Abstract P2-05-21: The AKT-mTOR pathway as a potential organ-specific drug target signature of hepatic metastases from breast cancer

Background: The identification of organ-specific targetable signatures may help design more effective treatment for patients with metastatic breast cancer (MBC). We took a multi-OMIC approach to assess whether the AKT-mTOR pathway is globally activated during metastatic progression or whether it represents an organ-specific target.

Methods: Snap frozen biopsies from 25 MBC patients enrolled in a prospective phase II trial were used. Sites of metastasis were classified as liver (n=8) and others (n=17), the latter including cutaneous, lung, lymph nodes, and intra-abdominal lesions. Signaling analysis of the 25 cases was performed using Reverse Phase Protein Microarray (RPPA) coupled with Laser Capture Microdissection. Activation of the AKT-mTOR pathway was quantified as phosphorylation of AKT (S473) and the mTOR target p70S6 (T389). Matched exome (WES) and RNASeq data were available for 17 of 25 patients, five with liver metastases. Sequencing data was processed using an in-house developed pipeline to identify somatic events including coding mutations, copy number alterations, gene fusions, and differential expression. Activation of the AKT-mTOR pathway and sequencing data were compared between hepatic and non-hepatic lesions using an integrated RPPA and genomic approach.

Results: Among liver metastases, AKT was activated in 4 of the 8 (50.0%) patients, while 6 of the 8 cases (75.0%) showed activation of p70S6. Sequencing data revealed mutation of PIK3CA in 4 of the 5 liver metastases (80.0%). Three of the PIK3CA mutated specimens with catalytic domain mutations (codons 1023 and 147) demonstrated co-activation of AKT and p70S6, while the fourth case, containing a helical domain mutation (E542K), had activation of p70S6 only. The PIK3CA wild-type liver metastasis demonstrated low activation of AKT and p70S6. For non-hepatic metastases AKT was activated in 2 of the 17 cases (11.8%) and p70S6 in 5 of the 17 patients (29.4%).

Discussion: Although these results need further validation, activation of the AKT-mTOR pathway appears to be a hepatic specific signature in MBC and could be used for the selection of targeted agents for hepatic lesions.

Citation Format: Pierobon M, Wong S, Reeder A, Anthony SP, Robert NJ, Northfelt DW, Jahanzeb M, Vocila L, Wulfkuhle J, Dunetz B, Aldrich J, Byron S, Craig D, Liotta L, Petricoin EF, Carpten J. The AKT-mTOR pathway as a potential organ-specific drug target signature of hepatic metastases from breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-05-21.

Abstract P6-11-10: IBL2001: Phase I/II study of a novel dose-dense schedule of oral indibulin for the treatment of metastastic breast cancer

Background: Indibulin (ZI0-301) is a novel, oral, synthetic small molecule microtubule inhibitor which binds tubulin at a different site than taxanes and vinca alkaloids. Preclinical data demonstrate indibulin does not interact with acetylated (neuronal) tubulins and in clinical studies has not exhibited the neurotoxicity associated with other tubulin binders. Indibulin has potent antitumor activity in human cancer cell lines, including multidrug-, taxane-, and vinblastine-resistant. Norton-Simon modeling based on cell line data suggested that dose dense (dd) administration could optimize efficacy while limiting toxicity.

Methods: Eligible patients (pts) have metastatic or unresectable locally advanced breast cancer, ECOG performance status ≤ 2, adequate organ function, measurable or nonmeasurable disease and any number of prior therapies. Uncontrolled gastrointestinal malabsorption syndrome and grade 2 or higher peripheral neuropathy are the principal exclusions. Adverse events (AEs) are graded by CTCAE v. 4.0. Objective disease status is evaluated according to RECIST 1.1. The primary objective of the phase (Ph) I portion of the study is to determine the maximum tolerated dose (MTD) of indibulin when given in dd fashion 5 days treatment, 9 days rest using standard 3+3 dose escalation schema.

