Prognostic and therapeutic relevance of molecular subtypes in high-grade serous ovarian cancer

Molecular classification of high-grade serous ovarian cancer (HGSOC) using transcriptional profiling has proven to be complex and difficult to validate across studies. We determined gene expression profiles of 174 well-annotated HGSOCs and demonstrate prognostic significance of the prespecified TCGA Network gene signatures. Furthermore, we confirm the presence of four HGSOC transcriptional subtypes using a de novo classification. Survival differed statistically significantly between de novo subtypes (log rank, P = .006) and was the best for the immunoreactive-like subtype, but statistically significantly worse for the proliferative- or mesenchymal-like subtypes (adjusted hazard ratio = 1.89, 95% confidence interval = 1.18 to 3.02, P = .008, and adjusted hazard ratio = 2.45, 95% confidence interval = 1.43 to 4.18, P = .001, respectively). More prognostic information was provided by the de novo than the TCGA classification (Likelihood Ratio tests, P = .003 and P = .04, respectively). All statistical tests were two-sided. These findings were replicated in an external data set of 185 HGSOCs and confirm the presence of four prognostically relevant molecular subtypes that have the potential to guide therapy decisions.

Abstract 743: Potent anti-tumor activity of the MEK1/2 inhibitor MEK162 in human non-small cell lung cancer (NSCLC) and squamous cell carcinoma of the head and neck (SCCHN) cell lines

BACKGROUND: MAPK pathway dysregulation is frequently seen in cancer. For NSCLC, this may be due to driver mutations or gene amplification in EGFR, KRAS, or BRAF, though tumors without such mutations frequently display pathway hyperactivity. Aberrant EGFR signaling in SCCHN may lead to hyperactivity of the MAPK or PI3K pathways. MEK162 (ARRY-438162) is a potent, tight binding, uncompetitive MEK inhibitor currently in clinical development for treatment of solid tumors. MEK162 has an IC50 of 10nM against purified MEK1/2. We evaluated whether MEK162 would inhibit NSCLC and SCCHN cell lines and whether specific molecular alterations predicted anti-tumor activity. We also evaluated the combination of MEK162 in combination with BYL719, a potent PI3K alpha inhibitor.

METHODS: The 50% inhibitory concentration (IC50) of MEK162, alone or in combination with BYL719, was determined in 40 human NSCLC and 30 SCCHN cell lines in vitro. Effects on MAPK and PI3K/AKT pathway signaling were studied by western blot analysis. Effects of MEK162 alone or in combination with BYL719 on cell cycle progression were also determined by flow cytometry.

RESULTS: Using previously published cut-offs for sensitivity in cell lines, among NSCLC cell lines, 20/40 (50%) were sensitive to MEK162 (IC50 ≤ 500nM), 9/40 were intermediately sensitive (IC50 500nM-1µM), and 11/40 were resistant (IC50 ≥ 1µm). Using the same cut-offs, 80% (24/30) of SCCHN cell lines were sensitive, 2/30 were intermediately sensitive, and 4/30 were resistant to MEK162. MEK162 exposure resulted in increased cells in G0/G1 and decreased cells in S-phase. MEK162 decreased phosphorylated ERK (p-ERK) in all cell lines treated and resulted in an increase in phosphorylated AKT (p-AKT), presumably as a compensatory result from MAPK pathway inhibition. Combined treatment with MEK162 and BYL719 resulted in synergistic growth inhibition for all cell lines and decreased levels of both p-ERK and p-AKT levels at 24 hours.

CONCLUSION: MEK162 potently inhibited growth of human NSCLC and SCCHN cell lines in most cell lines tested and led to synergistic inhibition when combined with BYL719. The compensatory increase in pAKT seen with MEK162 was abrogated with dual treatment with MEK162 and BYL719, demonstrating that synergy may be mediated by simultaneous blockade of MAPK and PI3K/AKT pathways. These data provide a preclinical rationale for evaluating MEK162, alone or in combination with BYL719, in metastatic NSCLC and SCCHN.

Supported by 1K23CA149079, P50 CA090440, V Foundation for Cancer Research, Jonsson Comprehensive Cancer Center, Wolfen Family Lung Cancer Research Program, Stiles Program in Oncology, National Lung Cancer Partnership and One Ball Matt Memorial Golf Tournament.

Citation Format: Deborah JL Wong, Edward B. Garon, Danielle D. Silveira, Naeimeh Kamranpour, Sharon Pitts, Meenal Chalukya, Habib Hamidi, Steven Dubinett, Ronald Linnartz, Richard S. Finn, Dennis J. Slamon. Potent anti-tumor activity of the MEK1/2 inhibitor MEK162 in human non-small cell lung cancer (NSCLC) and squamous cell carcinoma of the head and neck (SCCHN) cell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 743. doi:10.1158/1538-7445.AM2014-743

Abstract 1321: Identification of markers of sensitivity and resistance to palbociclib (PD0332991) in melanoma

