Altered immune response to vaccination in patients with plasma cell premalignancy

Introduction Patients with hematological malignancies, including multiple myeloma (MM), experience suboptimal responses to SARS-CoV-2 vaccination. Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM) are precursors to MM and exhibit altered immune cell composition and function. The SARS-CoV-2 pandemic and the subsequent population-wide vaccination represent an opportunity to study the real-life immune response to a common antigen. Here, we present updated results from the IMPACT study, a study we launched in November 2020 to characterize the effect of plasma cell premalignancy on response to SARS-CoV2 vaccination (vx). Methods We performed: (i) ELISA for SARS-CoV-2-specific antibodies on 1,887 peripheral blood (PB) samples (237 healthy donors (HD), and 550 MGUS, 947 SMM, and 153 MM patients) drawn preand post-vx;(ii) single-cell RNA, T cell receptor (TCR), and B cell receptor (BCR) sequencing (10x Genomics) on 224 PB samples (26 HD, and 20 MGUS, 48 SMM, and 24 MM patients) drawn preand post-vx;(iii) plasma cytokine profiling (Olink) on 106 PB samples (32 HD, and 38 MGUS and 36 SMM patients) drawn pre- and post-vx;and (iv) bulk TCR sequencing (Adaptive Biotechnologies) on 8 PB samples from 4 patients (2 MGUS, 2 SMM) drawn pre- and post-vx. Results Patients with MGUS and SMM achieved comparable antibody titers to HD two months post-vx. However, patient titers waned significantly faster, and 4 months post-vx we observed significantly lower titers in both MGUS (Wilcoxon rank-sum, p=0.030) and SMM (p=0.010). These results indicate impaired humoral immune response in patients with MGUS and SMM.At baseline, the TCR repertoire was significantly less diverse in patients with SMM compared to HD (Wilcoxon rank-sum, p=0.039), while no significant difference was observed in the BCR repertoire (p=0.095). Interestingly, a significant increase in TCR repertoire diversity was observed post-vx in patients with SMM (paired t-test, p=0.014), indicating rare T cell clone recruitment in response to vaccination. In both HD and patients, recruited clones showed upregulation of genes associated with CD4+ naive and memory T cells, suggesting preservation of the T cell response in SMM, which was confirmed by bulk TCR-sequencing in 4 patients.Lastly, by cytokine profiling, we observed a defect in IL-1beta and IL-18 induction post-vx in patients with SMM compared to HD (Wilcoxon rank-sum, p=0.047 and p=0.015, respectively), two key monocyte-derived mediators of acute inflammation, suggesting an altered innate immune response as well. Conclusion Taken together, our findings highlight that despite the absence of clinical manifestations, plasma cell premalignancy is associated with defects in both innate and adaptive immune responses. Therefore, patients with plasma cell premalignancy may require adjusted vaccination strategies for optimal immunization.

Humoral SARS-CoV-2 response in asymptomatic precursor plasma cell dyscrasia patients: IMPACT study results

