ALBERT

Description: Introduction: Disease control at five years would be a desirable endpoint for elderly multiple myeloma (MM) patients; however, the percentage of cases reaching this objective as well as the biomarkers to predict it, are not well defined. Objective and design: In order to gain further insight about long-term disease control (〉5 years progression-free) in elderly MM we have analyzed a homogeneous population of 435 newly-diagnosed transplant-ineligible (TNE) patients enrolled in two consecutive Spanish clinical trials (GEM2005MAS65, GEM2010MAS65), that included both proteasome inhibitors and immunomodulatory drugs. Results: Amongst the 435 patients included in this post-hoc study, only 18.8% remained alive and progression-free after five years of initiating treatment. Noteworthy, in these patients the overall survival (OS) rate at 10-years was 69.4%, as compared to 11.4% for those patients progressing during the first five years (p〈 0.001). Baseline variables significantly associated with long-term progression free survival in the univariate analysis were younger age, ISS 1, R-ISS 1, hemoglobin ≥ 12g/dl, normal LDH, and standard-risk cytogenetic abnormalities and the presence of a monoclonal gammopathy of unknown significance (MGUS)-like immunophenotypic profile in the bone marrow. Complete responses (CR) and minimal residual disease (MRD) negativity were also associated with long-term progression free survival. In the multivariate analysis, an hemoglobin level ≥12g/dl (OR 2.61; 95% CI 1.47 - 4.61, p=0.001) and a MGUS-like immunophenotypic profile in the bone marrow (OR 3.33; 95% CI 1.30 - 8.54, p=0.002) were the two baseline variables significantly and independently associated with a higher probability of long-term disease-free survival. When the depth of response (including MRD) was included in the logistic regression model, Hb level ≥12g/dl (OR 2.18; p=0.010) and the MGUS-like signature (OR 4.99, p

Description: Background: MM and AL are the two most common malignant monoclonal gammopathies. Both diseases result from the accumulation of clonal PCs, but their clinical behavior is significantly different suggesting fundamental differences in disease biology. Previous attempts to identify genetic hallmarks that could explain such differences have been unsuccessful. Furthermore, it is unknown if MM and AL arise from the same or different normal PC counterparts. Aim: To define a transcriptional atlas of the normal PC development in peripheral blood (PB) and bone marrow (BM) for comparison with the transcriptional programs of clonal PCs in MM and AL. Methods: A total of 93 subjects were studied. In 7 healthy adults (HA), PB PCs were phenotypically sorted according to heavy-chain isotypes (IgG, IgA and IgM). In addition, 5 different BM PCs subsets were isolated based on the differential expression of CD19, CD39, CD81 and CD56, due to their ascribed role in dissecting unique BM PC differentiation states. Clonal PCs from patients with MM (n=38) and AL (n=41) were isolated by FACS according to patient-specific aberrant phenotypes. Due to small numbers of PCs sorted from each subset in HA and clonal PCs in AL patients, we used an RNAseq method optimized for limited cell numbers. Differential expression across all pairwise comparisons between groups was analyzed with Deseq2 R package followed by k-means clustering of genes in R. Single-cell RNAseq (scRNAseq, 10xGenomics) was performed in a total of 35,910 PCs from 3 HA, 2 MM and 2 AL. We used Seurat R package to remove batch effect followed by canonical correlation to perform an integrated analysis of all single PCs from HA, MM and AL subjects. Results: Principal component analysis of RNAseq data unveiled two major clusters of normal PCs: those in PB and those in BM (with some transcriptional diversity between CD19+ and CD19- PCs), whereas the CD19+CD39+CD81+CD56- BM subset co-localized with PB and CD39- BM PCs (Panel A). Clonal PCs from MM and AL patients clustered together, and both displayed some transcriptional variance related to the spatial location of normal PCs (i.e. PB or BM). In total, 2174 genes were found significantly deregulated after cross-comparing the 10 PC groups (adj.p-value1) and semi-supervised k-means clustering unveiled 8 transcriptional modules (Panel B). Namely, the transition from PB into BM PCs was characterized by genes related to proliferation (clusters 1 & 2), whereas CD39+ and CD39- BM PC subsets differed on the expression of genes associated with proliferation, homing, and metabolism (1, 2, 4 & 6). Thus, CD19+CD39+CD81+CD56- BM PCs emerged as a novel subset that bridges new-born PB with long-lived (CD39-) BM PCs. Interestingly, clonal PCs from MM and AL shared transcriptional programs related to quiescence (5 & 6) with long-lived BM PCs; however, skewing of polyclonal immunoglobulin gene expression (3) and active gene transcription (8) emerged as hallmarks of the neoplastic transformation from normal, long-lived PCs into clonal PCs. That notwithstanding, the later displayed expression levels of the proliferation and homing transcriptional modules (1 & 4) similar to new-born PB and CD39+ BM PCs. Of note, a small transcriptional cluster of genes related to ribosome biogenesis (7) was significantly more expressed in MM than AL. These findings led us to integrate scRNAseq profiles of normal and clonal BM PCs from MM and AL patients, to define PC clusters based on their transcriptional program rather than their normal vs malignant status (Panel C). This strategy unveiled 11 different PC clusters with unequal distribution between groups. Thus, more than half of clonal PCs in MM and AL were assigned to a cluster that is also predominant in normal PCs (1). By contrast, other clusters with a transcriptional program similar to that of new-born PCs (2 & 5) became rarer in MM and AL. Furthermore, a cluster of PCs with an immature-like phenotype (6) was detectable in MM but almost absent in AL. Conclusions: This is the first integrated analysis of the transcriptional programs of normal PC subsets and clonal PCs in MM and AL, both at the bulk and single-cell levels. Our results unveil shared and exclusive transcriptional states in normal and clonal PCs, together with unique differences between clonal PCs in MM and AL. Thus, we provide here a fundamental resource to understand normal PC development and the cellular origin of both malignant monoclonal gammopathies. Figure Figure. Disclosures Puig: Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Ocio:Pharmamar: Consultancy; AbbVie: Consultancy; Janssen: Consultancy, Honoraria; Seattle Genetics: Consultancy; BMS: Consultancy; Takeda: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Sanofi: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Mundipharma: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Array Pharmaceuticals: Research Funding. Oriol:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Martinez Lopez:Bristol Myers Squibb: Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau. Mateos:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees. Lahuerta:Takeda: 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; Celgene: 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. San-Miguel:Sanofi: Consultancy; Takeda: Consultancy; Novartis: Consultancy; MSD: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Brystol-Myers Squibb: Consultancy; Amgen: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees.

Description: Introduction: SMM is an asymptomatic and heterogeneous plasma cell disorder. Both Spanish Myeloma and ECOG Groups have demonstrated that pts at high risk of progression to active MM benefit from early treatment with R-based regimens. Our next step was to design this phase 2, single arm trial, focusing on the same population, but with the potential goal of cure, defined by sustained minimal residual disease negativity (MRD-ve) at 5 years after HDT-ASCT. Patients and methods: Ninety SMM pts at high-risk of progression (〉50% at 2 yrs), younger than 70 years and transplant candidates were included. The high risk was defined by the presence of both ≥PC 10% and MC ≥3g/dL (Mayo) or ifonly one criterion was present, pts must 〉95%of aberrant PCs within the total PCsBM compartment by immunophenotyping plus immunoparesis (Spanish). Induction therapy consisted on six 4-weeks cycles of KRd in which K was given at dose of 36 mg/m2 twice per week plus R at dose of 25 mg on days 1-21 and dexamethasone at dose of 40 mg weekly. Melphalan at dose of 200 mg/m2 followed by ASCT was given as intensification therapy