Efficacy In Multiple Myeloma Research Articles

Cancer-Cell-Biomimetic Nanoparticles for Targeted Therapy of Multiple Myeloma Based on Bone Marrow Homing.

Multiple myeloma (MM) is the second most common hematological malignancy. It is characterized by abnormal transformation and uncontrolled clonal proliferation of malignant plasma cells in the bone marrow (BM), which can destroy bone structure and inhibit hematopoiesis. Although there are new therapeutic methods, they are not curative, mainly because it is difficult to deliver an effective amount of drug to BM, leading to a failure to eradicate MM cells inside the BM. BM homing is an important and unique characteristic of MM cells and it is mainly affected by surface molecules on the tumor cell membrane. Inspired by this mechanism, an MM-mimicking nanocarrier is developed by coating bortezomib (BTZ)-loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC) nanoparticles with the MM cell membrane. The MM-mimicking nanoparticles can enter the BM based on BM homing as a "Trojan horse" and target the tumor cells through homologous targeting. In this way, drug availability at the myeloma site is enhanced so as to inhibit MM growth. In addition, these MM-mimicking nanoparticles can escape phagocytosis by the MPS and have a long circulation effect. The in vivo therapeutic results demonstrate an excellent treatment efficacy for MM. Accordingly, this strategy may be a promising platform for the treatment of MM.

Impact of Corticosteroids on Efficacy of BCMA Targeted CAR-T Therapy in Multiple Myeloma

Impact of Corticosteroids on Efficacy of BCMA Targeted CAR-T Therapy in Multiple Myeloma

Single-Cell Profiling Reveals Contribution of Tumor Extrinsic and Intrinsic Factors to BCMA-Targeted CAR-T Cell Efficacy in Multiple Myeloma

▪Background: BCMA CAR-T cell therapy has shown great promise in relapsed/refractory multiple myeloma (RRMM) patients, even though there is unpredictable variability in the duration and depth of response. The mechanisms behind these divergent outcomes and relapse are not well understood and heterogeneity of MM patients at the level of both tumor genomics and tumor microenvironment (TME) likely contributes to this important knowledge gap. To explore this question, we performed a longitudinal high resolution single cell genomic and proteomic analysis of bone marrow (BM) and peripheral blood (PB) samples in MM patients treated with BCMA CAR-T.Methods: Longitudinal comprehensive immune phenotyping of 3.5 million peripheral blood mononuclear cells (PBMC, CD45+CD66b-) from 11 BCMA CAR-T (idecabtagene vicleucel, ide-cel) patients was achieved via mass cytometry (CyTOF) with a panel of 39 markers. In addition, a total of 45,161 bone marrow mononuclear cells (BMMC) were analyzed from 6 patients before initiation of ide-cel therapy and at relapse by unbiased mRNA profiling via single-cell RNA-seq (scRNA-seq) using the GemCode system (10x Genomics). Downstream analysis was performed using the CATALYST and Seurat R packages, respectively. Immune cell populations are reported as % of PBMC and CD138- BMMC respectively, unless noted otherwise. Reported p values correspond to non-parametric tests or paired t test where applicable.Results: We compared baseline immune cell populations in the PB and the TME (BM) with regards to depth of CAR-T response. In PB, good responders (≥VGPR) had a higher proportion of CD8+ T cells (37% in good vs 11% in poor responders (<VGPR), p=0.08) and a lower proportion of CD14+ monocytes (30% vs 61%, p=0.28) and NK cells (2% vs 6%, p=0.08). In the TME, a similar trend was confirmed for CD8+ T cells and CD14+ monocytes. (Fig. 1A)Longitudinal analysis of PBMCs revealed phenotypic changes coinciding with CAR-T expansion; CD14+ monocytes declined from week 0 to week 4 after CAR-T infusion (40% vs 13%, p=0.04), while (non-CAR) CD8+ T cells expanded from week 0 to week 4 (32% vs 43%, p=0.15). The non-CAR CD8+ T cell expansion is characterized by differentiation towards a CD8+ effector-memory phenotype (EM, CCR7-CD45RA-) (73% vs 92% of CD8+ T cells, p=0.005). (Fig. 1B) BM samples at CAR-T relapse showed reversal of this shift: CD14+ monocyte levels remain constant or are slightly elevated, while non-CAR CD8+ T cells decrease at relapse.scRNA-seq of BMMC revealed significant gene expression changes between screening and relapse tumor samples, suggesting tumor-intrinsic factors of CAR-T response. For example, when comparing the pre and post tumor samples of a patient with durable response (PFS 652 days), we observed a significant upregulation of gene expression of pro-inflammatory chemokines (CCL3, CCL4), anti-apoptotic genes (MCL-1, FOSB, JUND), and NF-kB signaling genes (NFKBIA) in post tumor. Gene Set Enrichment Analysis (GSEA) of differentially expressed genes showed significant enrichment for TNFA signaling via NF-kB Hallmark Pathway (p.adj = 0.04). We observed similar statistically significant findings between other screening and relapse samples within our cohort, as well as upon comparison of baseline samples of poor vs good responders. (Fig. 1C, D) Thus, our data suggest that anti-apoptotic gene expression could be one of the tumor intrinsic mechanisms of CAR-T therapy resistance. Notably, we did not observe loss of BCMA expression in any tumor samples.Conclusion: Single cell immune profiling and transcriptomic sequencing highlights changes in the PB, TME and within the tumor, which in concert may influence CAR-T efficacy. Our integrated data analysis indicates general immune activation after CAR-T cell infusion that returns to baseline levels at relapse. Specifically, the expansion of non-CAR cytotoxic CD8+ EM T cells provides a rationale for co-administration of IMiDs to enhance CAR-T efficacy. Significant up-regulation of anti-apoptotic genes at baseline in poor responders, and at relapse in good responders, suggest a novel tumor-mediated escape mechanism. Targeting the MCL-1/BCL-2 axis may augment CAR-T efficacy by sensitizing tumor cells and enhancing the effect of CAR-T killing. We will confirm these findings in a longitudinal cohort of BMMC/PBMC CITE-seq patients (n=23) and will present results at the conference. [Display omitted] DisclosuresSebra: Sema4: Current Employment. Parekh: Foundation Medicine Inc: Consultancy; Amgen: Research Funding; PFIZER: Research Funding; CELGENE: Research Funding; Karyopharm Inv: Research Funding.

