delforge: Amgen, Celgene, Janssen, Sanofi: Honoraria, Research Funding. Zweegman: Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Van De Donk: BMS/Celgene: Consultancy, Honoraria; Janssen: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Cellectis: Research Funding; Takeda: Consultancy; Roche: Consultancy; Novartis /bayer/servier: Consultancy. Krevvata: Janssen: Current Employment. Rigat: Janssen: Current Employment, Current equity holder in publicly-traded company. Yang: Janssen: Current Employment. Vanquickelberghe: Janssen: Current Employment. de Boer: Janssen: Current Employment. Kampfenkel: Janssen: Current Employment. Vermeulen: Janssen: Current Employment, Current equity holder in publicly-traded company. Broyl: Celgene: Honoraria; Janssen Pharmaceuticals: Honoraria; Sanofi: Honoraria; Bristol-Meyer Squibb: Honoraria; Amgen: Honoraria. OffLabel Disclosure: The specific regimen combination is not yet approved in the maintenance setting.

Abstract: Pom-Dex is active and well tolerated in adverse cytogenetic patients with early RRMM, particularly in those with del(17p). Pom-Dex prolonged OS in adverse cytogenetic patients with early RRMM.

Abstract: Background. Lenalidomide plus Dexamethasone is approved at first relapse and beyond in Europe, and has transformed the prognosis of Myeloma in the relapse setting. Lenalidomide plus Dexamethasone is approved until progression, that could last for years, the median PFS in phase 3 studies being at 17 months at first relapse, but many patients eventually reach 5 to 7 years these days. Dexamethasone was showed to enhance lenalidomide-antitumor efficacy and to prolong the progression-free survival. However, long term exposure to dexamethasone is also known to be associated to an array of adverse events. Finally, IMiDs are known to act through immunomodulation a class-based mechanism. It is possible that lenalidomide might show efficacy on the long run without need to dexamethasone use, at least for some patients with myeloma. We sought to study the impact of dexamethasone discontinuation beyond six months and one year, and compare this analysis to patients treated on lenalidomide plus dexamethasone. Method. We have recruited 200 relapse refractory myeloma patients for this study from various IFM centers. The patients were to be older than 18 years old and treated with lenalidomide plus dexamethasone. We sought to study the impact of the various ways to use dexamethasone in the real life, and therefore dexamethasone was given according to physician decision. We identified groups according to dexamethasone given high dose (4 days 160mg total in a raw), given once a week at 40mg (considered standard dose), given at lower dose (considered low dose) and a group that had dexamethasone discontinued. Patients were not allowed to have other type of combination but lenalidomide plus dexamethasone. Result. A total of 200 patients were analyzed, median age of 57 years old (range 25-76). 17,5% patients had renal dysfunction at diagnosis. ISS was 2 for 20% and 3 for 20%. Approximately 10% had either del17p or t(4;14). 7% of patients had previous history of venous thrombosis before the treatment. Response rate, survival, including TTP, PFS, EFS and overall survival will be presented at ASH with updated follow-up. Conclusion. This study aims to investigate the importance of long run and exposure to Dexamethasone in the Lenalidomide-Dexamethasone regimen. We also wished to assess the optimal dose of dexamethasone that could be given to patients with prolonged exposure to lenalidomide plus dexamethasone. Disclosures Arnulf: Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. MACRO:millenium: Membership on an entity's Board of Directors or advisory committees; jansen: Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees. Facon:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millenium: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Onyx: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Pierre Fabre: Membership on an entity's Board of Directors or advisory committees. Leleu:LeoPharma: Honoraria; Pierre Fabre: Honoraria; BMS: Honoraria; Novartis: Honoraria; TEVA: Honoraria; Amgen: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Chugai: Honoraria.

