A phase II trial (AGO 2.11) in platinum-resistant ovarian cancer: a randomized multicenter trial with sunitinib (SU11248) to evaluate dosage, schedule, tolerability, toxicity and effectiveness of a multitargeted receptor tyrosine kinase inhibitor monotherapy

Bevacizumab in combination with chemotherapy for the treatment of advanced ovarian cancer: a systematic review

As increased angiogenesis has been linked with the progression of ovarian cancer, a number of anti-angiogenic agents have been investigated, or are currently in development, as potential treatment options for patients with advanced disease. Bevacizumab, a recombinant monoclonal antibody against vascular endothelial growth factor, has gained European Medicines Agency approval for the front-line treatment of advanced epithelial ovarian cancer, fallopian tube cancer or primary peritoneal cancer in combination with carboplatin and paclitaxel, and for the treatment of first recurrence of platinum-sensitive ovarian cancer in combination with carboplatin and gemcitabine. We conducted a systematic literature review to identify available efficacy and safety data for bevacizumab in ovarian cancer as well as for newer anti-angiogenic agents in development. We analyzed published data from randomized, controlled phase II/III clinical trials enrolling women with ovarian cancer to receive treatment with bevacizumab. We also reviewed available data for emerging anti-angiogenic agents currently in phase II/III development, including trebananib, aflibercept, nintedanib, cediranib, imatinib, pazopanib, sorafenib and sunitinib. Significant efficacy gains were achieved with the addition of bevacizumab to standard chemotherapy in four randomized, double-blind, phase III trials, both as front-line treatment (GOG-0218 and ICON7) and in patients with recurrent disease (OCEANS and AURELIA). The type and frequency of bevacizumab-related adverse events was as expected in these studies based on published data. Promising efficacy data have been published for a number of emerging anti-angiogenic agents in phase III development for advanced ovarian cancer. Further research is needed to identify predictive or prognostic markers of response to bevacizumab in order to optimize patient selection and treatment benefit. Data from phase III trials of newer anti-angiogenic agents in ovarian cancer are awaited.

Beyond bevacizumab: investigating new angiogenesis inhibitors in ovarian cancer

INTRODUCTION

Ovarian cancer is the most lethal gynecological cancer, mainly because of the advanced stage of the disease at diagnosis, with recent research investigating novel targets and agents into the clinical practice, with the aim to improve prognosis and quality of life. Angiogenesis is a significant target for ovarian cancer therapy.

AREAS COVERED

Areas covered in this review include the most common molecular pathways of angiogenesis, which have provided novel targets for tailored therapy in ovarian cancer patients. These therapeutic strategies comprise monoclonal antibodies and tyrosine kinase inhibitors. These drugs have as molecular targets such as vascular endothelial growth factor (VEGF), VEGF receptor, platelet-derived growth factor, fibroblast growth factor, angiopoietin and Ephrin type-A receptor 2.

EXPERT OPINION

The expansion in understanding the molecular biology that characterizes cancer cells has led to the rapid development of new agents to target important pathways, but the heterogeneity of ovarian cancer biology indicates that there is no predominant defect. This review attempts to discuss progress till date in tackling a more general target applicable to ovarian cancer angiogenesis.

The potential of sunitinib as a therapy in ovarian cancer

INTRODUCTION

Sunitinib malate (SU11248; Sutent®; Pfizer, Inc., New York) is a multi-kinase inhibitor currently approved for use in advanced renal cell carcinoma (RCC), imatinib-resistant/-intolerant gastrointestinal stromal tumours and progressive, well-differentiated pancreatic neuroendocrine tumours in patients with unresectable, locally advanced or metastatic disease.

AREAS COVERED

This article describes the mechanism of action and of the pharmacokinetics of sunitinib; further, it summarizes Phase I and II trials on the clinical efficacy, tolerability and safety of this agent in the setting of ovarian cancer (OC) treatment.

EXPERT OPINION

On the basis of the current literature, sunitinib has shown modest antitumour activity and acceptable toxicity. Studies investigating the impact of horizontal and vertical combinations should represent a priority of future research. Although clinical Phase II trials on the use of sunitinib in the treatment of OC demonstrated an acceptable profile of AEs, a greater comprehension of the toxicity of this compound is recommended.

Targeting tyrosine-kinases in ovarian cancer

INTRODUCTION

Epithelial ovarian cancer (EOC) is the leading cause of gynaecologic cancer death. Although in some cases initial treatment is effective, most of the women diagnosed with EOC will probably need medical treatment for their disease. There is a critical need to develop effective new strategies for the management of patients with advanced or recurrent EOC, and targeted therapy with tyrosine kinase inhibitors (TKIs) has continued to be an area of active research and development in this setting.