Synergistic Effects of Venetoclax and Daratumumab on Antibody-Dependent Cell-Mediated Natural Killer Cytotoxicity in Multiple Myeloma.

The prognosis of multiple myeloma (MM) has drastically improved owing to the development of new drugs, such as proteasome inhibitors and immunomodulatory drugs. Nevertheless, MM is an extremely challenging disease, and many patients are still refractory to the existing therapies, thus requiring new treatment alternatives. Venetoclax is a selective, orally bioavailable inhibitor of BCL-2 that shows efficacy in MM not only as a single agent but also in combination therapy, especially for MM patients with translocation t(11;14). However, many patients are refractory to this drug. Here, we treated the MM cell lines KMS12PE and KMS27 with a combination treatment of venetoclax targeting BCL-2 and daratumumab targeting CD38 to evaluate the synergistic cytotoxicity of these drugs in vitro. MM cell lines were co-cultured with natural killer (NK) cells at an effector:target ratio of 0.3:1 in the presence of serial concentrations of daratumumab and venetoclax, and the resulting apoptotic MM cells were detected by flow cytometry using annexin V. These results indicated that the antibody-dependent cell-mediated NK cytotoxicity was enhanced in KMS12PE and KMS27 cells harboring t(11;14) with a high BCL-2 expression, suggesting that the combination treatment of venetoclax and daratumumab should be especially effective in patients with these characteristics.

Novel Combination Therapies with the RNA Polymerase I Inhibitor CX-5461 Significantly Improve Efficacy in Multiple Myeloma

