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112 Clinical Significance and Transcriptional Profiling of Persistent Minimal Residual Disease (MRD) in Multiple Myeloma (MM) Patients with Standard-Risk (SR) and High-Risk (HR) Cytogenetics

Program: Oral and Poster Abstracts
Type: Oral
Session: 651. Myeloma: Biology and Pathophysiology, excluding Therapy: Genomic Landscape of Myeloma and Its Clinical Impacts
Hematology Disease Topics & Pathways:
Diseases, multiple myeloma, Adult, Therapies, Non-Biological, chemotherapy, Technology and Procedures, Plasma Cell Disorders, cytogenetics, Study Population, Lymphoid Malignancies, Clinically relevant, flow cytometry, NGS, RNA sequencing
Saturday, December 1, 2018: 10:15 AM
Grand Ballroom 7 (Marriott Marquis San Diego Marina)

Ibai Goicoechea, PhD1, Noemi Puig, MD, PhD2*, María Teresa Cedena3*, Lourdes Cordon4*, Maria-Belen Vidriales, MD5*, Leire Burgos6*, Juan Flores-Montero7*, Norma C. Gutierrez, MD, PhD8*, Maria Jose Calasanz, BSc, PhD9*, Maria Luisa Martin-Ramos3*, David Lara-Astiaso, PhD10*, Amaia Vilas-Zornoza, PhD11*, Diego Alignani, PhD10*, Idoia Rodriguez10*, Sarai Sarvide10*, Ramon Garcia-Sanz, MD, PhD12, Joaquin Martinez-Lopez, MD, PhD3*, Albert Oriol, MD13*, Rafael Rios, MD, PhD14*, Jesús Martín15*, Rafael Martínez16*, Josep Sarra17*, Miguel T Hernández, MD, PhD18*, Javier De La Rubia, MD19*, Isabel Krsnik20*, Jose Maria Moraleda21*, Luis Palomera, MD, PhD22*, Joan Bargay, MD, PhD23*, Alberto Orfao, MD, PhD7, Laura Rosiñol24*, Maria-Victoria Mateos, MD, PhD25, Juan Jose Lahuerta, MD, PhD26*, Joan Bladé, MD, PhD27, Jesus F San-Miguel, MD, PhD9 and Bruno Paiva, PhD9*

1Centro de Investigación Médica Aplicada, University of Navarra, Clínica Universidad de Navarra, Pamplona, Spain
2Departamento de Hematología, Hospital Universitario de Salamanca (HUSAL), IBSAL, IBMCC (USAL-CSIC), CIBERONC, Salamanca, Spain
3Hospital Universitario 12 de Octubre, Madrid, Spain
4Hospital Universitario La Fe, Valencia, Spain
5Hospital Universitario Salamanca, Salamanca, Spain
6Clinica Universidad de Navarra, Pamplona, Spain
7Cancer Research Center (IBMCC, USAL-CSIC), Department of Medicine and Cytometry Service (NUCLEUS), University of Salamanca; Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain
8Hospital Universitario De Salamanca, Salamanca, ESP
9Clínica Universidad de Navarra, Centro de Investigación Médica Aplicada (CIMA), IDISNA, CIBERONC, Pamplona, Spain
10Centro de Investigación Médica Aplicada, University of Navarra, Clinica Universidad de Navarra, Pamplona, Spain
11Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
12University Hospital of Salamanca, Salamanca, ESP
13Hospital Germans Trias i Pujol, Badalona, Spain
14Hospital Universitario Virgen de las Nieves de Granada, Granada, Spain
15Hospital Universitario Virgen del Rocío, Sevilla, Spain
16Hospital Clínico San Carlos, Madrid, Spain
17ICO L'HOSPITALET, Barcelona, Spain
18Department of Hematology, Hospital Universitario de Canarias, La Laguna, Spain
19Hematology Department, Universidad Católica de Valencia Hospital Dr. Peset, Valencia, Spain
20Hospital Universitario Puerta de Hierro, Hospital, Madrid, Spain
21Hospital Virgen de la Arrixaca, El Palmar, Spain, Murcia, ESP
22Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain
23Hospital Sont LLatzer, Palma de Mallorca, Spain
24Hospital Clinic, MADRID, ESP
25University Hospital of Salamanca, Salamanca, Spain
26Department of Hematology, Hospital Universitario 12 de Octubre, Madrid, Spain
27Servei d'Hematologia, Hospital Clínic de Barcelona, Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain

Background: Despite significant improvements in the treatment of MM, the outcome of patients with HR cytogenetics remains poor despite similar complete remission (CR) rates as compared to SR cases. Relapses among patients in CR are attributed to the persistence of MRD, but knowledge about the impact of MRD in patients with SR and HR cytogenetics, treated with modern therapies and monitored with next-generation techniques, is limited. Similarly, there is virtually no data about in vivo mechanisms of resistance in SR and HR MM; however, since MRD represents those very few cells that are resistant to treatment, it could be hypothesized that profiling MRD cells may shed light into the mechanisms of resistance in both SR and HR patients.

