Giles, Francis Joseph

Abstract Dysregulation of ErbB-mediated signaling is observed in up to 90% of solid tumors. ErbB family cross-talk is implicated in the development of resistance and metastasis, including CNS metastases. Inhibition of multiple ErbB receptors may result in improved patient outcomes. EO1001 is a novel, patented, oral, brain-penetrating, irreversible pan-ErbB inhibitor targeting EGFR (ErbB1), HER2 (ErbB2) and HER4 (ErbB4). METHODS: (1) In vitro testing. EO1001 demonstrates high specificity for the ErbB family of receptors with excellent, balanced equipotent activity against EGFR, HER2 and HER4 (0.4 to 7.4 nM). EO1001 inhibits signaling downstream of wild type EGFR, mutant EGFR (T790M, L858R and d746-750) and HER2. (2) PK and toxicity. In rodent studies in vivo, EO1001 exhibited a half-life of 16–20 hours. EO1001 rapidly enters the CNS and penetrates tumor tissue at higher concentrations relative to plasma. Safety of EO1001 was evaluated by repeat-dosing studies in SD rats and beagle dogs. Toxicities typical of the ErbB inhibitor class, including gastro-intestinal effects, weight loss and decreased activity were observed at higher dose groups in both species. Mortality was observed in SD rats at higher dose groups. (3) In vivo efficacy studies. EO1001 was studied following oral administration in several erbB-positive mouse xenograft models including N87 (Her2+), H1975 (EGFR/T790M), GBM12 (EGFR+), GBM39 (EGVRvIII+). Following oral administration, treatment with EO1001 resulted in a statistically significant improvement in outcomes compared to positive and negative controls in both CNS and systemic tumor models. EO1001 was well-tolerated with no gastrointestinal side effects observed at efficacious doses in these models. CONCLUSION: Based on research to date, EO1001 has the potential to be a best-in-class CNS-penetrating pan-ErbB inhibitor with a safety and pharmacokinetic profile amenable for use as a single agent and in combination with other agents. EO1001 is poised to enter phase 1-2a clinical testing in the second-half of 2019.

Abstract Targeting the B-cell receptor and phosphatidylinositol 3-kinase/mTOR signaling pathways has shown meaningful, but incomplete, antitumor activity in lymphoma. Glycogen synthase kinase 3 (GSK3) α and β are 2 homologous and functionally overlapping serine/threonine kinases that phosphorylate multiple protein substrates in several key signaling pathways. To date, no agent targeting GSK3 has been approved for lymphoma therapy. We show that lymphoma cells abundantly express GSK3α and GSK3β compared with normal B and T lymphocytes at the messenger RNA and protein levels. Utilizing a new GSK3 inhibitor 9-ING-41 and by genetic deletion of GSK3α and GSK3β genes using CRISPR/CAS9 knockout, GSK3 was demonstrated to be functionally important to lymphoma cell growth and proliferation. GSK3β binds to centrosomes and microtubules, and lymphoma cells treated with 9-ING-41 become arrested in mitotic prophase, supporting the notion that GSK3β is necessary for the progression of mitosis. By analyzing recently published RNA sequencing data on 234 diffuse large B-cell lymphoma patients, we found that higher expression of GSK3α or GSK3β correlates well with shorter overall survival. These data provide rationale for testing GSK3 inhibitors in lymphoma patient trials.