Abstract: High dose therapy (HDT) supported with autologous stem cell transplantation has been introduced in the management of aggressive myeloma. However, after single or tandem transplantation, almost all patients ultimately relapse. New strategies are required to control any residual disease after HDT. The Intergroupe Francophone du Myelome (IFM) initiated a trial designed to evaluate the impact of maintenance treatment with Thalidomide on the duration of response after HDT. From April 2000 to October 2003, 1004 myeloma patients at diagnosis under the age of 65 years were enrolled in the IFM 99 protocol. 780 of them, without or with only one adverse prognostic factor (beta-2 microglobuline 〉 3 mg/l or deletion of chromosome 13), were enrolled in the IFM 99 02 protocol. They were to receive the following treatment: 1) 3–4 cycles of the VAD regimen; 2) a first autologous transplant prepared with Melphalan 140 mg/m2; 3) a second autologous transplant prepared with Melphalan 200 mg/m2. Patients without progressive disease 2 months after the second transplant were randomized to receive: no maintenance treatment (arm A), maintenance treatment with Pamidronate (arm B) or maintenance treatment with Thalidomide and Pamidronate (arm C). As of May 2004, 580 patients (74%) have been randomized: 195 in arm A, 190 in arm B and 195 in arm C. Clinical characteristics of each group were similar. The median follow-up from diagnosis was 26 months (range: 6–50) Thalidomide was found to improve the Progression-free survival (PFS; p 〈 0.007) and the Event-free-survival (EFS; p 〈 0.01). Indeed, the 40-months post-diagnosis probability of PFS was 70% (95% CI= 42–80) in the Thalidomide arm versus 53% (95% CI= 37–65) in arm A, and 52% (95% CI= 36–68) in arm B. Most patients (60%) enrolled in arm A and B received Thalidomide at time of relapse. The overall survival was similar in the 3 treatment groups. Among the 580 randomized patients, 2 factors were found to be associated with a longer EFS : low beta-2-microglobulin at diagnosis (p 〈 0.01) and treatment arm (p 〈 0.01). Deletion of chromosome 13 (FISH analysis) was not related to EFS. In conclusion, the first analysis of the IFM9902 trial strongly suggests that Thalidomide is an effective maintenance treatment after high dose therapy for myeloma. The next analysis (November 2004) will be presented during the meeting.

Abstract: Background. Protein electrophoresis and immunofixation in the serum (SPEP - SIF) and urine (UPEP – UIF) have been routinely used for decades for characterizing and quantifying the M protein in Multiple Myeloma (MM). However, these techniques are notoriously tarnished with inaccuracy, despite improvements in recent years. The most important breakthrough in the field in recent years was the discovery of the Serum Free Light Chain Assay (sFLC), a routine quantitative and automated assay that measures kappa and lambda sFLC, however this was added to / rather than replaced traditional tests in the diagnostic armamentarium of MM. Recently, a new test quantifying paired clonal and non-clonal immunoglobulins (heavy/light chains HLC i.e. IgGκ/IgGλ) in serum was developed. Here we aim to assess the new HLC assays as tools to replace SPEP / IFE during MM patient monitoring Materials and methods. 110 Myeloma treated with pomalidomide and dexamethasone in two IFM studies (IFM 2009-02 in end stage RRMM and IFM 2010-02 in del17p and t(4;14) RRMM ) were included. The criteria for selection were that patients had measurable intact immunoglobulin myeloma according to IMWG criteria (M spike ≥10g/L), using serum and/or urine protein electrophoresis, with exclusion of patients solely measurable on UPEP and sFLC. All sera were collected centrally before initiation of treatment and sequentially every cycle until progression. Hevylite® (HLC) was measured in the biology laboratory of CHRU of Lille, France and results compared to traditional measurements. Along with SPEP, SIF, UPEP, UIF, and sFLC, we have also measured IgA HLC (IgA k and IgA l) and IgG (IgG k and IgG l) and the corresponding difference (clonal - non clonal) and ratio (clonal/non clonal). Results. Overall, 80% were measurable on SPEP with a median serum level of 31g/L (CI95% 19;42), and the remaining also had UPEP measurable myeloma with a median serum level of 0.66g/24h (CI95% 0.4;1.3). The median involved HLC level was 29.7g/L (CI95% 17.6;43.3), the median involved HLC difference clonal - non clonal was 28.8g/L (CI95% 15.6;42.7), the median involved HLC ratio clonal / non clonal was 51.9 (CI95% 18.3;203.9). Since all patients had a measurable intact immunoglobulin-based disease according to IMWG criteria, we have first confirmed that patients had also a measurable disease by HLC. All patients had an abnormal HLC ratio but one patient, who was measurable with an abnormal IgG L involved HLC test. Approximately 32% of patients had an M-spike below 20g/L and/or an electrophoretic migration in beta region meaning in the range of lack of sensitivity of the techniques used, all of whom had a measurable disease using involved HLC level and/or a measurable HLC ratio. We then sought to study the response rate according to HLC, and for that purpose we applied the exact same criteria as to the sFLC-based response criteria recommended by IMWG (e.g. normal ratio is CR and if abnormal ratio, then 〈 50% reduction in the difference clonal – non clonal is SD, ≥50% - 〈 90% reduction is PR, 〉 90% reduction is VGPR). The ORR in the 2 studies as a whole using traditional measurements was 32%, including 29% PR rate, absence of CR, and 44% had SD (SD and MR). Using HLC, the ORR was 36%, including 26% PR rate and 4.0% CR, and 33% had SD (r² 0.823, p 〈 .0001). Interestingly, 7 patients classified as SD with regular techniques, were progressive disease using HLC, anticipating a progression of Myeloma. Similarly, 5 patients classified as SD with regular techniques, were ≥PR using HLC. Conclusion. HLC is a new routine quantitative and automated assay that measures Immunoglobulin heavy chain/light chain pairs immunoassay, allowing diagnosis, prognosis and precise assessment of the response to treatment and disease progression in all cases with Myeloma treated with pomalidomide and dexamethasone in 2 different clinical trials. Our study indicates that HLC may be used as a replacement for traditional tests and may offer greater sensitivity in some instances. Furthermore, obviating the need for interpretation may standardize assessments of patients during trials. Future studies might confirm this data analysis in larger trials. Disclosures Karlin: Janssen: Honoraria; celgene: Consultancy, Honoraria; Sandoz: Consultancy. Hulin:Celgene: Honoraria. Stoppa:Celgene Jansen: Honoraria. Marit:Celgene, Janssen: Congress expenses Other.

