Salvage bevacizumab (rhuMAB VEGF)-based therapy after multiple prior cytotoxic regimens in advanced refractory epithelial ovarian cancer

Collateral damage: toxic effects of targeted antiangiogenic therapies in ovarian cancer

First-line chemotherapy fails in more than 20% of patients with epithelial ovarian cancer and about 40-50% of women who respond to initial treatment relapse within 2 years. In the recurrent setting, second-line chemotherapeutic agents have a 15-20% response rate with no cures. Fortunately, clinical investigations that have assessed the efficacy of new, biologically targeted therapies have reinvigorated therapeutic options for patients living with ovarian and other malignancies. In view of the fact that ovarian cancer is one of the most angiogenic neoplasms, there is great hope that implementing targeted agents with antiangiogenic properties will improve outcomes. However, as experience grows with the antitumour activity of these drugs, new toxic effects are emerging. The effects of antiangiogenic agents on molecules and processes that also have physiologically important roles in healthy tissues are at the crux of these toxic effects, or "collateral damage". This review discusses the leading toxic effects encountered and anticipated in clinical investigation and practice with antiangiogenic agents in patients with ovarian cancer, with particular focus on potential management strategies.

Role of vascular endothelial growth factor inhibitors in the treatment of gynecologic malignancies

This article reviews the history and current status of vascular endothelial growth factor targeted therapy for the most common gynecologic malignancies - epithelial ovarian, endometrial and cervical cancers. The biologic rationale for targeting vascular endothelial growth factor (VEGF) for these disease sites is well-founded, and pre-clinical studies have supported the development of anti-VEGF agents. Their classification, known mechanisms of action, unique toxicities and clinical development are herein explored, the latter including issues related to study design, disease site and disease setting.

Targeted therapies in epithelial ovarian cancer

Molecularly targeted therapy is relatively new to ovarian cancer despite the unquestionable success with these agents in other solid tumours such as breast and colorectal cancer. Advanced ovarian cancer is chemosensitive and patients can survive several years on treatment. However chemotherapy diminishes in efficacy over time whilst toxicities persist. Newer biological agents that target explicit molecular pathways and lack specific chemotherapy toxicities such as myelosuppression offer the advantage of long-term therapy with a manageable toxicity profile enabling patients to enjoy a good quality of life. In this review we appraise the emerging data on novel targeted therapies in ovarian cancer. We discuss the role of these compounds in the front-line treatment of ovarian cancer and in relapsed disease; and describe how the development of predictive clinical, molecular and imaging biomarkers will define the role of biological agents in the treatment of ovarian cancer.

Emerging role of pemetrexed in ovarian cancer

The current treatment of choice of epithelial ovarian cancer involves aggressive tumor cytoreductive surgery followed by platinum- and taxane-based chemotherapy; however, despite the encouraging activity of these agents, most ovarian carcinomas relapse and many patients die from drug-resistant disease. After the failure of platinum- and taxane-based schedules, several cytotoxic agents have demonstrated activity in advanced ovarian cancer but none were able to induce significant and durable responses. Among the new cytotoxic agents, pemetrexed plays an emerging role in different tumors, demonstrating competitive activity and a promising safety profile. In ovarian cancer, pemetrexed has been investigated, with encouraging results, as a single agent and in association with platinum compounds; moreover, the drug has shown interesting activity both in platinum-sensitive and platinum-resistant ovarian cancer. According to these clinical results it appears reasonable to explore the combination of pemetrexed with other cytotoxic agents and also with targeted therapies in relapsed ovarian cancer patients.

What is the benefit of bevacizumab combined with chemotherapy in patients with recurrent ovarian, fallopian tube or primary peritoneal malignancies?

The aim of this retrospective analysis was to investigate the efficacy and adverse effects of the monoclonal antivascular endothelial growth factor antibody bevacizumab (Avastin(R)) combined with chemotherapeutic agents in non-protocol patients with recurrent ovarian, fallopian tube, or primary peritoneal malignancies. Using our databases, we identified patients treated with bevacizumab combination therapy since June 2005. Responses were evaluated with Response evaluation Criteria in Solid tumors and serum CA125 Rustin criteria. Toxicity was assessed according to the Common toxicity Criteria (CTC) v.3.0. Data from 64 patients were included. The median patient age was 58 years, and they had undergone a median of 4.5 (range, 1-10) prior cytotoxic chemotherapy regimens. The median length of follow-up was 8 months (range, 2-29). The most commonly used combinations were bevacizumab plus taxanes (26.6%) and plus cyclophosphamide (26.6%). A median of 4 cycles of therapy with a median bevacizumab dose of 3,600 mg (range, 500-18,240) were administered. An overall response rate of 21.3% was observed in 13 patients with partial response, and another 42.6% of patients had stable disease. Among the patients with elevated pretreatment serum CA125 concentration, an overall response rate of 46.3% (25/54) was observed according to modification of the Rustin criteria. Fifteen (23.4%) patients had grades 3 or 4 adverse events. Gastrointestinal perforations occurred in 2 (3.1%) patients. Seventeen (26.6%) patients had improved performance status scores. Bevacizumab combined with chemotherapy showed promising clinical benefits, with significant response of serum CA125 concentration and moderate adverse effects.