Abstract Purpose: Myelofibrosis is characterized by bone marrow fibrosis, atypical megakaryocytes, splenomegaly, constitutional symptoms, thrombotic and hemorrhagic complications, and a risk of evolution to acute leukemia. The JAK kinase inhibitor ruxolitinib provides therapeutic benefit, but the effects are limited. The purpose of this study was to determine whether targeting AURKA, which has been shown to increase maturation of atypical megakaryocytes, has potential benefit for patients with myelofibrosis. Patients and Methods: Twenty-four patients with myelofibrosis were enrolled in a phase I study at three centers. The objective of the study was to evaluate the safety and preliminary efficacy of alisertib. Correlative studies involved assessment of the effect of alisertib on the megakaryocyte lineage, allele burden, and fibrosis. Results: In addition to being well tolerated, alisertib reduced splenomegaly and symptom burden in 29% and 32% of patients, respectively, despite not consistently reducing the degree of inflammatory cytokines. Moreover, alisertib normalized megakaryocytes and reduced fibrosis in 5 of 7 patients for whom sequential marrows were available. Alisertib also decreased the mutant allele burden in a subset of patients. Conclusions: Given the limitations of ruxolitinib, novel therapies are needed for myelofibrosis. In this study, alisertib provided clinical benefit and exhibited the expected on-target effect on the megakaryocyte lineage, resulting in normalization of these cells and reduced fibrosis in the majority of patients for which sequential marrows were available. Thus, AURKA inhibition should be further developed as a therapeutic option in myelofibrosis. See related commentary by Piszczatowski and Steidl, p. 4868

62 Background: We have previously reported that mutations in SPOP promote bromodomain and extra-terminal motif (BET) protein upregulation and BET inhibitor resistance in prostate cancer (Zhang et al., Nature Medicine 23(9):1055-1062, 2017). Other studies indicate that histone acetyltransferases (HATs) such as P300 are also upregulated in SPOP-mutated prostate cancer (Blattner et al., Cancer Cell 31: 436-451, 2017). Methods: We examined the anti-cancer effect of NEO2734 (Epigene Therapeutics Inc), a novel dual inhibitor of both BET and CBP-P300, in prostate cancer using cell line, organoid and patient-derived xenografts (PDX) as working models. We examined the anti-cancer effect of NEO2734 (Epigene Therapeutics Inc), a novel dual inhibitor of both BET and CBP-P300, in prostate cancer using cell line, organoid and patient-derived xenografts (PDX) as working models. Results: We demonstrated that while prostate cancer cell lines expressing F133V, the most frequent SPOP mutant, are very resistant to both BET inhibitor JQ1 and CBP/P300 inhibitor CPI-637, they are very sensitive to simultaneous cotreatment with JQ1 and CPI-637. Similarly, we demonstrated that F133V mutant cells are also very sensitive to NEO2734. We established PDX and organoid models from a patient with prostate cancer expressing a novel SPOP mutation Q165P. Computer simulation analysis reveals that the Q165P mutation causes larger conformational fluctuation, indicating that the structure of Q165P is less stable than that of wild type SPOP. Accordingly, co-immunoprecipitation assay showed that Q165P mutation impaired the dimerization ability of SPOP. We further showed that the Q165P mutant organoid was very sensitive to NEO2734 in vitro and the Q165P mutant PDX was very sensitive to NEO2734 in mice. Conclusions: These PDX-based pre-clinical studies indicate that the inhibition of both BET and CBP-P300, either by co-administration of two agents, or by treatment with the dual inhibitor, NEO2734, is effective in SPOP-mutated prostate cancer. These data provide a strong rationale for the inclusion of patients with SPOP-mutated prostate cancer in clinical studies of NEO2734.

Abstract Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, is a complex regulator of numerous cellular functions. GSK-3β is a unique kinase which is constitutively active in resting and nonstimulated cells. GSK-3β has been implicated in a wide range of diseases including neurodegeneration, inflammation and fibrosis, noninsulin-dependent diabetes mellitus, and cancer. It is a regulator of NF-κB–mediated survival of cancer cells, which provided a rationale for the development of GSK-3 inhibitors targeting malignant tumors. Recent studies, many of them reported over the past decade, have identified GSK-3β as a potential therapeutic target in more than 15 different types of cancer. Whereas only active GSK-3β is expressed in cancer cell nucleus, aberrant nuclear accumulation of GSK-3β has been identified as a hallmark of cancer cells in malignant tumors of different origin. This review focuses on the preclinical and clinical development of GSK-3 inhibitors and the potential therapeutic impact of targeting GSK-3β in human cancer. Clin Cancer Res; 23(8); 1891–7. ©2017 AACR.

