Monoclonal Gammopathy of Undetermined Significance (MGUS): Predictors of Outcome and Recognition of an Evolving Type.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5052-5052
Author(s):  
Laura Rosiñol ◽  
Joan Bladé ◽  
Ma Teresa Cibeira ◽  
Silvia Montoto ◽  
Jordi Esteve ◽  
...  

Abstract MGUS occurs in up to 3% of persons older than 50 years and the probability of malignant evolution is 1% per year. The risk of progression from MGUS to a symptomatic monoclonal gammopathy has been investigated in a number of series. However, only the presenting features have been considered while the evolutive pattern during the first years of follow-up has not been taken into account. The aim of our study was to investigate the predictors of outcome considering both the initial features and the pattern of evolution of the M-protein size during the first three years in a large series of patients with MGUS with long follow-up. Three-hundred and fifty nine patients (160 M, 199 F; median age 66 yrs) diagnosed with MGUS at a single institution were included in the study. Patients who showed an inequivocal increase in their M-protein size at the serum electrophoresis during the first three years of follow-up were considered as evolving while the remainders were considered as non-evolving. In the overall series the median values for serum M-protein level and for the proportion of bone marrow plasma cells (BMPC) were 14.8 g/L and 4%, respectively. Three hundred an thirty patients had a non-evolving MGUS while 29 fulfilled the criteria for the evolving type. The M-protein size and the proportion of BMPC at diagnosis were similar in both types of MGUS. The IgG type was more frequent in the non-evolving (65% vs. 45%, p=0.005) whereas the IgA and IgM type were more frequent in the evolving type (55% vs. 32%, p=0.04). Overall, 32 patients developed malignant transformation after a median follow-up of 93 months. Fourteen of the 29 (48%) evolving patients developed symptomatic multiple myeloma while only 18 out of the 330 (5%) remaining patients with non-evolving MGUS progressed to a malignant condition. The progression rate at 10 and 20 years of follow-up for the evolving and the non-evolving types was 55% vs. 10% and 80% vs. 13%, respectively. No patient in the non-evolving type evolved to a malignant condition after the first 12 years of follow-up. The predictors for malignant transformation at the univariate analysis were: the type of MGUS (evolving vs. non-evolving, p<0.001), a proportion of BMPC higher than 5% (p=0.001), the immunoglobulin isotype (IgA vs. IgG, p=0.007) and the M-protein size greater than 15 g/L (p=0.05). At the multivariate analysis the features significantly associated to a higher risk of progression were: the evolving type (RR 12.1, p<0.001,), the IgA type (RR 2.9, p=0.006) and the M-protein concentration (RR 2.2, p=0.044). Conclusions: The evolutive pattern of the serum M-protein during the first years of follow-up is the most important risk factor for progression in patients with MGUS.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4838-4838
Author(s):  
L. Rosiñol ◽  
S. Montoto ◽  
J. Bladé ◽  
M.T. Cibeira ◽  
M. Rozman ◽  
...  

Abstract Background: MGUS is a common disorder characterized by the presence of a small serum M-protein in individuals with no evidence of multiple myeloma (MM), Waldenström’s macroglobulinemia (WM) or primary amyloidosis (AL). Although about one fourth of these individuals will evolve into a malignant disease with a transformation rate of 1% per year, there are not well-established predictors of outcome. Aim: To identify predictor features of malignant transformation in a large series of patients with MGUS and prolonged follow-up. Patients and methods: Four hundred and thirty-four patients (200 M/234 F; median age 66 years) diagnosed with MGUS in a single institution from September 1970 to January 2001 with a minimum follow-up of one year were included in the study. All patients had an M-protein size < 30g/L. Bone marrow aspirates were reviewed independently by two of the authors and the proportion of bone marrow plasma cells (BMPC) were estimated from a 500 cell-count by each observer. The median follow-up was 5.2 years (range: 1–28.8 years) with 84 patients followed for more than 10 years. Results: The type of M-protein was IgG in 67.2% of the cases, IgA in 18.8%, IgM in 11.9%, light chain in 1% and biclonal in 1%. The light chain was kappa type in 56.4% of the patients. The median M-protein size was 15.6 g/L (<10 g/L in 10.8%, 10–20 g/L in 61.7%, and > 20g/L in 27.4%). The median percentage of BMPC in 305 reviewed samples was 4.6% (range: 0.4–25). After a median follow-up of 5.2 years, 50 patients (11.5%) have evolved into a malignant monoclonal gammopathy (44 MM, 5 WM and 1 AL). The median time to progression was 5.4 yrs (range: 1.4 – 16.9). The risk of transformation was 15.4% (95% CI: 10.5–20.3) and 34% (95% CI 22.6–45.3) and 34% (95% CI: 22.6–45.3) at 10 and 20 years, respectively. The variables associated with a higher risk of transformation were IgA-type (p=0.003), kappa light chain (p=0.009), the amount of M-protein (<15 vs >15 g/L, p=0.005) and the percentage of BMPC (<5% vs >5%, p=0.007). Conclusions: In this series of patients with MGUS, the type (i.e. IgA or kappa) and size of M-protein (>15g/L) as well as the percentage of bone marrow plasma cells (>5%) significantly predicted malignance transformation.