Targeted therapies in epithelial ovarian cancer

Epithelial ovarian cancer remains a major women's health problem due to its high lethality. Despite great efforts to develop effective prevention and early detection strategies, most patients are still diagnosed at advanced stages of disease. This pattern of late presentation has resulted in significant challenges in terms of designing effective therapies to achieve long-term cure. One potential promising strategy is the application of targeted therapeutics that exploit a myriad of critical pathways involved in tumorigenesis and metastasis. This review examines three of the most provocative targeted therapies with current or future applicability in epithelial ovarian cancer.

A current review of targeted therapeutics for ovarian cancer

Difficult to detect, ovarian cancer typically presents at an advanced stage. Significant progress has been achieved in the treatment of ovarian cancer with therapeutics focused on DNA replication or cell division. However, despite sensitivity to induction chemotherapy the majority of patients will develop recurrent disease. Conventional agents for recurrent disease offer little in terms of long-term responses. Various targeted therapeutics have been explored in the management of ovarian cancer. These include monoclonal antibodies to epidermal growth factor receptors, small molecule tyrosine kinase inhibitors, monoclonal antibodies directed at the vascular endothelial growth factor (bevacizumab), and the small tyrosine kinase inhibitors that target the vascular endothelial growth factor receptor. Recently, several other agents have come forth as potential therapeutic agents in the management of ovarian cancer. These include monoclonal antibodies to the folate receptor, triple angiokinase inhibitors, PARP inhibitors, aurora kinase inhibitors, inhibitors of the Hedgehog pathway, folate receptor antagonists, and MTOR inhibitors.

Antivascular therapy for epithelial ovarian cancer

Ovarian cancer is the fifth largest cancer killer in women. Improved understanding of the molecular pathways implicated in the pathogenesis of ovarian cancer has led to the investigation of novel targeted therapies. Ovarian cancer is characterized by an imbalance between pro- and antiangiogenic factors in favor of angiogenesis activation. Various antivascular strategies are currently under investigation in ovarian cancer. They can schematically be divided into antiangiogenic and vascular-disrupting therapies. This paper provides a comprehensive review of these new treatments targeting the tumor vasculature in this disease. Promising activities have been detected in phase II trials, and results of phase III clinical trials are awaited eagerly.

The role of antiangiogenesis therapy: bevacizumab and beyond

The importance of angiogenesis in tumour growth and development is well known. Overexpression of vascular endothelial growth factor (VEGF), the key mediator of angiogenesis, is associated with poor prognosis in cancer. As a result, several therapeutic agents that inhibit the actions of VEGF or its receptors are currently in development for use in advanced solid tumours, such breast, colorectal, lung and renal cancer. Clinical data from trials of anti-VEGF agents in this group of tumours are discussed, with a particular focus on the efficacy and safety of bevacizumab, the anti-VEGF agent at the most advanced stage of development in those tumour types. Future potential uses of bevacizumab in cancer therapy will be discussed.

Current status of anti-angiogenic agents in the treatment of ovarian carcinoma

During the last decade we have assisted in the development of new therapeutic strategies for the treatment of ovarian cancer, based on the best knowledge of molecular biology. One of the most promising strategies under investigation is antiangiogenic therapy. Bevacizumab is a monoclonal humanised antibody targeting vascular endothelial growth factor (VEGF), which has shown antitumour activity in ovarian cancer in preclinical models as well as in clinical trials, both in monotherapy and in combination with other therapies. Currently, ongoing phase III trials are testing bevacizumab as a front-line therapy with carboplatin and paclitaxel. Bevacizumab has been generally well tolerated with mild frequent toxicities (proteinuria, hypertension and bleeding). However, the drug may result in other uncommon, but potentially life-threatening side effects, such as arterial thromboembolism, wound healing complications, and gastrointestinal perforation or fistulae, which should be considered when the drug is administered. Other new therapeutic antiangiogenic strategies that include small-molecule tyrosine kinase inhibitors, antibodies neutralising the VEGF receptor (VEGFR) and soluble VEGFR hybrids (VEGF Trap) are being investigated with promising early results.