Background: Melanoma, a malignancy originating in pigment-producing melanocytes, is generally resistant to conventional treatments such as radiotherapy or chemotherapy. Molecular targeted therapeutics against BRAF and MEK have shown marked efficacy for patients with metastatic melanoma. However these targeted therapies have a limited duration of response. Palbociclib is a highly selective inhibitor of cyclin dependent kinases 4 and 6 (CDK4/6) that has been shown to inhibit growth of malignant cell lines in vitro and in vivo by preventing the phosphorylation of Rb and stopping the progression G1/S of cell cycle. Cyclin D-CDK4/6-Rb axis has been shown to be dysregulated in 85-90% of melanomas and may represent a new therapeutic target. Our main goal in this study was to evaluate the therapeutic potential of palbociclib in a large panel of human melanoma cell lines to identify potential biomarkers of sensitivity and resistance. Material and Methods: We evaluated the response to palbociclib treatment in 48 melanoma cell lines. A comprehensive biomarker screen was performed using mutation and gene expression (Agilent) data. The mechanism of action of the drug was investigated by western blot (WB) analysis measuring phospho-Rb and senescence markers. Effects on the cell cycle and apoptosis were study by flow cytometry. Results: A marked differential response to palbociclib was observed across the melanoma cell lines with IC50s ranging from 28nM to over 1µM. A subset (14/48) of cell lines were classified as sensitive at clinically achievable concentrations (IC50<150nM). BRAF and NRAS activating mutation did not correlate with sensitivity in vitro. Increased expression of genes correlating with cyclin D-CDK4/6 activation strongly predicted for palbociclib sensitivity. We also found that genomic and expression markers of activation of the hedgehog/smoothened (SHH) pathway strongly predicted for in vitro resistance to palbociclib. These markers included chromosomal amplification of SHH, and high baseline expression of SMO and GLI2. Protein analysis by WB showed a dramatic decrease in phospho-Rb protein only in sensitive cell lines and also it caused a decrease in FOXM1 protein, indicating palbociclib may partially act by inducing senescence in treated cells. Flow cytometry analysis confirmed that palbociclib induces a strong G1/S arrest, but not significant apoptosis. Conclusion: Nearly 30% of the melanoma cell lines evaluated were found to be sensitive to palbociclib in vitro. Response to palbociclib did not correlate with BRAF and NRAS mutational status. A gene expression signature for CDK 4/6 activation successfully identified those cell lines most sensitive to palbociclib. We also identified markers of hedgehog/smoothened/GLI activation that strongly predicted for resistance to palbociclib. These data support the development of CDK 4/6 inhibitors in melanoma and provide a hypothesis for patient enrichment in clinical trials.

Note: This abstract was not presented at the meeting.

Citation Format: Erika M. von Euw, Dylan Conklin, Hong-Mei Rong, Ke-Wei Gong, Richard S. Finn, Dennis J. Slamon. Identification of markers of sensitivity and resistance to palbociclib (PD0332991) in melanoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1321. doi:10.1158/1538-7445.AM2014-1321

Abstract 4557: Expression of p16 in colon cancer and cyclin D1 in gastric cancer predicts response to CDK4/6 inhibition in vitro

Background: Cyclin-dependent kinases (CDKs) play a significant role in regulating cell cycle progression through association with cyclins. CDK4 and CDK6 interact with cyclin D1 to mediate hyperphosphorylation of retinoblastoma (Rb) during early G1 phase. Palbociclib is a highly selective inhibitor of CDK4 and CDK6 which functions by blocking pRb phosphorylation resulting in G1 arrest in sensitive cell lines. We evaluated the effect of palbociclib in gastric and colon cancer cell lines to explore potential biomarkers of response and to guide patient selection in colon and gastric cancer.

Methods: Panels of 17 gastric and 27 colon cancer cell lines were exposed in vitro to palbociclib over various concentrations to generate dose response curves. Analysis of variance (ANOVA) was used to identify differentially expressed genes between sensitive and resistant cell lines. Genes identified by ANOVA and effects of palbociclib on pRB were analyzed via western blot.

Results: Palbociclib was found to have potent anti-proliferative activity in the low nanomolar range (< 150 nM) for 14 of the 44 gastric and colon cancer cell lines tested. In gastric cancer, cyclin D1-amplified cells cells expressed greater sensitivity to the compound when compared to cyclin D1-negative cells. HER2 amplified cell lines were also statistically more sensitive than HER2 negative cells. Combination studies with palbociclib and trastuzumab demonstrated significant synergy in HER2 amplified gastric cancer models. Furthermore, cyclin E emerged as a biomarker for resistance to the compound in gastric cancers. Contrary to observations made in other cancers, expression levels of p16 (CDK4 inhibitor) and p21 (CDK2 inhibitor) in colon cancer indicated that p16 loss and p21 gain predict for resistance rather than sensitivity to CDK4 and CDK6 inhibition.

Conclusions: Palbociclib demonstrates anti-proliferative activity in several gastric and colon cancer cell lines. Molecular markers found to predict for sensitivity to this agent enhance patient selection for future clinical studies of palbociclib.