followed by two KRd consolidation cycles and maintenance with R at dose of 10 mg plus dexamethasone at dose of 20 mg weekly for up to 2 yrs. The primary end-point was to evaluate the MRD-ve rate by next generation flow (NGF) after induction and ASCT and our aim was to increase the MRD -ve rate from 34% (reported in NDMM pts after VTD and ASCT) to at least 50%. Results: Between June 2015 and June 2017, 90 high-risk SMM pts were recruited. Twenty-eight pts (32%) shared at least one of the new biomarkers predicting imminent risk of progression to MM. On February 4th, 2019, 71 pts were already receiving maintenance treatment; 7 pts had finalized the treatment and there were 11 early discontinuations (4 biochemical relapses during maintenance, 2 Informed Consent refusal, 3 adverse events and two deaths). After a median follow-up of 32 months (8-128), 93% of pts remain alive and free of progression and 98% of them alive. In the intent-to-treat pts' population, after induction, the ≥CR rate was 41% and increased to 59% after HDT-ASCT and to 70% after consolidation. In the same analysis, MRD-ve rate was observed in 30% of pts after induction, 52% after HDT-ASCT and 57% after consolidation. If we focus on the 83 pts who completed induction, HDT-ASCT and consolidation, the ≥CR/undetectable MRD rates were 42%/31%, 64%/56% and 76%/63% after each step, respectively. Concerning toxicity, during induction, G3-4 neutropenia and thrombocytopenia were reported in 5 (6%) and 10 pts (11%), respectively. G3-4 infections were reported in 16 pts (18%), followed by skin rash in 8 pts (9%). One patient reported G1 atrial fibrillation and another cardiac failure secondary to respiratory infection. Three pts reported hypertension (G2 in two and G3 in one). In all but two of the pts, PBSC collection was successful with a median of 4.10 x 106/Kg CD34 cells collected. All pts engrafted but one patient developed late graft failure. During consolidation, 2 pts developed G3-4 neutropenia, 3 pts G3-4 infections and 1 pt skin rash. Maintenance treatment is ongoing and one patient had to discontinue due to a second primary malignancy (lung cancer) and other due to sustained thrombocytopenia. Conclusions: The primary end point of the trial was met, and 56% of the pts who completed induction and HDT-ASCT achieved MRD-ve. This "curative strategy for high risk SMM" continues being encouraging and 93% of pts remain alive and progression-free at 30 months and 98% of pts alive. Disclosures Mateos: GSK: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria; Takeda: 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; Pharmamar: Membership on an entity's Board of Directors or advisory committees; EDO: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Rodriguez Otero:Celgene Corporation: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria; Takeda: Consultancy; BMS: Honoraria; Kite Pharma: Consultancy. Oriol:Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy; Takeda: Consultancy, Speakers Bureau; Celgene Corporation: Consultancy, Speakers Bureau. Paiva:Amgen, Bristol-Myers Squibb, Celgene, Janssen, Merck, Novartis, Roche, and Sanofi; unrestricted grants from Celgene, EngMab, Sanofi, and Takeda; and consultancy for Celgene, Janssen, and Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau. Rosinol Dachs:Janssen, Celgene, Amgen and Takeda: Honoraria. Amor:Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Puig:Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria; The Binding Site: Honoraria. De La Rubia:AMGEN: Consultancy; Celgene Corporation: Consultancy; Takeda: Consultancy; Janssen: Consultancy; AbbVie: Consultancy. De Arriba:Takeda: Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Lopez Jimenez:GILEAD SCIENCES: Honoraria, Other: Education funding. Ocio:Celgene: Consultancy, Honoraria, Research Funding; BMS: Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Mundipharma: Research Funding; AbbVie: Consultancy; Sanofi: Research Funding; Seattle Genetics: Consultancy; Array Pharmaceuticals: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Pharmamar: Consultancy. Bladé:Jansen, Celgene, Takeda, Amgen and Oncopeptides: Honoraria. San-Miguel:Amgen, Bristol-Myers Squibb, Celgene, Janssen, MSD, Novartis, Roche, Sanofi, and Takeda: Consultancy, Honoraria.

