IgA Plasma Cells Are Long-Lived Residents of Gut and Bone Marrow That Express Isotype- and Tissue-Specific Gene Expression Patterns

Antibody secreting plasma cells are made in response to a variety of pathogenic and commensal microbes. While all plasma cells express a core gene transcription program that allows them to secrete large quantities of immunoglobulin, unique transcriptional profiles are linked to plasma cells expressing different antibody isotypes. IgA expressing plasma cells are generally thought of as short-lived in mucosal tissues and they have been understudied in systemic sites like the bone marrow. We find that IgA+ plasma cells in both the small intestine lamina propria and the bone marrow are long-lived and transcriptionally related compared to IgG and IgM expressing bone marrow plasma cells. IgA+ plasma cells show signs of shared clonality between the gut and bone marrow, but they do not recirculate at a significant rate and are found within bone marrow plasma cells niches. These data suggest that systemic and mucosal IgA+ plasma cells are from a common source, but they do not migrate between tissues. However, comparison of the plasma cells from the small intestine lamina propria to the bone marrow demonstrate a tissue specific gene transcription program. Understanding how these tissue specific gene networks are regulated in plasma cells could lead to increased understanding of the induction of mucosal versus systemic antibody responses and improve vaccine design.

Differences and Similarities in Treatment Paradigms and Goals Between AL Amyloidosis and Multiple Myeloma

Although there are similarities in the treatment paradigms between AL amyloidosis and multiple myeloma, there are also fundamental differences. A similarity is of course the use of anti-plasma cell drugs in both diseases; however, the most serious mistake a hemato-oncologist can make is to use the same treatment schedule in dosing and frequency in AL amyloidosis patients as in multiple myeloma patients. AL amyloidosis patients with >10% bone marrow plasma cell infiltration in particular are at risk of receiving a more intensive treatment than they can tolerate. This difference in dosing and frequency is true for many anti-clonal drugs, but it is most apparent in the use of high-dose melphalan and autologous stem cell transplantation. While in multiple myeloma in the age group of ≤70 years, more than 80% of patients are fit enough to receive this intensive treatment, this is the case in less than 20% of AL amyloidosis patients. A similarity is the alignment in the goal of treatment. Although in AL amyloidosis has long been recognized that the goal should be complete hematological remission, this has become more apparent in multiple myeloma in recent years. A common goal in the coming years will be to evaluate the role of minimal residual disease to improve survival in both diseases.

Identification of biomarkers and signaling pathways during the treatment of multiple myeloma

Multiple myeloma (MM) is an incurable hematologic malignancy, which is characterized by increased bone marrow plasma cells, osteolytic lesions, and anemia. Here, our aim is to characterize significant biomarkers and signaling pathways during the treatment of MM by using bioinformatic methods. The GSE180018 dataset was generated by DNBSEQ-G400 (Homo sapiens). The KEGG and GO analyses showed the biological processes such as " Protein export”, “Protein processing in endoplasmic reticulum”, “Vibrio cholerae infection”, “Fc gamma R-mediated phagocytosis" are mainly affected in FOXM1 KO MM cells. Moreover, we identified the significant genes including CD44, NOTCH1, SELL, RAC2, HSPA8, VAV1, DDIT3, PLK1, HYOU1, ITGAL in FOXM1 KO MM cells. Therefore, our study may provide further guidance for the drug development of MM.

A Randomized Placebo-Controlled Phase 2 Study of Metformin for the Prevention of Progression of Monoclonal Gammopathy of Undetermined Significance and Low Risk Smoldering Multiple Myeloma