BACKGROUNDrDNA transcription is consistently dysregulated in cancer, mediated through oncogenic and tumour-suppressive pathways, and in particular by cMYC1. RNA polymerase I (Pol I) transcriptional hyperactivity is a consistent feature of many cancers, and has been shown to provide a survival checkpoint in haematological tumour cells2.Our laboratory developed CX-5461, a highly selective small molecule inhibitor of Pol I transcription of ribosomal genes3, currently in a phase 1 clinical trial in relapsed/refractory haematological malignancies (Peter MacCallum Cancer Centre, Australia). CX-5461 induces cell death via a p53-dependent nucleolar surveillance response, and a p53-independent nucleolar-specific DNA damage response (DDR), killing malignant cells while sparing normal cells2,4. We demonstrated that single-agent treatment with CX-5461 provides a significant survival benefit in murine models of B-cell lymphoma, acute myeloid leukaemia and now multiple myeloma (MM)2,4-6. However, despite this improvement, drug resistance eventually occurs, indicating combination drug therapy is essential. AIMto examine the efficacy of CX-5461 in combination with other agents having proven clinical or promising preclinical efficacy in MM. METHODSwe conducted a boutique, high-throughput screen in human myeloma cell lines of CX-5461 combined with a targeted range of agents. We measured the effect of CX-5461 on proliferation, cell death, cell cycle distribution, biomarkers of DDR and on-target effects. The effect of combining CX-5461 with one candidate, the histone deacetylase inhibitor (HDACi) panobinostat, was tested in vivo using both the tVk*MYC murine model of MM6 and in KaLwRij mice transplanted with 5T33 cells. RESULTSCX-5461 showed increased anti-proliferative effect and cell death in combination with multiple drug classes. The proteasome inhibitor carfilzomib and the HDACi panobinostat demonstrated the most impressive synergy with CX-5461. Using both the MYC-driven tVk*MYC model and the non-MYC-driven 5T33-KaLwRij models of MM, we showed that CX-5461 with panobinostat provides a significant survival advantage. Prolonged combination dosing in the slower tVk*MYC model did not cause haematological toxicity beyond that seen with single agents.We are currently interrogating the molecular synergistic response of this combination, including p53-dependent and -independent responses, and the ATM/ATR signalling pathway. Ongoing work is investigating the efficacy of the triplet drug combination of CX-5461, panobinostat and carfilzomib, both in vitro and in vivo. CONCLUSIONCX-5461 shows increased efficacy when combined with multiple drug classes, with panobinostat and carfilzomib showing the most promise in vitro. Combination of CX-5461 with panobinostat produces a survival advantage in both the tVk*MYC and the 5T33-KaLwRij models of MM. These results will direct the subsequent clinical trial using combination drug therapy. REFERENCES1.Bywater et al., Nature Reviews Cancer 20132.Bywater et al., Cancer Cell 20123.Drygin et al., Cancer Research 20114.Quin et al, Oncotarget, 20165.Devlin et al., Cancer Discovery 20166.Hein et al., Blood 20177.Chesi et al., Blood 2012Figure 1. Combination treatment with CX-5461 + panobinostat gives increased survival in the tVk*MYC model of MM. Mice were transplanted with 3.5x10^5 cells, then treatment was started 49 days post-transplant. Mice were treated with CX-5461 35mg/kg orally weekly and panobinostat 7.5mg/kg IP MWF. [Display omitted] DisclosuresHarrison:Celgene: Consultancy, Research Funding, Speakers Bureau.

Safety and Tolerability of Daratumumab in Patients with Relapsed Light Chain (AL) Amyloidosis: Preliminary Results of a Phase II Study

Daratumumab is a human IgG1k monoclonal antibody targeting the CD38 surface antigen on plasma cells, and has proven efficacy in multiple myeloma. AL amyloidosis is a plasma cell disorder in which clonal bone marrow plasma cells produce immunoglobulin light chains that misfold into fibrils that are deposited in organs, leading to organ dysfunction and failure. While the biology of the clonal plasma cell in AL amyloidosis is distinct from that of myeloma, clonal plasma cells in AL amyloidosis do express surface CD38, providing a rationale for the use of daratumumab in AL amyloidosis. Infusion reactions (IR) of 48% were reported in patients who received daratumumab as monotherapy for relapsed multiple myeloma. Therefore, we designed a clinical trial to study tolerability of daratumumab in patients with relapsed AL amyloidosis (clinicaltrials.gov identifier: NCT02841033). The primary objective was to determine the safety and tolerability of infusion of daratumumab, with respect to IR. The secondary objectives were to assess hematologic response, clinical response and time to next treatment.Accrual on this clinical trial started in April 2017. Patients with relapsed AL amyloidosis after ≥1 prior therapy, and involvement of at least one major vital organ , eGFR of >20 mL/min, AST/ALT < 3xULN, NTproBNP <8500 pg/mL, LVEF >30%, FEV1 >50% in patients with known COPD or chronic smokers, and ECOG performance status of <3, received daratumumab at 16 mg/kg IV infusion weekly for weeks 1-8, followed by every 2 weeks for weeks 9-24 and every 4 weeks thereafter until progression or unacceptable toxicities, for up to 24 months. The first infusion of daratumumab was administered in 1000 mL, the second infusion in 500 mL if no grade 1 or greater reactions occurred throughout the first 3 hours of the first infusion, and subsequent doses were administered in 500 mL of saline. All patients received acetaminophen, diphenhydramine, loratidine, famotidine, monteleukast and methyprednisolone (100 mg for the first 2 infusions and 60 mg thereafter) 30-60 minutes prior to infusion. Ondansetron was added after developement of grade 1 nausea/vomiting in the first 2 patients. Diphenhydramine, famotidine and methyprednisolone (40 mg) were also administered 2 hours after the start of infusion during the first 2 infusions even if there was no reaction. Methylprednisolone 20 mg (or its equivalent) and monteleukast were adminsitered 24 and 48 hours after start of infusion for the first 2 infusions and then monteleukast was optional. All patients received prophylaxis with acyclovir.At data cut-off (July 23, 2017) 8 patients have been enrolled. The median age was 63 years (range, 60-83), and median number of prior therapies was 3 (range, 1-6): 6 (75%) had received HDM/SCT, 5 (62.5%) had received immunomodulatory agents, and 7 (87.5%) proteosome inhibitors. Three patients were refractory to prior therapy and the median time from last therapy was 15 months. The median time from diagnosis to enrollment on this trial was 68 months. The median number of organ systems involved was 2 (range, 1-4). Five patients (62.5%) had involvement of >2 organ systems. All 8 (100%) patients had cardiac biomarker stage II or III disease. Median NT-proBNP level was 1650.5 pg/mL (range, 656-3962) and urine protein excretion was 0.41 g/24 h (range, 0-10.1), while median dFLC was 196.8 mg/L (range, 20.4-854). At the time of this report, 7 patients continue on study and a total of 65 infusions have been completed. The median number of infusions received per patient is 9 (range, 2-12). One patient was removed from the protocol after developing progression of plasma cell dyscrasia markers after 2 cycles. No patient experienced a grade 3-4 IR. Only 2 patients experienced grade 1 nausea and vomiting during first infusion, which resolved after an antiemetic, without experiencing IR. There was no interruption or delay of infusion. No hospitalization for IR was required. The median time of first infusion was 6.5 hours and 2nd infusion was 4.2 hours. Hematologic responses were rapid and are shown in Figure 1.Daratumumab infusion is well tolerated in patients with relapsed AL amyloidosis, when administered with appropriate pre and post-medications. Infusion related reactions were minimal and not comparable to reported incidence in myeloma. Preliminary data suggest a rapid hematologic response after 1 dose of daratumumab in patients with AL amyloidosis. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Pre-Clinical Efficacy of the Anti-CD38 Monoclonal Antibody (mAb) Isatuximab in Acute Myeloid Leukemia (AML)