Description: * A.R. and M.L. have contributed equally. INTRODUCTION: Myelodysplastic syndrome (MDS) is a clonal disease that arises from the expansion of mutated hematopoietic stem cells. Oxidative stress could play an important role in the pathology of MDS since a correlation has been observed between high ROS levels and decreased survival in MDS patients. In addition, the oxidation of proteins leads to their aggregation, change and conformational changes that can cause the loss of their functions. Due to alteration of the proteome has been described in patients with MDS, in this study we considered the discovery of protein carbonylation to analyze its oxidation pattern. In addition, as the oxidative stress signaling pathways can regulate the cell cycle through p53, we analyzed p21, an important p53 target during the stress response. Finally, the possible benefit of treatment with Deferasirox as antioxidant therapy was studied. METHODS: Carbonylation pattern was analyzed in the different cell lines (n = 14, 6 MDS, 4 reactive controls and 4 MDS + DFX) by immunohistochemistry by derivatization with 2,4-dinitrophenylhydrazine (DNPH) and detection with anti-DNP antibodies. The degree of protein carbonylation was studied, also by derivatization and detection with anti-DNP, in primary cells of erythroblasts expanded for 11 days, by one-dimensional and two-dimensional electrophoresis (n = 16; 7 MDS, 6 controls, 2 reactive controls and 1 MDS + DFX). Expression levels of p21 were analyzed by qRT-PCR (n=19; 8C, 8 MDS, 3DFX). RESULTS: Immunohistochemical assays revealed a higher level of carbonylation in patients with MDS (Fig. 1a). Interestingly, Deferasirox-treated MDS patients had lower levels than non-treated patients (Fig. 1b). In addition, to evaluate the carbonylation in the erythroid precursors, the pattern of carbonylated proteins in the expanded erythroblasts was analyzed. Again, a higher level of MDS was observed compared to the control group, which was reversed after treatment with Deferasirox. Two-dimensional electrophoresis revealed that differences in carbonylation are due to a limited number of proteins or aggregates, rather than to a large spectrum of proteins. Finally, an increased p21 expression was observed in patients with myelodysplasia and, surprisingly, this effect was reversed with Deferasirox treatment. CONCLUSION: Patients with MDS showed a differential protein pattern respect to control patients, both in the myeloid and erythroid series. The increase in oxidative stress in myelodysplastic patients seems to activate signaling pathways involving p21. Treatment with Deferasirox can reverse the level of oxidation and the increase of p21 in patients with MDS. Disclosures Martinez Lopez: Celgene: Research Funding, Speakers Bureau; Jansen: Research Funding, Speakers Bureau; BMS: Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau.

Description: Background: The international criteria for definition CR, requires, among other parametres, a negative IF both in serum and urine; however, urine IF is not always performed. In the belief that this lack could bias the comparison between trials, the First Trial Independent Response Adjudication Committee (FTIRAC) recommended that patients who met all CR criteria except the availability of a urine IF should be classified as VGPR (Blood 2014; 124 [abstract 3460]) but this criteria is not always applied which may translate into differences in CR rates between trials. However, it is unknown (1) if this conversion has a real clinical basis, (2) if urine IF results alter the clinical meaning of CR, or (3) on the contrary, if patients in CR with and those without a documented negative urine IF have a similar prognosis, in which case this rule would underestimate the CR rates, increasing the biases and magnifying the problem that was intended to improve. Aim: To determine the value of urine negative IF in the definition of CR. Methods: 459 patients were enrolled into the GEM2012MENOS65phase3 trial and treated with 6 induction cycles of bortezomib, lenalidomide, and dexamethasone, HDT/ASCT and 2 consolidation courses. Evaluable patients were enrolled in a maintenance trail (NCT02406144). Excluding 6 patients who discontinued early, 453 were evaluable. At diagnosis, the M-component was detected exclusively in serum in 173 of these patients and in serum and urine in 212 patients; 68 patients had pure Bence-Jones M-protein (BJMM). The protein studies were performed in each cycle. At the time of negative IF, bone marrow aspirates were analysed for count of PCs and monitoring minimal residual disease (MRD) following EuroFlow SOPs (median limit of detection of 3x10-6).The response classifications were made according to the IMWG criteria, but we applied the FTIRAC criteria, and, patients with