Phase I pharmacokinetic and pharmacodynamic study of the pan-PI3K/mTORC vascular targeted pro-drug SF1126 in patients with advanced solid tumours and B-cell malignancies

BACKGROUND

SF1126 is a peptidic pro-drug inhibitor of pan-PI3K/mTORC. A first-in-human study evaluated safety, dose limiting toxicities (DLT), maximum tolerated dose (MTD), pharmacokinetics (PK), pharmacodynamics (PD) and efficacy of SF1126, in patients with advanced solid and B-cell malignancies.

PATIENTS AND METHODS

SF1126 was administered IV days 1 and 4, weekly in 28day-cycles. Dose escalation utilised modified Fibonacci 3+3. Samples to monitor PK and PD were obtained.

RESULTS

Forty four patients were treated at 9 dose levels (90-1110 mg/m(2)/day). Most toxicity was grade 1 and 2 with a single DLT at180 mg/m(2) (diarrhoea). Exposure measured by peak concentration (C(max)) and area under the time-concentration curve (AUC(0-)(t)) was dose proportional. Stable disease (SD) was the best response in 19 of 33 (58%) evaluable patients. MTD was not reached but the maximum administered dose (MAD) was 1110 mg/m(2). The protocol was amended to enrol patients with CD20+ B-cell malignancies at 1110 mg/m(2). A CLL patient who progressed on rituximab [R] achieved SD after 2 months on SF1126 alone but in combination with R achieved a 55% decrease in absolute lymphocyte count and a lymph node response. PD studies of CLL cells demonstrated SF1126 reduced p-AKT and increased apoptosis indicating inhibition of activated PI3K signalling.

CONCLUSION

SF1126 is well tolerated with SD as the best response in patients with advanced malignancies.

A phase I study of daily oral TRC102 (methoxyamine) to enhance the therapeutic effects of pemetrexed in patients with advanced refractory cancer

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Background: TRC102 (methoxyamine) is a small molecule inhibitor of base-excision repair (BER) that enhances the cytotoxicity of alkylator and antimetabolite chemotherapy and reverses chemotherapy resistance. TRC102 inhibits BER by stabilizing abasic sites produced by glycosylase removal of damaged DNA bases. Methods: A phase 1 trial evaluated the safety, PK, and PD of oral TRC102 combined with intravenous pemetrexed in patients with advanced refractory cancer. Patients were required to have ECOG PS ≤ 1 and adequate organ function. TRC102 was escalated in cohorts of 3–6 patients in combination with standard dose pemetrexed. All patients received TRC102 alone on Days 1–4 of a 2 week cycle followed by the combination of pemetrexed and TRC102 every 3 weeks thereafter. Results: Eight patients were treated with a total of 22 cycles of TRC102 at 15 mg/m2 (n=3) and 30 mg/m2 (n=5). No adverse events were attributed to TRC102 alone, and grade 3–4 neutropenia without fever, grade 3 thrombocytopenia, and grade 1–2 fatigue and asthenia were considered possibly related to the combination of TRC102 and pemetrexed. One patient at 30 mg/kg TRC102 experienced grade 3 anemia during Cycle 2 that was considered a dose-limiting toxicity. He recovered after 2 units PRBCs and a 50% dose-reduction of TRC102, and remained on study through Cycle 5. Clinical PK analyses indicate that TRC102 plasma concentrations required for in vivo activity are achievable with daily oral administration (Cmax = 49–62 ng/mL, half-life = 29–40 hr), and PD studies confirm that TRC102 stabilizes pemetrexed-induced abasic sites in these patients. Conclusions: Daily oral TRC102 is tolerated at doses that potentiate the clinical activity of pemetrexed in patients with advanced refractory cancer. Phase 2 studies are planned in multiple indications.