Blood ◽  
1996 ◽  
Vol 87 (3) ◽  
pp. 912-918 ◽  
Author(s):  
L Baldini ◽  
A Guffanti ◽  
BM Cesana ◽  
M Colombi ◽  
O Chiorboli ◽  
...  

The presenting clinico-hematologic features of 386 patients with nonmyelomatous monoclonal gammopathy (MG) were correlated with the frequency of malignant transformation to evaluate the most important variables conditioning its evolution into multiple myeloma (MM) or Waldenstrom macroglobulinemia (WM). Most of the patients (335) had monoclonal gammopathy of undetermined significance (MGUS: 39 IgA, 242 IgG, 54 IgM): the remaining 51 patients (12 IgA, 39 IgG) fulfilled all of the MGUS diagnostic criteria (according to Durie) except that bone marrow plasma cell (BMPC) content was 10% to 30%, and so they were defined as having monoclonal gammopathy of borderline significance (MGBS). There were no significant differences between the MGUS and MGBS groups in terms of age, sex, or median follow-up. After a median follow- up of 70 and 53 months, respectively, 23 of 335 MGUS and 19 of 51 MGBS patients had undergone a malignant evolution. Univariate analysis of the IgA and IgG patients showed that the cumulative probability of the disease evolving into MM correlated with diagnostic definition (MGBS v MGUS), BMPC content (> or = 10% v < 5% and < or = 5% v > 5%) and reduced serum polyclonal Ig. In the IgG cases, there was also a significant correlation with detectable Bence Jones proteinuria, serum monoclonal component (MC) levels and age at diagnosis (> 70 v < = or 55 years). In the IgG cases as a whole, the same variables remained in the Cox model where the BMPC percentage was considered after natural logarithmic transformation and the monoclonal component as g/dL value. The relative risks of developing MM are the following: 2.4 for each 1 g/dL increase of IgG, serum MC, 3.5 for detectable light chain proteinuria, 4.4 for the increase of 1 unit in log. BMPC percentage, 6.1 for age > 70, 3.6 and 13.1 for a reduction in one or two polyclonal Ig. In conclusion, our study allows the identification of a particular subset of MGUS patients (MC < = or 1.5 g/dL, BMPC < 5%, no reduction in polyclonal Ig and no detectable light chain proteinuria) at very low- risk of evolution, who can be considered as having benign monoclonal gammopathies. We also describe a previously undefined group of MG patients (with monoclonal gammopathy of borderline significance) who are at high-risk of malignant evolution. These findings could have a considerable impact on the cost/benefit ratio of monitoring programs in these patients.


2021 ◽  
Vol 11 (6) ◽  
Author(s):  
A. Visram ◽  
C. Soof ◽  
S. V. Rajkumar ◽  
S. K. Kumar ◽  
S. Bujarski ◽  
...  

AbstractSoluble BCMA (sBCMA) levels are elevated in monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM). However, the association between sBCMA levels and prognosis in MGUS and SMM has not been studied. We retrospectively analyzed sBCMA levels in stored samples from 99 MGUS and 184 SMM patients. Baseline sBCMA levels were significantly higher in MGUS and SMM patients progressing to MM during clinical follow up. When stratified according to the median baseline sBCMA level for each cohort, higher levels were associated with a shorter PFS for MGUS (HR 3.44 comparing sBCMA ≥77 vs <77 ng/mL [95% CI 2.07–5.73, p < 0.001] and SMM (HR 2.0 comparing sBCMA ≥128 vs <128 ng/mL, 95% 1.45–2.76, p < 0.001) patients. The effect of sBCMA on PFS was similar even after adjusting for the baseline MGUS or SMM risk stratification. We evaluated paired serum samples and found that sBCMA increased significantly in MGUS and SMM patients who eventually progressed to MM, whereas among MGUS non-progressors the sBCMA level remained stable. While our results require independent validation, they suggest that sBCMA may be a useful biomarker to identify MGUS and SMM patients at increased risk of progression to MM independent of the established risk models.


