Faculty Bibliography

The multiple myeloma treatment landscape has changed dramatically. This change, paralleled by an increase in scientific knowledge, has resulted in significant improvement in survival. However, heterogeneity remains in clinical outcomes, with a proportion of patients not benefiting from current approaches and continuing to have a poor prognosis. A significant proportion of the variability in outcome can be predicted on the basis of clinical and biochemical parameters and tumor-acquired genetic variants, allowing for risk stratification and a more personalized approach to therapy. This article discusses the principles that can enable the rational and effective development of therapeutic approaches for high-risk multiple myeloma.

INTRODUCTION/BACKGROUND:PD-1 and PD-L1 have been studied interchangeably in the clinic as checkpoints to reinvigorate T cells in diverse tumor types. Data for biologic effects of checkpoint blockade in human premalignancy are limited. METHODS:We analyzed the immunologic effects of PD-L1 blockade in a clinical trial of atezolizumab in patients with asymptomatic multiple myeloma (AMM), a precursor to clinical malignancy. Genomic signatures of PD-L1 blockade in purified monocytes and T cells in vivo were also compared to those following PD-1 blockade in lung cancer patients. Effects of PD-L1 blockade on monocyte-derived dendritic cells were analyzed to better understand its effects on myeloid antigen-presenting cells. RESULTS:In contrast to anti-PD-1 therapy, anti-PD-L1 therapy led to a distinct inflammatory signature in CD14+ monocytes and increase in myeloid-derived cytokines (e.g. IL-18) in vivo. Treatment of AMM patients with atezolizumab led to rapid activation and expansion of circulating myeloid cells which persisted in the bone marrow. Blockade of PD-L1 on purified monocyte-derived dendritic cells (DCs) led to rapid inflammasome activation and synergized with CD40L-driven DC maturation, leading to greater antigen-specific T cell expansion. CONCLUSIONS:These data show that PD-L1 blockade leads to distinct systemic immunologic effects compared to PD-1 blockade in vivo in humans, particularly manifest as rapid myeloid activation. These findings also suggest an additional role for PD-L1 as a checkpoint for regulating inflammatory phenotype of myeloid cells and antigen-presentation in DCs, which may be harnessed to improve PD-L1-based combination therapies. TRIAL REGISTRATION/BACKGROUND:NCT02784483Funding: NCI CA197603, CA238471, CA208328.

Multiple myeloma (MM) is the second most common hematologic malignancy. While major advances have been made in the disease, it is still incurable. Although antifolate-based drugs are not commonly used to treat myeloma, new generation analogs with distinct patterns of preclinical and clinical activity may offer an opportunity to identify new classes of potentially active drugs. Pralatrexate (PDX), which was approved for the treatment of relapsed or refractory peripheral T-cell lymphoma in 2009, may be one such drug. Pralatrexate exhibits a potency and pattern of activity distinct from its predecessors like methotrexate (MTX). We sought to understand the activity and mechanisms of resistance of multiple myeloma to these drugs, which could also offer potential strategies for selective use of the drug. We demonstrate that PDX and MTX both induce a significant decrease in cell viability in the low nanomolar range, with PDX exhibiting a more potent effect. We identified a series of myeloma cell lines exhibiting markedly different patterns of sensitivity to the drugs, with some lines frankly resistant, and others exquisitely sensitive. These differences were largely attributed to the basal RFC (Reduced Folate Carrier) mRNA expression levels. RFC mRNA expression correlated directly with rates of drug uptake, with the most sensitive lines exhibiting the most significant intracellular accumulation of pralatrexate. This mechanism explains the widely varying patterns of sensitivity and resistance to pralatrexate in multiple myeloma cell lines. These findings could have implications for this class of drugs and their role in the treatment of multiple myeloma.

Daratumumab has proven to be highly efficacious for relapsed and refractory multiple myeloma (MM) and has recently been approved in the frontline setting for MM patients ineligible for transplantation. In the future, expanded indications are possible for daratumumab and other anti-CD38 monoclonal antibodies in development. For several years, it has been recognized that these therapies interfere with blood bank testing by binding to CD38 on red blood cells and causing panagglutination on the Indirect Antiglobulin Test. This can lead to redundant testing and significant delays in patient care. Given the anticipated increase in utilization of anti-CD38 monoclonal antibodies, as well as the transfusion needs of MM patients, it is critical to understand the nature of this interference with blood bank testing and to optimize clinical and laboratory procedures. In this review, we summarize the pathophysiology of this phenomenon, examine the clinical data reported to date, describe currently available methods to resolve this issue, and lastly provide a guide to clinical management of blood transfusions for patients receiving anti-CD38 monoclonal antibodies.

