Martin Oft

IL-23 promotes tumour incidence and growth

Chronic inflammation has long been associated with increased incidence of malignancy and similarities in the regulatory mechanisms have been suggested for more than a century. Infiltration of innate immune cells, elevated activities of matrix metalloproteases and increased angiogenesis and vasculature density are a few examples of the similarities between chronic and tumour-associated inflammation. Conversely, the elimination of early malignant lesions by immune surveillance, which relies on the cytotoxic activity of tumour-infiltrating T cells or intra-epithelial lymphocytes, is thought to be rate-limiting for the risk to develop cancer. Here we show a molecular connection between the rise in tumour-associated inflammation and a lack of tumour immune surveillance. Expression of the heterodimeric cytokine interleukin (IL)-23, but not of its close relative IL-12, is increased in human tumours. Expression of these cytokines antagonistically regulates local inflammatory responses in the tumour microenvironment and infiltration of intra-epithelial lymphocytes. Whereas IL-12 promotes infiltration of cytotoxic T cells, IL-23 promotes inflammatory responses such as upregulation of the matrix metalloprotease MMP9, and increases angiogenesis but reduces CD8 T-cell infiltration. Genetic deletion or antibody-mediated elimination of IL-23 leads to increased infiltration of cytotoxic T cells into the transformed tissue, rendering a protective effect against chemically induced carcinogenesis. Finally, transplanted tumours are growth-restricted in hosts depleted for IL-23 or in IL-23-receptor-deficient mice. Although many strategies for immune therapy of cancer attempt to stimulate an immune response against solid tumours, infiltration of effector cells into the tumour tissue often appears to be a critical hurdle. We show that IL-23 is an important molecular link between tumour-promoting pro-inflammatory processes and the failure of the adaptive immune surveillance to infiltrate tumours.

Dinaciclib (SCH 727965), a Novel and Potent Cyclin-Dependent Kinase Inhibitor

Cyclin-dependent kinases (CDK) are key positive regulators of cell cycle progression and attractive targets in oncology. SCH 727965 inhibits CDK2, CDK5, CDK1, and CDK9 activity in vitro with IC50 values of 1, 1, 3, and 4 nmol/L, respectively. SCH 727965 was selected as a clinical candidate using a functional screen in vivo that integrated both efficacy and safety parameters. Compared with flavopiridol, SCH 727965 exhibits superior activity with an improved therapeutic index. In cell-based assays, SCH 727965 completely suppressed retinoblastoma phosphorylation, which correlated with apoptosis onset and total inhibition of bromodeoxyuridine incorporation in >100 tumor cell lines of diverse origin and background. Moreover, short exposures to SCH 727965 were sufficient for long-lasting cellular effects. SCH 727965 induced regression of established solid tumors in a range of mouse models following intermittent scheduling of doses below the maximally tolerated level. This was associated with modulation of pharmacodynamic biomarkers in skin punch biopsies and rapidly reversible, mechanism-based effects on hematologic parameters. These results suggest that SCH 727965 is a potent and selective CDK inhibitor and a novel cytotoxic agent. Mol Cancer Ther; 9(8); 2344–53. ©2010 AACR.

Potent intestinal Th17 priming through peripheral lipopolysaccharide-based immunization

Lipopolysaccharide (LPS) is a potent natural adjuvant, commonly used to amplify Th1 responses. Here, we report that systemic immunization using LPS generates large numbers of specific Th17 cells in murine small intestinal lamina propria. The priming of these Th17 cells required IL‐23p19 production by bone marrow‐derived cells. In contrast, IL‐23 had no impact on Th1 differentiation or overall numbers of Ag‐specific regulatory T cells. Experiments using T‐cell adoptive transfers revealed a previously unappreciated mechanism for how Th17 responses are amplified in vivo: stimulation through LPS expanded precommitted Th17 cells rather than causing Th17 differentiation. Second, LPS drove Th17 cell expansion independently of IL‐23, demonstrating that this cytokine is not necessary for expansion and possibly functions at an earlier stage in Th17 priming. Our data provide an impetus for using LPS‐based peripheral vaccination to augment specific T‐cell‐mediated immunity in the gut mucosa.