Antiangiogenic drugs in ovarian cancer

BACKGROUND

There is a critical need to develop effective new strategies for the management of patients with advanced epithelial ovarian cancer.

OBJECTIVE

The purpose of this manuscript is to discuss the rationale for, and initial clinical results of, attempts to interfere with the process of tumor angiogenesis as a novel treatment paradigm in ovarian cancer.

RESULTS/CONCLUSION

Phase II clinical trial data provide strong support for the suggestion that antiangiogenic agents have the potential to play a major therapeutic role in this difficult malignancy. It is reasonable to acknowledge that the pending results of several ongoing evidence-based randomized Phase III trials that directly explore the clinical utility of this strategy may substantially alter the current standard management approaches in advanced ovarian cancer.

Complete remission of ovarian cancer induced intractable malignant ascites with intraperitoneal bevacizumab. Immunological observations and a literature review

Malignant ascites resistant to conventional drugs frequently affects ovarian cancer patients at the end of life. Here we report the case of a patient who benefited from complete resolution of ascites after low dose intraperitoneal administration of bevacizumab. Immunological analyses showed an initial increase in proportion and function of CD8(+) effector T cells and a reduction of circulating T(reg) cells. A review of the current literature regarding bevacizumab in ovarian cancer is reported. Bevacizumab has shown a high efficacy in the treatment of ovarian cancer. Intraperitoneal administration induces an immune activation and appears promising in the treatment of malignant ascites.

Sustained progression-free survival with weekly paclitaxel and bevacizumab in recurrent ovarian cancer

OBJECTIVE

To determine efficacy, toxicity, and survival in patients with recurrent epithelial ovarian cancer (EOC) receiving combination of weekly paclitaxel and biweekly bevacizumab (PB).

METHODS

We reviewed chemotherapy logs identifying all patients receiving combination PB. Toxicities were graded using CTCAEv3.0 criteria. Response rates (RR) were measured using RECIST criteria or by CA-125 levels per modified Rustin criteria. RR and progression-free survival (PFS) were determined and plotted using Kaplan-Meier survival analysis.

RESULTS

Fifty-one patients receiving at least two cycles of chemotherapy were evaluable for survival and 55 patients receiving one cycle of PB were evaluable in toxicity analysis. The mean number of previous regimens was four. The overall median PFS was 7 months and median OS was 12 months. The overall response rate (ORR) was 60% (CR 25% and PR 35%). Median PFS for complete and partial responders were 14 and 5 months respectively. Stable disease was seen in 26% with median PFS of 6 months. Thirteen experienced treatment delays for a variety of factors. The most G3/4 toxicities were fatigue (16%), hematologic (9%) and neurotoxicity (7%). Three patients (5%) experienced bowel perforations.

CONCLUSIONS

Combination of paclitaxel and bevacizumab is feasible and demonstrates an acceptable toxicity profile and a high response rate. These observations should be useful in planning future clinical trials with this combination therapy.

Understanding and managing the possible adverse effects associated with bevacizumab

PURPOSE

The adverse events associated with bevacizumab therapy are characterized, and the underlying pathophysiology, risk factors, frequency, and management of these events are described.

SUMMARY

The adverse events associated with bevacizumab include hypertension, proteinuria, thromboembolism, impaired wound healing, bleeding, perforation, reversible leukoencephalopathy syndrome, skin rash, and infusion-related hypersensitivity reactions. Patients should be monitored for these events throughout the course of bevacizumab therapy. Hypertension is by far the most common adverse event associated with bevacizumab. Blood pressure should be routinely monitored, and hypertension should be medically managed with antihypertensive drugs as deemed appropriate during bevacizumab therapy. Patients should be monitored for proteinuria every three to four weeks, and bevacizumab should be discontinued with persistent proteinuria of >2+. Thromboembolic events, impaired wound healing, bowel and nasal septum perforation, and bleeding share similar pathophysiology. Thromboembolic events should be managed in accordance with guidelines established by the American College of Chest Physicians, and bevacizumab should be discontinued for new life-threatening venous or arterial thromboembolism. To minimize the risk of bleeding or impaired wound healing, bevacizumab should be started at least four weeks after surgery or discontinued for at least six to eight weeks before elective surgery. The management of other adverse events is more anecdotal, with relatively few reports of their occurrence with bevacizumab.

CONCLUSION

Many of the potential serious complications of bevacizumab can be averted by close monitoring of patient-specific variables, which should be measured at baseline and then at predetermined intervals throughout the course of therapy to maximize patient safety.

Anti-angiogenesis therapy with bevacizumab for patients with ovarian granulosa cell tumors

OBJECTIVE

Ovarian granulosa cell tumors tend to respond poorly to chemotherapy. We examined the clinical efficacy of bevacizumab with or without concurrent chemotherapy and evaluated the angiogenic characteristics of these patients' tumors.

