AZD2014, an Inhibitor of mTORC1 and mTORC2, Is Highly Effective in ER+ Breast Cancer When Administered Using Intermittent or Continuous Schedules

mTOR is an atypical serine threonine kinase involved in regulating major cellular functions, such as nutrients sensing, growth, and proliferation. mTOR is part of the multiprotein complexes mTORC1 and mTORC2, which have been shown to play critical yet functionally distinct roles in the regulation of cellular processes. Current clinical mTOR inhibitors only inhibit the mTORC1 complex and are derivatives of the macrolide rapamycin (rapalogs). Encouraging effects have been observed with rapalogs in estrogen receptor-positive (ER(+)) breast cancer patients in combination with endocrine therapy, such as aromatase inhibitors. AZD2014 is a small-molecule ATP competitive inhibitor of mTOR that inhibits both mTORC1 and mTORC2 complexes and has a greater inhibitory function against mTORC1 than the clinically approved rapalogs. Here, we demonstrate that AZD2014 has broad antiproliferative effects across multiple cell lines, including ER(+) breast models with acquired resistance to hormonal therapy and cell lines with acquired resistance to rapalogs. In vivo, AZD2014 induces dose-dependent tumor growth inhibition in several xenograft and primary explant models. The antitumor activity of AZD2014 is associated with modulation of both mTORC1 and mTORC2 substrates, consistent with its mechanism of action. In combination with fulvestrant, AZD2014 induces tumor regressions when dosed continuously or using intermittent dosing schedules. The ability to dose AZD2014 intermittently, together with its ability to block signaling from both mTORC1 and mTORC2 complexes, makes this compound an ideal candidate for combining with endocrine therapies in the clinic. AZD2014 is currently in phase II clinical trials.

First-in-Human Pharmacokinetic and Pharmacodynamic Study of the Dual m-TORC 1/2 Inhibitor AZD2014

PURPOSE

AZD2014 is a novel, oral, m-TORC 1/2 inhibitor that has shown in vitro and in vivo efficacy across a range of preclinical human cancer models.

EXPERIMENTAL DESIGN

A rolling six-dose escalation was performed to define an MTD (part A), and at MTD a further cohort of patients was treated to further characterize toxicities and perform pre- and posttreatment biopsies (part B). AZD2014 was administered orally twice a day continuously. Flow cytometry, ELISA, and immunohistochemistry were used to quantify pharmacodynamic biomarkers. Pharmacokinetic analysis was carried out by mass spectrometry.

RESULTS

A total of 56 patients were treated across a dose range of 25 to 100 mg. The MTD was 50 mg twice daily. The dose-limiting toxicities were fatigue and mucositis. At the MTD, the most common adverse events (AE) were fatigue (78%), nausea (51%), and mucositis (49%), but these were equal to or greater than grade 3 in only 5% of patients. Drug levels achieved at the MTD (AUC SS: 6686 ng·h/mL, Cmax ss 1,664 ng/mL) were consistent with activity in preclinical models. A reduction in p-S6 levels and Ki67 staining was observed in 8 of 8 and 5 of 9 evaluable paired biopsy samples. Partial responses were seen in a patient with pancreatic cancer and a patient with breast cancer, who were found to have a PDGFR and ERBB2 mutation, respectively.

CONCLUSIONS

The recommended phase II dose for further evaluation of AZD2014 is 50 mg twice daily, and at this dose it has been possible to demonstrate pharmacologically relevant plasma concentrations, target inhibition in tumor, and clinical responses.

A retrospective analysis of RET translocation, gene copy number gain and expression in NSCLC patients treated with vandetanib in four randomized Phase III studies

Background

To determine the prevalence of RET rearrangement genes, RET copy number gains and expression in tumor samples from four Phase III non-small-cell lung cancer (NSCLC) trials of vandetanib, a selective inhibitor of VEGFR, RET and EGFR signaling, and to determine any association with outcome to vandetanib treatment.

