Targeting the interaction between tumor suppressor p53 and the E3 ligase MDM2 represents an attractive treatment approach for cancers with wild-type or functional TP53. Indeed, several small molecules have been developed and evaluated in various malignancies. We provide an overview of MDM2 inhibitors under preclinical and clinical investigation, with a focus on molecules with ongoing clinical trials, as indicated by ClinicalTrials.gov . Because preclinical and clinical exploration of combination strategies is underway, data supporting these combinations are also described. We identified the following molecules for inclusion in this review: RG7112 (RO5045337), idasanutlin (RG7388), AMG-232 (KRT-232), APG-115, BI-907828, CGM097, siremadlin (HDM201), and milademetan (DS-3032b). Information about each MDM2 inhibitor was collected from major congress records and PubMed using the following search terms: each molecule name, "MDM2"and "HDM2." Only congress records were limited by date (January 1, 2012-March 6, 2020). Special attention was given to available data in hematologic malignancies; however, available safety data in any indication are reported. Overall, targeting MDM2 is a promising treatment strategy, as evidenced by the increasing number of MDM2 inhibitors entering the clinic. Additional clinical investigation is needed to further elucidate the role of MDM2 inhibitors in the treatment of human cancers.

MDM2 inhibition: an important step forward in cancer therapy

Purpose: Sabatolimab (MBG453) and spartalizumab are mAbs that bind T-cell immunoglobulin domain and mucin domain-3 (TIM-3) and programmed death-1 (PD-1), respectively. This phase I/II study evaluated the safety and efficacy of sabatolimab, with or without spartalizumab, in patients with advanced solid tumors. Patients and Methods: Primary objectives of the phase I/Ib part were to characterize the safety and estimate recommended phase II dose (RP2D) for future studies. Dose escalation was guided by a Bayesian (hierarchical) logistic regression model. Sabatolimab was administered intravenously, 20 to 1,200 mg, every 2 or 4 weeks (Q2W or Q4W). Spartalizumab was administered intravenously, 80 to 400 mg, Q2W or Q4W. Results: Enrolled patients (n = 219) had a range of cancers, most commonly ovarian (17%) and colorectal cancer (7%); patients received sabatolimab (n = 133) or sabatolimab plus spartalizumab (n = 86). The MTD was not reached. The most common adverse event suspected to be treatment-related was fatigue (9%, sabatolimab; 15%, combination). No responses were seen with sabatolimab. Five patients receiving combination treatment had partial responses (6%; lasting 12–27 months) in colorectal cancer (n = 2), non–small cell lung cancer (NSCLC), malignant perianal melanoma, and SCLC. Of the five, two patients had elevated expression of immune markers in baseline biopsies; another three had >10% TIM-3–positive staining, including one patient with NSCLC who received prior PD-1 therapy. Conclusions: Sabatolimab plus spartalizumab was well tolerated and showed preliminary signs of antitumor activity. The RP2D for sabatolimab was selected as 800 mg Q4W (alternatively Q3W or Q2W schedules, based on modeling), with or without 400 mg spartalizumab Q4W.

Phase I/Ib Clinical Trial of Sabatolimab, an Anti–TIM-3 Antibody, Alone and in Combination with Spartalizumab, an Anti–PD-1 Antibody, in Advanced Solid Tumors

TIM-3 is a promising target to selectively kill acute myeloid leukemia stem cells