Pre-Clinical Efficacy of the Anti-CD38 Monoclonal Antibody (mAb) Isatuximab in Acute Myeloid Leukemia (AML)

Renal Response in Relapsed Refractory Multiple Myeloma Patients with Severe Renal Impairment at treatment Initiation: Intermediate Data of a Large, Observational, Prospective Study

Introduction: Renal impairment (RI) is a common complication of multiple myeloma (MM) that causes significant morbidity and mortality. Approximately 20%-30% of patients (pts) at diagnosis and more than 50% of pts with advanced disease present RI. Moreover, pts with Acute Kidney Injury (AKI) are more likely to suffer advanced mortality and have worse prognosis. Thus, reverting renal dysfunction is critical for the management of these pts. However, there is little information on the renal evolution of pts with relapsed refractory MM (RRMM) receiving treatment with novel agents in clinical practice.Aims: This is an observational, prospective, multicenter study aimed to evaluate the renal response to the administered therapy in pts with RRMM and moderate (clearance [CrCl] 30-50 mL/min) or severe (CrCl<30 mL/min) RI. We present results focused on the subgroup of pts with severe RI from an intermediate analysis 15 mos) after completion of the inclusion period (cut-off: May 8, 2017).Methods: Renal and MM responses were evaluated according to International Myeloma Working Group criteria. eGFR by the Cockroft-Gault (CG), Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas were compared to analyse renal response. Descriptive statistics have been used for response rates and Kaplan Meier estimates for Progression-Free Survival (PFS) and overall survival (OS).Results: A total of 327 pts were recruited and 99 pts with severe RI at study entry were included in the current analysis (mean ± SD age 75 ± 10 years, 49% male, 58% in first relapse). Main comorbidities were arterial hypertension (59%) and diabetes (27%). At diagnosis, 46% of pts had ISS stage III. Median time (range) from MM diagnosis was 2.5 (0.2-10.4) years. Main MM types were Ig G (50%), Bence Jones (20%), and Ig A (13%); 13% of pts with severe RI presented with high risk cytogenetic abnormalities. Main anti-myeloma therapies were: lenalidomide (LEN; 37%), bortezomib (BORT; 31%), and other treatments (OT; 32%: different chemotherapy regimens, 20%; and other non-chemotherapy treatments, 12%).The mean baseline eGFRs according to CG, MDRD and CKD-EPI formulas were 20.0/19.9/19.1 (± 7.5/9.4/9.0) mL/min,with a strong correlation between them (coefficients: CG/MDRD = 0.91; CG/CKD-EPI = 0.93; MDRD/CKD-EPI = 0.99). Using RIFLE classification, the proportion of pts with AKI during the MM treatment was 51.5%. Overall, 26.3% (95% CI, 16.7%-33.8%) of patients had a renal response (2.1% renal complete response [renalCR], 2.1% renal partial response [renalPR], and 22.1% renal minor response [renalMR]) according to the CG formula while responses measured by the MDRD formula, were 24.0% (3.1% renalCR, 2.1% renalPR, and 18.8% renalMR). Median time to best renal response was 1.7mos (range, 0.5-8.9 mos). After adjusting by demographic and clinical characteristics (52 evaluable pts), ISS stage III was statistically significantly associated with poor renal response. There were no significant differences in GFR improvement between pts according to the administered treatment (P = 0.306). The overall MM efficacy response rate (≥ PR) was 35.4%. The overall response rates were 48.4% and 38.9% for pts receiving BORT and LEN, respectively whereas only 11.5% of pts receiving OT achieved at least PR. PFS was 14.9 mos with LEN-based, 6.5 mos with BORT-based, and 2.6mos with OT (P=0.0003). OS was 24.6mos with LEN-based, 14.6 mos with BORT-based, and 4.6mos with OT (P < 0.0001).Conclusions: This observational study shows that LEN- and BORT-based treatments are the regimens most commonly used in the clinical practice in RRMM pts with severe RI. These therapies can improve RI in approximately 26% of pts, with no differences between treatments. Despite this, there are still many pts who develop AKI during the course of treatment. DisclosuresMorales:Alexion: Other: Personal fees; Celgene: Other: Personal fees. de la Rubia:Amgen: Other: Honoraria; Janssen: Other: Honoraria; Celgene: Other: Honoraria.

