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4390 Determining Outcome in IgM Gammopathies: Integration of Molecular, Flow Cytometry and Clinical Factors in an International, Multicenter Series (the SAL-TO Study)

Program: Oral and Poster Abstracts
Session: 623. Mantle Cell, Follicular, Waldenstrom’s, and Other Indolent B Cell Lymphomas: Clinical and Epidemiological: Poster III
Hematology Disease Topics & Pathways:
Research, Translational Research, Lymphomas, Clinical Research, Indolent lymphoma, Diseases, Real-world evidence, Lymphoid Malignancies, Biological Processes, Molecular biology
Monday, December 9, 2024, 6:00 PM-8:00 PM

Irene Dogliotti, MD1*, Cristina Jimenez, PhD2*, Veronica Peri3*, Martina Ferrante, PhD4*, Davide Musto5*, Silvio Mercadante, PhD5*, Gian Maria Zaccaria, PhD6*, Marco Ghislieri, PhD7*, Giulia Benevolo, MD4*, Enrique M. Ocio8, Araceli Rubio, MD9*, Ilda Maria Murillo, MD9*, Fernando Escalante10*, Carmen Aguilera, MD11*, Aránzazu García Mateo, PhD12*, Alfonso Garcia de Coca13*, Roberto Hernandez14*, Julio Dávila-Valls15*, Federica Cavallo3*, Noemi Puig, PhD16, Almudena Navarro Bailon, MD17*, Veronica Gonzalez-Calle, MD, PhD18*, Maria Eugenia Sarasquete, PhD18*, Miguel Alcoceba, PhD19*, Simone Ragaini4*, Michele Clerico4*, Chiara Consoli, MD3*, Maria Garcia Alvarez, PhD18*, Carmen Chillon, MD18*, Alejandro Medina, PhD18*, Marcos Gonzalez Diaz, MD18*, Norma C. Gutierrez20*, Benedetto Bruno, MD, PhD4, Daniela Drandi4*, Simone Ferrero, MD21 and Ramon García-Sanz, MD, PhD18

1Division of Hematology, AOU Città della Salute e della Scienza di Torino, Torino, Italy
2Haematology Department, University Hospital of Salamanca, Research Biomedical Institute of Salamanca (IBSAL), CIBERONC and Center for Cancer Research-IBMCC (USAL-CSIC), Salamanca, ESP
3Hematology Division I, Department of Molecular Biotechnologies and Health Sciences, University of Turin/University Hospital A.O.U. “Città della Salute e della Scienza”, Turin, Italy
4Division of Hematology 1, Department of Biotechnology and Health Sciences, University of Torino, Torino, Italy
5Division of Hematology 1, Department of Molecular Biotechnologies and Health Sciences, University of Torino, Torino, Italy
6Department of Electrical and Information Engineering (DEI), Polytechnic University of Bari, Bari, Italy
7Department of Electronics and Telecommunications, Politecnico di Torino, Turin, 10129, Italy and PolitoBIOMed Lab, Politecnico di Torino, Torino, Italy
8Hospital Universitario Marqués de Valdecilla (IDIVAL), Universidad de Cantabria, Santander, Spain
9Hematology Department, Hospital Miguel Servet, Zaragoza, Spain
10Hospital Universitario de Leon, Leon, Spain
11Hematology Department, Regional Hospital of El Bierzo, Leon, Spain
12Department of Hematology, Hospital General de Segovia, Segovia, Spain
13Department of Hematology, Clinical Hospital of Valladolid, Valladolid, Spain
14Hematology Department, Hospital Virgen de la Concha, Zamora, Spain
15Hospital Universitario Nuestra Senora de Sonsoles, Avila, ESP
16Hospital Universitario de Salamanca (HUSAL), IBSAL, IBMCC (USAL-CSIC), CIBERONC, Salamanca, Spain
17Hospital Universitario de Salamanca, Salamanca, Spain
18Haematology Department, University Hospital of Salamanca, Research Biomedical Institute of Salamanca (IBSAL), CIBERONC and Center for Cancer Research-IBMCC (USAL-CSIC), Salamanca, Spain
19Department of Hematology, University Hospital of Salamanca (HUS/IBSAL), CIBERONC and Cancer Research Center of Salamanca-IBMCC (USAL-CSIC), Salamanca, Spain
20Institute of Biomedical Research of Salamanca (IBSAL), University Hospital, Salamanca, Spain
21Department of Molecular Biotechnology and Health Sciences, Hematology Division, University of Torino, Torino, TO, Italy

Background:

Waldenström macroglobulinemia (WM) is a rare, indolent B-cell lymphoproliferative disorder, often preceded by a history of IgM monoclonal gammopathy of undetermined significance (IgM-MGUS). WM progression mechanisms are not fully understood given the complex integration of clinical and molecular features.