Blood ◽  
2010 ◽  
Vol 116 (12) ◽  
pp. 2019-2025 ◽  
Author(s):  
Giada Bianchi ◽  
Robert A. Kyle ◽  
Colin L. Colby ◽  
Dirk R. Larson ◽  
Shaji Kumar ◽  
...  

Abstract Monoclonal gammopathy of undetermined significance (MGUS) is associated with a long-term risk of progression to multiple myeloma (MM) or related malignancy. To prevent serious myeloma-related complications, lifelong annual follow-up has been recommended, but its value is unknown. We reviewed all patients from southeastern Minnesota seen at Mayo Clinic between 1973 and 2004 with MGUS who subsequently progressed to MM. Of 116 patients, 69% had optimal follow-up of MGUS. Among these, abnormalities on serial follow-up laboratory testing led to the diagnosis of MM in 16%, whereas MM was diagnosed only after serious MM-related complications in 45%. In the remaining, workup of less serious symptoms (25%), incidental finding during workup of unrelated medical conditions (11%), and unknown (3%) were the mechanisms leading to MM diagnosis. High-risk MGUS patients (≥ 1.5 g/dL and/or non-IgG MGUS) were more likely to be optimally followed (81% vs 64%), and be diagnosed with MM secondary to serial follow-up testing (21% vs 7%). This retrospective study suggests that routine annual follow-up of MGUS may not be required in low-risk MGUS. Future studies are needed to replicate and expand our findings and to determine the optimal frequency of monitoring in higher-risk MGUS patients.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5080-5080 ◽  
Author(s):  
David Dingli ◽  
Robert A. Kyle ◽  
Vincent S. Rajkumar ◽  
Grzegorz S. Nowakowski ◽  
Dirk R. Larson ◽  
...  

Abstract Background: Solitary plasmacytoma of bone (SBP) is a localized collection of monoclonal plasma cells that is potentially curable with local radiation therapy but associated with a high risk of progression to multiple myeloma. We hypothesized that an abnormal immunoglobulin free light (FLC) ratio at diagnosis may be a prognostic indicator of transformation risk. Methods: We identified a cohort of 133 patients with SBP for whom stored serum taken at the time of diagnosis was available. The diagnosis was ascertained and serum FLC determined in 126 patients. Results: From this cohort, 48 patients have progressed to myeloma and the median time to progression among those who progressed was 1.9 years. On univariate analysis, age (p&lt;0.001), gender (p=0.035), abnormal FLC ratio at diagnosis (p=0.009) and persistence of serum or urine M-protein after therapy (p=0.0070 were all associated with a shorter overall survival (OS) and time to progression to multiple myeloma. Progression by Normal FLC(0.26–1.65) Progression by Normal FLC(0.26–1.65) On multivariate analysis, an abnormal FLC ratio retained its independence in a model that includes age at diagnosis but lost its significance when combined with persistence of the serum or urine M-protein. However, serum or urine M-proteins are not detectable in a significant number of patients with SBP and therefore not informative. Conclusion: The FLC ratio at the time of diagnosis of SBP is a powerful predictor of risk and a useful aid to management of patients with this condition.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2707-2707
Author(s):  
Nadine Abdallah ◽  
David L Murray ◽  
Angela Dispenzieri ◽  
Prashant Kapoor ◽  
Morie A. Gertz ◽  
...  