PO-07 Comparison of primary thromboprophylaxis agents (PTA) efficacy in multiple myeloma (MM) treated with immunomodulators (IMID): a network meta-analysis

PO-07 Comparison of primary thromboprophylaxis agents (PTA) efficacy in multiple myeloma (MM) treated with immunomodulators (IMID): a network meta-analysis

Design and Synthesis of Novel Epigenetic Inhibitors Targeting Histone Deacetylases, DNA Methyltransferase 1, and Lysine Methyltransferase G9a with In Vivo Efficacy in Multiple Myeloma.

Concomitant inhibition of key epigenetic pathways involved in silencing tumor suppressor genes has been recognized as a promising strategy for cancer therapy. Herein, we report a first-in-class series of quinoline-based analogues that simultaneously inhibit histone deacetylases (from a low nanomolar range) and DNA methyltransferase-1 (from a mid-nanomolar range, IC50 < 200 nM). Additionally, lysine methyltransferase G9a inhibitory activity is achieved (from a low nanomolar range) by introduction of a key lysine mimic group at the 7-position of the quinoline ring. The corresponding epigenetic functional cellular responses are observed: histone-3 acetylation, DNA hypomethylation, and decreased histone-3 methylation at lysine-9. These chemical probes, multitarget epigenetic inhibitors, were validated against the multiple myeloma cell line MM1.S, demonstrating promising in vitro activity of 12a (CM-444) with GI50 of 32 nM, an adequate therapeutic window (>1 log unit), and a suitable pharmacokinetic profile. In vivo, 12a achieved significant antitumor efficacy in a xenograft mouse model of human multiple myeloma.

The Immunomodulatory Effect and Clinical Efficacy of Daratumumab in a Patient With Cold Agglutinin Disease

Daratumumab is a monoclonal antibody directed against the transmembrane glycoprotein CD38 expressed on plasma cells and lymphoplasmocytes, with a proven efficacy in multiple myeloma. Here we show its clinical efficacy in a patient with cold agglutinin disease (CAD) relapsed after multiple lines of therapy. CAD is caused by cold reactive autoantibodies that induce complement mediated hemolysis and peripheral circulatory symptoms. The disease is also characterized by the presence of monoclonal IgM gammopathy and of a lymphoid bone marrow infiltration that benefits from B-cell targeting therapies (i.e., rituximab) but also from plasma cell directed therapies, such as proteasome inhibitors. In the patient described, we also show that daratumumab therapy influenced the dynamics of several immunoregulatory cytokine levels (IL-6, IL-10, IL-17, IFN-γ, TNF-α, TGF-β) indicating an immunomodulatory effect of the drug beyond plasma cell depletion. In addition, we provide a literature review on the use of daratumumab in autoimmune conditions, including multi-treated and refractory patients with autoimmune hemolytic anemia (both CAD and warm forms), Evans syndrome (association of autoimmune hemolytic anemia and immune thrombocytopenia) and non-hematologic autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis.

Inhibition of P-Glycoprotein Does Not Increase the Efficacy of Proteasome Inhibitors in Multiple Myeloma Cells.