Description: Introduction: Patients with PNH often need surgery due to disease-related complications. However, surgery, anesthesia, and possible surgical complications, including inflammation and acidosis, can trigger complement activation, making surgery an important risk factor for hemolysis (Ando K, et al. Ann Hematol 2012;91:1987-8; van Bijnen ST, et al. Eur J Haematol 2011;87:376-8). Here we report data on the clinical management and treatment results of patients with PNH undergoing surgery. Patients and Methods: We collected data on 14 surgical interventions of 11 patients (8 males; age, 25-76 years). All patients had a high prevalence of PNH clone cells (55-99% in PMN) and were receiving eculizumab (ECU). Types of surgery were: 6 laparoscopic cholecystectomies, a transjugular intrahepatic portosystemic shunt, a distal splenorenal shunt, a laparoscopic Achilles allograft ligamentoplasty, a gastrectomy, an emergency appendectomy, and 3 urologic interventions. Ten patients received ECU 900 mg, while one (patient E, surgery 6) received 1200 mg since he had developed hemolysis at a previous surgical intervention (surgery 5). In two cases (patient G, surgery 8; patient H surgery 11), an additional dose of ECU was administered before surgery. Patient H (surgery 11) had developed hemolysis at previous surgical interventions (surgeries 9 and 10). In most cases, either the date of the ECU dose was taken into account when scheduling surgery or the ECU dose was moved forward to coincide with the date of surgery. The time between the last ECU dose and surgery was normally one day (range, 1-8). Results: In nine cases, transfusions were required due to hemorrhagic complications. Patient I (surgery 12) had a thrombotic event leading to acute myocardial infarction one week after surgery. Increased hemolysis was observed (increased LDH and/or presence of hemoglobinuria) in five cases (patients E, H, I and K; surgeries 5, 9, 10, 12 and 14) during the week following surgery. Two of these patients (patients E and H) later underwent additional surgery (surgery 6, and surgeries 10 and 11, respectively). The pre-surgical ECU dose was increased in surgery 6 (patient E) and an extra dose was administrated in surgery 11 (patient H) and no hemolysis was observed. (See Table.) Discussion: Our findings lead us to recommend that the date of surgery and/or the date of the ECU dose should be adapted to allow as short a time as possible between the last dose of ECU and surgery. Preferably, ECU should be administered just before surgery in order to avoid complications. The normal ECU dose could be increased or an extra dose be administered in order to minimize the risk of hemolysis in high-risk patients or in those with a previous history of surgery-related hemolysis. Table Table. Disclosures No relevant conflicts of interest to declare.

Description: Continuous treatment with lenalidomide (R) and dexamethasone (d) is a standard of care for multiple myeloma (MM) patients (pts) not candidates for autologous stem cell transplantation (ASCT). As previously reported, the addition of Clarithromycin (C) to Rd has proven to be safe and effective, and case-control analyses suggested a significant additive value with the combination. C optimizes the therapeutic effect of glucocorticoids by increasing the area under the curve, has immunomodulatory effects and may have direct antineoplastic properties. However, there are not randomized phase III trials confirming these results. GEM-Claridex in an open, randomized, phase III trial for untreated newly diagnosed MM pts ineligible for ASCT. Enrolled pts were randomly assigned 1:1 to receive 28-day cycles of R (25mg po qd days 1-21), d (40mg po [20mg in pts 〉75 years], days 1, 8, 15 and 22) plus or minus C (500mg po bid) until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall response rate (ORR), overall survival (OS) and minimal residual disease (MRD) negativity rate and safety. MRD was evaluated in 99 pts using Euroflow NGF (limit of detection, 2x10-6). As expected, most pts in CR were tested for MRD whereas the majority of pts with missing MRD data achieved VGPR or less and were thus considered as MRD-positive for intent to treat analyses. Two hundred and eighty-eight pts were included (144 to C-Rd and 144 to Rd). Median age was 76 (range: 65-93), 36.8% of pts had ISS 3 and 15.6% presented with high-risk cytogenetic abnormalities. Key baseline characteristics were well balanced between the two arms. The addition of C to Rd resulted in deeper responses with a ≥ complete response (CR) rate of 20.1% in the C-Rd arm compared to 11.2% in the Rd arm (p = 0.037). Also, the ≥ very good partial response (VGPR) rate was 52.8% in the C-Rd arm as compared to the 37.1% in the Rd arm (p = 0.007). MRD analysis was performed at suspected CR and yearly afterwards. On intent-to-treat, 5/144 (3,5%) and 9/143 (6,2%) of pts achieved undetectable MRD with C-Rd and Rd, respectively (p = 0,7). With a median follow-up of 16 months (range, 1-47), no significant differences were observed in PFS: in the C-Rd arm the median was 23 months and has not been reached in the Rd arm (p = 0.09); furthermore, although disease progression and/or death rate was comparable in both arms (C-Rd: 57/144 [39.6%] vs Rd: 45/144 [31.2%]), a trend towards