Abstract Background: MASS-FIX is a screening method for serum and urine monoclonal proteins in multiple myeloma and related plasma cell disorders, which uses immunoglobulin enrichment coupled with matrix-assisted laser desorption ionization time-of-flight mass-spectrometry (MALDI-TOF). In addition to superior sensitivity over conventional gel-based techniques, MASS-FIX can distinguish therapeutic monoclonal antibodies (MoAb) from patient's M protein. As the utilization of therapeutic MoAbs increases, it is essential to understand the persistence pattern of these therapeutic antibodies in the serum. We designed this study to evaluate the duration of daratumumab detection by MASS-FIX in the serum of treated patients. Methods: We used a prospectively maintained database at Mayo clinic to identify patients with multiple myeloma and related plasma cell disorders who were treated with a daratumumab-containing regimen anytime during their disease course and had serial MASS-FIX data available after discontinuation of daratumumab. A univariate analysis was performed to assess for factors that may impact the clearance of daratumumab. Results: We included 125 patients with plasma cell disorders who received daratumumab as first or subsequent line of treatment between March 15 th, 2016, and March 4 th, 2020. The median age was 60.2 years and 57% were male. The most common diagnoses were multiple myeloma (70%) and light chain amyloidosis (18%). Daratumumab-based treatments were initiated after a median of 28.8 (IQR: 6.4-76.3) months from initial diagnosis. The most common regimen used was daratumumab, bortezomib and dexamethasone (23%); 26% underwent transplant after daratumumab-based induction. The median duration of treatment with a daratumumab-based regimen was 208 (IQR: 99-479) days. The median follow-up from the time of daratumumab discontinuation was 457 (95% CI: 346-NR) days. By last follow up, daratumumab was not detected by MASS-FIX in 93 (74%) patients but remained detectable in 32 (26%) patients. The median time from daratumumab discontinuation to disappearance of daratumumab by MASS-FIX was 160 (IQR: 107-233) days. On univariate analysis, the presence of ≥0.5 grams of urine protein was associated with earlier disappearance of daratumumab on MASS-FIX [risk ratio (RR): 2.0, P=0.02). The median time from daratumumab discontinuation to disappearance of daratumumab on MASS-FIX was 116 (95%CI: 76-160) days in patients with urine protein ≥0.5 grams and 203 (95%CI: 162-216) days in patients with urine protein &lt;0.5 grams (P=0.02). There was no association between the time to disappearance of daratumumab by MASS-FIX and old age ≥70 (RR: 0.9, P=0.81], male gender (RR: 0.9, P=0.60), eGFR &lt;60 (RR: 1.0, P=0.98), daratumumab schedule (every 1/2 weeks vs &gt;2weeks) (RR: 1.0, P=0.97), treatment duration (&lt;200 days vs ≥200 days) ( RR: 1.0, P=0.95), or transplantation status (RR: 1.0, P=0.98). Conclusion: The therapeutic monoclonal antibody daratumumab remains detectable in the serum of treated patients by MASS-FIX for several months after discontinuation and the duration varies between individual patients. This data has implications for diagnostic and monitoring testing and may provide guidance for reuse of daratumumab in clinical trials and practice. Proteinuria is associated with earlier disappearance of daratumumab by MASS-FIX and may have implications in patients with amyloidosis and monoclonal immunoglobulin deposition disease (MIDD). Further studies are needed to identify additional factors associated with the timing of disappearance. Disclosures Murray: Mayo Clinic: Other: Has received patents for the Mass-Fix technology which has been licensed to the Binding Site with potential royalties.. Dispenzieri: Takeda: Research Funding; Alnylam: Research Funding; Pfizer: Research Funding; Oncopeptides: Consultancy; Sorrento Therapeutics: Consultancy; Janssen: Consultancy, Research Funding. Kapoor: Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Amgen: Research Funding; Ichnos Sciences: Research Funding; Regeneron Pharmaceuticals: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Gertz: Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Ionis Pharmaceuticals: Other: Advisory Board; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; Aurora Biopharma: Other: Stock option; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring. Dingli: Alexion: Consultancy; Novartis: Research Funding; Apellis: Consultancy; Janssen: Consultancy; Sanofi: Consultancy; GSK: Consultancy. Kumar: Antengene: Consultancy, Honoraria; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Merck: Research Funding; Roche-Genentech: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Oncopeptides: Consultancy; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Carsgen: Research Funding; Tenebio: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1968-1968
Author(s):  
Elena Zamagni ◽  
Giuseppe Bandini ◽  
Annalisa Pezzi ◽  
Paola Tacchetti ◽  
Ilaria Rizzello ◽  
...  