Abstract: Multiple myeloma (MM) is rare in young patients, especially before age 40 years at diagnosis, representing & lt;2% of all patients with MM. Little is known about the disease characteristics and prognosis of these patients. In this study, we examined 214 patients diagnosed with MM at age ≤40 years over 15 years, in the era of modern treatments. Among them, 189 patients had symptomatic MM. Disease characteristics were similar to older patients: 35% had anemia, 17% had renal impairment, and 13% had hypercalcemia. The staging was ISS-1 in 52.4%, ISS-2 in 27.5%, and ISS-3 in 20.1%. Overall, 18% of patients had high-risk cytogenetics [del 17p and/or t(4;14)]. Ninety percent of patients received intensive chemotherapy followed by autologous stem cell transplant, and 25% of patients had allogeneic stem cell transplant predominantly at time of relapse. The median follow-up was 76 months, the estimated median overall survival was 14.5 years, and the median progression free-survival was 41 months. In multivariate analysis, bone lesions (hazard ratio [HR] , 3.95; P = .01), high ISS score (HR, 2.14; P = .03), and high-risk cytogenetics (HR, 4.54; P & lt; .0001) were significant risk factors for poor outcomes. Among predefined time-dependent covariables, onset of progression (HR, 13.2; P & lt; .0001) significantly shortened overall survival. At 5 years, relative survival compared with same age- and sex-matched individuals was 83.5%, and estimated standardized mortality ratio was 69.9 (95% confidence interval, 52.7-91.1), confirming that MM dramatically shortens the survival of young patients despite an extended survival after diagnosis.

