Treatment Option For Myeloma Patients Research Articles

CS1 CAR-T targeting the distal domain of CS1 (SLAMF7) shows efficacy in high tumor burden myeloma model despite fratricide of CD8+CS1 expressing CAR-T cells

Despite improvement in treatment options for myeloma patients, including targeted immunotherapies, multiple myeloma remains a mostly incurable malignancy. High CS1 (SLAMF7) expression on myeloma cells and limited expression on normal cells makes it a promising target for CAR-T therapy. The CS1 protein has two extracellular domains – the distal Variable (V) domain and the proximal Constant 2 (C2) domain. We generated and tested CS1-CAR-T targeting the V domain of CS1 (Luc90-CS1-CAR-T) and demonstrated anti-myeloma killing in vitro and in vivo using two mouse models. Since fratricide of CD8 + cells occurred during production, we generated fratricide resistant CS1 deficient Luc90- CS1- CAR-T (ΔCS1-Luc90- CS1- CAR-T). This led to protection of CD8 + cells in the CAR-T cultures, but had no impact on efficacy. Our data demonstrate targeting the distal V domain of CS1 could be an effective CAR-T treatment for myeloma patients and deletion of CS1 in clinical production did not provide an added benefit using in vivo immunodeficient NSG preclinical models.

POS-774 BORTEZOMIB BASED CHEMOTHERAPY AND BONE MARROW FOLLOWED BY RENAL TRANSPLANTATION IN MULTIPLE MYELOMA: CASE REPORT AND SYSTEMATIC REVIEW

Kidney transplantation (KT) is traditionally not considered a cost-effective and viable option in myeloma patients with ESRD due to its overall low survival rate. With the introduction of highly effective chemotherapeutic agents (Proteasome inhibitors) followed by autologous stem cell transplantation (ASCT), KT is turning to be a promising treatment option for myeloma patients with ESRD. The systematic review aims to look at the outcomes of KT in patients of multiple myeloma, who have achieved hematological remission after treatment with Bortezomib based chemotherapy and ASCT.

Myeloma Cell Associated Therapeutic Protein Discovery Using Single Cell RNA-Seq Data

Multiple myeloma (MM) is a hematological cancer of the antibody-secreting plasma cells. Despite therapeutic advancements, MM remains incurable due to high incidence of drug-resistant relapse. In recent years, targeted immunotherapies, which take advantage of the immune system's cytotoxic defenses to specifically eliminate tumor cells expressing certain cell surface and intracellular proteins have shown promise in combating this and other B cell hematologic malignancies. A major limitation in the development of these therapies lies in the discovery of optimal candidate targets, which require both high expression in tumor cells as well as stringent tissue specificity. In an effort to identify potential myeloma-specific target antigens, we performed an unbiased search for genes with specific expression in plasma and/or B cells using single-cell RNA-sequencing (scRNAseq) of 53 bone marrow samples taken from 42 patients. By comparing >40K plasma cells to >97K immune cells across our cohort, we were able to identify a total of 181 plasma cell-associated genes, including 65 that encode cell-surface proteins and 116 encoding intracellular proteins. Of particular interest is that the plasma cells from each patient were shown to be transcriptionally distinct with unique sets of genes expressed defining each patient's malignant plasma cells. Using pathway enrichment analysis, we found significant overrepresentation of cellular processes related to B-Cell receptor (BCR) signaling, protein transport, and endoplasmic reticulum (ER) stress, involving genes such as DERL3, HERPUD1, PDIA4, PDIA6, RRBP1, SSR3, SSR4, TXNDC5, and UBE2J1. To note, our strategy successfully captured several of the most promising MM therapeutic targets currently under pre-clinical and clinical trials, including TNFRSF17(BCMA), SLAMF7, and SDC1 (CD138). Among these, TNFRSF17 showed very high plasma cell expression, with concomitant sharp exclusion of other immune cell types. To ascertain tissue specificity of candidate genes outside of the bone marrow, we analyzed gene and protein expression data from the Genotype-Tissue Expression (GTEx) portal and Human Protein Atlas (HPA). We found further support for several candidates (incl. TNFRSF17,SLAMF7, TNFRSF13B (TACI), and TNFRSF13C) as being both exclusively and highly expressed in lymphoid tissues. While several surface candidates were not found to be lymphocyte-restricted at the protein level, they remain relevant considerations as secondary targets for bi-specific immunotherapy approaches currently under development. To further investigate potential combinatorial targeting, we examine sample-level patterns of candidate co-expression and mutually-exclusive expression using correlation analysis. As the majority of our detected plasma cell-specific genes encode intracellular proteins, we investigated the potential utility of these epitopes as therapeutic targets via MHC presentation. Highly expressed candidates include MZB1, SEC11C, HLA-DOB, POU2AF1, and EAF2. We analyzed protein sequences using NetMHC and NETMHCII to predict high-affinity peptides for common class-I and class-II HLA alleles. To correlate MHC allelic preference with candidate expression in our cohort, we performed HLA-typing for 29 samples using Optitype. To support our scRNAseq-driven findings, we cross-referenced gene expression data with 907 bulk RNA-sequencing samples, including 15 from internal studies and 892 from the Multiple Myeloma Research Foundation (MMRF), as well as bulk global proteomics data from 4 MM cell lines (TIB.U266, RPMI8226, OPM2, MM1ST) and 4 patients. We see consistent trends across both cohorts, with high positive correlation (Pearson R ranging between 0.60 and 0.99) for a majority of genes when comparing scRNA and bulk RNA expression in the same samples. Our experimental design and analysis strategies enabled the efficient discovery of myeloma-associated therapeutic target candidates. In conclusion, this study identified a set of promising myeloma CAR-T targets, providing novel treatment options for myeloma patients. Disclosures Goldsmith: Wugen Inc.: Consultancy. DiPersio:Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Immunotherapy in Multiple Myeloma.