Citation Format: Zev A. Wainberg, Ann Yufa, Adrian Anghel, Amy M. Rogers, Tin Manivong, Shahriar Adhami, Habib Hamidi, Dylan Conklin, Richard S. Finn, Dennis J. Slamon. Expression of p16 in colon cancer and cyclin D1 in gastric cancer predicts response to CDK4/6 inhibition in vitro. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4557. doi:10.1158/1538-7445.AM2014-4557

Prognostic and therapeutic relevance of molecular subtypes in high-grade serous ovarian cancer

Molecular classification of high-grade serous ovarian cancer (HGSOC) using transcriptional profiling has proven to be complex and difficult to validate across studies. We determined gene expression profiles of 174 well-annotated HGSOCs and demonstrate prognostic significance of the prespecified TCGA Network gene signatures. Furthermore, we confirm the presence of four HGSOC transcriptional subtypes using a de novo classification. Survival differed statistically significantly between de novo subtypes (log rank, P = .006) and was the best for the immunoreactive-like subtype, but statistically significantly worse for the proliferative- or mesenchymal-like subtypes (adjusted hazard ratio = 1.89, 95% confidence interval = 1.18 to 3.02, P = .008, and adjusted hazard ratio = 2.45, 95% confidence interval = 1.43 to 4.18, P = .001, respectively). More prognostic information was provided by the de novo than the TCGA classification (Likelihood Ratio tests, P = .003 and P = .04, respectively). All statistical tests were two-sided. These findings were replicated in an external data set of 185 HGSOCs and confirm the presence of four prognostically relevant molecular subtypes that have the potential to guide therapy decisions.

Pleiotrophin mediates hematopoietic regeneration via activation of RAS

Hematopoietic stem cells (HSCs) are highly susceptible to ionizing radiation-mediated death via induction of ROS, DNA double-strand breaks, and apoptotic pathways. The development of therapeutics capable of mitigating ionizing radiation-induced hematopoietic toxicity could benefit both victims of acute radiation sickness and patients undergoing hematopoietic cell transplantation. Unfortunately, therapies capable of accelerating hematopoietic reconstitution following lethal radiation exposure have remained elusive. Here, we found that systemic administration of pleiotrophin (PTN), a protein that is secreted by BM-derived endothelial cells, substantially increased the survival of mice following radiation exposure and after myeloablative BM transplantation. In both models, PTN increased survival by accelerating the recovery of BM hematopoietic stem and progenitor cells in vivo. PTN treatment promoted HSC regeneration via activation of the RAS pathway in mice that expressed protein tyrosine phosphatase receptor-zeta (PTPRZ), whereas PTN treatment did not induce RAS signaling in PTPRZ-deficient mice, suggesting that PTN-mediated activation of RAS was dependent upon signaling through PTPRZ. PTN strongly inhibited HSC cycling following irradiation, whereas RAS inhibition abrogated PTN-mediated induction of HSC quiescence, blocked PTN-mediated recovery of hematopoietic stem and progenitor cells, and abolished PTN-mediated survival of irradiated mice. These studies demonstrate the therapeutic potential of PTN to improve survival after myeloablation and suggest that PTN-mediated hematopoietic regeneration occurs in a RAS-dependent manner.

Value of primary tumor gene signatures in colon cancer when national quality standards are adhered to: preliminary results of an international prospective multicenter trial

BACKGROUND

The purpose of this study was to determine if gene signatures are informative in colon cancer (CC) when National Quality Standards (NQS) are adhered to. Several studies have demonstrated the prognostic potential of gene signatures in primary CC. This has never been evaluated prospectively with adherence to NQS.

METHODS

This was a prospective, international, multicenter trial. Eligibility criteria were: no distant metastasis, ≥12 lymph nodes (LNs), and no adjuvant chemotherapy for LN-negative CC. RNA from frozen tumor samples was considered reliable if RNA Integrity Number >9. Using an Agilent whole human genome array, 44,000 genes were analyzed in primary tumors for differential gene expression (DGE). ANOVA applied at 2-fold expression level was performed in at least 8 experiments to obtain the DGEs.

RESULTS

Molecular analysis was completed in 113 of 128 patients. With median follow-up of 27 months, 11.5 % recurred within 3 years after surgery. Significant DGE was identified in recurrent tumors reflected by upregulation (UR) in cellular proliferation and by downregulation (DR) in prodifferentiating panel of 9 genes, independent of T or N classification. By multivariate analysis 3-year disease-free survival was 12.5 % in the UR/DR group versus 93.4 % in the non-UR/DR group (p < .0001; HR = 24.2; 95 % CI 4.8-120.4).

CONCLUSIONS

This is the first prospective trial to evaluate gene signatures in CC with adherence to a 12-node minimum quality standard. Certain molecular pathways may be prognostically relevant if both surgery and pathology are standardized, regardless of T or N classification. Careful consideration should be made to include surgical quality measures when planning clinical trials to evaluate the true effect of molecular markers in CC.

PP2A inhibition overcomes acquired resistance to HER2 targeted therapy

BACKGROUND

HER2 targeted therapies including trastuzumab and more recently lapatinib have significantly improved the prognosis for HER2 positive breast cancer patients. However, resistance to these agents is a significant clinical problem. Although several mechanisms have been proposed for resistance to trastuzumab, the mechanisms of lapatinib resistance remain largely unknown. In this study we generated new models of acquired resistance to HER2 targeted therapy and investigated mechanisms of resistance using phospho-proteomic profiling.

RESULTS

Long-term continuous exposure of SKBR3 cells to low dose lapatinib established a cell line, SKBR3-L, which is resistant to both lapatinib and trastuzumab. Phospho-proteomic profiling and immunoblotting revealed significant alterations in phospho-proteins involved in key signaling pathways and molecular events. In particular, phosphorylation of eukaryotic elongation factor 2 (eEF2), which inactivates eEF2, was significantly decreased in SKBR3-L cells compared to the parental SKBR3 cells. SKBR3-L cells exhibited significantly increased activity of protein phosphatase 2A (PP2A), a phosphatase that dephosphorylates eEF2. SKBR3-L cells showed increased sensitivity to PP2A inhibition, with okadaic acid, compared to SKBR3 cells. PP2A inhibition significantly enhanced response to lapatinib in both the SKBR3 and SKBR3-L cells. Furthermore, treatment of SKBR3 parental cells with the PP2A activator, FTY720, decreased sensitivity to lapatinib. The alteration in eEF2 phosphorylation, PP2A activity and sensitivity to okadaic acid were also observed in a second HER2 positive cell line model of acquired lapatinib resistance, HCC1954-L.

