Citations

TPS592 Background: Persistent cell proliferation (Ki67 > 10%) on tumor biopsies as early as 2-4 weeks (wks) on neo endocrine therapy (ET) identifies resistant tumors in ~20% patients (pts) with early stage ER+ HER2- BC who are at high risk of relapse. Palbo plus ET significantly improves progression free survival in pts with ET naïve or resistant advanced ER+ HER2- BC, and is being evaluated in the adjuvant setting. However, biomarkers predictive of palbo sensitivity are unknown. Ki67 analysis of serial tumor biopsies in the neo palbo and ana (NeoPalAna) trial demonstrated that 2 wks of palbo plus ana potently inhibited Ki67 and induced complete cell cycle arrest (CCCA, Ki67≤2.7%) in tumors with high Ki67 post 4 wks ana run-in. This study is therefore aimed to prospectively investigate the biological activity of palbo plus ana in ET resistant ER+ HER2- BC. Methods: The primary objective is to assess the rate of CCCA (central Ki67 ≤2.7%) after 2 wks of neo palbo and ana. Secondary objectives include analysis of tumor biopsies to explore response biomarkers. Key inclusions include women with clinical stage 2/3 ER+ HER2- BC, central Ki67 > 10% after ≥2 wks of any neo ET, adequate organ function. Key exclusions include prior CDK 4/6 inhibitor, treatment of BC except ET, concomitant use of strong CYP3A4 inhibitor. Pts receive palbo (125mg PO daily, days 1-21, 28-day cycle), ana (1 mg PO daily) and goserelin (if premenopausal). Pts with C1D15 Ki67 > 10% will discontinue study. If C1D15 Ki67 ≤10%, pt will receive 4 cycles of treatment, and additional 10-12 days of palbo if counts normalized within 3 wks post C4D28. Following surgery, pts are eligible for 2 years of adjuvant palbo. A sample size of 37 (stage 1, n = 12, stage 2 n = 25) by simon optimal two stage phase II design will be employed to assess whether the rate of CCCA is ≤5% vs ≥20% (90% power, alpha 0.1). Stage 2 will proceed if ≥1 had CCCA in stage 1. If ≤3 of 37 had CCCA, this regimen will be considered ineffective. The study is active and has enrolled 4 pts. Clinical trial information: NCT01723774.

The purposes of this study were to test the hypothesis that heat stress and hepatic thermal ablation induce nerve growth factor inducible (VGF) and to determine intrahepatic versus systemic VGF expression induced by thermal ablation in vivo and in patients. Hepatocytes and HCC cells were subjected to moderate (45°C) or physiologic (37°C) heat stress for 10 min and assessed for VGF expression at 0‐72 h post-heat stress ( n ≥ 3 experiments). Orthotopic N1S1 HCC-bearing rats were randomized to sham or laser thermal ablation (3 W × 90 s), and liver/serum was harvested at 0‐7 days postablation for analysis of VGF expression ( n ≥ 6 per group). Serum was collected from patients undergoing thermal ablation for HCC ( n = 16) at baseline, 3‐6, and 18‐24 h postablation and analyzed for VGF expression. Data were analyzed using ordinary or repeated-measures one-way analysis of variance and post hoc pairwise comparison with Dunnett’s test. Moderate heat stress induced time-dependent VGF mRNA (3- to 15-fold; p < 0.04) and protein expression and secretion (3.1- to 3.3-fold; p < 0.05). Thermal ablation induced VGF expression at the hepatic ablation margin at 1 and 3 days postablation but not remote from the ablation zone or distant intrahepatic lobe. There was no detectable serum VGF following hepatic thermal ablation in rats and no increase in serum VGF following HCC thermal ablation in patients at 3‐6 and 18‐24 h postablation compared to baseline (0.71- and 0.63-fold; p = 0.27 and p = 0.16, respectively). Moderate heat stress induces expression and secretion of VGF in HCC cells and hepatocytes in vitro, and thermal ablation induces local intrahepatic but not distant intrahepatic or systemic VGF expression in vivo.