Background: Multiple Myeloma (MM) is thought to evolve from the precursor conditions monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM (SMM), which are common premalignant disorders that progress to overt MM in a subset of individuals for reasons that are poorly understood. Despite increasing interest in preventing disease progression in this patient population, the standard of care still consists of close surveillance until progression to MM; however, once MM develops it cannot be cured. Therefore, the identification of prevention and interception strategies for patients with MGUS and SMM is of considerable importance. A promising pharmacologic intervention to reduce the risk of progression of MGUS/SMM to MM is metformin, a drug commonly used to treat type 2 diabetes but that is also considered safe for use in non-diabetic populations. In vivo and in vitro studies have revealed that metformin has direct antitumor effects across a variety of cancers including MM, and recent epidemiological data suggests it may reduce the risk of MM in diabetic patients with MGUS. Here, we describe the first randomized controlled trial testing the efficacy of metformin in reducing clinical signs of disease progression in patients with MGUS and SMM (NCT04850846). Study Design and Methods: This is a phase II single center, randomized controlled trial of metformin vs. placebo in patients with high-risk MGUS and low-risk SMM. The primary objective of the study is to determine whether metformin can reduce or stabilize serum monoclonal (M-)protein concentrations from baseline to 6-months. Exploratory objectives include mass spectrometry quantification of M-protein, examination of molecular evolution of tumor cells in response to metformin, as well as changes in other clinical laboratory parameters in response to metformin. To be eligible, patients must have high-risk MGUS or low-risk SMM. High-risk MGUS is defined as bone marrow plasma cell concentration <10% with one or more of the following higher-risk features: serum M-protein level ≥1.5 g/dL to <3 g/dL or abnormal free light-chain (FLC) ratio (<0.26 or>1.65); a forthcoming amendment will include non-IgG subtype as an additional high-risk feature. Low-risk SMM is defined as bone marrow plasma cells ≥10%with the absence of any features of high-risk SMM. Metformin and its corresponding placebo are the pharmacological treatments. The metformin dose is 1500 milligrams/day, provided in 500 milligram pills. To minimize gastrointestinal symptoms, metformin is started at a low dose of 500 milligram (1 pill) per day and participants gradually increase the dosage over the course of the first month of treatment until the full 1500 milligram (3 pill) per day regimen is achieved. The study treatment period is 6 months, with primary outcomes assessed at the end of the 6-month treatment period. Conclusions and Future Directions: While the cornerstone of clinical management in MGUS and SMM is to delay therapy until progression to symptomatic MM, patients and oncologists continually seek new ways to prevent end organ damage and incurable malignancy. This trial is positioned to provide preliminary but robust mechanistic data to support the development of novel prevention strategies for MGUS and SMM patients. Disclosures Marinac: GRAIL Inc: Research Funding; JBF Legal: Consultancy. Sperling: Adaptive: Consultancy. Parnes: Sigilon: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; UniQure: Membership on an entity's Board of Directors or advisory committees; Sunovion: Consultancy; I-mAb: Consultancy; Aspa: Consultancy; Genentech/Hoffman LaRoche: Research Funding; Shire/Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Richardson: Protocol Intelligence: Consultancy; Regeneron: Consultancy; Sanofi: Consultancy; Secura Bio: Consultancy; AbbVie: Consultancy; Janssen: Consultancy; GlaxoSmithKline: Consultancy; AstraZeneca: Consultancy; Karyopharm: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Oncopeptides: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding. Ghobrial: AbbVie, Adaptive, Aptitude Health, BMS, Cellectar, Curio Science, Genetch, Janssen, Janssen Central American and Caribbean, Karyopharm, Medscape, Oncopeptides, Sanofi, Takeda, The Binding Site, GNS, GSK: Consultancy. Nadeem: Karyopharm: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: metformin, which is an anti-diabetic medication

A Novel Early Relapse Prediction Score Based on Age, ISS and Disease Status at the Time of Transplant in Patients with Newly Diagnosed Multiple Myeloma. a Study of the EBMT Chronic Malignancies Working Party