CONCLUSIONS

Our data suggests that decreased eEF2 phosphorylation, mediated by increased PP2A activity, contributes to resistance to HER2 inhibition and may provide novel targets for therapeutic intervention in HER2 positive breast cancer which is resistant to HER2 targeted therapies.

Cardiac safety results from a phase II, open-label, multicenter, pilot study of two docetaxel-based regimens plus bevacizumab for the adjuvant treatment of subjects with node-positive or high-risk node-negative breast cancer

Purpose

Adding antiangiogenic therapy to standard chemotherapy has improved response rates and progression-free survival in metastatic breast cancer (BC) patients. This phase II study evaluated cardiac safety of bevacizumab with/without trastuzumab with two docetaxel-based regimens in early BC.

Methods

127 women with non-metastatic node-positive or high-risk node-negative BC were enrolled. Women with human epidermal growth factor receptor 2 (HER2)-negative BC (n = 93) received docetaxel/doxorubicin/cyclophosphamide (TAC) + bevacizumab, while women with HER2-positive disease (n = 34) received docetaxel/carboplatin/trastuzumab (TCH) + bevacizumab, every 3 weeks for six cycles. Maintenance therapy with bevacizumab alone or bevacizumab plus trastuzumab, respectively, was given every 3 weeks for 52 weeks. The primary objective was to evaluate cardiac safety, as measured by the incidence of ≥ grade 3 clinical congestive heart failure (CHF); the secondary objective was assessment of safety and toxicity.

Results

At least one cardiac adverse event (AE; CHF, cardiomyopathy, or left ventricular dysfunction) was reported in 26.1% of TAC (n = 92) and 17.6% of TCH subjects (n = 34); there were no cardiac deaths. ≥ Grade 3 clinical CHF was observed in 4.3% in the TAC plus bevacizumab stratum and 0% in the TCH plus bevacizumab stratum. A ≥ grade 3 treatment-emergent AE (any kind) related to study treatment was observed in 59.8% in the TAC with bevacizumab and 52.9% in the TCH plus bevacizumab stratum.

Conclusion

Adding bevacizumab to a docetaxel-based regimen with trastuzumab did not appear to increase cardiotoxicity.

Trial registration

ClinicalTrials.gov Identifier: NCT00446030, registered March 8, 2007.

Mesenchymal gene program-expressing ovarian cancer spheroids exhibit enhanced mesothelial clearance

Metastatic dissemination of ovarian tumors involves the invasion of tumor cell clusters into the mesothelial cell lining of peritoneal cavity organs; however, the tumor-specific factors that allow ovarian cancer cells to spread are unclear. We used an in vitro assay that models the initial step of ovarian cancer metastasis, clearance of the mesothelial cell layer, to examine the clearance ability of a large panel of both established and primary ovarian tumor cells. Comparison of the gene and protein expression profiles of clearance-competent and clearance-incompetent cells revealed that mesenchymal genes are enriched in tumor populations that display strong clearance activity, while epithelial genes are enriched in those with weak or undetectable activity. Overexpression of transcription factors SNAI1, TWIST1, and ZEB1, which regulate the epithelial-to-mesenchymal transition (EMT), promoted mesothelial clearance in cell lines with weak activity, while knockdown of the EMT-regulatory transcription factors TWIST1 and ZEB1 attenuated mesothelial clearance in ovarian cancer cell lines with strong activity. These findings provide important insights into the mechanisms associated with metastatic progression of ovarian cancer and suggest that inhibiting pathways that drive mesenchymal programs may suppress tumor cell invasion of peritoneal tissues.

Ganitumab (AMG 479) inhibits IGF-II-dependent ovarian cancer growth and potentiates platinum-based chemotherapy

PURPOSE

Insulin-like growth factor 1 receptor (IGF-IR) has been implicated in the pathogenesis of ovarian cancer. Ganitumab is an investigational, fully human monoclonal antibody against IGF-IR. Here, we explore the therapeutic potential of ganitumab for the treatment of ovarian cancer.

EXPERIMENTAL DESIGN

The effects of ganitumab were tested in vitro against a panel of 23 established ovarian cancer cell lines. The ability of ganitumab to inhibit IGF-I-, IGF-II-, and insulin-mediated signaling was examined in vitro and in tumor xenografts using ovarian cancer models displaying IGF-IR/PI3K/AKT pathway activation by two distinct mechanisms, PTEN loss and IGF-II overexpression. Drug interactions between ganitumab and cisplatin, carboplatin, or paclitaxel were studied in vitro and in vivo.