AREAS COVERED

This review summarises the available evidence on the use of TKIs in the clinical management of women with EOC. This article consists of material obtained via Medline, PubMed and EMBASE literature searches up to March 2013.

EXPERT OPINION

Several Phase I/II and III trials evaluated TKIs in EOC; however, it is difficult to draw conclusions on the efficacy of TKI regimens in these patients. TKIs seem to be better tolerated than conventional chemotherapy with a different toxicity profile. A better understanding of the signalling pathways, the toxicity profiles, the potential pharmacokinetic interactions as well as the identification of predictive biomarkers are needed to better identify a targeted patient population before these agents become part of routine treatment.

Evaluation of potentially predictive markers for anti-angiogenic therapy with sunitinib in recurrent ovarian cancer patients

INTRODUCTION

In ovarian cancer, new therapeutic strategies are needed because the vast majority of patients develop a recurrence and resistance to platinum derivates. Attached to the AGO-OVAR2.11 study investigating the multityrosine kinase inhibitor sunitinib in recurrent platinum refractory ovarian cancers, this translational research project assesses the potential value of serum vascular endothelial growth factor (VEGF), soluble VEGF receptor-3 (sVEGFR-3), and angiopoietin-2 (Ang-2) levels for progression-free survival (PFS).

MATERIALS AND METHODS

Longitudinal serum samples were taken while the patient was on study drugs. Serum concentration of VEGF, sVEGFR-3, and Ang-2 was determined by ELISA. The slope of the markers was correlated to the PFS.

RESULTS

Patients showing a decrease in VEGF concentration had a median PFS of 10.5 months [confidence interval (CI), 2.89-12.25] compared to 2.9 months (CI, 1.48-5.32) in the case of an increase (P = .17). The stratified log-rank test showed a trend for longer PFS if a decrease of Ang-2 was observed (P = .089). Dichotomized in absolute decrease or increase, the PFS was 8.4 months (CI, 2.89-12.26) versus 2.7 months (CI, 1.05-5.32), respectively. Patients with a reduction of the sVEGFR-3 concentration had a median PFS of 4.76 months (CI 2.86-10.65) versus 8.61 months (CI, 1.05-not estimable) in patients with an increase of sVEGFR-3. This observation was statistically not significant in the log-rank test (P = .81).

CONCLUSION

Ang-2 could potentially identify a patient population that might have a better PFS when under anti-angiogenic treatment, like the tyrosine kinase inhibitor sunitinib.

Polypharmacology: drug discovery for the future

In recent years, even with remarkable scientific advancements and a significant increase of global research and development spending, drugs are frequently withdrawn from markets. This is primarily due to their side effects or toxicities. Drug molecules often interact with multiple targets, coined as polypharmacology, and the unintended drug-target interactions could cause side effects. Polypharmacology remains one of the major challenges in drug development, and it opens novel avenues to rationally design the next generation of more effective, but less toxic, therapeutic agents. This review outlines the latest progress and challenges in polypharmacology studies.

Mechanisms of resistance to anti-angiogenesis therapies

Angiogenesis, the formation of new blood vessels from preexisting ones, provides oxygen and nutrients to actively proliferating tumor cells. Hence, it represents a critical aspect of tumor progression and metastasis. Because inhibition of angiogenesis represents a major approach to cancer treatment, the development of inhibitors of angiogenesis is a major challenge. The first FDA approved anti-angiogenic drug bevacizumab, a humanized monoclonal antibody directed against the Vascular Endothelial Growth Factor (VEGF), has been approved for the treatment of metastatic colorectal, lung, breast, and kidney cancers. The encouraging results have lead to the development, in the past few years, of other agents targeting angiogenic pathways as potent anti-cancer drugs and a number of them have been approved for metastatic breast, lung, kidney, and central nervous system cancers. Despite a statistically significant increase in progression free survival, which has accelerated FDA approval, no major benefit to overall survival was described and patients inevitably relapsed due to acquired resistance. However, while progression free survival was increased by only a few months for the majority of the patients, some clearly benefited from the treatment with a real increase in life span. The objective of this review is to present an overview of the different treatments targeting angiogenesis, their efficacy and the mechanisms of resistance that have been identified in different cancer types. It is essential to understand how resistance (primary or acquired over time) develops and how it may be overcome.

Palliative systemic therapy for women with recurrent epithelial ovarian cancer: current options

OBJECTIVES

To review the available systemic treatments for women with recurrent ovarian cancer.