Aim: To determine the clinical impact of MRD in MM patients with SR vs HR cytogenetics, and to identify transcriptional mechanisms determining MRD resistance by investigating the transcriptome of MRD cells in both patient subgroups.

Methods: This study was conducted in a series of 390 patients enrolled in the PETHEMA/GEM2012 trial (6 induction cycles with VRD followed by ASCT and 2 courses of consolidation with VRD). FISH was analyzed on CD138 purified PCs at diagnosis. MRD was predefined to be prospectively assessed following induction, transplant and consolidation, using next-generation flow (NGF) according to EuroFlow. In 40 patients [28 with SR and 12 with HR cytogenetics: i.e., t(4;14), t(14;16) and/or del(17p)], diagnostic and MRD tumor cells persisting after VRD-induction were isolated by FACS according to patient-specific aberrant phenotypes. Due to the small number of sorted MRD cells (median of 25,600) we used a 3’ end RNAseq method optimized for generating libraries from low-input starting material (MARSeq). Differential expression analyses were performed with DESeq2 R package.

Results: At the latest time-point in which MRD was assessed, MRD-positive rates progressively increased (p =.006) from SR patients (148/300, 49%) to cases with t(4;14) (24/42, 57%) and del(17p) (29/38, 76%). Furthermore, MRD levels were significantly superior in patients with del(17p) compared to SR FISH (0.02% vs 0.006%, p =.009), while MRD levels in patients with t(4;14) (0.004%) were similar to those in SR MM. Only 10 patients had a t(14;16) and 4 were MRD-positive.

Among patients achieving MRD-negativity (<2x10-6), 3-year progression-free survival (PFS) rates were similar for those with SR FISH, t(4;14) and del(17p) (90%, 100% and 89%; p >.05). Conversely, 3-year PFS rates for MRD-positive patients decreased from those having SR FISH to those with t(4;14) and del(17p) (59%, 46% and 24%, respectively), with statistically significant differences between the first and the latest subgroups (p <.001).

Since clearance of MRD notably lowered the risk of relapse and persistence of MRD significantly shortened the PFS in each cytogenetic group (p ≤.001), we investigated the unique features of MRD cells persisting after VRD-induction by comparing their transcriptome to that of patient-matched tumor cells at diagnosis (n=40). Accordingly, MRD cells showed 763 genes significantly deregulated (Padj <.05), including a cluster of proteasome subunits and proteasome related genes (i.e. PSMB5, PSMC3IP, BTRC, HUWE1, FBXL20 and TRIM69). Gene set enrichment analysis unveiled biologic determinants of MRD resistance such as the IL6-JAK-STAT signaling pathway in SR patients and the ROS pathway in HR patients (FDR <0.1). Interestingly, the number of genes deregulated in MRD cells of SR patients was 9-fold higher than HR cases suggesting that, whereas in SR MM, a few tumor cells with specific gene regulatory networks may have higher probability to persist VRD induction, the presence of HR cytogenetic alterations is associated per se, with a transcriptional program that allows a few MRD cells to persist treatment.

Conclusions: This is one of the largest studies integrating patients’ cytogenetics and MRD status. Our results, based on intensive treatment and MRD monitoring using NGF, unveil that achieving MRD-negativity may overcome the poor prognosis of HR cytogenetics. By contrast, persistent MRD significantly reduces PFS rates, particularly in patients with del(17p). Interestingly, MRD cells from SR and HR patients may have different transcriptional mechanisms leading to VRD resistance, and further understanding of these could provide knowledge on how to eradicate MRD in both patient subgroups.

Disclosures: Puig: Takeda: Consultancy, Honoraria; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Garcia-Sanz: Affimed: Research Funding. Martinez-Lopez: BMS: Research Funding; Pfizer: Research Funding; Vivia: Honoraria; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Research Funding. Oriol: Celgene: 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; Takeda: 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, Speakers Bureau. Rios: Amgen, Celgene, Janssen, and Takeda: Consultancy. De La Rubia: Ablynx: Consultancy, Other: Member of Advisory Board. Mateos: 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; GSK: Consultancy, 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; Celgene: 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; 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. Lahuerta: Janssen: 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; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bladé: Janssen: Honoraria. San-Miguel: Amgen: Honoraria; BMS: Honoraria; Novartis: Honoraria; Sanofi: Honoraria; Celgene: Honoraria; Roche: Honoraria; Janssen: Honoraria.

*signifies non-member of ASH