METHODS

We conducted a retrospective review of all patients seen at our institution from February 2004 to October 2008 who received bevacizumab for ovarian sex cord-stromal tumors. We performed immunohistochemical staining for vascular endothelial growth factor (VEGF) and CD31 when tissue was available; microvessel density was measured based on CD31 staining. Clinical data were abstracted from a chart review.

RESULTS

We identified 8 patients who were treated with bevacizumab; 7 had adult granulosa cell tumors and one had a juvenile granulosa cell tumor. All patients had recurrent disease and had been previously treated with cytotoxic chemotherapy (median 3.5 regimens; range, 1-6). One patient had a complete clinical response to bevacizumab therapy, 2 patients had a partial response, 2 patients had stable disease, and 3 patients' disease progressed, yielding a response rate of 38% and a clinical benefit rate of 63%. The median progression-free survival was 7.2 months and overall survival was not reached at a median follow-up of 23.6 months after initiating bevacizumab. VEGF overexpression and microvessel density were associated with poor outcome but sample size was too small to calculate statistical significance.

CONCLUSIONS

Anti-VEGF therapy is highly effective in patients with granulosa cell tumors. Based on our observations, a prospective trial has been initiated using single-agent bevacizumab in patients with recurrent ovarian sex cord-stromal tumors.

The biology of ovarian cancer: new opportunities for translation

Over the past two decades, the 5-year survival for ovarian cancer patients has substantially improved owing to more effective surgery and treatment with empirically optimized combinations of cytotoxic drugs, but the overall cure rate remains approximately 30%. Many investigators think that further empirical trials using combinations of conventional agents are likely to produce only modest incremental improvements in outcome. Given the heterogeneity of this disease, increases in long-term survival might be achieved by translating recent insights at the molecular and cellular levels to personalize individual strategies for treatment and to optimize early detection.

Preclinical studies and clinical utilization of monoclonal antibodies in epithelial ovarian cancer

OBJECTIVE

To present an overview of selected monoclonal antibodies (mAbs) that have been studied in epithelial ovarian cancer with a focus on combination treatment with conventional chemotherapy.

METHODS

The authors perform a narrative review of the literature. Preclinical studies that provided rationale for mAb use are examined, and selected clinical trials that evaluated efficacy and tolerability are reviewed.

RESULTS

Numerous mAbs have been utilized in epithelial ovarian cancer, including bevacizumab (anti-vascular endothelial growth factor), trastuzumab (anti-human epidermal growth factor-2), cetuximab (anti-epidermal growth factor receptor), and oregovomab (anti-CA125). Favorable preclinical results have lead to the development of a number of clinical trials. Side-effects have been minimal and combination therapy has been well-tolerated. Efficacy has been variable in the clinical trials.

CONCLUSIONS

Targeted treatment with mAbs in conjunction with cytotoxic chemotherapy has been an important research area during the last decade. This therapeutic approach holds promise for improved outcomes in patients with ovarian cancer.

Anti-idiotypic antibody abagovomab in advanced ovarian cancer

Ovarian cancer is the fifth most common malignancy with approximately 22,000 newly diagnosed cases each year in the USA. Standard of care after cytoreductive surgery is the application of carboplatin and paclitaxel. The newly developed anti-idiotypic monoclonal antibody abagovomab demonstrated promising results in Phase I/II trials. This new type of drug is currently being tested in a Phase II/III trial in ovarian cancer patients with a complete response after standard first-line chemotherapy. Activating the cancer hosts immune system is a new strategy that is worth being pursued in the fight against ovarian cancer.

Association of vascular endothelial growth factor and vascular endothelial growth factor receptor-2 genetic polymorphisms with outcome in a trial of paclitaxel compared with paclitaxel plus bevacizumab in advanced breast cancer: ECOG 2100

PURPOSE

No biomarkers have been identified to predict outcome with the use of an antiangiogenesis agent for cancer. Vascular endothelial growth factor (VEGF) genetic variability has been associated with altered risk of breast cancer and variable promoter activity. Therefore, we evaluated the association of VEGF genotype with efficacy and toxicity in E2100, a phase III study comparing paclitaxel versus paclitaxel plus bevacizumab as initial chemotherapy for metastatic breast cancer.

PATIENTS AND METHODS

DNA was extracted from tumor blocks of patients from E2100. Three hundred sixty-three samples were available to evaluate associations between genotype and outcome. Genotyping was performed for selected polymorphisms in VEGF and VEGF receptor 2. Testing for associations between each polymorphism and efficacy and toxicity was performed.