Abstract Allogeneic stem cell transplantation (allo-SCT), which provides a tumor-free graft, is an alternative approach to autologous transplantation for multiple myeloma (MM) that offers the possibility of cure through a graft vs myeloma effect (GVM). However, the inherent non relapse mortality (NRM) and the high post-transplant relapse rate are the major shortcomings of this strategy which continues to have a controversial role in MM treatment. To highlight the long-term clinical outcomes of allo-SCT, we performed a retrospective analysis on 102 patients (pts) with MM who received at our Institution either a myeloablative (MA) (74 pts) or a non-myeloablative (NMA) (28 pts) conditioning regimen between 1990 and 2014. The MA regimen consisted in low dose TBI and cyclophosphamide (cyclo) ± melphalan (mel) or busulfan-cyclo. The NMA regimen was mel-fludarabine. Graft versus host disease (GVHD) prophylaxis consisted in cyclosporine + methotrexate (83%) or mycophenolate (17%), with the addition of thymoglobulin for unrelated or related female vs male recipient donors. The median age was 42 yrs (IQR 38-47), 60% pts were male. The hematopoietic cell donors were sibling in 77 pts and unrelated in 25, while the source of stem cells was peripheral blood in 65 and bone marrow in 37 pts. Fifty-six pts received allo-SCT as first-line therapy, 31 as second-line and 13 as third or fourth-line. Median time from diagnosis to allo-SCT was 22 months. Response status at the time of transplant was at least PR in 63% of the pts, including ≥ VGPR in 36% and CR in 12%. Overall, the response rate after allo-SCT was as follows: CR 58%, VGPR 19%, PR 18%. Median CR duration was 10 years (44% at 15 years). The incidence of acute grade II-IV and III-IV GVHD was 25% and 15%, respectively. The incidence of all grades chronic cGVHD was 48%, grade ≥2: 24%, with a median onset time of 178 days. By competitive risks analysis, the cumulative incidence of cGVHD at 1 and 3 years was 20% and 32%, respectively. On univariate analysis, the gender combination of female donor-male patient resulted in significantly higher incidence of cGVHD (sub hazard ratio, SHR, 2.3, P= 0.03). The cumulative incidence of NRM was 6.6% at 100 days, 11% at 1 year and 14.4% at 3 years, with lack of statistically significant relationship with the conditioning regimen. By univariate analysis, < PR prior to allo-SCT (SHR 2.8) and all grades cGVHD (SHR 4.6) were significantly associated with an increased NRM. By competitive risks analysis, the cumulative incidence of relapse was 50% at 5 years, 58% at 10 years and 59% at 15 years. On univariate analysis, sibling donor (SHR 0.54, P=0.047), all grades cGVHD (SHR 0.5, P=0.011) and ≥VGPR after allo-SCT (SHR 0.38, P=0.001) were significantly associated with extended time to progression. All grades cGVHD (SHR 0.43, P=0.005) and ≥VGPR after allo-SCT (SHR 0.36, P= 0.001) were independent predictors for a lower risk of progression on multivariate analysis. With a median follow-up of 13 years, overall survival (OS) was 43% at 5 years and 34% at 10 years. In univariate analysis, low ISS stage at diagnosis, sibling donor, absence of female donor-male patient gender combination, ≥VGPR prior to allo-SCT and first-line allo-SCT were significantly related to OS. Multivariate analysis confirmed an OS benefit for having a sibling donor (HR 0.30, P<0.001), absence of female donor-male patient gender combination (HR 0.51, P=0.022) and being in ≥ VGPR prior to allo-SCT (HR 0.41, P=0.003). In conclusion, this retrospective analysis performed with an extended follow-up of 13 years shows that a fraction of MM pts can be long-term survivors after allo-SCT, one third of them being potentially cured. The best outcomes were obtained when allo-SCT was applied in pts in an early phase of their disease and with a small residual tumor size. The major challenge, both with MA and NMA allo-SCT, was the relatively high post-transplant relapse rate. The presence of cGVHD was protective for the risk of progression, supporting the role of GVM, but increased the risk of NRM. New approaches aimed at modulating cGVHD are warranted. In addition, incorporation of novel agents before and after allo-SCT to increase the rate and duration of high-quality responses, as well as identification of those patients mostly benefiting from this procedure, will likely contribute to improve long-term outcomes. Disclosures Zamagni: Celgene Corporation: Honoraria, Speakers Bureau; Janssen Pharmaceuticals: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau. Cavo:Sanofi: Consultancy, Honoraria; Onyx: Honoraria; Jansenn: Consultancy, Honoraria; Millenium Pharmaceuticals: Honoraria; Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; BMS: Honoraria.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1795-1795
Author(s):  
Anna Benedetta Dalla Palma ◽  
Laura Notarfranchi ◽  
Jessica Crosara ◽  
Mario Pedrazzoni ◽  
Fabrizio Accardi ◽  
...  