Abstract Nilotinib, an orally bioavailable, selective Bcr-Abl tyrosine kinase inhibitor, is 30-fold more potent than imatinib in pre-clinical models, and overcomes most imatinib resistant BCR-ABL mutations. In this phase 2 open-label study, 400 mg nilotinib was administered orally twice daily to 280 patients with Philadelphia chromosome–positive (Ph+) chronic myeloid leukemia in chronic phase (CML-CP) after imatinib failure or intolerance. Patients had at least 6 months of follow-up and were evaluated for hematologic and cytogenetic responses, as well as for safety and overall survival. At 6 months, the rate of major cytogenetic response (Ph ≤ 35%) was 48%: complete (Ph = 0%) in 31%, and partial (Ph = 1%-35%) in 16%. The estimated survival at 12 months was 95%. Nilotinib was effective in patients harboring BCR-ABL mutations associated with imatinib resistance (except T315I), and also in patients with a resistance mechanism independent of BCR-ABL mutations. Adverse events were mostly mild to moderate, and there was minimal cross-intolerance with imatinib. Grades 3 to 4 neutropenia and thrombocytopenia were observed in 29% of patients; pleural or pericardial effusions were observed in 1% (none were severe). In summary, nilotinib is highly active and safe in patients with CML-CP after imatinib failure or intolerance. This clinical trial is registered at http://clinicaltrials.gov as ID no. NCT00109707.

Abstract Gain-of-function mutations of the receptor tyrosine kinase KIT play a key role in the pathogenesis of systemic mastocytosis (SM), gastrointestinal stromal tumors (GISTs), and some cases of acute myeloid leukemia (AML). Whereas KIT juxtamembrane domain mutations seen in most patients with GIST are highly sensitive to imatinib, the kinase activation loop mutant D816V, frequently encountered in SM, hampers the binding ability of imatinib. We investigated the inhibitory activity of the novel tyrosine kinase inhibitor EXEL-0862 against 2 subclones of human mast cell line-1 (HMC-1)—HMC-1.1, harboring the juxtamembrane domain mutation V560G, and HMC-1.2, carrying V560G and the activation loop mutation D816V, found in more than 80% of patients with SM. EXEL-0862 inhibited the phosphorylation of KIT in a dose-dependent manner and decreased cell proliferation in both mast cell lines with higher activity against HMC-1.2 cells. The phosphorylation of KIT-dependent signal transducer and activator of transcription-3 (STAT3) and STAT5 was abrogated upon exposure to nanomolar concentrations of EXEL-0862. In addition, EXEL-0862 induced a time- and dose-dependent proapoptotic effect in both mast cell lines and caused a significant reduction in mast-cell content in bone marrow samples from patients with SM harboring D816V and from those without the D816V mutation. We conclude that EXEL-0862 is active against KIT activation loop mutants and is a promising candidate for the treatment of patients with SM and other KIT-driven malignancies harboring active site mutations.

AbstractWe present results of 2 similarly designed but separate phase 2 studies involving single-agent lenalidomide (CC-5013, Revlimid) in a total of 68 patients with symptomatic myelofibrosis with myeloid metaplasia (MMM). Protocol treatment consisted of oral lenalidomide at 10 mg/d (5 mg/d if baseline platelet count < 100 × 109/L) for 3 to 4 months with a plan to continue treatment for either 3 or 24 additional months, in case of response. Overall response rates were 22% for anemia, 33% for splenomegaly, and 50% for thrombocytopenia. Response in anemia was deemed impressive in 8 patients whose hemoglobin level normalized from a baseline of either transfusion dependency or hemoglobin level lower than 100 g/L. Additional treatment effects in these patients included resolution of leukoerythroblastosis (4 patients), a decrease in medullary fibrosis and angiogenesis (2 patients), and del(5)(q13q33) cytogenetic remission accompanied by a reduction in JAK2V617F mutation burden (1 patient). Grade 3 or 4 adverse events included neutropenia (31%) and thrombocytopenia (19%). We conclude that lenalidomide engenders an intriguing treatment activity in a subset of patients with MMM that includes an unprecedented effect on peripheral blood and bone marrow abnormalities.