Abstract: Background Frontline ASCT is the standard of care for patients with symptomatic NDMM less than 66 years of age. 3-drug combinations are the standard induction regimens prior to ASCT. Consolidation therapy after ASCT is aimed at improving disease control through deepening responses. Maintenance therapy is administered with the objective of prolonging response duration. The all-oral combination of weekly ixazomib plus lenalidomide and dexamethasone (IRd) was recently evaluated in NDMM, was generally well tolerated and appeared active (Kumar et al, Lancet Oncology 2014;13:1503-12). We analyzed the safety and efficacy of the triplet IRd combination prior to, and as consolidation after ASCT followed by ixazomib maintenance in the initial management of MM in patients younger than 66 years in a phase 2 study (NCT01936532). Methods Patients received 3 cycles of induction therapy with Ixazomib 4 mg on days 1, 8 and 15 plus Lenalidomide 25 mg on days 1 through 21 and dexamethasone 40 mg on days 1-8-15 and 22 of a 28-day cycle followed by Melphalan 200 mg/m2 and ASCT. Two months after ASCT, patients received an early consolidation with 2 cycles of IRd identical to induction therapy followed by a late consolidation phase with 6 additional cycles of IR without dexamethasone. One month after the last consolidation cycle, patients received maintenance therapy with Ixazomib single-agent 4 mg on days 1, 8 and 15 of a 28-day cycle, during 12 months. The primary end-point was the complete response (CR) rate after extended consolidation therapy. The secondary objectives were to evaluate the overall response rate (ORR) after induction, after ASCT, after consolidation and after maintenance, to evaluate the safety of induction therapy, the feasibility of extended consolidation, the feasibility of maintenance with Ixazomib, the duration of response, progression-free and overall survival. Responses (central lab, Dr Dejoie, Nantes) were assessed according to the IMWG criteria. Toxicity was evaluated according to NCI CTCAE, version 4.03. Results From 11/2014 to 04/2015, 42 patients (21 males, 21 females, median age 60 years (43-65)) with NDMM were enrolled in 10 centers from IFM. ISS was 1 in 12 cases (29%), 2 in 23 cases (54%) and 3 in 7 patients (17%), respectively. Adverse cytogenetics (17p deletion, and/or t(4;14); central lab, Dr Avet-Loiseau) was observed in 8 patients (19%). Induction with IRd was very well tolerated. Out of 120 cycles administered for 42 patients, only 13 cases of non-hematologic grade 3-4 toxicities were reported: infections (8 cases), abdominal pain (2), atrial fibrillation (1), thrombosis (1), and DRESS syndrome leading to study withdrawal (1). No renal or liver toxicity was reported. No cardiac failure and no ischemic heart disease was documented. No grade 3-4 peripheral neuropathy was described. Response rates increased at each step of the strategy. Following 3 induction cycles of IRd, the ORR was 81%, including 12% CR plus 24% very good partial response (VGPR), and 2 patients progressed (5%). Following ASCT, the VGPR rate or better was 78% including 38% CR. Following consolidation (early 2 cycles + extended 6 cycles), the VGPR rate or better was 80% including 44% CR. The feasibility of the consolidation phase with IRd (2 cycles) and IR (6 cycles) was excellent: 34 / 37 patients who started consolidation completed the 8 planned cycles (3 discontinuations: 2 patient decisions, 1 progression to plasma cell leukemia). 34/42 patients (81%) were able to receive maintenance therapy with Ixazomib following extended consolidation. Results of maintenance and of minimal residual disease evaluation will be presented during the meeting. At the cut-off date of June 30 2016, with a median follow-up of 16 months, 3 patients / 42 (7%) have progressed, 2 during induction and 1 during consolidation, and 2 (5%) died from progressive disease. Conclusions The all-oral triplet combination IRd administered as induction prior to, and as consolidation following ASCT is safe, convenient, and effective, leading to 80% VGPR and 44% CR before maintenance. Final results on response rates following maintenance and MRD data will be presented during the meeting. Updated results on PFS and OS will also be presented. Disclosures Moreau: takeda: Honoraria; celgene: Honoraria; janssen: Honoraria; BMS: Honoraria; Novartis: Honoraria; Amgen: Honoraria. Hulin:celgene: Honoraria; janssen: Honoraria; takeda: Honoraria. Facon:Millenium/Takeda: Consultancy; Celgene: Consultancy, Speakers Bureau; Novartis: Consultancy; Amgen: Consultancy, Speakers Bureau; Bristol: Consultancy; Janssen: Consultancy, Speakers Bureau; Karyopharm: Consultancy. Leleu:TEVA: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; LeoPharma: Honoraria; Pierre Fabre: Honoraria; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Janssen: Honoraria. Roussel:celgene: Honoraria; takeda: Honoraria; janssen: Honoraria. avet-Loiseau:takeda: Honoraria; janssen: Honoraria; celgene: Honoraria; amgen: Honoraria. Attal:sanofi: Consultancy; amgen: Consultancy, Research Funding; janssen: Consultancy, Research Funding; celgene: Consultancy, Research Funding.

Abstract: Serum FLC analysis is a more sensitive indicator of disease than urinalysis. Improved sensitivity of serum over urine measurements during monitoring translates into valuable prognostic information.