P-Glycoprotein is a well-known drug transporter associated with chemotherapy resistance in a number of cancers, but its role in modulating proteasome inhibitor efficacy in multiple myeloma is not well understood. The second-generation proteasome inhibitor carfilzomib is thought to be a substrate of P-glycoprotein whose efficacy may correlate with P-glycoprotein activity; however, research concerning the first-in-class proteasome inhibitor bortezomib is inconsistent. We show that while P-glycoprotein gene expression increases with the disease stages leading to multiple myeloma it does not affect the survival of newly diagnosed patients treated with bortezomib. Moreover, RNA-seq on LP-1 cells demonstrated minimal basal P-glycoprotein expression which did not increase after exposure to bortezomib or carfilzomib. Only one (KMS-18) of nine multiple myeloma cell lines expressed P-glycoprotein, including RPMI-8226 cells that are resistant to bortezomib or carfilzomib. We hypothesized that by inhibiting P-glycoprotein multiple myeloma cell sensitivity to proteasome inhibitors would increase; however, the sensitivity of multiple myeloma cells lines to proteasome inhibition was not enhanced by the specific P-glycoprotein inhibitor tariquidar. In addition, targeting glucosylceramide synthase with eliglustat did not inhibit P-glycoprotein activity nor improve proteasome inhibitor efficacy except at a high concentration. To confirm these negative findings, tariquidar did not substantially increase the cytotoxicity of bortezomib or carfilzomib in P-glycoprotein-expressing K562/ADM cells. We conclude the following: P-glycoprotein expression may not correlate with the survival of newly diagnosed multiple myeloma patients treated with proteasome inhibitors. P-glycoprotein is poorly expressed in many multiple myeloma cell lines, and its inhibition does not appreciably enhance the efficacy of proteasome inhibitors.

The HGF/c-MET axis as a potential target to overcome survival signals and improve therapeutic efficacy in multiple myeloma.

Multiple myeloma (MM) accounts for about 10% of hematologic malignancies, and it is the second most frequent hematologic neoplasm after lymphomas. The exact etiology of MM is still unknown and, despite the introduction of more effective and safe drugs in recent years, MM remains an incurable disease. Intrinsic and acquired resistance of malignant B cells to pharmacological treatments still represents an obstacle for survival improvement. Activation of the hepatocyte growth factor/c-MET axis has been reported as involved in MM pathogenesis: hepatocyte growth factor (HGF) levels are in fact higher in sera from MM patients than in healthy controls, the HGF/c-MET pathway may be activated in an autocrine or paracrine manner, and it is interesting to note that a higher c-MET phosphorylation is associated with disease progression. Several studies have further demonstrated the over-activation of c-MET either in resistant cell lines or in primary malignant plasma cells purified from bone marrow of patients resistant to chemotherapy. For this reason, c-MET has been proposed as a potential marker of multidrug resistance in the disease. Here, we first summarize the potential role of HGF/c-MET interaction in disease evolution and then describe novel approaches targeting this axis which could be conceptually utilized, alone or in combination with standard therapies, to treat MM and possibly overcome drug resistance.

Tumor microenvironment-targeted nanoparticles loaded with bortezomib and ROCK inhibitor improve efficacy in multiple myeloma

Drug resistance and dose-limiting toxicities are significant barriers for treatment of multiple myeloma (MM). Bone marrow microenvironment (BMME) plays a major role in drug resistance in MM. Drug delivery with targeted nanoparticles have been shown to improve specificity and efficacy and reduce toxicity. We aim to improve treatments for MM by (1) using nanoparticle delivery to enhance efficacy and reduce toxicity; (2) targeting the tumor-associated endothelium for specific delivery of the cargo to the tumor area, and (3) synchronizing the delivery of chemotherapy (bortezomib; BTZ) and BMME-disrupting agents (ROCK inhibitor) to overcome BMME-induced drug resistance. We find that targeting the BMME with P-selectin glycoprotein ligand-1 (PSGL-1)-targeted BTZ and ROCK inhibitor-loaded liposomes is more effective than free drugs, non-targeted liposomes, and single-agent controls and reduces severe BTZ-associated side effects. These results support the use of PSGL-1-targeted multi-drug and even non-targeted liposomal BTZ formulations for the enhancement of patient outcome in MM.

Clinical Research of Dendritic Cell-Mediated Tumor-Associated Antigen-Specific Cytotoxic T Lymphocytes in the Treatment of Multiple Myeloma and Non-Hodgkin Lymphoma

To investigate the safety and efficacy of tumor-associated antigen-specific cytotoxic T lympho- cytes (TAA-CTL) in the treatment of multiple myeloma (MM) and non-Hodgkin lymphoma (NHL). Peripheral blood mononuclear cells (PBMNC)of patients were collected. Dendritic cells (DC) were loaded with multiple tumor-associated antigens (TAA) (NY-ESO-1, MAGE-A3, MAGE-A4, WT1, Survivin, PRAME, LMP1 and LMP2A), then co-cultured with PBMNC to induce cytotoxic T lymphocytes (CTL). The phenotypes of cell products were detected, and the disease statuse was evaluated in 7 patients during or after infusion. The changes of TAA-CTL amount in the PBMNC of patients were measured by using IFN-γ ELISpot assay. TAA-CTL products were generated comprising CD3+ T cells (mean 82.98%) with a mixture of CD4+ (mean 42.09%) and CD8+ (mean 25.32%) T cells. Among them, 70% expressed effectors memory markers (CD45RO+CD62L-CCR7-). Each patient received TAA-CTL infusions for 1-4 times, and none of them showed obvious adverse reactions. The clinical symptoms and laboratory or imaging examination of 5 patients achieved positive effects. After cell therapy, the spot-forming cells (SFC) levels of most patients gradually increased and the peak often appeared about 2-3 weeks after the infusion. TAA-CTLs preliminarily show its safety and efficacy in MM and NHL patients, however, a larger population sample is needed to explore its clinical application value.