To review the use of monoclonal antibodies (mAbs) in the treatment of multiple myeloma (MM) and the management of most common side effects. Review of journal articles related to mAbs in MM. The therapeutic options for MM have improved dramatically and the development of mAbs has been associated with improvement in clinical outcomes and favorable toxicity profiles. With appropriate pre-medications and nursing management, mAbs are a well-tolerated treatment option for myeloma patients.

Identification of Dual PI3K/mTOR and BCL2 Inhibitors for the Treatment of High Risk Multiple Myeloma

IntroductionMultiple myeloma (MM) is an incurable malignant plasma cell disease with the highest incidence occurring at 65-70 years of age while 10% of patients are diagnosed below 55 years of age. The International Myeloma Working Group recently proposed new risk stratification standards for MM patients: high-risk (HR), standard (SR) and low-risk (LR) groups (Leukemia 2014, 28, 269−77). Although a median overall survival of LR patients is > 10 years from the diagnosis, new drugs and therapeutic innovations are urgently needed for HR patients (20%) who have a median overall survival of only two years. To identify new treatment options for MM patients, we compared ex vivo drug sensitivity data from primary CD138+ cells to standard risk stratification markers. Ex vivo responses indicated a number of investigational drugs as potential novel options for HR MM patients with links to risk markers.MethodsBone marrow aspirates were collected from newly diagnosed (n=14) and relapsed/refractory (n=21) MM patients. Cytogenetics were determined by fluorescence in situ hybridization (FISH) and the patients stratified based on the presence or absence of adverse FISH markers (t(4;14) and 17p del). Plasma cells (CD138+) were enriched from freshly isolated bone marrow samples and exome sequencing performed using DNA extracted from the CD138+ cells and matched skin biopsies. Ex vivo drug sensitivity was assessed by measuring the viability of the cells after 3-day incubation with 306 different oncology drugs in a 10,000-fold concentration range. Drug sensitivity scores were calculated based on the normalized area under the dose response curve (Scientific Reports 2014, 4, 5193) and select sensitivities determined by comparing results to healthy bone marrow cells. Based on drug sensitivities, the patients were classified in four different groups (sensitive, moderately sensitive, resistant and highly resistant).ResultsOf the 35 patients included in this study, 11 were classified as HR (31%) and 24 as SR/LR (69%). In the HR group 6/11 (55%) had t(4;14) and 5/11 patients (45%) had 17p13 del. In the SR/LR group common abnormalities included 13 monosomy/13q del (10/24), 1q gain (10/24) and K/NRAS mutation (11/24). Within the HR group, other co-occurring abnormalities included 1q gain (9/11), 13 monosomy/13q del (6/11), K/NRAS mutation (5/11), and TP53 mutation (2/11). Based on overall ex vivo drug sensitivity profiles of all patients, the majority of HR patients were classified as moderately sensitive (8/11; 73%) while SR/LR patients had diverse responses from sensitive to highly resistant. In the HR group, the highest select sensitivities were to BH3 mimetics and PI3K/mTOR inhibitors. While the t(4;14) is predicted to lead to upregulation and increased activity of the FGFR3, which could be targeted by FGFR inhibitors, none of the t(4;14) samples showed sensitivity to these drugs. However, with the exception of one t(4;14) sample, the rest all showed good sensitivity to dual PI3K/mTOR inhibitors, but not to rapalogs, suggesting that inhibition of PI3K and the mTORC1/2 complexes is required to inhibit t(4;14) cell growth rather than mTORC1 alone. Of the 17p del patients, 3/5 were classified as moderately sensitive, 1/5 sensitive and 1/5 highly resistant based on ex vivo drug response of CD138+ cells. All showed select