METHODS

A literature review was conducted for recurrent ovarian cancer articles in English, including randomized trials, Phase II trials, or reviews.

RESULTS

We discuss the efficacy and toxicity outcomes associated with systemic therapy for platinum-sensitive and platinum-resistant ovarian cancer. Clearly, platinum-based combination systemic therapy shows a prolonged progression-free interval compared with single-agent chemotherapy with a low toxicity profile. No clear superior management strategy exists for platinum-resistant/refractory disease. Novel targeted antiangiogenic agents (eg, bevacizumab), angiopoeitin inhibitors (eg, AMG 386), and poly ADP ribose polymerase inhibitors (eg, olaparib) are reviewed.

CONCLUSION

Although combination platinum-based chemotherapy has shown benefits for women with platinum-sensitive recurrent ovarian cancer, the optimal treatment strategy for those with platinum-resistant or platinum-refractory disease is not clear. Molecular and genetic targeted therapies may provide opportunities for those women with tumor profiles that show sensitivity for specific agents.

The changing landscape of therapeutic strategies for recurrent ovarian cancer

Advanced epithelial ovarian cancer, cancer of the fallopian tube and primary peritoneal cancer have a poor prognosis and a high rate of disease recurrence following primary therapy. Recurrent ovarian cancer is currently classified according to sensitivity to platinum-based chemotherapy. Data on targeted therapy provide evidence of improvement with systemic treatment in addition to chemotherapy. Other strategies, although not proven in randomized trials, offer interesting options for future research and therapeutic development. In this review, the covered treatment modalities include surgery, chemotherapy and targeted therapy, immunological approaches and irradiation.

Investigational agents in development for the treatment of ovarian cancer

Although significant success has been achieved in the treatment of advanced and recurrent ovarian cancer, there is clearly room for improvement. The use of targeted agents in this patient population has the promise to provide improved survival and quality of life. There are a myriad of relevant pathways under exploration in all settings of ovarian cancer. Clinical trial data are accumulating for antiangiogenic therapy, including vascular endothelial growth factor (VEGF)-specific inhibitors and multiple angiogenic signaling target inhibitors, as well as poly-ADP-ribose polymerase (PARP) inhibitors. Other types of tumorigenic pathway inhibitors, including those that target phosphatidylinositol-3-kinase (PI3K), mammalian target of rapamycin (mTOR), protein kinase B (AKT), Src, folate receptor alpha, and insulin-like growth factor-1 receptor (IGF-1R) pathways are in earlier phases of development for ovarian cancer. Attempts to target the epidermal growth factor receptor (EGFR) of ovarian tumors have been met with limited success; however, newer agents that inhibit this pathway show promise. Finally, with recognition of the role of Wee-1 in p53-deficient tumors, an inhibitor of this tyrosine kinase is being evaluated in recurrent ovarian cancer. The logistical challenge is to determine the optimal timing and proper combinations of novel agents independently as well as concomitantly with conventional chemotherapeutics. Reported results have been modest; however, our growing understanding of these pathways will be potentially reflected in greater impact on response and survival.

Clinical trials and future potential of targeted therapy for ovarian cancer

Ovarian cancer is the leading cause of death in women with gynecological cancer. Most patients are diagnosed at an advanced stage with a poor prognosis. Currently, surgical tumor debulking followed by chemotherapy based on platinum and taxane is the standard treatment for advanced disease. However, these patients remain at great risk for recurrence and developing drug resistance. Therefore, new treatment strategies are needed to improve outcomes for patients with advanced and recurrent ovarian cancer. Several agents targeted at particular molecules have been developed for ovarian cancer and are now entering clinical trials. The functional targets of these agents are aberrations in tumor tissues including angiogenesis, the human epidermal growth factor receptor family, poly(ADP-ribose) polymerase (PARP), mammalian target of rapamycin (mTOR) signaling pathway, and α-folate receptor (α-FR). The anti-angiogenic compound bevacizumab has been reported as the most effective targeted agent. Bevacizumab plus chemotherapy prolonged progression-free survival (PFS) both for advanced and platinum-sensitive recurrent ovarian cancer, but did not increase overall survival. A PARP inhibitor, olaparib, applied as maintenance treatment also improved PFS in platinum-sensitive relapsed ovarian cancer. Furthermore, mTOR inhibitors and a monoclonal antibody to α-FR, farletuzumab, are attractive treatment strategies either alone or combined with chemotherapy. Understanding the tumor molecular biology and identifying predictive biomarkers are essential steps in selecting the best treatment strategies. This article reviews available clinical data on the most promising targeted agents for ovarian cancer.