RESULTS

In vitro, growth inhibition varied significantly among individual ovarian cancer cell lines. IGF-II mRNA and phospho-IGF-IR protein expression were quantitatively correlated with response to ganitumab, and PTEN mutations conferred resistance to ganitumab. Ganitumab potently inhibited baseline and IGF-I-, IGF-II-, and insulin-induced IGF-IR and IGF-IR/insulin hybrid receptor signaling in vitro and in vivo. Synergistic and additive drug interactions were seen for ganitumab and carboplatin or paclitaxel in vitro. Furthermore, ganitumab significantly increased the efficacy of cisplatin in ovarian cancer xenograft models in vivo.

CONCLUSIONS

These observations provide a biologic rationale to test ganitumab as a single agent or in combination with carboplatin/cisplatin and paclitaxel in patients with ovarian cancer. Moreover, assessment of tumor expression of IGF-II, phospho-IGF-IR, or PTEN status may help select patients with ovarian cancer who are most likely to benefit from ganitumab. Clin Cancer Res; 20(11); 2947-58. ©2014 AACR.

Dichloroacetate should be considered with platinum-based chemotherapy in hypoxic tumors rather than as a single agent in advanced non-small cell lung cancer

OBJECTIVES

Dichloroacetate (DCA) is a highly bioavailable small molecule that inhibits pyruvate dehydrogenase kinase, promoting glucose oxidation and reversing the glycolytic phenotype in preclinical cancer studies. We designed this open-label phase II trial to determine the response rate, safety, and tolerability of oral DCA in patients with metastatic breast cancer and advanced stage non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

This trial was conducted with DCA 6.25 mg/kg orally twice daily in previously treated stage IIIB/IV NSCLC or stage IV breast cancer. Growth inhibition by DCA was also evaluated in a panel of 54 NSCLC cell lines with and without cytotoxic chemotherapeutics (cisplatin and docetaxel) in normoxic and hypoxic conditions.

RESULTS AND CONCLUSIONS

Under normoxic conditions in vitro, single-agent IC50 was >2 mM for all evaluated cell lines. Synergy with cisplatin was seen in some cell lines under hypoxic conditions. In the clinical trial, after seven patients were enrolled, the study was closed based on safety concerns. The only breast cancer patient had stable disease after 8 weeks, quickly followed by progression in the brain. Two patients withdrew consent within a week of enrollment. Two patients had disease progression prior to the first scheduled scans. Within 1 week of initiating DCA, one patient died suddenly of unknown cause and one experienced a fatal pulmonary embolism. We conclude that patients with previously treated advanced NSCLC did not benefit from oral DCA. In the absence of a larger controlled trial, firm conclusions regarding the association between these adverse events and DCA are unclear. Further development of DCA should be in patients with longer life expectancy, in whom sustained therapeutic levels can be achieved, and potentially in combination with cisplatin.

Abstract PD1-5: Targeting PI3K overcomes in vivo resistance to everolimus in estrogen receptor (ER+) breast cancer

Background: The selective mTORC1 inhibitor everolimus (RAD001/Affinitor®) has recently been approved, in combination with exemestane, for treatment of advanced hormone receptor positive breast cancer after demonstrating significantly improved progression free survival for patients having progressed on a previous non-steroidal aromatase inhibitor. However, despite these improved outcomes many tumors go on to develop resistance to everolimus. Alterations in PI3K/AKT signaling, either through activating mutations in PIK3CA or loss of PTEN, have been shown to influence responses to everolimus treatment in vitro (Weigelt et al., 2011). In this study we used cell line xenograft models of everolimus resistance to assess the potential of a pan-PI3K inhibitor (BKM120) or a p110a-specific inhibitor (BYL719) to reverse resistance either as single agents or in combination with anti-ER therapy (Fulvestrant).

Materials and Methods: Everolimus resistant xenografts were developed from three originally everolimus sensitive ER+ cell lines carrying distinct genetic alterations that confer aberrant PI3K/AKT signaling; ZR75-1 (PTEN null), MCF7 (PIK3CA mutant) and KPL1 (wild-type). Mice were treated by daily oral everolimus (10 mg/kg) until tumors began to progress on treatment (∼ 35 days of daily treatment). Mice that developed everolimus resistant tumors were randomized into six treatment groups (n = 6) as follows: continued on everolimus (10 mg/kg), fulvestrant (5 mg/wk), BKM120 (35 mg/kg), BYL719 (50 mg/kg), fulvestrant + BKM120 or BYL719.

Results: All three cell line xenografts were initially responsive to everolimus. ZR75-1 xenografts were allowed to progress on everolimus until they reached a mean tumor volume greater than that on day zero, at which point mice were randomized into treatment groups. Tumor selected to continue on everolimus gained a mean tumor volume of 550 mm3 over the six-week duration of study, demonstrating resistance to everolimus. These tumors showed a partial response to Fulvestrant (28% TGI), BYL719 alone (40% TGI) and BYL719 combined with fulvestrant (61% TGI). In contrast, over 100% tumor growth inhibition (tumor regression) was observed with both single agent BKM120 or BKM120 plus fulvestrant. This is consistent with our in vitro findings that PTEN null tumor cells might be less sensitive to inhibition by BYL719 yet sensitive to BKM120. Data from the ongoing PIK3CA mutant and wild-type KPL1 models will inform whether these molecular subtypes of ER+ breast cancer are more sensitive to the pan-PI3K inhibitor or the p110α-specific inhibitor. Comprehensive pharmacodynamic analyses of these tumor tissues may identify the additional molecular determinants responsible for resistance to everolimus and help guide the design of future clinical studies.