IL-23 orchestrates the switch from tumor immune surveillance to tumor-promoting inflammation

Human tumor cells acquire and accumulate mutations and transcriptional changes that provide growth and survival signals and a tumor-promoting microenvironment. Over the last few decades it has become clear that the mammalian immune system is able to recognize these genetic and epigenetic changes, and that T cells specific to oncogenes and oncofetal antigens are present in human cancer patients and their tumors. Immune-mediated inflammation, however, increases tumor incidence and progression. Epidemiologically, inflammatory disease-inducing cytokines have also been linked to tumor progression. However, the nature of the pro-inflammatory T cells that control the chronic inflammatory response, and their regulation by cytokines like IL-23, only became known recently. This review attempts to summarize our knowledge of pro-inflammatory T cells in cancer, and the cytokines that contribute to the deregulation of tumor-promoting inflammation and its inhibitory consequences on the tumor cell elimination by cytotoxic T cells.

Abstract A194: PEGylated human IL-10 (AM0010) in advanced solid tumors

Purpose PEGylated IL-10 induces the rejection of tumors in mice and establishes immunological memory. PEG-IL-10 induces phosphorylation and activation of the anti-apoptotic STAT3 in tumor infiltrating activated CD8 T cells. This leads to the expansion of tumor reactive CD8 T cells both within the tumor and in the periphery. The primary objective of this phase 1 study is to establish the safety, tolerability and the anti-tumor-activity of human PEGylated IL-10 (AM0010). Other objectives include pharmacokinetics, AM0010 immunogenicity and AM0010 induced immune activation. Procedures Patients with advanced melanoma, renal cell cancer, colorectal cancer, prostate cancer, ovarian cancer and pancreatic cancer were enrolled in escalating cohorts of 3-6 patients each followed by expansion cohorts. AM0010 was self-administrated daily subcutaneously at doses of 1 to 40 μg/kg. PK, anti-drug antibodies and immune responses were monitored. Results More than 90 patients were enrolled in escalation and expansion cohorts with AM0010 monotherapy at doses between 1 and 40 μg/kg. An MTD is not yet established through the planned maximally administered dose. Common treatment related adverse events (TrAE) included injection site reaction, rash, fatigue, thrombocytopenia and anemia. Most adverse events were low grade. G3 adverse events were observed including anemia, thrombocytopenia, rash, increased lipase, dyslipidemia, transaminitis. Only one patient discontinued treatment due to TrAEs. On continuous dosing the terminal half-life of AM0010 half-life is estimated to be 24 hrs. Exposures increased linearly with increasing doses. At the therapeutic dose (> 20 μg/kg), AM00010 induced a characteristic immune activation signature, detectable in the serum of patients: The Th1 cytokine IL-18 was dose dependently increased in all patients; IFNg, IL-4, GM-CSF, IL-7 and FasL were elevated in every patient dosed at the therapeutic dose. AM0010 also induced a reduction of TGFβ in the serum. AM0010 treatment induced an increase of activated PD-1 positive CD8 T cells both in the tumor tissue and in circulation. The immune activation observed in patients was consistent with the CD8 mediated tumor immunity observed in preclinical models. As monotherapy, partial responses (PR) were observed in patients with RCC, melanoma and lymphoma. In particular, 19% of RCC patients, had a PR and an additional 62% had stable disease (n = 16). In addition, prolonged stable disease with or without tumor reductions were observed in several other indications, including patients with pancreatic, lung, ovarian or colon cancer. Conclusion In Monotherapy, AM0010 has a well-tolerated safety profile and leads to sustained and systemic immune stimulation. The pharmacodynamics and clinical activity observed support the ongoing monotherapy expansions and combination regimens with checkpoint inhibitors as well as cytotoxic chemotherapies. Trial registration: www.clinicaltrials.gov NCT02009449 Citation Format: Jeffrey R. Infante, Aung Naing, Kyriakos P. Papadopoulos, Karen A. Autio, Patrick A. Ott, Deborah J. Wong, Gerald S. Falchook, Manish Patel, Shubham Pant, Melinda Whiteside, Johanna C. Bendell, Todd M. Bauer, Filip Janku, Milind Javle, Rivka Colen, Nizar Tannir, Martin Oft. PEGylated human IL-10 (AM0010) in advanced solid tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A194.

CD8+ T cell stimulation with pegylated recombinant human IL-10 in the patient with advanced solid tumors - a Phase I study.

Meeting abstracts In preclinical studies, PEGylated IL-10 (PEG-IL-10) but not non-PEG IL-10 induces tumor rejection by the directly activating and increasing the proliferation of tumor specific CD8 T cells within the tumor. PEG-IL-10 activates STAT3 and STAT1 in tumor infiltrating CD8 T cells. PEG-