Rationale and Aim: In patients with Myeloma, early relapse following Autologous Haematopoietic Cell Transplantation (Auto-HCT) is a poor prognostic marker. Two groups have published scoring systems to predict early relapse. The CIBMTR score is based on cytogenetics, the bone marrow plasma cell percentage at the time of Auto-HCT and serum albumin. The GIMEMA Simplified early relapse in multiple myeloma (S-ERMM) score is a cumulative score based on a raised serum lactate dehydrogenase (LDH), t(4;14), del17p, low albumin, bone marrow plasma percentage >60%, and lambda light chain. The aim of the current study was to develop a scoring system to predict early relapse post-Auto-HSCT-1 using readily available variables. Study design and statistics: Within the EBMT database, there were 8,206 patients meeting the following eligibility criteria: First auto transplant 2014-2019, Known sex, ISS at diagnosis, cytogenetics analysis at diagnosis, disease status at Auto-HCT, Interval diagnosis-Auto-HCT > 1 month and <= 12 months, conditioning with Melphalan 200 mg/m2 and known information on relapse; tandem auto-allo patients were excluded. The analysis consisted of two steps: (1) Training: modeling based on 4,389 patients (611 events for PFS12) transplanted between 2014 and 2017, with internal validation carried out by bootstrapping; and (2) Testing: the models obtained were applied to 3,817 patients (346 events for PFS12) transplanted in 2018 and 2019 for external validation. The characteristics of the two cohorts are first reported separately and then together (Table 1). Possible adjustment factors analyzed for the prognostic model included Age at Auto-HCT, Known sex, ISS at diagnosis, disease status at Auto-HCT, and time from diagnosis to Auto-HCT. Complete cytogenetic information was not available at the time of this analysis and will be included in the later analysis. The shape of the effect of age and of time from diagnosis to Auto-HCT was investigated both by the analysis of residuals and by applying boot-strap backward selection among different alternatives. The final results were confirmed in a robustness analysis excluding patients undergoing tandem Auto-HCT. Results: Comparison of the training and validation cohorts revealed no relevant differences (Table 1). Importantly, OS and PFS of both cohorts were overlapping with the probability of PFS at 12 months being 83.3% and 86.8%, respectively. The cumulative incidence of relapse at 12 month was 15.7% and 12.1%, respectively. Among patients who relapsed early, this occurred at a median of 6.64 months (0.56-11.99) in the first cohort, and at 5.85 months (0.1- 11.99) in the second cohort. The final model included (1) disease status at Auto-HCT, (2) age at Auto-HCT, and (3) ISS at diagnosis. Considering the order of magnitude of the coefficients, the points attributed in the risk score were: 0 for CR or VGPR; 1 for PR or SD/MR; 3 for Rel/Prog; 0 / 1/ 2 respectively for ISS I / II / III and -1 for Age<=55 yrs; -2 for Age (55-75 yrs]; -3 for Age>=75 yrs. The Hazard Ratio for a +1 point is 1.52 i.e. the risk of early relapse/death increased on average by 52% for each additional point in the score. The distribution of risk scores was as follows: Score= -2 (n=757), -1 (n=1,481), 0 (n=1,358), 1 (n=647), and 2 (n=146). The score allows separation of the PFS12 curves (Figure 1), with the lowest risk group (N=757) having a PFS at 12 months of 91%, and the highest risk group (N=146) having a PFS at 12 months of 65%. Despite some minor differences in the risk factors between the training and validation cohorts, the score has a similar average effect (HR=1.48 i.e. + 48% hazard for each additional point) and worked well in separating the curves, in particular in identifying the patients at high risk of early relapse. Discussion and conclusion: The new EBMT score to predict early relapse post-Auto-HCT uses the easily available variables of age and ISS stage at diagnosis as well as the dynamic variable of response to induction. With this simple approach, we were able to clearly identify patients at high risk of early relapse. To our surprise, older age emerged as a protective factor against relapse. This may reflect a relative selection bias in that older patients with higher risk disease may not have been selected for transplant. Impact of cytogenetics will be presented at the Congress. In conclusion, this novel scoring system is robust and easy to use in routine daily practice. Figure 1 Figure 1. Disclosures Beksac: Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Oncopeptides: Consultancy. Blaise: Jazz Pharmaceuticals: Honoraria. Leleu: Karyopharm Therapeutics: Honoraria; AbbVie: Honoraria; Bristol-Myers Squibb: Honoraria; Amgen: Honoraria; Merck: Honoraria; Mundipharma: Honoraria; Novartis: Honoraria; Carsgen Therapeutics Ltd: Honoraria; Oncopeptides: Honoraria; Janssen-Cilag: Honoraria; Gilead Sciences: Honoraria; Celgene: Honoraria; Pierre Fabre: Honoraria; Roche: Honoraria; Sanofi: Honoraria; Takeda: Honoraria, Other: Non-financial support. Forcade: Novartis: Consultancy, Other: Travel Support, Speakers Bureau; Gilead: Other: Travel Support, Speakers Bureau; Jazz: Other: Travel Support, Speakers Bureau; MSD: Other: Travel Support. Rabin: Janssen: Consultancy, Honoraria, Other: Travel support for meetings; BMS / Celgene: Consultancy, Honoraria, Other: Travel support for meetings; Takeda: Consultancy, Honoraria, Other: Travel support for meetings. Kobbe: Celgene: Research Funding. Sossa: Amgen: Research Funding. Hayden: Jansen, Takeda: Other: Travel, Accomodation, Expenses; Amgen: Honoraria. Schoenland: Pfizer: Honoraria; sanofi: Research Funding; janssen,Prothena,Takeda,: Consultancy, Honoraria. Yakoub-Agha: Jazz Pharmaceuticals: Honoraria.