Abstract 1843: Melflufen efficacy in multiple myeloma with TP53 aberrations

Abstract Introduction Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by clonal evolution and heterogeneous genetic abnormalities. Deletion of the short arm of chromosome 17 (del17p) harboring TP53 is a high-risk abnormality associated with aggressive disease and therapy resistance. Here, we tested in vitro and ex vivo efficacy of a peptide-drug conjugate melflufen, currently in phase 3 clinical trials for relapsed/refractory multiple myeloma (RRMM), in an isogenic myeloma p53-abrogated cell line model and patient samples. Methods Efficacy of melflufen versus melphalan was tested in the AMO-1 cell line, which displays biallelic wildtype TP53 and retains aspects of a functional p53 system, and AMO-1 clones with either complete loss of p53 or expressing point-mutated p53 protein (R282W hotspot mutation), created using the CRISPR/Cas9 system and modified via Sleeping Beauty vectors. We assessed toxicity and apoptosis using Annexin V and Alamar blue assays. Ex vivo sensitivity to the drugs was examined by flow cytometry in CD138+ plasma cells isolated from MM patients with confirmed del17p or TP53 mutations. We also analyzed response rates in a subpopulation of patients with confirmed del17p from OP-106 HORIZON, an ongoing phase 2 study evaluating the efficacy of melflufen plus dexamethasone in patients with RRMM (NCT02963493). Results Whereas loss of p53 functionality strongly impaired melphalan induced cytotoxicity in the AMO-1 MM cell line model system, treatment with melflufen showed superior efficacy in the parental cells, and was effective independent of the respective TP53 status. Although at low dosages wild-type cells were still more sensitive, in contrast to melphalan this effect was overcome by slight dose increases of melflufen, due to the much steeper dose-effect relationships in the p53 deficient sublines. In contrast to melphalan, the melflufen effect was only partially blocked by combined pre-treatment with inhibitors of apoptosis and necroptosis. Similar results were observed in patient-derived material with melflufen displaying superior activity towards TP53 mutated plasma cells. Analysis of OP-106 HORIZON trial data showed comparable ORR of 20% (CI 95% 4.3-48.1) in the del17p subpopulation (n=15) to 26.2% (CI 95% 18.8-34.6) in the total population (n=136). Conclusions Melflufen is able to trigger myeloma cell death regardless of p53 status, and thus overcome p53-deficiency-mediated melphalan resistance. It demonstrates better ex vivo efficacy in MM patient derived plasma cells harboring del17p or TP53 mutations. Melflufen response rates in the del17p Citation Format: Ana Slipicevic, Umair Munawar, Thorsten Stühmer, Johan Aschan, Fredrik Lehmann, Nina N. Nupponen, Juho Miettinen, Maiju-Emilia Huppunen, Caroline A. Heckman, María-Victoria Mateos, Paula Rodríguez Otero, Paul Richardson, Ralf Bargou. Melflufen efficacy in multiple myeloma with TP53 aberrations [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1843.

Dihydroartemisinin Induces Growth Arrest and Overcomes Dexamethasone Resistance in Multiple Myeloma.

The discovery of artemisinin (ART) for malaria treatment won the 2015 Nobel Prize in Medicine, which inspired the rediscovery and development of ART for the treatment of other diseases including cancer. In this study, we investigated the potential therapeutic effect of ART and dihydroartemisinin (DHA) on multiple myeloma (MM) cells including primary MM cells and in 5TMM3VT mouse model. Both in vitro and in vivo experiments showed that DHA might be a more promising anti-MM agent with significantly improved efficacy compared to ART. Mechanistic analyses suggested that DHA activated the mitochondrial apoptotic pathway by interacting with ferrous (Fe2+) ions and oxygen to produce reactive oxygen species (ROS). Intriguingly, DHA could reverse the upregulated expression of B-cell lymphoma 2 (Bcl-2) protein, a typical mitochondrial apoptotic marker, induced by dexamethasone (Dexa) in MM. We further demonstrated that DHA treatment could overcome Dexa resistance and enhance Dexa efficacy in MM. Additionally, DHA combined with Dexa resulted in increased ROS production and cytochrome C translocation from the mitochondria to the cytoplasm, resulting in alterations to the mitochondrial membrane potential and caspase-mediated apoptosis. In summary, our study demonstrated that DHA was superior to ART in MM treatment and overcame Dexa resistance both in vitro and in vivo, providing a promising therapeutic strategy for MM therapy.