PURPOSE/OBJECTIVE:Multiple myeloma (MM) is a malignancy of plasma cells, with a median survival of 6 years. Despite recent therapeutic advancements, relapse remains mostly inevitable, and the disease is fatal in the majority of patients. A major challenge in the treatment of patients with relapsed MM is the timely identification of treatment options in a personalized manner. Current approaches in precision oncology aim at matching specific DNA mutations to drugs, but incorporation of genome-wide RNA profiles has not yet been clinically assessed. METHODS:We have developed a novel computational platform for precision medicine of relapsed and/or refractory MM on the basis of DNA and RNA sequencing. Our approach expands on the traditional DNA-based approaches by integrating somatic mutations and copy number alterations with RNA-based drug repurposing and pathway analysis. We tested our approach in a pilot precision medicine clinical trial with 64 patients with relapsed and/or refractory MM. RESULTS:We generated treatment recommendations in 63 of 64 patients. Twenty-six patients had treatment implemented, and 21 were assessable. Of these, 11 received a drug that was based on RNA findings, eight received a drug that was based on DNA, and two received a drug that was based on both RNA and DNA. Sixteen of the 21 evaluable patients had a clinical response (ie, reduction of disease marker ≥ 25%), giving a clinical benefit rate of 76% and an overall response rate of 66%, with five patients having ongoing responses at the end of the trial. The median duration of response was 131 days. CONCLUSION/CONCLUSIONS:Our results show that a comprehensive sequencing approach can identify viable options in patients with relapsed and/or refractory myeloma, and they represent proof of principle of how RNA sequencing can contribute beyond DNA mutation analysis to the development of a reliable drug recommendation tool.

Phase 3 studies combining histone deacetylase inhibitors with bortezomib were hampered by gastrointestinal (GI) intolerance, which was not observed when combined with immunomodulatory drugs. This study is a single-center phase 2 study of panobinostat with lenalidomide and dexamethasone (FRD). Twenty-seven relapsed multiple myeloma patients were enrolled. Twenty-two patients (81%) were lenalidomide refractory and 9 (33%), 14 (52%), and 7 (26%) were refractory to pomalidomide, bortezomib, and carfilzomib, respectively. High-risk molecular findings were present in 17 (63%) patients. Responses included 2 complete responses (CRs), 4 very good partial responses (VGPRs), 5 partial responses (PRs), and 9 minimal responses (MRs) for an overall response rate of 41%, clinical benefit rate of 74%, and a disease control rate of 96%. The median progression-free survival (PFS) was 7.1 months. In the 22 lenalidomide-refractory patients, there were 1 CR, 4 VGPRs, 3 PRs, and 7 MRs, with a median PFS of 6.5 months. Median overall survival was not reached. Grade 3/4 toxicities were primarily hematologic. Gene expression profiling of enrollment tumor samples revealed a set of 1989 genes associated with short (<90 days) PFS to therapy. MAGEA1 RNA and protein expression were correlated with short PFS, and laboratory studies demonstrated a role for MAGE-A in resistance to panobinostat-induced cell death. FRD demonstrates durable responses, even in high-risk, lenalidomide-refractory patients, indicating the essential role of panobinostat in attaining responses. MAGEA1 expression may represent a functional biomarker for resistance to panobinostat. In contrast to PANORAMA 1, there were no significant GI toxicities and primarily expected hematologic toxicities. This trial was registered at www.clinicaltrials.gov as #NCT00742027.