Programmed death-1 (PD-1) immune checkpoint blockade has achieved clinical successes in cancer therapy. However, the response rate of anti-PD-1 agents remains low. Additionally, a subpopulation of patients developed hyperprogressive disease upon PD-1 blockade therapy. Combination therapy with targeted agents may improve immunotherapy. Recent studies show that p53 activation in the myeloid linage suppresses alternative (M2) macrophage polarization, and attenuates tumor development and invasion, leading to the hypothesis that p53 activation may augment antitumor immunity elicited by anti-PD-1 therapy. Using APG-115 that is a MDM2 antagonist in clinical development as a pharmacological p53 activator, we investigated the role of p53 in immune modulation and combination therapy with PD-1 blockade. In vitro treatment of bone marrow-derived macrophages with APG-115 resulted in activation of p53 and p21, and a decrease in immunosuppressive M2 macrophage population through downregulation of c-Myc and c-Maf. Increased proinflammatory M1 macrophage polarization was observed in the spleen from mice treated with APG-115. Additionally, APG-115 has co-stimulatory activity in T cells and increases PD-L1 expression in tumor cells. In vivo, APG-115 plus anti-PD-1 combination therapy resulted in enhanced antitumor activity in Trp53wt, Trp53mut, and Trp53-deficient (Trp53−/−) syngeneic tumor models. Importantly, such enhanced activity was abolished in a syngeneic tumor model established in Trp53 knockout mice. Despite differential changes in tumor-infiltrating leukocytes (TILs), including the increases in infiltrated cytotoxic CD8+ T cells in Trp53wt tumors and M1 macrophages in Trp53mut tumors, a decrease in the proportion of M2 macrophages consistently occurred in both Trp53wt and Trp53mut tumors upon combination treatment. Our results demonstrate that p53 activation mediated by APG-115 promotes antitumor immunity in the tumor microenvironment (TME) regardless of the Trp53 status of tumors per se. Instead, such an effect depends on p53 activation in Trp53 wild-type immune cells in the TME. Based on the data, a phase 1b clinical trial has been launched for the evaluation of APG-115 in combination with pembrolizumab in solid tumor patients including those with TP53mut tumors.

/pdf/mdm2-inhibitor-apg-115-synergizes-with-pd-1-blockade-through-2jj6b3a7cz.pdf

MDM2 inhibitor APG-115 synergizes with PD-1 blockade through enhancing antitumor immunity in the tumor microenvironment

Targeting oncogene and non-oncogene addiction to inflame the tumour microenvironment

p53 is a transcription factor that plays a central role in guarding the genomic stability of cells through cell-cycle arrest or induction of apoptosis. However, the effects of p53 in antitumor immunity are poorly understood. To investigate the role of p53 in controlling tumor-immune cell cross-talk, we studied murine syngeneic models treated with HDM201, a potent and selective second-generation MDM2 inhibitor. In response to HDM201 treatment, the percentage of dendritic cells increased, including the CD103+ antigen cross-presenting subset. Furthermore, HDM201 increased the percentage of Tbet+Eomes+ CD8+ T cells and the CD8+/Treg ratio within the tumor. These immunophenotypic changes were eliminated with the knockout of p53 in tumor cells. Enhanced expression of CD80 on tumor cells was observed in vitro and in vivo, which coincided with T-cell-mediated tumor cell killing. Combining HDM201 with PD-1 or PD-L1 blockade increased the number of complete tumor regressions. Responding mice developed durable, antigen-specific memory T cells and rejected subsequent tumor implantation. Importantly, antitumor activity of HDM201 in combination with PD-1/PD-L1 blockade was abrogated in p53-mutated and knockout syngeneic tumor models, indicating the effect of HDM201 on the tumor is required for triggering antitumor immunity. Taken together, these results demonstrate that MDM2 inhibition triggers adaptive immunity, which is further enhanced by blockade of PD-1/PD-L1 pathway, thereby providing a rationale for combining MDM2 inhibitors and checkpoint blocking antibodies in patients with wild-type p53 tumors. SIGNIFICANCE: This study provides a mechanistic rationale for combining checkpoint blockade immunotherapy with MDM2 inhibitors in patients with wild-type p53 tumors.