Methods

Archival tumor samples from the ZODIAC (NCT00312377, vandetanib ± docetaxel), ZEAL (NCT00418886, vandetanib ± pemetrexed), ZEPHYR (NCT00404924, vandetanib vs placebo) and ZEST (NCT00364351, vandetanib vs erlotinib) studies were evaluated by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in 944 and 1102 patients.

Results

The prevalence of RET rearrangements by FISH was 0.7% (95% CI 0.3–1.5%) among patients with a known result. Seven tumor samples were positive for RET rearrangements (vandetanib, n = 3; comparator, n = 4). 2.8% (n = 26) of samples had RET amplification (innumerable RET clusters, or ≥7 copies in > 10% of tumor cells), 8.1% (n = 76) had low RET gene copy number gain (4–6 copies in ≥40% of tumor cells) and 8.3% (n = 92) were RET expression positive (signal intensity ++ or +++ in >10% of tumor cells). Of RET-rearrangement-positive patients, none had an objective response in the vandetanib arm and one patient responded in the comparator arm. Radiologic evidence of tumor shrinkage was observed in two patients treated with vandetanib and one treated with comparator drug. The objective response rate was similar in the vandetanib and comparator arms for patients positive for RET copy number gains or RET protein expression.

Conclusions

We have identified prevalence for three RET biomarkers in a population predominated by non-Asians and smokers. RET rearrangement prevalence was lower than previously reported. We found no evidence of a differential benefit for efficacy by IHC and RET gene copy number gains. The low prevalence of RET rearrangements (0.7%) prevents firm conclusions regarding association of vandetanib treatment with efficacy in the RET rearrangement NSCLC subpopulation.

Trial registration

Randomized Phase III clinical trials (NCT00312377, ZODIAC; NCT00418886, ZEAL; NCT00364351, ZEST; NCT00404924, ZEPHYR).

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1146-8) contains supplementary material, which is available to authorized users.

A phase I trial of vertical inhibition of IGF signalling using cixutumumab, an anti-IGF-1R antibody, and selumetinib, an MEK 1/2 inhibitor, in advanced solid tumours

BACKGROUND

We completed a phase I clinical trial to test the safety and toxicity of combined treatment with cixutumumab (anti-IGF-1R antibody) and selumetinib (MEK 1/2 inhibitor).

METHODS

Patients with advanced solid tumours, refractory to standard therapy received selumetinib hydrogen sulphate capsules orally twice daily, and cixutumumab intravenously on days 1 and 15 of each 28-day cycle. The study used a 3+3 design, with a dose-finding cohort followed by an expansion cohort at the maximally tolerated dose that included pharmacokinetic and pharmacodynamic correlative studies.

RESULTS

Thirty patients were enrolled, with 16 in the dose-finding cohort and 14 in the expansion cohort. Grade 3 or greater toxicities included nausea and vomiting, anaemia, CVA, hypertension, hyperglycaemia, and ophthalmic symptoms. The maximally tolerated combination dose was 50 mg twice daily of selumetinib and 12 mg kg(-1) every 2 weeks of cixutumumab. Two patients achieved a partial response (one unconfirmed), including a patient with BRAF wild-type thyroid carcinoma, and a patient with squamous cell carcinoma of the tongue, and six patients achieved time to progression of >6 months, including patients with thyroid carcinoma, colorectal carcinoma, and basal cell carcinoma. Comparison of pre- and on-treatment biopsies showed significant suppression of pERK and pS6 activity with treatment.

CONCLUSIONS

Our study of anti-IGF-1R antibody cixutumumab and MEK 1/2 inhibitor selumetinib showed that the combination is safe and well-tolerated at these doses, with preliminary evidence of clinical benefit and pharmacodynamic evidence of target inhibition.

Abstract 912: Targeting HER family signaling in low HER2-expressing breast cancer: activity of the selective and equipotent EGFR, HER2 and HER3 signaling inhibitor, AZD8931, in models of low HER2-expressing disease

Effective therapies for women with low-HER2 expressing breast cancer remain a significant unmet clinical need. We have detected significant phosphorylated-HER and HER2:HER3 dimer expression in clinical breast cancer samples without HER2 amplification suggesting that HER signaling may play a role in these tumors. It is our hypothesis that ligand-driven signaling is the major route of HER family activation in the absence of HER2 amplification.