RESULTS

The VEGF-2578 AA genotype was associated with a superior median overall survival (OS) in the combination arm when compared with the alternate genotypes combined (hazard ratio = 0.58; 95% CI, 0.36 to 0.93; P = .023). The VEGF-1154 A allele also demonstrated a superior median OS with an additive effect of each active allele in the combination arm but not the control arm (hazard ratio = 0.62; 95% CI, 0.46 to 0.83; P = .001). Two additional genotypes, VEGF-634 CC and VEGF-1498 TT, were associated with significantly less grade 3 or 4 hypertension in the combination arm when compared with the alternate genotypes combined (P = .005 and P = .022, respectively).

CONCLUSION

Our data support an association between VEGF genotype and median OS as well as grade 3 or 4 hypertension when using bevacizumab in metastatic breast cancer.

Vascular endothelial growth factor expression in ovarian cancer: a model for targeted use of novel therapies?

PURPOSE

Angiogenesis has a vital role in tumor growth and metastasis, and vascular endothelial growth factor (VEGF) represents a potent cytokine in this process. However, the influence of VEGF in ovarian cancer remains controversial. Interest has focused on the use of antiangiogenic drugs in ovarian cancer. This study aims to establish the pattern of expression and effect on prognosis of VEGF in a large population of ovarian cancer patients and to potentially identify a cohort in whom antiangiogenic therapy is appropriate.

EXPERIMENTAL DESIGN

Using a tissue microarray of 339 primary ovarian cancers, the expression of VEGF was assessed immunohistochemically. Coupled to a comprehensive database of clinicopathologic variables, its effect on these factors and survival was studied.

RESULTS

Tumors expressing high levels of VEGF had significantly poorer survival (P = 0.04). Factors shown to predict prognosis independently of each other were age, International Federation of Gynecologists and Obstetricians stage, and the absence of macroscopic disease after surgery. VEGF was independently predictive of prognosis on multivariate analysis (P = 0.02). There was no correlation between VEGF and any clinicopathologic variable. High expression of VEGF was seen in only 7% of the tumors, suggesting that the role of antiangiogenic drugs may be limited to a small subset of patients.

CONCLUSION

High VEGF expression occurs in a small proportion of ovarian cancers, and this independently predicts poor prognosis. The small percentage of tumors with high levels of VEGF activity suggests that the role of bevacizumab may potentially be limited to a few patients; these patients could be targeted by molecular profiling.

The use of bevacizumab in refractory ovarian granulosa-cell carcinoma with symptomatic relief of ascites: a case report

BACKGROUND

The potential role of bevacizumab in the treatment of ovarian granulosa-cell tumors has not been evaluated.

CASE

An 82 year old woman with refractory ovarian granulosa-cell carcinoma was treated with bevacizumab with symptomatic relief of ascites.

CONCLUSION

Bevacizumab may have a role in the management of malignant ascites in the patient with refractory granulosa-cell carcinoma of the ovary which should be confirmed in a larger series of well selected patients.

Safety and immunogenicity study of NY-ESO-1b peptide and montanide ISA-51 vaccination of patients with epithelial ovarian cancer in high-risk first remission

PURPOSE

The cancer-testis antigen NY-ESO-1 is expressed by >40% of advanced epithelial ovarian cancers and is a promising immunotherapeutic target. In this study, we describe the effects of vaccination with the HLA-A*0201-restricted NY-ESO-1b peptide on patients with epithelial ovarian cancer in high-risk first remission.

EXPERIMENTAL DESIGN

After primary surgery and chemotherapy, high-risk epithelial ovarian cancer patients in first clinical remission received NY-ESO-1b peptide and Montanide every 3 weeks for five vaccinations. Tumor expression was evaluated by immunohistochemistry. Toxicity was monitored using National Cancer Institute Common Toxicity Criteria Scale Version 2. NY-ESO-1 specific humoral immunity (ELISA), T-cell immunity (tetramer and ELISPOT), and delayed-type hypersensitivity were assessed on weeks 0, 1, 4, 7, 10, 13, and 16.

RESULTS

Treatment-related adverse events included grade 1 fatigue, anemia, pruritus, myalgias, and hyperthyroidism and grade 2 hypothyroidism. There were no grade 3/grade 4 adverse events. Three of four patients (75%) with NY-ESO-1-positive tumor showed T-cell immunity by tetramer (0.6-9.5%) and ELISPOT (range, 35-260 spots). Four of five patients (80%) with NY-ESO-1-negative tumor showed T-cell immunity by tetramer (1.0-12.1%) and/or ELISPOT (range, 35-400 spots). With a median follow-up of 11.3 months, six of nine patients (67%) have recurred, with a median progression-free survival of 13 months (95% confidence interval, 11.2 months-not reached). Three of nine patients remain in complete clinical remission at 25, 38, and 52 months.