sensitivity to BH3 mimetics/BCL2 inhibitors (navitoclax/ABT-263 and venetoclax/ABT-199/GDC-0199), while response to other drugs varied. Therefore, blocking cell survival signaling is likely essential for this group of HR MM patients.ConclusionBy assessing the ex vivo sensitivity of primary plasma cells to a large collection of oncology drugs and comparing these data to standard risk stratification markers for MM, we have been able to identify potential new treatment options for high risk MM patients including dual PI3K/mTOR and BCL2- inhibitors. Although a larger cohort of patients is required to support the correlation between specific drug sensitivities and risk markers, these preliminary data indicate that currently used risk markers may be useful to predict the use of novel treatments. DisclosuresSilvennoinen:Janssen-Cilag: Research Funding; Celgene: Research Funding; Janssen-Cilag: Honoraria; Sanofi: Honoraria; Celgene: Honoraria. Porkka:BMS: Honoraria; BMS: Research Funding; Novartis: Honoraria; Novartis: Research Funding; Pfizer: Research Funding. Heckman:Celgene: Research Funding.

Mtor and PI3K Inhibitors Block Myeloma Cell Growth in a Synergistic Manner.

Abstract 1843Poster Board I-869Introduction: The mammalian target of rapamycin (mToR) plays a crucial role in cell growth due to its role as nutrient dependent regulator of important cytokine signaling pathways. In multiple myeloma, mToR is involved in the phosphoinositide-3-kinase (PI3K)-AKT pathway which can be activated by the loss of the tumor suppressor phosphatase and tensin homolog (PTEN) or by stimulation with growth and survival factors such as interleukin-6 (IL-6) and insulin-like growth factor-1 (IGF-1). Inhibitors of the mToR pathway (sirolimus/rapamycin, everolimus and temsirolimus) are approved for immunosuppression and/or cancer treatment. However, the clinical activity of mToR inhibitors may be limited by the fact that, after inhibition of the rapamycin-sensitive mToR-Raptor complex, AKT is activated by the rapamycin-insensitive mToR-Rictor complex. In this regard, the inhibitory effect of mToR inhibitors was evaluated in combination with PI3K inhibitors in vitro and in vivo. Results: Rapamycin and everolimus induced a dose-dependent growth inhibition in six human malignant plasma cell lines. Growth inhibition was mediated by G1 cell cycle arrest and in a subset of cell lines by induction of apoptosis. Overexpression of Bcl-XL or Mcl-1 proteins did not prevent from apoptosis induction by mToR inhibitors, nor did sensitivity to rapamycin-induced apoptosis correlate with the p53 mutation status. In the INA-6 SCID mouse xenograft model, treatment with rapamycin resulted in a significant survival benefit compared to untreated mice. Six out of 14 rapamycin treated mice did not develop plasmacytomas during the observation period of 149 days. Remarkably, short term treatment of plasmacytoma bearing mice led to a significant shrinkage of the plasma cell tumor. Explanted tissue showed apoptotic plasma cells, a finding confirmed by immunohistological staining using an antibody specific for the human cleaved form of poly (ADP-ribose) polymerase (PARP). The combination of rapamycin and the PI3K inhibitor Ly294002 led to an increase of growth inhibition in all tested plasma cell lines. The additional growth inhibition by Ly294002 appeared to be due to AKT activation upon mToR inhibition by the rapamycin-insensitive Rictor complex, indicated by increased AKT phosphorylation at Ser473 as determined by Western blot analysis. Conclusion: Clinical trials currently evaluate mToR inhibitors for their potential to expand treatment options for myeloma patients. The data presented here suggest that a combination of mToR inhibitors with PI3K inhibitors may lead to additive therapeutic chances. Disclosures:Guenther:Novartis: Consultancy, Research Funding. Gramatzki:Novartis: Consultancy, Research Funding, Speakers Bureau.