Inhibition of MDM2 Promotes Antitumor Responses in p53 Wild-Type Cancer Cells through Their Interaction with the Immune and Stromal Microenvironment.

p53 is a transcription factor that plays a central role in guarding genomic stability of the cell through cell cycle arrest or induction of apoptosis. It has also been reported that p53 participates in the regulation of tumor immunity and in homeostatic regulation of immune responses. However, the immunomodulatory effect of p53 in tumor and the tumor microenvironment is not well understood. From gene expression and immunohistochemical analysis of pre- and post-treatment biopsies from patients treated with the MDM2 inhibitor NVP-CGM097, we observed upregulation of immune checkpoint transcripts (PD1 and PDL1), and an increase in the number of CD8+ tumor infiltrating lymphocytes. To investigate the immunomodulatory effect of p53 in more detail, we studied murine syngeneic models treated with NVP-HDM201, a potent and selective second generation MDM2 inhibitor. We performed multi-color FACS analysis on tumors and tumor draining lymph nodes. With NVP-HDM201 treatment, we observed increase in numbers of CD103+ DC cells, capable of antigen cross-presentation. Furthermore, NVP-HDM201 increased the percentage of Tbet+EOMES-T cells in tumors as well as tumor draining lymph nodes and also resulted in increased ratios of CD8+ Tcells/Treg in tumor. In addition, levels of both PD-L1 on CD45- cells and PD-1 on CD4+ T cells were increased. Importantly, PD-1 and PD-L1 blockade enhanced HDM201 activity in p53 WT syngeneic mouse models but not in p53 mutated models. The rate of complete tumor regressions (CR) was significantly increased with combination treatment as compared to either treatment alone. The animals that achieved complete regressions also developed long lasting anti-tumor memory against the specific tumor cells as evidenced by re-challenge experiments. Taken together, these results demonstrate that MDM2 inhibition triggered adaptive immunity which was further enhanced by blockade of PD-1/PD-L1 pathway, thereby providing a rationale for combining MDM2 inhibitors and checkpoint blocking antibodies in cancer patients with wildtype p53. Citation Format: Hui Qin Wang, Jinsheng Liang, Iain Mulford, Fiona Sharp, Swann Gaulis, Yan Chen, Gina Trabucco, David Quinn, Joseph D. Growney, Matthew J. Meyer, Juliet Williams, Peter Hammerman, Francesco Hofmann, Glenn Dranoff, Jeffrey Engelman, Jennifer Mataraza, Ensar Halilovic. PD-1/PD-L1 blockade enhances MDM2 inhibitor activity in p53 wild-type cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5560.

Abstract 5560: PD-1/PD-L1 blockade enhances MDM2 inhibitor activity in p53 wild-type cancers