Discussion: These pre-clinical data indicate that targeting PI3K either alone or in combination with fulvestrant overcomes resistance to everolimus in ER+ breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD1-5.

PD-0332991, a potent and selective inhibitor of cyclin-dependent kinase 4/6, demonstrates inhibition of proliferation in renal cell carcinoma at nanomolar concentrations and molecular markers predict for sensitivity

BACKGROUND

PD-0332991 is an inhibitor of cyclin-dependent kinases (CDK) 4 and 6, and was evaluated to determine its anti-proliferative effects in 25 renal cell carcinoma (RCC) cell lines.

MATERIALS AND METHODS

Half-maximal inhibitory concentrations (IC50) of PD-0332991 were determined with cell line proliferation assays, as were its effects on the cell cycle, apoptosis, and retinoblastoma (RB) phosphorylation. Molecular markers for response prediction, including p16, p15, cyclin D1 (CCND1), cyclin E1 (CCNE1), E2F transcription factor 1 (E2F1), RB, CDK4 and CDK6, were studied using array comparative genomic hybridization (CGH) and gene expression.

RESULTS

IC50 values for PD-0332991 ranged from 25.0 nM to 700 nM, and the agent demonstrated G0/G1 cell-cycle arrest, induction of late apoptosis, and blockade of RB phosphorylation. Through genotype and expression data p16, p15 and E2F1 were identified as having significant association between loss and sensitivity to PD-0332991: p16 (p=0.021), p15 (p=0.047), and E2F1 (p=0.041).

CONCLUSION

PD-0332991 has antiproliferative activity in RCC cell lines, and molecular markers predict for sensitivity to this agent.

Health-related quality of life with adjuvant docetaxel- and trastuzumab-based regimens in patients with node-positive and high-risk node-negative, HER2-positive early breast cancer: results from the BCIRG 006 Study

BACKGROUND

This study aims to describe and compare health-related quality of life (HRQL) in patients with node-positive and high-risk node-negative HER2-positive early breast cancer receiving adjuvant docetaxel and trastuzumab-based or docetaxel-based regimens alone.

METHODS

Eligible patients (n = 3,222) were randomly assigned to either four cycles of adjuvant doxorubicin and cyclophosphamide followed by four cycles of docetaxel (AC→T) or one of two trastuzumab-containing regimens: adjuvant doxorubicin and cyclophosphamide followed by docetaxel plus trastuzumab administered for 1 year (AC→TH) or six cycles of docetaxel plus carboplatin combined with trastuzumab administered for 1 year (TCH). The European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire C30 and BR-23 were administered at baseline, the start of cycle 4 (mid), and the end of chemotherapy (EOC), as well as at 6, 12, and 24 months after chemotherapy.

RESULTS

Compliance rates for the EORTC questionnaires were acceptable at 72%-93% of eligible patients out to the 12-month assessment. Systemic side effect (SE) change scores were significantly improved for TCH-treated patients compared with AC→TH and AC→T at EOC, suggesting improved tolerability. Physical functioning (PF) was only slightly worse at midpoint for those receiving TCH, compared with patients who were just starting on taxane in an AC→TH regimen, but was otherwise similar between arms. All treatment arms recovered from the deterioration in SE, PF, and Global Health Scale scores by 1 year and median future perspective change scores continued to improve throughout treatment and follow-up.

CONCLUSION

HRQL outcomes for adjuvant docetaxel and trastuzumab-based regimens are favorable and support TCH as a more tolerable treatment option.

Lapatinib in combination with capecitabine plus oxaliplatin (CapeOx) in HER2-positive advanced or metastatic gastric, esophageal, or gastroesophageal adenocarcinoma (AC): The TRIO-013/LOGiC Trial

LBA4001

Background: HER2 amplification is common in upper GI tract (UGIT) adenocarcinomas and inhibition improves clinical outcomes. Lapatinib ditosylate (L), a dual anti EGFR and anti HER2 tyrosine kinase inhibitor with preclinical activity against these cancers, was investigated in a phase III, randomized, double blind trial evaluating efficacy and safety in combination with CapeOx as first-line treatment of advanced or metastatic HER2+ UGIT ACs. Methods: Subjects had measurable and/or non-measurable disease with overexpression or amplification of HER2 (IHC2+ and FISH amplified, or IHC 3+, or FISH, CISH, or SISH amplified). HER2 status was reviewed by the central lab. Subjects were randomized 1:1 to CapeOx q3w (oxaliplatin 130mg/m2 day 1; capecitabine 850mg/m2/BID days 1 – 14), and daily L (1250mg) (CapeOx+L) or placebo (CapeOx+P). The primary efficacy population (PEP) comprised all subjects whose tumors were centrally confirmed to be FISH amplified. The primary endpoint was overall survival (OS) of the PEP. Secondary endpoints included progression free survival (PFS), overall response rate (ORR) and safety. Results: 545 pts were randomized and 487 had HER2+ centrally confirmed. The primary endpoint was not reached with a hazard ratio (HR) for OS of CapeOx+L compared to CapeOx+P of 0.91 (95% CI 0.73, 1.12, p=0.35); median 12.2 vs. 10.5 months, respectively. HR for uncensored PFS was 0.86 (95% CI 0.71 - 1.04, p=0.10); median 6.0 vs. 5.4 months. The analysis of PFS censored by the time of subsequent anticancer therapy as per protocol showed a HR of 0.82 (95% CI 0.68, 1.00, p=0.04). ORR was 53% in the CapeOx+L arm and 40% in the CapeOx+P arm. Pre-specified subgroup analyses showed significant improvements in OS in Asian pts (HR= 0.68) and those under 60 years (HR=0.69). There was no association between IHC and OS. Toxicity profiles were similar except for increased overall diarrhea, and skin toxicity and grade 3+ diarrhea (12 vs 3%) with CapeOx+L. Conclusions: The addition of L to CapeOx did not reach its primary endpoint, though certain subgroups showed improvement. Further clinical and molecular analyses will be presented. Clinical trial information: NCT00680901.