The identification of risk factors for progression is critical in the clinical management and appropriate follow up of patients with pre-malignant Asymptomatic Monoclonal Gammopathies (AMG) including Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM). The development of prognostic score and consequently the early identification of patients with possible short-term progression to Multiple Myeloma (MM) could lead to anticipate the treatment. In this study, we retrospectively evaluated possible risk factors of short-term progression to active MM in a large cohort of MGUS and SMM patients admitted to a single haematological center (Hematology and BMT Unit, University Hospital of Parma) between 2010 and 2018. We analysed a total cohort of 235 patients diagnosed with AMG (81 MGUS and 154 SMM) according to the IMWG recently updated diagnostic criteria. All patients analysed underwent to Bone Marrow (BM) examination; moreover, imaging evaluation was performed in 22 MGUS and 123 SMM patients, in order to exclude the presence of bone disease. In a subgroup of AMG patients (n=50), bone mineral density (BMD) evaluation by Dual-energy X-ray Absorptiometry (DXA) was also available. Median age of the AMG patients analysed was 68 years (range 35-93 years). Median percentage of BM plasma cells (BMPCs) was 12% (range 2-55%) in the entire population, 7% (range 2-9) in MGUS and 15% (range 10-55) in SMM patients. Median serum M-protein was 1.7 g/dL (range: 0.17-4.5), 1.5 g/dL (range 0.17-4.5) in MGUS and 1.8 g/dL (range 0.4-2.7) in SMM patients. An abnormal free light chain (FLC) ratio was found in 70% of AMG patients, among the ones that performed the analysis; regarding SMM patients, FLC ratio value was available in 97 patients: in 72 (76%) the ratio was unbalanced, 37 (39%) had a FLC ratio ≤ 0.125 or ≥ 8 and in 14 (15%) it was > 20; among MGUS patients, value was collected in 41 patients and in 21 (51%) it was <0.26 or >1.65. The presence of immunoparesis in one or two uninvolved immunoglobulins occurred in 59% of the entire population. The median follow up time was 18 months (range 0 - 111 months) for whole population. Overall 44 patients of the entire cohort progressed to MM (41 SMM and 3 MGUS) with a median TTP of 14.5 months. By univariate analysis we found that percentage of BMPCs, entity of M-protein and presence of immunoparesis were significantly correlated with progression to active MM (p<0.001 for each variable). On the other hand, abnormal FLC ratio did not reach a statistical significance, as well as value of the involved FLC (p=0.059). Nevertheless, the presence of a FLC ratio < 0.125 or > 8 (as used in Mayo scoring system for SMM) showed a relationship at the limit of statistical significance in this subgroup of patients (p=0.052). Any significant correlation was not observed with age, sex, Ig isotype, light chain's type and the BMD values (p=NS). Afterwards, we applied Kaplan Meier method on risk factors resulted significant in univariate analysis demonstrating that they also significantly influenced the time to progression to MM. Finally, through a binomial logistic regression, we developed a new prognostic score for whole population. By combining the values of M-protein (< 2, score=0 or ≥ 2 g/dL, score=1) and the percentage of BMPC (<10%, score=0, 10-20%, score=1 and >20%, score=2), we obtained six groups at different probability of progression to active MM (Table 1). Given that result, we stratified patients in 3 groups: low-risk (score=0), intermediate-risk (score=1) and high-risk (score≥2); log-rank test confirmed that high-risk patients had a significantly shorter time to progression to symptomatic MM as compared to intermediate and low-risk patients (p<0.001). In conclusion, our results show that in patients with AMG the clinical factors, which mostly impact on the short-term risk of progression to active MM, are the entity of the PCs infiltrate and the MC related to the tumoral mass. The development of a clinical score based on BMPCs and M-protein will permit to overcome the traditional distinction between MGUS and SMM in the evaluation of the progression of AMG patients to active MM. Disclosures Giuliani: Janssen: Research Funding.


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