CONCLUSION

Vaccination of high-risk HLA-A*0201-positive epithelial ovarian cancer patients with NY-ESO-1b and Montanide has minimal toxicity and induces specific T-cell immunity in patients with both NY-ESO-1-positive and NY-ESO-1-negative tumors. Additional study is warranted.

Profound but dysfunctional lymphangiogenesis via vascular endothelial growth factor ligands from CD11b+ macrophages in advanced ovarian cancer

Severe ascites is a hallmark of advanced ovarian cancer (OVCA), yet the underlying mechanism that creates an imbalance between peritoneal vascular leakage and lymphatic drainage is unknown. Here, we identified and characterized peritoneal lymphatic vessels in OVCA mice, a model generated by implantation of human OVCA cells into athymic nude mice. The OVCA mice displayed substantial lymphangiogenesis and lymphatic remodeling, massive infiltration of CD11b(+)/LYVE-1(+) macrophages and disseminated carcinomatosis in the mesentery and diaphragm, and progressive chylous ascites formation. Functional assays indicated that the abnormally abundant lymphatic vessels in the diaphragm were not conductive in peritoneal fluid drainage. Moreover, lipid absorbed from the gut leaked out from the aberrant mesenteric lymphatic vessels. Our results indicate that vascular endothelial growth factor (VEGF)-C, VEGF-D, and VEGF-A from CD11b(+) macrophages are responsible for producing OVCA-induced dysfunctional lymphangiogenesis, although other cell types contribute to the increased ascites formation. Accordingly, the combined blockade of VEGF-C/D and VEGF-A signaling with soluble VEGF receptor-3 and VEGF-Trap, respectively, markedly inhibited chylous ascites formation. These findings provide additional therapeutic targets to ameliorate chylous ascites formation in patients with advanced OVCA.

Clinical and biological significance of vascular endothelial growth factor in endometrial cancer

PURPOSE

Vascular endothelial growth factor (VEGF) is critical for angiogenesis and tumor progression; however, its role in endometrial cancer is not fully known. Therefore, we examined the clinical and therapeutic significance of VEGF in endometrial carcinoma using patient samples and an endometrioid orthotopic mouse model.

EXPERIMENTAL DESIGN

Following Institutional Review Board approval, VEGF expression and microvessel density (MVD) counts were evaluated using immunohistochemistry in 111 invasive endometrioid endometrial cancers by two independent investigators. Results were correlated with clinicopathologic characteristics. For the animal model, Ishikawa or Hec-1A cancer cell lines were injected directly into the uterine horn. Therapy experiments with bevacizumab alone or in combination with docetaxel were done and samples were analyzed for markers of angiogenesis and proliferation.

RESULTS

Of 111 endometrial cancers, high expression of VEGF was seen in 56% of tumors. There was a strong correlation between VEGF expression and MVD (P < 0.001). On multivariate analysis, stage (P = 0.04), grade (P = 0.003), VEGF levels (P = 0.03), and MVD (P = 0.037) were independent predictors of shorter disease-specific survival. In the murine model, whereas docetaxel and bevacizumab alone resulted in 61% to 77% tumor growth inhibition over controls, combination therapy had the greatest efficacy (85-97% inhibition over controls; P < 0.01) in both models. In treated tumors, combination therapy significantly reduced MVD counts (50-70% reduction over controls; P < 0.01) and percent proliferation (39% reduction over controls; P < 0.001).

CONCLUSIONS

Increased levels of VEGF and angiogenic markers are associated with poor outcome in endometrioid endometrial cancer patients. Using a novel orthotopic model of endometrioid endometrial cancer, we showed that combination of antivascular therapy with docetaxel is highly efficacious and should be considered for future clinical trials.

Angiogenesis as a strategic target for ovarian cancer therapy

Angiogenesis is a complex and highly regulated process that is crucial for tumor growth and metastasis. Insights into the molecular mechanisms of tumor angiogenesis have led to the identification of potential angiogenic targets and the development of novel antivascular agents. Many of these agents are being evaluated in clinical trials and have shown promising antitumor activity. This Review highlights the results of the latest clinical studies of antivascular agents in ovarian cancer and discusses the challenges and opportunities for future clinical trials.