The HSP90 inhibitor NVP-AUY922 potently inhibits non-small cell lung cancer growth

Heat shock protein 90 (HSP90) is involved in protein folding and functions as a chaperone for numerous client proteins, many of which are important in non-small cell lung cancer (NSCLC) pathogenesis. We sought to define preclinical effects of the HSP90 inhibitor NVP-AUY922 and identify predictors of response. We assessed in vitro effects of NVP-AUY922 on proliferation and protein expression in NSCLC cell lines. We evaluated gene expression changes induced by NVP-AUY922 exposure. Xenograft models were evaluated for tumor control and biological effects. NVP-AUY922 potently inhibited in vitro growth in all 41 NSCLC cell lines evaluated with IC50 < 100 nmol/L. IC100 (complete inhibition of proliferation) < 40 nmol/L was seen in 36 of 41 lines. Consistent gene expression changes after NVP-AUY922 exposure involved a wide range of cellular functions, including consistently decreased dihydrofolate reductase after exposure. NVP-AUY922 slowed growth of A549 (KRAS-mutant) xenografts and achieved tumor stability and decreased EGF receptor (EGFR) protein expression in H1975 xenografts, a model harboring a sensitizing and a resistance mutation for EGFR-tyrosine kinase inhibitors in the EGFR gene. These data will help inform the evaluation of correlative data from a recently completed phase II NSCLC trial and a planned phase IB trial of NVP-AUY922 in combination with pemetrexed in NSCLCs.

Therapeutic potential of the poly(ADP-ribose) polymerase inhibitor rucaparib for the treatment of sporadic human ovarian cancer

Here, we investigate the potential role of the PARP inhibitor rucaparib (CO-338, formerly known as AG014699 and PF-01367338) for the treatment of sporadic ovarian cancer. We studied the growth inhibitory effects of rucaparib in a panel of 39 ovarian cancer cell lines that were each characterized for mutation and methylation status of BRCA1/2, baseline gene expression signatures, copy number variations of selected genes, PTEN status, and sensitivity to platinum-based chemotherapy. To study interactions with chemotherapy, we used multiple drug effect analyses and assessed apoptosis, DNA fragmentation, and γH2AX formation. Concentration-dependent antiproliferative effects of rucaparib were seen in 26 of 39 (67%) cell lines and were not restricted to cell lines with BRCA1/2 mutations. Low expression of other genes involved in homologous repair (e.g., BCCIP, BRCC3, ATM, RAD51L1), amplification of AURKA or EMSY, and response to platinum-based chemotherapy was associated with sensitivity to rucaparib. Drug interactions with rucaparib were synergistic for topotecan, synergistic, or additive for carboplatin, doxorubicin or paclitaxel, and additive for gemcitabine. Synergy was most pronounced when rucaparib was combined with topotecan, which resulted in enhanced apoptosis, DNA fragmentation, and γH2AX formation. Importantly, rucaparib potentiated chemotherapy independent of its activity as a single agent. PARP inhibition may be a useful therapeutic strategy for a wider range of ovarian cancers bearing deficiencies in the homologous recombination pathway other than just BRCA1/2 mutations. These results support further clinical evaluation of rucaparib either as a single agent or as an adjunct to chemotherapy for the treatment of sporadic ovarian cancer.

Progression-free survival (PFS) as surrogate endpoint for overall survival (OS) in clinical trials of HER2-targeted agents in HER2-positive metastatic breast cancer (MBC): An individual patient data (IPD) analysis

610

Background: The gold standard endpoint in randomized clinical trials (RCTs) in MBC is OS, which has the disadvantage of requiring extended follow-up and being confounded by subsequent anti-cancer therapies. Although therapeutics have been approved based on PFS, its use as a primary endpoint is controversial. This study, the first IPD meta-analysis of targeted agents in MBC, aimed to collect data from RCTs of HER2-targeted agents in HER2+ MBC, assessing to what extent PFS correlates with, and may be used as, a surrogate for OS. Methods: A search was conducted in April 2011. Eligible RCTs accrued HER2+ MBC patients (pts) in 1992-2008. Collaboration was obtained from industrial partners (Roche, GSK) for industry-led studies. Investigator-assessed PFS was defined as the time from randomization to clinical or radiological progression, or death. A correlation approach was used: at the individual level, to estimate the association between PFS and OS using a bivariate survival model and at the trial level, to estimate the association between treatment effects on PFS and OS. Squared correlation values close to 1.0 would indicate strong surrogacy. Results: The search strategy resulted in 2137 eligible pts in 13 RCTs testing trastuzumab or lapatinib. We collected IPD data from 1963 pts in 9 RCTs. One phase II RCT did not have sufficient follow-up data so that 1839 pts in 8 RCTs were retained (5 evaluating trastuzumab, 3 lapatinib); 6 out of 8 RCTs were first-line. At the individual level, the Spearman rank correlation using Hougaard copula was equal to r=0.66 (95% CI 0.65 to 0.66) corresponding to an r2 of 0.42. At the trial level, the squared correlation between treatment effects on PFS and OS was provided by R2=0.33 (95% CI -0.22 to 0.86) using Hougaard copula and R2=0.53 (95% CI 0.22 to 0.83) using log hazard ratios from Cox models. Conclusions: In RCTs of HER2-targeted agents in HER2+ MBC, PFS is moderately correlated with OS and treatment effects on PFS are modestly correlated with treatment effects on OS, similarly to first-line chemotherapy in MBC (Burzykowski et al JCO 2008). PFS does not completely substitute for OS.