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Prospective evaluation of patient perceptions and willingness to undergo pharmacodynamic and pharmacokinetic tests in early phase oncology trials

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Background: Increasing numbers of clinical trials include optional or mandatory pharmaco-dynamic and -kinetic assays. Since little is known about patients’ (pts) perceived willingness to undergo specific tests and the number of tests pts would tolerate on a single trial, this study was conducted. Secondary purposes included correlating test number and type with demographics, prior test experience, coverage, and inconvenience. Methods: Exploratory correlative study using a multi-item self-report questionnaire to measure pts willingness (0–10 scale, 0 = not willing, 10 = very willing) to undergo imaging (e.g., MRI, ECHO), invasive (e.g., tumor, skin biopsies [bx]) and less invasive tests (e.g., blood, urine). 61 pts (22 female, 39 male) with advanced malignancies participating in phase I or II trials at one institution were enrolled from June 2008-December 2008. Descriptive and non-parametric statistics were used. Results: Statistically significant (p < 0.01) inverse relationships were found between the number of imaging studies (e.g., CT, ECHO), tests required (e.g., tumor, skin bx, blood draws) and pts reported willingness to undergo these tests. Pts were least willing to undergo tumor bx (median 5.5, interquartile range [IQR] 3.5–10), skin bx (6.8, 3.1–10), and unexpectedly MRIs (8, 4–10) (all p < 0.01). Surprisingly, inconvenience and prior negative experiences for the more invasive tests (e.g., skin bx) did not negatively affect willingness to undergo these tests in the future as opposed to most imaging studies. College-educated were more willing to undergo tests than non-college educated. Few pts were unwilling to undergo tests/procedures at all, if mandatory for enrollment. Conclusions: Results provide improved understanding of pts willingness to undergo trial requirements and suggest that adequate explanation (e.g., MRI) and test rationale may affect willingness to undergo tests. Findings can be used to improve study design and consent procedures to minimize patient discomfort and inconvenience. The overall willingness of advanced stage cancer pts to undergo study specific tests/procedures is high.

No significant financial relationships to disclose.

EPC2407, a new beta-tubulin vascular disrupting agent with potent apoptosis and cell growth inhibition

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Background: Compounds which bind to colchicine-like sites of microtubules have contributed greatly to the armamentarium of cancer therapies. But new modes of administration of taxanes and potent new vascular disruption agent molecules such as combretastatin continue to challenge drug development for ways to improve the therapeutic index in this important class. EPC2407 is a novel 4-aryl chromene of nM anti-tumor potency; it is crossing the translational bridge based on an array of preclinical anti-tumor pharmacology and supported by multiple toxicology trials which included drug exposure data. Methods: Vascular disrupting agents demand careful preclinical workup. What we have done is summarized in the table below. This data is from cellular metabolic, cell proliferation, vascular endothelial, in vivo tumor, and animal toxicokinetic and safety studies. Results: Please see table below of the preclinical experiments. Conclusions: A Phase I clinical trial has been designed and initiated to replicate the safety margin shown by the analysis of preclinical drug exposure data. The critical safety issue for human dosing was the dose exposure which might produce the well known ECG abnormality of delayed repolarization or prolonged QTc. A dose related QTc effect was demonstrated in cynomolgus monkeys after a 2 min infusion which achieved acute plasma exposures higher than 3836 nM. These effects were dose related and persisted only through 4 short half-lives of the parent compound. Initial human analysis fails to show any prolongation of the QTc. [JW1] [JW1]THE END HERE, all else was draft.

[Table: see text]

No significant financial relationships to disclose.