PD-1 Blockade Reinvigorates Bone Marrow CD8+ T Cells from Patients with Multiple Myeloma in the Presence of TGFβ Inhibitors

Immune-checkpoint inhibitors have shown therapeutic efficacy in various malignant diseases. However, anti-programmed death (PD)-1 therapy has not shown clinical efficacy in multiple myeloma. Bone marrow (BM) mononuclear cells were obtained from 77 newly diagnosed multiple myeloma patients. We examined the expression of immune-checkpoint receptors in BM CD8+ T cells and their functional restoration by ex vivo treatment with anti-PD-1 and TGFβ inhibitors. We confirmed the upregulation of PD-1 and PD-L1 expression in CD8+ T cells and myeloma cells, respectively, from the BM of multiple myeloma patients. PD-1-expressing CD8+ T cells from the BM of multiple myeloma patients coexpressed other checkpoint inhibitory receptors and exhibited a terminally differentiated phenotype. These results were also observed in BM CD8+ T cells specific to myeloma antigens NY-ESO-1 and HM1.24. BM CD8+ T cells from multiple myeloma patients exhibited reduced proliferation and cytokine production upon T-cell receptor stimulation. However, anti-PD-1 did not increase the proliferation of BM CD8+ T cells from multiple myeloma patients, indicating that T-cell exhaustion in multiple myeloma is hardly reversed by PD-1 blockade alone. Intriguingly, anti-PD-1 significantly increased the proliferation of BM CD8+ T cells from multiple myeloma patients in the presence of inhibitors of TGFβ, which was overexpressed by myeloma cells. Our findings indicate that combined blockade of PD-1 and TGFβ may be useful for the treatment of multiple myeloma.

Measurable Residual Disease by Next-Generation Flow Cytometry in Multiple Myeloma.

Assessing measurable residual disease (MRD) has become standard with many tumors, but the clinical meaning of MRD in multiple myeloma (MM) remains uncertain, particularly when assessed by next-generation flow (NGF) cytometry. Thus, we aimed to determine the applicability and sensitivity of the flow MRD-negative criterion defined by the International Myeloma Working Group (IMWG). In the PETHEMA/GEM2012MENOS65 trial, 458 patients with newly diagnosed MM had longitudinal assessment of MRD after six induction cycles with bortezomib, lenalidomide, and dexamethasone (VRD), autologous transplantation, and two consolidation courses with VRD. MRD was assessed in 1,100 bone marrow samples from 397 patients; the 61 patients without MRD data discontinued treatment during induction and were considered MRD positive for intent-to-treat analysis. The median limit of detection achieved by NGF was 2.9 × 10-6. Patients received maintenance (lenalidomide ± ixazomib) according to the companion PETHEMA/GEM2014MAIN trial. Overall, 205 (45%) of 458 patients had undetectable MRD after consolidation, and only 14 of them (7%) have experienced progression thus far; seven of these 14 displayed extraosseous plasmacytomas at diagnosis and/or relapse. Using time-dependent analysis, patients with undetectable MRD had an 82% reduction in the risk of progression or death (hazard ratio, 0.18; 95% CI, 0.11 to 0.30; P < .001) and an 88% reduction in the risk of death (hazard ratio, 0.12; 95% CI, 0.05 to 0.29; P < .001). Timing of undetectable MRD (after induction v intensification) had no impact on patient survival. Attaining undetectable MRD overcame poor prognostic features at diagnosis, including high-risk cytogenetics. By contrast, patients with Revised International Staging System III status and positive MRD had dismal progression-free and overall survivals (median, 14 and 17 months, respectively). Maintenance increased the rate of undetectable MRD by 17%. The IMWG flow MRD-negative response criterion is highly applicable and sensitive to evaluate treatment efficacy in MM.

Lipidomic Profiling of Plasma Samples in Patients with Newly Diagnosed Multiple Myeloma; A Biomarker Study for Predicting the Response and Toxicities of Melphalan, Prednisolone and Bortezomib (MPB) Regimen : An Ancillary Study of the JCOG1105 (JCOG1105A1)

Lipidomic Profiling of Plasma Samples in Patients with Newly Diagnosed Multiple Myeloma; A Biomarker Study for Predicting the Response and Toxicities of Melphalan, Prednisolone and Bortezomib (MPB) Regimen : An Ancillary Study of the JCOG1105 (JCOG1105A1)