Background TIM-3 is expressed on leukemic stem cells (LSCs) and blasts in AML,1 2 and TIM-3 expression on MDS blasts correlates with disease progression.3 Functional evidence for TIM-3 in AML was established with an anti-TIM-3 antibody which inhibited engraftment and development of human AML in immuno-deficient murine hosts.1 TIM-3 promotes an autocrine stimulatory loop via the TIM-3/Galectin-9 interaction, supporting LSC self-renewal.4 In addition to its cell-autonomous role on LSCs/blasts, TIM-3 also has a critical role in immune system regulation, in adaptive (CD4+ and CD8+ T effector cells, regulatory T cells) and innate (macrophages, dendritic cells, NK cells) immune responses.5 MBG453 is a high-affinity, humanized anti-TIM-3 IgG4 antibody (Ab) (stabilized hinge, S228P), which blocks the binding of TIM-3 to phosphatidylserine (PtdSer). Recent results from a multi-center, open label phase Ib dose-escalation study (NCT03066648) in patients with high-risk MDS and no prior hypomethylating agent therapy evaluating MBG453 in combination with decitabine demonstrated encouraging preliminary efficacy with an overall response rate of 58%,6 and MBG453 combined with azacitidine also showed encouraging response rates.7 Preclinical experiments were undertaken to define the mechanism of action of the hypomethylating agent and anti-TIM-3 combination. Methods THP-1 cells (a human monocytic AML cell line) were pre-treated with decitabine and co-cultured with anti-CD3 activated healthy human donor peripheral blood mononuclear cells (PBMCs) in an Incucyte-based assay to measure cell killing. The ability of MBG453 to mediate antibody-dependent cellular phagocytosis (ADCP) was measured by determining the phagocytic uptake of an engineered TIM-3-overexpressing Raji cell line in the presence of MBG453 by phorbol 12-myristate 13-acetate (PMA)-activated THP-1 cells. Patient-derived AML xenograft studies were undertaken in immune-deficient murine hosts to evaluate the combination of decitabine and MBG453. Results MBG453 was determined to partially block the TIM-3/Galectin-9 interaction in a plate-based MSD (Meso Scale Discovery) assay, supported by a crystal structure of human TIM-3.8 Pre-treatment of THP-1 cells with decitabine enhanced sensitivity to immune-mediated killing in the presence of MBG453. MBG453 was determined to mediate modest ADCP, relative to controls. MBG453 did not enhance the anti-leukemic activity of decitabine in patient-derived xenograft studies in immuno-deficient hosts. Conclusions Taken together, these results support both direct anti-leukemic effects and immune-mediated modulation by MBG453. Further studies are ongoing to determine: (1) whether MBG453 can mediate physiologically relevant ADCP of TIM-3-expressing leukemic cells; and (2) the potential of MBG453 to impact the autocrine feedback loop of TIM-3/Galectin-9. Ethics Approval The human tissue used in these studies was under the Novartis Institutes of BioMedical Research Ethics Board IRB, Approval Number 201252867. References Kikushige Y, Shima T, Takayanagi S, et al. TIM-3 is a promising target to selectively kill acute myeloid leukemia stem cells. Cell Stem Cell 2010;7(6):708–717. Jan M, Chao MP, Cha AC, et al. Prospective separation of normal and leukemic stem cells based on differential expression of TIM3, a human acute myeloid leukemia stem cell marker. Proc Natl Acad Sci USA 2011; 108(12): 5009–5014. Asayama T, Tamura H, Ishibashi M, et al. Functional expression of Tim-3 on blasts and clinical impact of its ligand galectin-9 in myelodysplastic syndromes. Oncotarget 2017;8(51): 88904–88917. Kikushige Y, Miyamoto T, Yuda J, et al. A TIM-3/Gal-9 autocrine stimulatory loop drives self-renewal of human myeloid leukemia stem cells and leukemic progression. Cell Stem Cell 2015; 17(3):341–352. Acharya N, Sabatos-Peyton C, Anderson AC. Tim-3 finds its place in the cancer immunotherapy landscape. J Immunother Cancer 2020; 8(1):e000911. Borate U, Esteve J, Porkka K, et al. Phase Ib Study of the Anti-TIM-3 Antibody MBG453 in combination with decitabine in patients with high-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Blood 2019;134 (Supplement_1):570. Borate U, Esteve J, Porkka K, et al. Abstract S185: Anti-TIM-3 antibody MBG453 in combination with hypomethylating agents (HMAs) in patients (pts) with high-risk myelodysplastic syndrome (HR-MDS) and acute myeloid leukemia (AML): a Phase 1 study. EHA 2020. Sabatos-Peyton C. MBG453: A high affinity, ligand-blocking anti-TIM-3 monoclonal Ab. AACR 2016.

https://jitc.bmj.com/content/jitc/8/Suppl_3/A267.1.full.pdf

439 Dual modes of action for anti-TIM-3 antibody MBG453 in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML): preclinical evidence for immune-mediated and anti-leukemic activity

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Fiona Sharp

Author Tools

Chat about Author

Papers

Inhibition of MDM2 Promotes Antitumor Responses in p53 Wild-Type Cancer Cells through Their Interaction with the Immune and Stromal Microenvironment.

Abstract 5560: PD-1/PD-L1 blockade enhances MDM2 inhibitor activity in p53 wild-type cancers

439 Dual modes of action for anti-TIM-3 antibody MBG453 in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML): preclinical evidence for immune-mediated and anti-leukemic activity