Front line treatment of elderly multiple myeloma in the era of novel agents

Front line treatment of elderly multiple myeloma in the era of novel agents Marie-Dominique Venon2, Aldo M Roccaro1,3, Julie Gay2, Anne-Sophie Moreau1,2, Remy Dulery2, Thierry Facon2, Irene M Ghobrial1, Xavier Leleu1,21Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA; 2Service des Maladies du Sang, Hopital Huriez, CHRU, Lille, France; 3Units of Blood Diseases and Cell Therapies, University of Bresica, Medical School, Bresica, ItalyAbstract: Melphalan combined with prednisone (MP) has long been the historical treatment of reference for a large proportion of elderly myeloma (MM) patients ineligible for autologous stem cell transplantation, and is still the backbone of new regimens that include the new era of novel agents. Melphalan–prednisone–thalidomide (MPT) and melphalan–prednisone–bortezomib (Velcade®, MPV), proved superior to MP, currently appear to be the treatments of choice for this population. In the near future melphalan–prednisone–lenalidomide (Revlimid®, MPR) will also provide a third therapeutic option (MPT, MPV, and MPR), in elderly multiple myeloma, eventually. These options could lead to more personalized treatment approaches, based on patient comorbidities, as the three novel agents have somewhat different toxicity profiles. Dexamethasone-based regimen is another option and questions regarding the relative efficacy of melphalan-based versus low-dose dexamethasone-based regimens will require randomized phase III trials. More intensive approaches with new drug combinations or with the incorporation of polyethylene glycolated (PEGylated) liposomal doxorubicin will also require additional studies. Additionally, the important issue of maintenance treatment needs to be further investigated. These new and emerging therapies offer multiple effective treatment options for MM patients and greatly enhanced treatment strategies for clinicians.Keywords: multiple myeloma, elderly, bortezomib, thalidomide, revlimid, IMiDs, supportive care

Front line treatment of elderly multiple myeloma in the era of novel agents

Melphalan combined with prednisone (MP) has long been the historical treatment of reference for a large proportion of elderly myeloma (MM) patients ineligible for autologous stem cell transplantation, and is still the backbone of new regimens that include the new era of novel agents. Melphalan-prednisone-thalidomide (MPT) and melphalan-prednisone-bortezomib (Velcade((R)), MPV), proved superior to MP, currently appear to be the treatments of choice for this population. In the near future melphalan-prednisone-lenalidomide (Revlimid((R)), MPR) will also provide a third therapeutic option (MPT, MPV, and MPR), in elderly multiple myeloma, eventually. These options could lead to more personalized treatment approaches, based on patient comorbidities, as the three novel agents have somewhat different toxicity profiles. Dexamethasone-based regimen is another option and questions regarding the relative efficacy of melphalan-based versus low-dose dexamethasone-based regimens will require randomized phase III trials. More intensive approaches with new drug combinations or with the incorporation of polyethylene glycolated (PEGylated) liposomal doxorubicin will also require additional studies. Additionally, the important issue of maintenance treatment needs to be further investigated. These new and emerging therapies offer multiple effective treatment options for MM patients and greatly enhanced treatment strategies for clinicians.