Abstract Introduction: MutHER is a phase II trial that demonstrated the anti-tumor activity of the pan-HER inhibitor neratinib in HER2mut, non-amplified MBC. The major challenges to accrue to this trial were the large number of pts to screen for the 2-3% HER2mut population and the high rate (24%) of poor quality tumor DNA for sequencing. The goals of this ctDNA study were: 1) the concordance of HER2mut detected by ctDNA versus tumor testing; 2) the incidence of ctDNA HER2mut in HER2 non-amplified MBC; 3) changes in HER2mut variant allele frequency (VAF) on neratinib therapy. Methods: A sample size of 30 negative (neg) controls was needed to ensure 90% confidence if ctDNA testing has &gt;90% specificity in detecting HER2mut. Thus, plasma from MBC pts obtained at screening for MutHER trial (Neg control: 40 pts without HER2mut on tumor testing; Positive (pos) control: 14 pts with known HER2mut who received neratinib) were subjected to Guardant360 ctDNA 70-gene panel sequencing (all exons of HER2 included). ctDNA from the 14 neratinib treated pts were also analyzed at week (wk) 4 and upon progression. ctDNA data from MBC pts clinically tested at Guardant Health were interrogated for HER2mut incidence. Results: Among the 14 pts with tumor pos for HER2mut, ctDNA sequencing identified the same HER2mut in 11, discrepant HER2mut in 1, and neg in 2. The 2 pts with ctDNA neg for HER2mut had progressive disease (PD) and stable disease (SD &gt; 6 months) on neratinib, respectively. Among the 40 neg controls, 8 were not evaluable (no detectable ctDNA or assay unsuccessful) and all 32 successfully sequenced cases were neg for HER2mut. The sensitivity and specificity of ctDNA for HER2mut detection was 11/14 (79%, 90% CI: 53-94%) and 32/32 (100%, 90% CI: 91-100%), respectively. Among the 11 paired baseline and wk 4 samples, 9 (82%) had lower HER2mut VAFs at wk 4 than at baseline, with 1 complete response (CR), 1 partial response (PR), 5 SD, and 4 PD at wk 8 as best tumor response. Two pts had higher wk 4 ctDNA HER2mut VAFs and both had radiographic PD at wk 8. The absolute HER2mut VAF levels at wk 4 were significantly associated with TTP (Spearman rho=-0.69, p=0.02) and tumor size change (rho=0.67, p=0.05). The HER2mut VAFs were significantly higher at progression than wk 4 in all pts (p&lt;0.01). One pt acquired a new HER2mut T798I, which is analogous to the gate-keeper mutation EGFR T790M. The incidence of HER2mut without amplification in unselected consecutive MBC clinically tested by Guardant360 was 3% (48/1,584), with mutation pattern similar to published tumor testing data. Conclusions: ctDNA sequencing is sensitive and highly specific in detecting HER2mut, offering a non-invasive method to identify pts for trials of HER2mut-targeted therapy. Decreased HER2mut VAFs at wk 4 was observed in 82% of cases, consistent with the on-target effect of neratinib. Increased HER2mut VAFs at wk 4 is a potential early marker of progression. Citation Format: Cynthia Ma, Ron Bose, Feng Gao, Rachel Freedman, Melinda Telli, Gretchen Kimmick, Eric Winer, Michael Naughton, Matthew Goetz, Christy Russell, Debu Tripathy, Melody Cobleigh, Andres Forero, Timothy Pluard, Carey Anders, Shana Thomas, Jill Anderson, Caroline Bumb, Kimberly Banks, Richard Lanman, Richard Bryce, Alshad Lalani, John Pfeifer, Daniel Hays, Mark Pegram, Kimberly Blackwell, Philippe Bedard, Hussam Al-Kateb, Matthew Ellis. Circulating tumor DNA (ctDNA) sequencing for HER2 mutation (HER2mut) screening and response monitoring to neratinib in metastatic breast cancer (MBC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT011. doi:10.1158/1538-7445.AM2017-CT011