AZD8931 is an orally bioavailable and highly selective small molecule inhibitor of EGFR, HER2 and HER3 signaling, which shows greatest potency when HER signaling is ligand-driven(1). In a range of low HER2 breast cancer cell lines, AZD8931 inhibited heregulin-driven proliferation (GI50 range 0.05 to 0.38μM) HER2:HER3 signaling, HER3:PI3K interaction and downstream signaling. In vivo, twice-daily oral dosing of AZD8931 showed significant monotherapy anti-tumor efficacy in a xenograft model of low HER2 breast cancer (MDA-MB-175VII) at well-tolerated doses (90% TGI at 12.5 mg/kg/bid).

We further evaluated the activity of AZD8931 in combination with paclitaxel, a commonly used standard of care chemotherapy for patients with advanced breast cancer expressing low levels of HER2. Pre-clinically, the combination of AZD8931 with paclitaxel showed at least additive activity in vitro in a range of breast cell lines and additive efficacy in vivo in a BT474 (high HER2) xenograft model at well tolerated doses (AZD8931 12.5 mg/kg/bid TGI 63%; paclitaxel 7.5mg/kg/qw TGI 41%; combination TGI 95%). Combination work in the low HER2 xenograft model is ongoing.

These data demonstrate that AZD8931 inhibits ligand-driven HER family receptor activation, receptor dimerization, PI3K interaction and downstream signaling leading to anti-tumor activity in vivo. These data also support the potential clinical utility of AZD8931 for the therapeutic treatment of low HER2 expressing breast cancers in combination with paclitaxel.

1 Hickinson et al. Clin.Cancer Res (2010) 16:1159-69.

Citation Format: Gayle Marshall, Susan Ashton, Georgina Speake, Celina D'Cruz, Michael Grondine, Cath Trigwell, Graham Bigley, Garry Beran, Katy Lynaugh, Teresa C. Klinowska. Targeting HER family signaling in low HER2-expressing breast cancer: activity of the selective and equipotent EGFR, HER2 and HER3 signaling inhibitor, AZD8931, in models of low HER2-expressing disease. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 912. doi:10.1158/1538-7445.AM2013-912

Expression of Ki-67 and cytokeratin 20 in hyperplastic polyps of the colorectum

AIMS

To study the expression of Ki-67 and cytokeratin 20 (CK20) in a group of hyperplastic polyps (including a group with "atypical" features) with the aim of determining whether upper crypt Ki-67 staining and lower crypt CK20 staining correlated with these atypical features, as assessed by light microscopy.

METHODS

Fifty seven formalin fixed, paraffin wax embedded hyperplastic colorectal polyps from 53 patients were selected on histological grounds; these comprised 26 typical polyps and 31 with atypical features, which included nuclear hyperchromatism, basal crowding, and increased mitotic activity. These polyps were examined using a standard immunohistochemical method with antibodies against CK20 and Ki-67. Comparisons were made with normal mucosa, adenomatous polyps, and carcinomas.

RESULTS

Of the 26 typical polyps, 17 showed the usual pattern of lower crypt Ki-67 and upper crypt CK20 staining; one with upper crypt Ki-67 staining but normal surface CK20 staining; seven with Ki-67 confined to the lower half of crypts but with scattered lower crypt CK20; and one with both upper crypt Ki-67 staining, together with scattered CK20 basal staining. Of the 31 polyps with atypical features, 11 showed the usual staining pattern of lower crypt Ki-67 staining and surface staining with CK20; two showed Ki-67 staining extending into the upper half of crypts, but with a normal surface staining with CK20; 14 showed Ki-67 confined to the lower half of crypts, but scattered lower crypt staining with CK20; and four showed upper crypt Ki-67 staining together with scattered CK20 lower crypt staining.