Effects of mitomycin C and carboplatin pretreatment on multidrug resistance-associated P-glycoprotein expression and on subsequent suppression of tumor growth by doxorubicin and paclitaxel in human metastatic breast cancer xenografted nude mice

Overexpression of P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP), and several other proteins has been associated with development of multidrug resistance by cancer cells, which represents a significant obstacle to successful treatment by chemotherapy. We had previously demonstrated that a single noncytotoxic dose of mitomycin C (MMC), carboplatin, or one of several other DNA cross-linking agents suppressed mRNA expression of the mdr1 gene coding for Pgp, leading to a subsequent suppression of Pgp protein levels and a concomitant decrease in drug efflux. Pretreatment with MMC led to a 5- to 10-fold decrease in the ED50 for cell killing by a subsequent agent such as the Pgp substrate, doxorubicin, but did not affect killing by the non-Pgp substrate, cisplatin. In this study, we report that MMC and carboplatin each significantly suppressed Pgp protein levels in human MDA-MB-435 cells xenografted as solid tumors into the lateral mammary fat pads of female nude mice, with a similar time course as had previously been observed in cell culture. Pretreatment of mice with MMC or carboplatin 48-72 h prior to receiving either doxorubicin or paclitaxel caused a significantly greater reduction in tumor growth rate compared to either agent alone or the combination given simultaneously. These data suggest that a combination chemotherapy regimen consisting of a DNA cross-linking agent given to modulate the MDR phenotype, followed by a second cytotoxic agent, may be an effective treatment for human patients with de novo or late stage acquired multidrug-resistant malignancies.

Chemotherapy plus radiotherapy compared with radiotherapy alone in the treatment of locally advanced, unresectable, non-small-cell lung cancer. A meta-analysis

BACKGROUND

Survival of patients with locally advanced, unresectable (stage III), non-small-cell lung cancer treated with radiotherapy is poor. Trials of the addition of chemotherapy to radiotherapy have produced conflicting results.

OBJECTIVE

To compare chemotherapy plus radiotherapy with radiotherapy alone in patients with stage III, non-small-cell lung cancer.

DATA SOURCES

English-language journal articles published between 1987 and 1995 identified in a MEDLINE search.

STUDY SELECTION

Randomized trials that reported survival after previously untreated patients received chemotherapy plus radiotherapy or radiotherapy alone were reviewed.

DATA EXTRACTION

For all eligible articles, reported survival curves were used to determine the relative risk for death in each of 3 years. These data were combined to determine a pooled estimate of the relative risk for death at 1, 2, and 3 years.

DATA SYNTHESIS

Fourteen articles reporting on a total of 2589 patients were reviewed. Compared with radiotherapy, the combination of chemotherapy and radiotherapy reduced the risk for death at 1 year (relative risk, 0.88 [95% Cl, 0.80 to 0.96]), 2 years (relative risk, 0.87 [Cl, 0.81 to 0.94]), and 3 years (relative risk, 0.83 [Cl, 0.77 to 0.90]). This corresponded to a mean gain in life expectancy of about 2 months. The magnitude of the treatment effect was similar when trials of concurrently and sequentially administered chemotherapy were considered separately.

CONCLUSION

The addition of chemotherapy to radiotherapy improves survival in patients with locally advanced, unresectable, non-small-cell lung cancer. The absolute benefit is relatively small, however, and should be balanced against the increased toxicity associated with the addition of chemotherapy.

Dissociation between plasma and brain amino acid profiles and short-term food intake in the rat

The relationship between plasma and brain amino acids and short-term food intake after administration of albumin, or its constituent amino acids, was examined. Rats given protein (0.85 g chicken egg albumin) or an amino acid mixture patterned after egg albumin reduced their food intake during 1 h of feeding beginning 30 min after gavage. Similarly, when given separately, the essential (EAA) and nonessential amino acid (NEAA) fractions of egg albumin caused comparable decreases in food intake. As the dose increased from 0.5 to 1.5 g the duration of anorexia prolonged to 12 h. Little change occurred in plasma amino acids at 30 and 60 min after albumin at 0.85 g, although many increased by 25-50% at 60 min after 1.5 g. Marked changes in plasma occurred after gavage with the total mixture of constituent free amino acids and after either EAA or NEAA fractions. Brain amino acid concentrations were little affected by albumin and did not show consistent changes after the amino acid treatments. Thus the reductions in food intake after ingestion of albumin or of its constituent amino acids were not predicted from the resulting changes in either plasma or brain concentrations of amino acids.