Introduction: Patients with hematologic malignancies, including multiple myeloma (MM), experience worse SARS-CoV-2 infection outcomes and sub-optimal vaccine responses. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) precede MM and affect ∼5% of individuals age >=50. We previously showed that individuals with MGUS and SMM exhibit immune dysregulation. Here, we investigate the immune response to SARS-CoV-2 vaccination in these asymptomatic but potentially immunocompromised individuals. Methods: The IMPACT study (IRB #20-332) is a prospective study at Dana-Farber Cancer Institute in collaboration with MMRF, which enrolled individuals nationwide with a diagnosed plasma cell dyscrasia and healthy individuals. As of October 2021, 3,005 individuals completed a questionnaire regarding prior infection or vaccination. We obtained 1,350 blood samples from 628 participants and analyzed anti-SARS-CoV-2 IgG antibody titer by ELISA. Results: 2,771 (92%) participants were fully vaccinated (2 doses BNT162b2 or mRNA-1273;1 dose Ad26.COV2.s), 269 (9%) had received a 3rd mRNA vaccine dose, and 234 (8%) were unvaccinated. 1,387 (46%) and 1,093 (36%) participants received mRNA vaccines (BNT162b2 and mRNA-1273), and 139 (5%) participants received an adenovirus vector vaccine (Ad26.COV2.S). 34 (1%) individuals reported SARS-CoV-2 infection after full vaccination. We measured antibody titers in 201 MGUS, 223 SMM, 40 smoldering Waldenstrom macroglobulinemia (SWM), 64 MM, and 100 healthy controls. Multiple linear regression model estimated the association between various clinical variables and post-vaccination antibody titers. As previously reported, having MM was associated with low antibody titer (p < 0.001). Of note, having SMM, regardless of risk stratification by 2/20/20 criteria, was also associated with low antibody titers, indicating that even low-risk SMM patients have a poor response to vaccination. MGUS and SWM diagnoses were not significantly associated with antibody titers. Additionally, male sex (p < 0.010), elapsed time after vaccination (p < 0.001), and BNT162b2 vaccine (p < 0.001) were associated with low antibody titers. SARS-CoV-2 infection prior to vaccination was associated with high antibody titers. We identified 25 patients (6 MGUS, 10 SMM, 2 SWM, 7 MM) who submitted blood samples after both the 2nd and 3rd dose. In these patients we observed a significant increase in antibody titer after a 3rd dose (p = 0.002). We also observed that antibody titers of patients after a 3rd dose (13 MGUS, 12 SMM, 2 SWM, 31 MM) were comparable to that of healthy individuals after a 2nd dose (p = 0.833). Conclusion: Our data indicates that suboptimal response to SARS-CoV-2 does not only occur with MM and cancer patients receiving therapy but also in precursor asymptomatic patients including low-risk SMM.

Single-cell RNA-sequencing for immune profiling of SARS-CoV2 vaccine response in healthy individuals and patients with precursor plasma cell malignancies

Introduction: Patients with hematological malignancies exhibit inferior response to SARS-CoV2 vaccination, compared to healthy individuals, however little is known about patients with precursor hematological malignancies and the cellular underpinnings of vaccination response. Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Myeloma (SMM) are plasma cell premalignancies that precede Multiple Myeloma (MM) and exhibit signs of immune dysregulation;they affect approximately 5% of the population over 50 years of age, who remain largely undiagnosed, due to lack of screening. In November 2019, we launched the IMPACT study to characterize the immune response to SARS-CoV2 vaccination in patients with plasma cell dyscrasias and healthy individuals. Methods: We performed single-cell RNA-sequencing on 224 peripheral blood mononuclear cell samples drawn from 118 IMPACT (IRB #20-332) participants with MGUS (n=20), SMM (n=48), or MM (n=24), as well as healthy individuals (n=26). Samples were collected before vaccination and after 2 doses of BNT162b2 (Pfizer-BioNtech) (n=123), mRNA-1273 (Moderna) (n=83) or 1 dose of Ad26.COV2.S (Janssen) (n=14). Results: Overall, we sequenced 2,025,611 cells from 224 samples of 118 patients with MGUS, SMM, MM and healthy individuals pre- and post-vaccination for SARS-CoV2, and profiled 553,082 T-cells, 95,392 B-cells, 74,394 NK cells, 195,371 Monocytes, and 35,236 Dendritic cells (DC). We identified activated clusters of B-cells, NK cells and DCs expressing genes such as CD83, CD69, CXCR4, and genes related to the NF-kB and AP-1 pathways. We compared cell type abundances pre- and post-vaccination within each participant population and found that activated CD83+ cells significantly increased post-vaccination in healthy individuals and patients with MGUS (paired t-test, q < 0.1), but not in patients with SMM or overt MM. At baseline, patients with SMM and MM had significantly fewer memory B-cells and significantly more cytotoxic T-cells and NK cells, compared to healthy individuals (Wilcoxon, q < 0.1), which could partly explain the differences observed post-vaccination. Patients with MM also had significantly higher levels of tolerogenic IL-10-expressing DCs (DC10) at baseline (Wilcoxon, q < 0.1), which could be dampening antigen-specific T-cell responses. Conclusion: We identified a significant expansion of activated B-cell, NK cell and DC subpopulations expressing CD83, CD69 and CXCR4, following vaccination in healthy individuals and patients with MGUS, but less so in patients with SMM and overt MM. Our results provide insight into the cellular mechanisms of immune response to SARS-CoV2 vaccination in healthy individuals and patients with precursor plasma cell malignancies and suggest that asymptomatic individuals with SMM may exhibit inferior response to vaccination.

