Glenn Begley

Checkpoint inhibitors represent an effective treatment approach for a variety of cancers through their inhibition of immune regulatory pathways within the tumor microenvironment (TME). Unfortunately only a minority of patients with cancer achieve clinical benefit from immunotherapy, with the TME emerging as an important predictor of outcomes and sensitivity to therapy. The extent and pattern of T-cell infiltration can vary prominently within/across tumors and represents a biological continuum. Three immune profiles have been identified along this continuum: 'immune-desert' or 'T-cell cold' phenotype, 'immune-active', 'inflamed', or 'T-cell hot' phenotype, and 'immune excluded' phenotype. Of the three profiles, immune excluded remains the most ill-defined with no clear, universally accepted definition even though it is commonly associated with lack of response to immune checkpoint inhibitors and poor clinical outcomes. To address this, 16 multidisciplinary cancer experts from around the world were invited to participate in a symposium using a three-round modified Delphi approach. The first round was an open-ended questionnaire distributed via email and the second was an in-person discussion of the first round results that allowed for statements to be revised as necessary to achieve a maximum consensus (75% agreement) among the rating committee (RC). The final round questionnaire was distributed to the RC via email and had a 100% completion rate. The Delphi process resulted in moving us closer to a consensus definition for immune exclusion that is practical, clinically pertinent, and applicable across a wide range of cancer histologies. A general consensus of the role of immune exclusion in resistance to checkpoint therapy and five research priorities emerged from this process. Together, these tools could help efforts designed to address the underlying mechanisms of immune exclusion that span cancer types and, ultimately, aid in the development of treatments to target these mechanisms to improve patient outcomes.

A human neutrophil- and eosinophil-specific surface antigen, GFA-2, has been found to be involved in the antibody-dependent cell-mediated cytotoxicity (ADCC) to extracellular targets, and in phagocytosis. The monoclonal antibody (MAb) WEM-G11 was produced which recognizes the GFA-2 structure. This MAb, when used as F(ab')2, stimulated human neutrophils to kill antibody-coated P815 cells and, in the case of human eosinophils, increased their cytotoxic effect on schistosomula of Schistosoma mansoni in a dose-dependent manner. MAb WEM-G11 F(ab')2 also stimulated the phagocytosis of antibody-coated sheep erythrocytes by neutrophils. The effect of WEM-G11 F(ab')2 was specific, because other MAb, whether tested in the form of F(ab')2 fragments or as whole IgG, failed to stimulate neutrophils despite binding to these cells. In contrast to the F(ab')2 fragments of these cells. In contrast to the F(ab')2 fragments of WEM-G11, the whole IgG of this MAb inhibited ADCC and phagocytosis, presumably through interaction with granulocyte Fc receptors. WEM-G11 F(ab')2, and to a greater extent WEM-G11 IgG, induced degranulation, but only from cytochalasin B-treated neutrophils. GFA-2 was absent from lymphocytes, monocytes, erythrocytes, and myeloid and erythroid colony-forming cells, as shown by flow cytometry and colony-forming experiments. GFA-2 appeared at the promyelocytic stage and increased in density as neutrophils became more mature. In the mature neutrophil, the number of binding sites for WEM-G11 were found to be about 20,000 per cell. By immunoprecipitation, it appeared that GFA-2 consisted of a polypeptide chain of about 95,000 m.w. and a low m.w. peptide of about 43,000. By immunoblotting, it was demonstrated that the epitope recognized by WEM-G11 is in the chain of m.w. 95,000. GFA-2 thus constitutes a novel human granulocyte-specific antigen that is central to the functional activity and differentiation of these cells.

Microarray analysis of two interacting treatments: a linear model and trends in expression over time

1233 AMG 531 is a novel thrombopoietic agent that engages c-mpl and has been demonstrated to elevate platelet counts in normal individuals and in patients with idiopathic thrombocytopenic purpura (ITP)1. Consistent with this clinical data, AMG 531 increases platelet counts in mice in a dose-related fashion. We sought to determine whether AMG 531 would be an effective agent in models of chemo/radiotherapy induced thrombocytopenia. We therefore employed a model combining chemotherapy with radiation (CRT) that results in severe thrombocytopenia2. The effects of a single injection of AMG 531 were examined in this mouse model.Mice were treated with the combination of carboplatin (62.5 mg/kg) and 4 hours later sub-lethal irradiation (5 Gy total body irradiation). Two hours post-irradiation, groups were treated with either placebo (n=20) or AMG531 (n=20). Platelet counts in mice treated with placebo fell to 10% of the initial platelet count by day 10 after CRT and returned to normal by day 21. Animals that received only placebo showed nadir platelet counts of 700X106/mL and the nadir was brought forward to between days 5 and 6. At the dose studied this was then followed by a substantial overshoot in platelets though dose reduction was not investigated. Platelet counts were significantly improved (AMG 531 vs. placebo) between days 7 and 19 (p= 0.001 on day 7) when platelets recovered in the unsupported group to pre-treatment values. We conclude that AMG531 reduces the severity and duration of the thrombocytopenia resulting from CRT when compared to placebo-treated mice. The beneficial effect was similar to that seen historically for mice treated with CRT and that received other mpl ligands. Further work is required to establish the optimal dose and schedule for administration of AMG531 in chemotherapy induced thrombocytopenia. 1 Bussel, et al An Open-Label, Dose-Finding Study Evaluating the Safety and Platelet Response of a Novel Thrombopoietic Protein (AMG 531) in Thrombocytopenic Adult Patients with Immune Thrombocytopenic Purpura (ITP). Blood. 102(11): 86a 2003, November 16 2 Hokom, et al Pegylated Megakaryocyte Growth and Development Factor Abrogates the Lethal Thrombocytopenia Associated With Carboplatin and Irradiation in Mice. Blood. 86(12): 4486-92, 1995 Dec 15

A rift has opened and is widening between basic research (bench) and clinical research and patients (bed) who need their new treatments, diagnostics and preventive strategies. This problem involving the 'translation' of basic scientific findings into clinical applications and potential treatments or biomarkers for a condition like heart failure is widely recognized both in academia and industry. Despite the attempts that have been made by both sides to improve this situation, the high attrition rates of drug development and the problem with reproducibility and translatability of preclinical findings to human applications still persist. As a result, the return on investment of basic research has been limited in terms of clinical impact. In this scientific statement we describe and discuss various issues with relevance to this theme and try to dissect how to move our field towards the development of more effective heart failure drugs. We zoom in on facilitating the process of heart failure drug development, the unnecessary gaps ('valley of death') between the critical steps in heart failure drug development, validation and de-validation of new concepts as early as possible ('rigorous translation'). We describe forums on how to stimulate cross-talk and interaction between clinician-scientists, basic heart failure researchers, biotech and industry, and how to enable them to speak the same language, and lessons learned from successes outside the heart failure field.