shorter PFS was observed in the C-Rd group (Figure 1). This effect was less evident in younger ( 75 years and being early deaths. Overexposure to steroids due to the delayed clearance induced by C in this elderly population could explain our results. Figure Disclosures Puig: The Binding Site: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding. Rosinol Dachs:Janssen, Celgene, Amgen and Takeda: Honoraria. De Arriba:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Honoraria. Oriol:Celgene Corporation: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Janssen: Consultancy; Amgen: Consultancy, Speakers Bureau. De La Rubia:AbbVie: Consultancy; AMGEN: Consultancy; Celgene Corporation: Consultancy; Takeda: Consultancy; Janssen: Consultancy. Amor:Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Martín Sánchez:GILEAD SCIENCES: Research Funding. Rossi:BMS: Research Funding; Janssen, Celgene, Amgen: Consultancy. Coleman:Merck: Research Funding; Pharmacyclics: Speakers Bureau; Kite Pharmaceuticals: Equity Ownership; Gilead, Bayer, Celgene: Consultancy, Research Funding, Speakers Bureau. Paiva:Amgen, Bristol-Myers Squibb, Celgene, Janssen, Merck, Novartis, Roche, and Sanofi; unrestricted grants from Celgene, EngMab, Sanofi, and Takeda; and consultancy for Celgene, Janssen, and Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau. San-Miguel:Amgen, Bristol-Myers Squibb, Celgene, Janssen, MSD, Novartis, Roche, Sanofi, and Takeda: Consultancy, Honoraria. Bladé:Jansen, Celgene, Takeda, Amgen and Oncopeptides: Honoraria. Niesvizky:Takeda, Amgen, BMS, Janssen, Celgene: Consultancy, Research Funding. Mateos:EDO: Membership on an entity's Board of Directors or advisory committees; Pharmamar: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Takeda: 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; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria.

Description: Background Measurable residual disease (MRD) testing in multiple myeloma (MM) is increasingly being utilized in clinical trials for the assessment of disease response and as a prognostic tool for predicting response duration. However, there is only limited evidence to date for the use of MRD to make clinical decisions, a serious barrier to its potentially important role in the management of MM patients. This retrospective review analyzes the results of making clinical decisions to change therapy based on MRD assessments in MM patients. Methods We reviewed 373 patients with MM from 3 health centers through a retrospective search. Patients included in the study had at least one MRD assessment. Clinical decisions to change therapy based on MRD were made in 3 directions: 1. Stop or reduce treatment after MRD negative results; 2. Increase intensity of treatment after MRD positive results; 3. Start a new treatment line after MRD positive results. We gathered all the available data on clinical and biological parameters, induction treatment and response monitoring. MRD was assessed by flow cytometry or next-generation sequencing (Clonoseq) with sensitivity from 10-5to 10-6Statistical analyses were performed with SPSS software version 21.0 (SPSS, Inc., IBM, Armonk, NY). Results In 58 out of 373 (16%) patients a clinical decision to change therapy was made. Treatment was reduced or stopped in 24 cases (group 1). Intensity of treatment was increased in 20 cases(group 2) and a new treatment was started in 13cases(group 3). Most of these decisions were implemented during the post-ASCT maintenancephase, although in 3 cases ASCT was avoided based on the MRD result. For all 373 patients, the median progression-free survival (PFS) was 80 months. Of the 58 cases where a clinical decision was made to change therapy, 33 cases were MRD positive and 25 were MRD negative at the time the decisions were made. 33 patients in this group either remained MRD negative or eventually achieved MRD negativity. Patients in which a clinical decision was made to change therapy based on MRD (n=58) had a prolonged progression free survival versus those in which therapy remained the same (n=312) (median PFS 97 vs. 75 months, p=0.006) (Figure 1). Moreover, we once again confirmed that patients who achieve MRD negativity demonstrate a prolonged PFS vs those who don't achieve negativity (median PFS 97 vs. 57 months, p=0.0001). Conclusion Clinical decision-making to change therapy based on MRD in MM patients can improve patient outcomes. These results support the integration of MRD assessment in the management of MM patients. Disclosures Wong: Fortis: Research Funding; GSK: Research Funding; Roche: Research Funding; Janssen: Research Funding; Amgen: Consultancy; Sanofi: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Research Funding. Shah:GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. Barrio Garcia:Altum sequencing: Current Employment. Martin:GSK: Consultancy; Sanofi: Research Funding; AMGEN: Research Funding; Seattle Genetics: Research Funding; Janssen: Research Funding. Wolf:Adaptive: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.