A Phase II Study of Daratumumab in Patients with High-Risk MGUS and Low-Risk Smoldering Multiple Myeloma

Introduction : Daratumumab (Dara) is an anti-CD38 monoclonal antibody that is approved for use in patients with newly diagnosed and relapsed multiple myeloma (MM). We hypothesized that early therapeutic intervention with Dara in patients with high-risk MGUS (HR-MGUS) or low-risk SMM (LR-SMM) would lead to eradication of the tumor clone by achieving deep responses, resulting in prevention of progression to MM. We present results of our phase II, single arm study of Dara in HR-MGUS and LR-SMM. Methods : Patients enrolled on this study met eligibility for either HR-MGUS or LR-SMM. HR-MGUS is defined as <10% bone marrow plasma cells and <3g/dL M protein and at least 2 of the following 3 high-risk criteria: Abnormal serum free light chain ratio (SFLC) of <0.26 or >1.65, M protein ≥ 1.5g/dL or non-IgG M protein. LR-SMM is defined by one of the following 3 criteria: M protein ≥3g/dL, ≥10% bone marrow plasma cells, SFLC ratio <0.125 or >8. Dara (16mg/kg) was administered intravenously on a weekly schedule for cycles 1-2, every other week cycles 3-6, and monthly during cycles 7-20. The primary objective of this study was to determine the proportion of patients who achieve very good partial response (VGPR) or greater after 20 cycles of Dara. Secondary objectives included duration of response, safety, and rates of minimal residual disease (MRD)-negativity in VGPR or greater patients. Correlative studies included assessing changes in immune microenvironment, evaluating clonal heterogeneity using deep sequencing, and determining association of genomic aberrations correlating with either response to therapy or progression of disease. Results : At the time of data cutoff, a total of 42 patients were enrolled on this study from 2018 to 2020 with participation of 5 sites. The median age for all patients at enrolment was 60 years (range 38 to 76), with 22 males (52.4%) and 20 females (47.6%). Majority of patients enrolled were classified as LR-SMM (n = 37, 88.1%) and the remaining 5 patients had HR-MGUS (11.9%). 41 patients have started treatment and are included in toxicity assessment, and 40 patients have at least completed 16 cycles (range 6-20). Grade 3 toxicities were rare and only experienced in 5/41 patients including diarrhea (n =1/41; 2%), flu like symptoms (n = 1/41; 2%), headache (n=1/41; 2%), and hypertension (n=2/41; 5%). Most common toxicities of any grade included fatigue (n = 24/41, 51%), cough (n = 19/41, 46%), nasal congestion (n = 18/41, 44%), headache (n = 14/41, 34%), hypertension (n = 11/41, 27%), nausea (n = 13/41, 32%), and leukopenia (n = 13/41, 32%). No patients have discontinued therapy due to toxicity. Minimal response or better was observed in 82.9% of patients (34/41) and PR or better was observed in 51.2% of patients (21/41). This included overall CR (n = 4, 9.8%), VGPR (n = 1, 2.4%), PR (n = 16, 39.0%), MR (n = 13, 31.7%), and SD (n = 7, 17.1%). In the 40 patients who completed at least 16 cycles, response rates were as follows: MR or better 85% (34/40), PR or better 52.5% (21/40) and VGPR or better 12.5% (5/40). Median time to VGPR was 7 months. Median overall survival and progression-free survival have not been reached and no patients have progressed to overt multiple myeloma while on study. Conclusion : Dara is very well tolerated among patients with HR-MGUS and LR-SMM with minimal toxicities. Responses are seen in majority of patients. Early therapeutic intervention in this precursor patient population appears promising but longer follow up is required to define the role of single agent Dara in preventing progression to MM, therefore avoiding more toxic interventions in this low-risk patient population. Disclosures Nadeem: Karyopharm: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Yee: GSK: Consultancy; Oncopeptides: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Sanofi: Consultancy; Bristol Myers Squibb: Consultancy; Adaptive: Consultancy; Takeda: Consultancy; Karyopharm: Consultancy. Zonder: Caelum Biosciences: Consultancy; Amgen: Consultancy; BMS: Consultancy, Research Funding; Intellia: Consultancy; Alnylam: Consultancy; Janssen: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Regeneron: Consultancy. Rosenblatt: Attivare Therapeutics: Consultancy; Imaging Endpoints: Consultancy; Parexel: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Wolters Kluwer Health: Consultancy, Patents & Royalties. Mo: AbbVIE: Consultancy; BMS: Membership on an entity's Board of Directors or advisory committees; Eli Lilly: Consultancy; Epizyme: Consultancy; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees. Sperling: Adaptive: Consultancy. Richardson: Karyopharm: Consultancy, Research Funding; AstraZeneca: Consultancy; AbbVie: Consultancy; Takeda: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Janssen: Consultancy; GlaxoSmithKline: Consultancy; Protocol Intelligence: Consultancy; Secura Bio: Consultancy; Regeneron: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding. Ghobrial: AbbVie, Adaptive, Aptitude Health, BMS, Cellectar, Curio Science, Genetch, Janssen, Janssen Central American and Caribbean, Karyopharm, Medscape, Oncopeptides, Sanofi, Takeda, The Binding Site, GNS, GSK: Consultancy.