CONCLUSIONS

The normal pattern of lower crypt Ki-67 and upper crypt CK20 was seen in 28 of the 57 hyperplastic polyps and, in general, this corresponded with standard light microscopic appearances. Twenty one of the 57 polyps showed lower crypt mosaic CK20 staining, which in general corresponded with basal abnormalities on light microscopy, although seven specimens had normal appearances. Two smaller subsets emerged, one showing upper crypt Ki-67 staining in the presence of normal CK20 expression (three cases) and another in which a combination of lower crypt CK20 and upper crypt Ki-67 expression was seen (five cases). This last pattern was similar to that of neoplastic polyps and raises the possibility that a subgroup of hyperplastic polyps exists that may be a variant with malignant potential. Further studies with markers of mismatch repair genes and K-ras mutations may help to clarify this issue.

Cyclooxygenase-2 expression in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence

OBJECTIVE

Increased expression of the inducible cyclooxygenase 2 (COX-2) enzyme has been detected in esophageal and colonic adenocarcinoma, and intake of aspirin and non-steroidal anti-inflammatory drugs, known COX-2 inhibitors, have been associated with reduced tumor formation. Elevated COX-2 mRNA but variable protein expression has been demonstrated in Barrett's epithelium, and we have, therefore, sought to evaluate the expression of COX-2 protein throughout the Barrett's metaplasia-dysplasia-adenocarcinoma sequence.

METHODS

Paraffin-embedded esophageal biopsies from 56 different patients with Barrett's esophagus were analyzed for COX-2 expression by immunohistochemistry. Twenty contained nondysplastic intestinal and gastric metaplasia, 12 demonstrated low-grade dysplasia (LGD), 12 high-grade dysplasia (HGD), and 12 contained invasive adenocarcinoma.

RESULTS

Epithelial expression of COX-2 protein was detected in 75% (15/20) of benign cases, 83% (10/12) of cases with LGD, and 100% of cases with HGD or adenocarcinoma. Using a semiquantitative analysis, median staining scores for the groups were 2, 3, 14, and 13, respectively (scale 0-16), with the expression being significantly higher in the HGD and cancer groups compared to benign and LGD groups (p < 0.001).

CONCLUSIONS

This study demonstrates clear COX-2 expression in the epithelial cells in Barrett's metaplasia, confirms elevated expression in adenocarcinoma, and shows that the elevation in expression occurs in the progression from LGD to HGD.

A randomized study to evaluate the effect of a perioperative infusion of dopexamine on colonic mucosal ischemia after aortic surgery

PURPOSE

Colonic ischemia after aortic surgery is associated with increased mortality and morbidity rates. This study was conducted as a single-center side arm to a multicenter, randomized, placebo-controlled study to evaluate the effect of dopexamine hydrochloride on its incidence.

METHODS

Thirty patients, mean age 65.1 years (range, 46-84), undergoing elective infrarenal aortic surgery were entered. Preoperative hemodynamic and respiratory parameters were optimized. Patients were then randomly assigned to receive a perioperative infusion of dopexamine at 2 microg/kg per minute (n = 12) or 0.9% saline placebo (n = 18). All patients underwent colonoscopy and biopsy preoperatively and 1 week postoperatively. Specimens were assessed for evidence of mucosal ischemia, presence of mast cell tryptase, myeloperoxidase activity, and both the inducible and endothelial isoforms of nitric oxide synthase.

RESULTS

There was no significant difference in perioperative fluid and blood requirements or hemodynamic and respiratory parameters between the two groups. However, there was significantly less evidence of mucosal ischemic changes in dopexamine-treated patients (n = 1) compared with placebo (n = 8) (P =.049). Furthermore, when preoperative biopsies were compared with those performed 1 week postoperatively, nine (50%) patients in the placebo group and two (16.7%) in the dopexamine group scored worse. Although there was no significant difference in inflammatory markers between the two groups, both mast cell tryptase and myeloperoxidase expression were increased in patients with histologic evidence of ischemia (P <.05). Furthermore, inducible nitric oxide synthase staining within the vascular (P =.001) and lamina propria (P <.05) components of the mucosa was also significantly greater.

CONCLUSION

A perioperative dopexamine infusion affords significant histologic protection to colonic mucosa after aortic surgery.