Development of antiangiogenic agents for ovarian cancer

Epithelial ovarian cancer (EOC) remains a major source of cancer morbidity and mortality, despite advances in surgical and chemotherapeutic management. The molecular pathways that control angiogenesis have been demonstrated to be key to the pathogenesis of EOC, and have been shown to have prognostic significance. Increased understanding of the pathways and molecules involved in angiogenesis has allowed the identification of a number of targets for antiangiogenic therapies and the development of a variety of antiangiogenic drugs. There is now significant preclinical evidence, and a growing body of clinical data, demonstrating promising results with antiangiogenic drugs in the treatment of EOC. Single-agent VEGF inhibitor response rates in pretreated patients of between 15 and 20% have been reported, with much higher response rates when used in combination with chemotherapeutic agents. These benefits, however, must be balanced with the toxicities associated with these drugs, particularly the more serious ones, such as gastrointestinal perforation. The results of ongoing and future randomized clinical trials will confirm if, and how, antiangiogenic therapies should be integrated into the routine management of EOC. However, critical issues, such as the relative importance of combination remission induction regimens and maintenance therapy, remain poorly defined.

Opportunities and challenges in ovarian cancer research, a perspective from the 11th Ovarian cancer action/HHMT Forum, Lake Como, March 2007

Advances in surgery and chemotherapy have improved the 5-year survival for patients with epithelial ovarian cancer, but have not impacted on the ultimate rate of cure in a disease that is diagnosed in late stage and that recurs in the majority of patients. "Omic" technologies promise to define genetically driven aberrant signaling pathways in malignant cells, provided that bioinformatic expertise can be focused on a cancer that is neither common nor rare. Molecular therapeutics must be linked to molecular diagnostics to permit individualized therapy. Not only epithelial cancer cells but also stroma, vasculature and the immune response must be targeted. Closer collaboration between academic institutions, biotech and pharma will be required to facilitate this process and to interest the private sector in an orphan disease. New preclinical models may permit more efficient development of drugs and siRNA that can target dormant drug resistant stem cells. Strategies must be developed to deal with the heterogeneity of different grades and histotypes. Identification of women at increased risk will facilitate prevention and early detection in subsets of patients. BRCA1/2 might be sequenced in all ovarian cancer patients to identify new kindreds. Epidemiologic algorithms are being developed and validated. Awareness must be raised that oral contraceptives can reduce risk of developing ovarian cancer by 50%. Early detection is likely to require panels of complementary biomarkers, analyzed by sophisticated statistical techniques, to improve sensitivity while maintaining extremely high specificity. As ovarian cancer becomes a chronic disease, greater emphasis will be placed on the challenges facing survivors.

Phase II trial of bevacizumab in persistent or recurrent epithelial ovarian cancer or primary peritoneal cancer: a Gynecologic Oncology Group Study

PURPOSE

Vascular endothelial growth factor (VEGF) seems to be a promoter of tumor progression for epithelial ovarian cancer (EOC) and primary peritoneal cancer (PPC). We conducted a phase II trial to assess the efficacy and tolerability of single-agent bevacizumab, an anti-VEGF monoclonal antibody.

PATIENTS AND METHODS

Eligible patients had persistent or recurrent EOC/PPC after one to two prior cytotoxic regimens, measurable disease, and Gynecologic Oncology Group performance status of at least 2. Treatment consisted of bevacizumab 15 mg/kg intravenously every 21 days until disease progression or prohibitive toxicity. Primary end points were progression-free survival (PFS) at 6 months and clinical response.

RESULTS

The study consisted of 62 eligible and assessable patients, median age 57 years, 41 (66.1%) having received two prior regimens and 36 (58.1%) [CORRECTED] considered platinum resistant. Grade 3 adverse events at least possibly related to bevacizumab were hematologic (1), GI (3), hypertension (6), thromboembolism (1), allergy (2), hepatic (1), pain (3), coagulation (1), constitutional (1), and dyspnea (1). Grade 4 adverse events included pulmonary embolus (1), vomiting and constipation (1), and proteinuria (1). Thirteen patients (21.0%) experienced clinical responses (two complete, 11 partial; median response duration, 10 months), and 25 (40.3%) survived progression free for at least 6 months. Median PFS and overall survival were 4.7 and 17 months, respectively. There was no significant association of prior platinum sensitivity, age, number of prior chemotherapeutic regimens, or performance status with the hazard of progression or death.

CONCLUSION

Bevacizumab seems to be well tolerated and active in the second- and third-line treatment of patients with EOC/PPC and merits phase III investigation.

Recurrent epithelial ovarian cancer: pharmacotherapy and novel therapeutics

Epithelial ovarian cancer will strike between 1 - 2% of women in developed countries and, unfortunately, it largely remains a lethal disease due to late-stage at diagnosis and the eventual development of chemotherapy resistance. Ovarian cancer is initially treated with surgical resection and chemotherapy (primarily platinum/taxane combinations) and remission can be attained for the majority of patients. Despite this, most women will recur and require multiple further therapies. The purpose of this paper is to review the existing treatment options, including surgery, traditional chemotherapy as well as upcoming novel and targeted therapies that may one day improve outcomes in this disease.