OBJECTIVES/SPECIFIC AIMS: Type I Melanoma Antigen GEne (MAGE)-A3 was commonly detected in primary tumor cells from multiple myeloma (MM) patients. MAGE-A3 expression correlated with progression of disease and proliferation, suggesting a potential pathogenic role in this disease. MAGE-A complex with the RING domain protein Kap1 to form E3 ubiquitin ligases that can inactivate p53. We investigated pathogenic activity by silencing MAGE-A expression in primary MM cells and human myeloma cell lines (HMCL) by shRNA interference. Targeted lentiviral shRNA transduction efficiently knocked down MAGE-A mRNA and protein in p53-expressing MM.1r and H929 cells, and in p53-null ARP-1 and patient cells. METHODS/STUDY POPULATION: HMCL and MM patient samples. RESULTS/ ANTICIPATED RESULTS: Th is analysis showed that MAGE-A was not required for cell cycle progression. In contrast, MAGE-A was required for survival of proliferating myeloma cells. Silencing of MAGE-A led to activation of intrinsic apoptosis within 48-72 hrs, as shown by increased annexin V staining, loss of mitochondrial membrane polarization, and cleavage/ activation of caspase-9 and -3. Apoptosis was reversed by the pan-caspase inhibitor Q-VD-OPh. MAGE-A appeared to regulate p53-dependent and independent mechanisms of apoptosis. Silencing of MAGE-A resulted in loss of p53 ubiquitinylation and modulated expression of the p53 targets Bax and survivin. These changes were reversed by dual silencing of MAGE-A and p53. In p53-null HMCL, loss of MAGE-A still resulted in decreased survivin. Silencing MAGE-A also increased sensitivity to melphalan-induced apoptosis. DISCUSSION/SIGNIFICANCE OF IMPACT: These results demonstrate that MAGE-A plays a novel role in the survival of proliferating MM cells through the regulation of p53-dependent and independent mechanisms of apoptosis

PURPOSE: The type I Melanoma Antigen GEnes (MAGEs) are commonly expressed in cancers, fueling speculation that they may be therapeutic targets with oncogenic potential. They form complexes with RING domain proteins that have E3 ubiquitin ligase activity and promote p53 degradation. MAGE-A3 was detected in tumor specimens from patients with multiple myeloma and its expression correlated with higher frequencies of Ki-67(+) malignant cells. In this report, we examine the mechanistic role of MAGE-A in promoting survival of proliferating multiple myeloma cells. EXPERIMENTAL DESIGN: The impact of MAGE-A3 expression on survival and proliferation in vivo was examined by immunohistochemical analysis in an independent set of tumor specimens segregated into two groups: newly diagnosed, untreated patients and patients who had relapsed after chemotherapy. The mechanisms of MAGE-A3 activity were investigated in vitro by silencing its expression by short hairpin RNA interference in myeloma cell lines and primary cells and assessing the resultant effects on proliferation and apoptosis. RESULTS: MAGE-A3 was detected in a significantly higher percentage of relapsed patients compared with newly diagnosed, establishing a novel correlation with progression of disease. Silencing of MAGE-A showed that it was dispensable for cell cycling, but was required for survival of proliferating myeloma cells. Loss of MAGE-A led to apoptosis mediated by p53-dependent activation of proapoptotic Bax expression and by reduction of survivin expression through both p53-dependent and -independent mechanisms. CONCLUSIONS: These data support a role for MAGE-A in the pathogenesis and progression of multiple myeloma by inhibiting apoptosis in proliferating myeloma cells through two novel mechanisms. Clin Cancer Res; 17(13); 4309-19. (c)2011 AACR

The type I melanoma antigen gene (MAGE) proteins CT7 (MAGE-C1) and MAGE-A3 are commonly expressed in multiple myeloma (MM), and their expression correlates with increased plasma cell proliferation and poor clinical outcome. They belong to the cancer-testis antigen (CTAg) group of tumor-associated proteins, some of which elicit spontaneous immune responses in cancer patients. CT7 and MAGE-A3 are promising antigenic targets for therapeutic tumor vaccines in myeloma; therefore, it is critical to determine if they are immunogenic in MM patients. We analyzed cellular and humoral immune responses against CTAgs in patients with plasma cell dyscrasias: MM, monoclonal gammopathy of undetermined significance (MGUS), and Waldenstrom's macroglobulinemia (WM). Bone marrow lymphocytes from two of four untreated MM patients exhibited CT7-specific cellular immune responses as measured by an autologous cellular immunity assay, the first such immune response to CT7 to be reported in cancer patients. Sera from 24 patients were screened by ELISA for humoral immune responses to CTAgs. Two patients with MM demonstrated positive titers, one for MAGE-A1 and the other for SSX1. These data demonstrate that CTAgs, particularly CT7, are immunogenic in MM patients and merit further exploration as targets of immunological therapy in MM