A Next Generation Liquid Biopsy Approach for Multiple Myeloma

Direct-to-Patient (DTP) Multiple Myeloma (MM) research studies have been launched recently, including PCROWD (NCT02269592), PROMISE (NCT03689595) and the MMRF CureCloud Research Initiative (NCT03657251), aimed at enrolling thousands of individuals from whom comprehensive molecular and immune analyses will be generated from blood specimens and the resulting data aggregated with the correlating clinical information. To support the molecular characterization of liquid biopsies for such DTP efforts, a set of myeloma-specific liquid biopsy approaches were developed. First, a hybrid selection panel was developed that detects somatic variants present in a patient's circulating-free DNA (cfDNA) in 70 commonly altered MM and Clonal Hematopoiesis of Indeterminate Potential (CHIP) genes. For this MM 70-Gene cfDNA Assay, samples are received as blood in a StreckTM tube designed for stabilization of cfDNA and DNA is extracted from buffy coat using magnetic bead-based chemistry. Deep coverage sequencing (80,000x depth) is performed and duplex BAM files generated with UMI alignment and error correction allowing for sensitive detection of clinically relevant variants. Technical validation data on healthy donor cfDNA mixes was generated using samples with a range of cfDNA inputs. This data determined that the assay is capable of achieving >90% sensitivity for detecting somatic events present at 1% variant allele frequency with a specificity of <0.2 false positives per megabase. Using a clinical cohort, we observed a strong correlation between Bone Marrow Aspirate (BMA) and cfDNA samples with the vast majority of variants previously detected in BMA also identified via the MM-70 Gene panel analysis. Interestingly, we also saw evidence of additional somatic variants identified in cfDNA previously undetected in BMA analysis. Because one the aims of this effort is to return results to treating physicians, a clinical-grade (CLIA) pipeline was established. For that CLIA pipeline, the variants reported are a subset of all the events detected by the MM 70-Gene Assay. The events detected in the assay are reviewed by experienced molecular pathologists at the Dana Farber Cancer Institute (DFCI) who have developed a customized reporting process. These reports utilize an internally-developed knowledgebase of variant/gene annotations that leverages the DFCI expertise in hematologic malignancies and myeloma specifically. The reports are then provided back through providers to the patient via the CureCloud system for their use in clinical care and trial identification. In order to complement the MM-70 Gene panel with copy number and translocation information, we have been exploring Circulating Multiple Myeloma Cells (CMMCs). Our current approach involves automated capture of CMMCs using ferrofluids coated with MM-selective and discriminating antibodies to immunomagnetically enrich circulating plasma cells. The highly enriched CMMCs fractions generated in such a fashion are then submitted for molecular characterization. At the submission date of this abstract, 163 patients have been fully enrolled into CureCloud from which results will be presented. In summary, we have developed a robust and very sensitive clinical-grade next-gen liquid biopsy sequencing platform allowing for minimally invasive monitoring of MM disease genomics that can be used to complement other more classical approaches and to help support our Direct-To-Patient Initiatives. Especially in this post-COVID19 era, such liquid biopsy-based approaches that avoid clinic visits for the patients and can be performed through at-home mobile phlebotomy are emerging as important new options. Disclosures: Kim: LabCorp: Consultancy;Quanterix, Inc: Consultancy;PapGene, Inc: Consultancy. Ghobrial: AbbVie: Consultancy;GNS Healthcare: Consultancy;GlaxoSmithKline: Consultancy;Genentech: Consultancy;Noxxon Pharma: Consultancy;Novartis: Consultancy;Adaptive Biotechnologies: Consultancy, Honoraria;Sanofi: Consultancy, Honoraria;Celgene: Consultancy, Honoraria;Bristol-Myers Squibb: Consultanc , Honoraria;Janssen: Consultancy, Honoraria;Takeda: Consultancy, Honoraria;Cellectar: Honoraria;Karyopharm Therapeutics: Consultancy, Honoraria;Amgen: Consultancy, Honoraria.