Aims: To determine the impact of clinical, molecular and flow cytometry factors on overall survival (OS) and time to first treatment (TTFT) in a large, real life series of patients with IgM gammopathy.

Methods:

In this retrospective multicenter study, we collected real-life data on 577 patients with IgM gammopathy from 22 Spanish Centers. Moreover, 166 additional patients, treated at the University Hospital of Torino, Italy, were used as validation series. Multiparameter Flow Cytometry (MFC) and MYD88L265P evaluation (either by ddPCR or qPCR) were performed on baseline bone marrow (BM) samples in Salamanca and Torino laboratories respectively.

Results:

Overall median OS of the Spanish series was 126.7 months: 85.0 for symptomatic (sWM), 143.6 for asymptomatic WM (aWM), and 180.6 months for IgM-MGUS (p<0.001) respectively, while median TTFT for asymptomatic patients (aWM+MGUS) was 228.5 months, with 89% of pts remaining off treatment at 5 years. By multivariate analysis, significant clinical prognostic factors for OS included age > 65 years, male gender, diagnosis of sWM and beta-2-microglobulin >3, while age > 65 years, BM infiltration, hemoglobin <11.5 g/dl and platelets <100.000/mmc were associated with shorter TTFT.

Data from the Spanish and the Torino cohorts were pooled and divided into two groups based on high vs low baseline values of MYD88L265P Mut/WT ratio (cut-off point 0.162) and high vs low baseline MFC clonal B cell marrow infiltration (cut-off point 4.39%). By univariate analysis, the MYD88low group showed better OS (p=0.005, HR=0.44) and TTFT (p=0.024, HR=0.33) compared to the MYD88high group. Similarly, the MFClow group had increased OS (p=0.033, HR=0.65) and TTFT (p=0.008, HR=0.37) compared to the MFChigh group. Moreover, by combining MFC and MYD88 baseline levels, patients were stratified into low, intermediate and high risk classes (LR: MFClow/MYD88low, IR: either MFClow/MYD88high or MFChigh/MYD88low; HR: MFChigh/MYD88high). The high risk group significantly differed from the others in terms of OS (n= 156, p=0.005, HR=3.28, figure 1) and TTFT (n= 92, p=0.003, HR= 9.61), while the intermediate-risk group (p=0.015, HR=4.76) was also significantly different from the low risk group for TTFT. Multivariable analysis confirmed a significant impact of MYD88 mutation and MFC baseline levels on both OS and TTFT. Finally, competing risk analysis showed, in the MFChigh/MYD88high group, a statistically significant increment in disease-related rather than unrelated deaths at 5 years (2.2% vs 19%, p=0.002, for MFClow/MYD88low vs MFChigh/MYD88high respectively).

Conclusions: Our retrospective study shows that MYD88L265P, by PCR quantitative analysis, and marrow infiltration, by MFC, play a significant prognostic role in OS and in the treatment indications in patients with IgM gammopathy. Prospective validation studies may greatly help to define prognostic tools for IgM gammopathy and to better define patients with high risk WM.

Disclosures: Benevolo: BMS: Honoraria; Novartis: Honoraria; Janssen: Honoraria; GSK: Honoraria. Ocio: Pfizer: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria, Research Funding; Regeneron: Honoraria; GSK: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy; Takeda: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Menarini: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; Amgen: Honoraria; AbbVie: Consultancy, Honoraria. Puig: Pfizer, Sanofi, Amgen, BMS, Janssen, Takeda, and The Binding Site: Honoraria; Pfizer, Sanofi, Amgen, BMS-Celgene, Janssen, and Takeda: Consultancy. Gonzalez-Calle: Janssen, GSK, Pfizer, BMS: Consultancy, Other: Travel and accommodation, Speakers Bureau. Gutierrez: University Hospital of Salamanca: Current Employment; Amgen, Sanofi: Honoraria. Ferrero: Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Eli Lilly: Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees; EUSA Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Beigene: Research Funding, Speakers Bureau; Gilead: Research Funding, Speakers Bureau; Italfarmaco: Membership on an entity's Board of Directors or advisory committees; Gentili: Speakers Bureau; Sandoz: Consultancy, Speakers Bureau.

*signifies non-member of ASH