Dopexamine reduces the incidence of acute inflammation in the gut mucosa after abdominal surgery in high-risk patients

OBJECTIVE

To evaluate the effect of dopexamine on the incidence of acute inflammation in the stomach/duodenum in patients undergoing abdominal surgery > or =1.5 hrs with a minimum of one high-risk criterion.

DESIGN

Prospective, randomized, double-blind, placebo-controlled study. This study was conducted as a side arm to a multicenter, multinational study.

SETTING

University hospital in an adult intensive care unit.

PATIENTS

Thirty-eight patients.

INTERVENTIONS

Patients were stabilized with fluid, blood products, and supplementary oxygen to achieve predetermined goals: cardiac index > 2.5 L/min/m2, mean arterial blood pressure of 70 mm Hg, pulmonary arterial occlusion pressure of 10 mm Hg, hemoglobin of 100 g/L, and arterial saturation of 94%. After stabilization, the study drug (either placebo [group A], dopexamine 0.5 microg/kg/min [group B], or dopexamine 2.0 microg/kg/min [group C]) was commenced. The study drug infusion was started 2 to 12 hrs before surgery and infused for 24 hrs after surgery. Estimation of upper gut blood flow was assessed using a gastric tonometer, and gastroscopy with biopsy was performed before surgery (after induction of anesthesia) and 72 hrs after surgery. Comparisons were made between endoscopic findings and histologic proof of acute inflammatory changes. In addition, biopsies were assessed for the presence in the mucosa of mast cells, myeloperoxidase activity, and inducible nitric oxide synthase.

MEASUREMENTS AND MAIN RESULTS

Intramucosal pH decreased significantly with time in all three groups (p < .001), reaching the lowest point at the end of surgery. There was no difference among the groups. Endoscopy visualized acute inflammatory changes in 58.3% of group A patients, 46.2% of group B patients, and 53.90% of group C patients after hemodynamic optimization. At 72 hrs, dopexamine-treated patients compared with placebo-treated patients had a significantly lower incidence of gastric and duodenal acute inflammatory changes, as defined by myeloperoxidase activity (37.5% in groups B and C vs. 86% in group A; p < .05).

CONCLUSION

Dopexamine in doses of 0.5 and 2.0 microg/kg/min affords significant histologic protection to the upper gastrointestinal tract mucosa 72 hrs after operation in high-risk surgical patients undergoing abdominal surgery.

Vascular surgical society of great britain and ireland: randomized double-blind study of dopexamine versus placebo in aortic surgery

BACKGROUND: Mechanisms involved in the development of colon- ic ischaemia are not fully understood and there are conflicting reports regarding predisposing factors. The aim of this study was to evaluate the effect of dopexamine hydrochloride on the incidence of colonic ischaemia following aortic surgery and to correlate immunohistochemical markers of inflammatory activation in its pathogenesis. METHODS: Thirty patients, of mean age 65 (range 46-84) years, undergoing elective infrarenal aortic surgery were randomized to receive a perioperative infusion of either dopexamine 2 &mgr;g kg-1 min-1 (n = 12) or 0.9 per cent saline placebo (n = 18). All patients underwent colonoscopy and biopsy following induction of anaesthesia and at 1 week after operation. Sections were stained with haematoxylin and eosin, and for mast cell tryptase (MCT), myeloperoxidase (MPO) and both the inducible (iNOS) and endothelial (eNOS) isoforms of nitric oxide synthase. Sections were analysed blindly and independently by two histopathologists. Patient and operative data were collected and stored separately. RESULTS: Colonic ischaemia was noted in nine patients based on microscopic findings. Endoscopy alone had a sensitivity of 56 per cent. There was a significantly lower incidence of colonic ischaemia in patients receiving dopexamine compared with placebo (P < 0.05). One death resulted from colonic infarction in the placebo group 11 days after operation. There was increased MPO and MCT expression in patients with histological evidence of ischaemia (P < 0.05); iNOS staining within the vascular (P = 0.001) and lamina propria (P < 0.05) components of the mucosa was also significantly greater. No association was found with eNOS. CONCLUSION: Perioperative dopexamine infusion confers a degree of protection to colonic mucosa following aortic surgery, possibly through an anti-inflammatory effect.