Lapatinib in combination with capecitabine plus oxaliplatin (CapeOx) in HER2 positive advanced or metastatic gastric (A/MGC), esophageal (EAC), or gastroesophageal (GEJ) adenocarcinoma: The LOGiC trial

LBA4001

The full, final text of this abstract will be available at abstract.asco.org at 7:30 AM (EDT) on Monday, June, 3, 2013, and in the Annual Meeting Proceedings online supplement to the June 20, 2013, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

A randomized, multicenter, double-blind phase III study of palbociclib (PD-0332991), an oral CDK 4/6 inhibitor, plus letrozole versus placebo plus letrozole for the treatment of postmenopausal women with ER(+), HER2(–) breast cancer who have not received any prior systemic anticancer treatment for advanced disease

TPS652

Background: Palbociclib (PD-0332991) is an orally bioavailable selective inhibitor of CDK4/6 that prevents DNA synthesis by prohibiting progression of the cell cycle from G1 to S phase. In a randomized phase II trial comparing palbociclib (PD-0332991) plus letrozole (P + L) to letrozole (L) in postmenopausal women with ER(+), HER2(–) advanced breast cancer (ABC) who had not received any prior systemic anticancer therapy for their advanced disease, P + L demonstrated significantly longer progression-free survival (PFS) vs L (26.1 vs 7.5 mo; HR = 0.37, P < .001) and was generally well tolerated, with uncomplicated neutropenia as the most frequent adverse event (Finn et al SABCS 2012). Methods: Based on phase II data, a global, randomized, double-blind, phase III clinical trial was designed to demonstrate that P + L provides superior clinical benefit compared with L + placebo in postmenopausal women with ER(+), HER2(–) ABC who have not received any prior systemic therapy for their advanced disease. The study aims to assess whether P + L improves median PFS over L at HR of at least 0.7. Approximately 450 eligible patients with locoregionally recurrent or metastatic, pathologically confirmed ABC who are candidates to receive L as first-line treatment for their advanced disease will be randomized 2:1 to receive either P (125 mg QD 3 wk on, 1 wk off) + L (2.5 mg QD) or L (2.5 mg QD) + placebo. Patients who received anastrozole or letrozole as part of their (neo)adjuvant regimen are eligible if their disease progressed more than 12 months from completion of adjuvant therapy. Tumor tissue is required for participation. Secondary endpoints include overall survival, objective response, duration of response, clinical benefit, safety and tolerability, and patient-reported outcomes of health-related quality of life and disease- or treatment-related symptoms. Clinical trial information: NCT01740427.

Prognostic relevance of gene signatures in high-grade serous ovarian carcinoma

5510

Background: Transcriptional profiling of ovarian cancers has proven to be complex. As such it has been difficult to validate existing signatures across studies. Cancer Genome Atlas (TCGA) researchers have identified four molecular subtypes of high-grade serous ovarian cancer (HGSOC). However, survival duration did not differ significantly for the TCGA subtypes. Potential limitations of the TCGA data include short clinical follow-up (45% were alive at the time of last follow-up) and the need to unify gene expression measures from multiple platforms. Methods: Clinically annotated stage-II–IV HGSOC samples (n = 175) with >70% tumor cell content were profiled using the Agilent Whole Human Genome 4 x 44K chip. To identify subtypes non-negative matrix factorization (NMF) of mRNA expression was performed using ~2000 genes with the highest variability across patients. In parallel differentially expressed genes were identified using the Rosetta Similarity Search Tool as well as analysis of variance based on genes known to be involved in epithelial to mesenchymal transition. Results: Median follow-up time was 35 months (range, 0–202 months, 12% were alive at the time of last follow-up). NMF clustering confirmed four HGSOC subtypes (immunoreactive, differentiated, proliferative, and mesenchymal) on the basis of gene content in the clusters. Pathway signatures with therapeutic potential were identified for individual or multiple subtypes. Survival differed significantly between the four molecular subgroups in univariate (Hazard Ratio [HR] 2.4, 95% CI 1.5-4.1, p = 0.007) and multivariate (HR 2.3, 95% CI 1.3-4.0, p = 0.003) analyses when accounting for age, stage, grade, and postoperative residual tumor. Using the supervised clustering approach two distinct molecular subtypes of HGSOC based on epithelial and mesenchymal gene expression signatures were identified with significantly different survival outcomes. Conclusions: Here we independently validate and expand upon the molecular TCGA classification of HGSOC. The potential of these two prognostic classifiers may lie in their ability to recognize categories of patients that are more likely to respond to particular therapies.