Abstract Purpose: Based on promising preclinical data, we conducted a single-arm phase II trial to assess the clinical benefit rate (CBR) of neratinib, defined as complete/partial response (CR/PR) or stable disease (SD) ≥24 weeks, in HER2mut nonamplified metastatic breast cancer (MBC). Secondary endpoints included progression-free survival (PFS), toxicity, and circulating tumor DNA (ctDNA) HER2mut detection. Experimental Design: Tumor tissue positive for HER2mut was required for eligibility. Neratinib was administered 240 mg daily with prophylactic loperamide. ctDNA sequencing was performed retrospectively for 54 patients (14 positive and 40 negative for tumor HER2mut). Results: Nine of 381 tumors (2.4%) sequenced centrally harbored HER2mut (lobular 7.8% vs. ductal 1.6%; P = 0.026). Thirteen additional HER2mut cases were identified locally. Twenty-one of these 22 HER2mut cases were estrogen receptor positive. Sixteen patients [median age 58 (31–74) years and three (2–10) prior metastatic regimens] received neratinib. The CBR was 31% [90% confidence interval (CI), 13%–55%], including one CR, one PR, and three SD ≥24 weeks. Median PFS was 16 (90% CI, 8–31) weeks. Diarrhea (grade 2, 44%; grade 3, 25%) was the most common adverse event. Baseline ctDNA sequencing identified the same HER2mut in 11 of 14 tumor-positive cases (sensitivity, 79%; 90% CI, 53%–94%) and correctly assigned 32 of 32 informative negative cases (specificity, 100%; 90% CI, 91%–100%). In addition, ctDNA HER2mut variant allele frequency decreased in nine of 11 paired samples at week 4, followed by an increase upon progression. Conclusions: Neratinib is active in HER2mut, nonamplified MBC. ctDNA sequencing offers a noninvasive strategy to identify patients with HER2mut cancers for clinical trial participation. Clin Cancer Res; 23(19); 5687–95. ©2017 AACR.

AbstractThe liver differs from other organs in that two vascular systems deliver its blood – the hepatic artery and the portal vein. However, how the two systems interact is not fully understood. We therefore studied the microvascular geometry of rat liver hepatic artery and portal vein injected with the contrast polymer Microfil®. Intact isolated rat livers were imaged by micro‐CT and anatomic evidence for hepatic arteriolo‐portal venular shunts occurring between hepatic artery and portal vein branches was found. Simulations were performed to rule out the possibility of the observed shunts being artifacts resulting from image blurring. In addition, in the case of specimens where only the portal vein was injected, only the portal vein was opacified, whereas in hepatic artery injections, both the hepatic artery and portal vein were opacified. We conclude that mixing of the hepatic artery and portal vein blood can occur proximal to the sinusoidal level, and that the hepatic arteriolo‐portal venular shunts may function as a one‐way valve‐like mechanism, allowing flow only from the hepatic artery to the portal vein (and not the other way around).

Streptozotocin (STZ)-induced diabetes mellitus (DM) offers a very cost-effective and expeditious technique that can be used in most strains of rodents, opening the field of DM research to an array of genotypic and phenotypic options that would otherwise be inaccessible. Despite widespread use of STZ in small animal models, the data available concerning drug preparation, dosing and administration, time to onset and severity of DM, and any resulting moribundity and mortality are often limited and inconsistent. Because of this, investigators inexperienced with STZ-induced diabetes may find it difficult to precisely design new studies with this potentially toxic chemical and account for the severity of DM it is capable of inducing. Until a better option becomes available, attempts need to be made to address shortcomings with current STZ-induced DM models. In this paper we review the literature and provide data from our pancreatic islet transplantation experiments using single high-dose STZ-induced DM in NCr athymic nude mice with hopes of providing clarification for study design, suggesting refinements to the process, and developing a more humane process of chemical diabetes induction.