Germinal centre-driven maturation of B cell response to SARS-CoV-2 vaccination

Germinal centres (GC) are lymphoid structures where vaccine-responding B cells acquire affinity-enhancing somatic hypermutations (SHM), with surviving clones differentiating into memory B cells (MBCs) and long-lived bone marrow plasma cells (BMPCs). Induction of the latter is a hallmark of durable immunity after vaccination. SARS-CoV-2 mRNA vaccination induces a robust GC response in humans, but the maturation dynamics of GC B cells and propagation of their progeny throughout the B cell diaspora have not been elucidated. Here we show that anti-SARS-CoV-2 spike (S)-binding GC B cells were detectable in draining lymph nodes for at least six months in 10 out of 15 individuals who had received two doses of BNT162b2, a SARS-CoV-2 mRNA vaccine. Six months after vaccination, circulating S-binding MBCs were detected in all participants (n=42) and S-specific IgG-secreting BMPCs were detected in 9 out of 11 participants. Using a combined approach of single-cell RNA sequencing of responding blood and lymph node B cells from eight participants and expression of the corresponding monoclonal antibodies, we tracked the evolution of 1540 S-specific B cell clones. SHM accumulated along the B cell differentiation trajectory, with early blood plasmablasts showing the lowest frequencies, followed by MBCs and lymph node plasma cells whose SHM largely overlapped with GC B cells. By three months after vaccination, the frequency of SHM within GC B cells had doubled. Strikingly, S+ BMPCs detected six months after vaccination accumulated the highest level of SHM, corresponding with significantly enhanced anti-S polyclonal antibody avidity in blood at that time point. This study documents the induction of affinity-matured BMPCs after two doses of SARS-CoV-2 mRNA vaccination in humans, providing a foundation for the sustained high efficacy observed with these vaccines.

Expression of Cysteine-Rich Secreted Acidic Protein in Multiple Myeloma and Its Effect on the Biological Behavior of Cancer Cells

The multiple myeloma is a malignant clonal tumor of bone marrow plasma cells that is incurable and inevitably recurrent. The mechanisms of progression include tumor cell metastasis, immune escape, resistance to apoptosis, and malignant proliferation. The cysteine-rich secreted acidic protein is closely related to the growth, development, remodeling, and repair of cells and tissues. In our study, we divided myeloma patients and patients with other blood diseases into groups and measured the cysteine-rich secreted acidic protein (SPARC) content in the serum of different groups of patients as well as the prognostic differences. The U266 cells were transfected with interfering vectors and overexpressed SPARC vectors to determine the physiological functions of MM cells. Our results showed that SPARC was highly expressed in MM and the survival rate of the high SPARC expression group was lower than that of the low expression group. Interfering SPARC vectors inhibited cancer cell proliferation, migration, and invasion and promoted apoptosis. Overexpression of SPARC vectors promoted cancer cell development. SPARC affected the patient’s disease development by regulating the biological behavior of the MM cells.