Bevacizumab in the treatment of ovarian cancer

Current treatment for epithelial ovarian cancer involves a combination of surgery and chemotherapy with platinum- and taxane-based chemotherapy. With the recent approval of the anti-VEGF antibody bevacizumab by several regulatory bodies in colorectal and non-small-cell lung cancers, interest has developed regarding the potential role of bevacizumab therapy in ovarian cancer. Several case series and Phase II studies indicate that in ovarian cancer bevacizumab is active as a single agent or in combination with other drugs. Currently, ongoing Phase III trials are testing bevacizumab in front-line adjuvant therapy with carboplatin and paclitaxel. Bevacizumab has been generally well tolerated in ovarian cancer patients, but recent reports on increased risk of gastrointestinal perforations have gained attention. Bevacizumab offers a novel therapeutic modality in the treatment of epithelial ovarian cancers.

Bevacizumab demonstrates activity in advanced refractory fallopian tube carcinoma

The targeting of angiogenesis pathways in the treatment of gynecological cancers is an exciting development in cancer therapy. Bevacizumab has been shown to have activity in ovarian cancer through its inhibition of the vascular endothelial growth factor. Fallopian tube carcinoma is a rare malignancy and is often treated in a similar manner as ovarian carcinoma. We present a case of a complete response in a woman with refractory metastatic fallopian tube carcinoma treated with bevacizumab. This report demonstrates the significance of anti-angiogenesis therapy in the treatment of these tumors.

Erosive osteoarthritis during treatment with bevacizumab and paclitaxel in a patient with recurrent papillary serous carcinoma of the ovary

Bevacizumab (BVC) is currently used in recurrent ovarian cancer and as part of the initial treatment for ovarian cancer. The most serious toxicities associated with BVC include gastrointestinal perforations, delayed wound healing, and hemorrhage. Arthritis had never been addressed in patients who received BVC treatment. This is the first case report of arthritis emergence linked to BVC administration. A 59-year-old female with recurrent ovarian cancer received multiple hormonal and cytotoxic regimens for 5 years and then developed erosive osteoarthritis of the hands secondary to BVC and paclitaxel. This effect was confirmed by a significant improvement in her symptoms and signs, after treatment was discontinued.

Experience With Bevacizumab in the Management of Epithelial Ovarian Cancer

Müllerian duct adenocarcinomas, in particular epithelial ovarian cancers, continue to represent a major source of female cancer-related morbidity and mortality, despite advances in surgical management and innovations in cytotoxic chemotherapy. Angiogenesis-targeted therapy seems to be appropriate for exploration in these disease processes based on a wealth of evidence from preclinical and molecular epidemiology studies. Bevacizumab is a prototypical agent neutralizing vascular endothelial growth factor (VEGF), a critical angiogenic promoter related to tumor progression, malignant effusions, and prognosis in ovarian cancer. Phase II trials have demonstrated the activity of bevacizumab as a single agent and in combination with other modalities such as low-dose metronomic cyclophosphamide. Historical studies have supported these observations. Unique toxicities have been ascribed to the administration of bevacizumab and other anti-VEGF molecules for patients with this disease and other solid tumors. Although most of these toxicities (such as proteinuria, hypertension, and bleeding) are generally mild, and are either self-limiting or controllable, other adverse effects, though uncommon, may be serious (these include arterial thromboembolism, wound healing complications, and GI perforation or fistulae). Phase III trials are now in progress to determine the role of this drug in primary therapy as an adjunct to platinum-taxane chemotherapy. This article reviews the background and rationale for anti-VEGF therapy of ovarian cancer, summarizes efficacy and safety data from phase II trials and historical studies of bevacizumab in this disease, introduces the implementation of bevacizumab in phase III front-line trials, examines controversial aspects related to anti-VEGF therapy, and proposes future directions regarding bevacizumab and other angiogenic growth factor–targeted therapeutics.

Vascular endothelial growth factor gene polymorphisms are associated with prognosis in ovarian cancer

PURPOSE

Vascular endothelial growth factor (VEGF), an important regulator of angiogenesis and vascular permeability, is involved in various steps of ovarian carcinogenesis. Gene polymorphisms within the gene encoding VEGF were shown to be independently associated with an adverse outcome in various malignancies. No data are available for ovarian cancer.

EXPERIMENTAL DESIGN

In the present multicenter study, we examined three common polymorphisms within the VEGF gene (-634G/C, -1154G/A, and -2578C/A) known to be associated with an increased VEGF production in 563 Caucasian patients with ovarian cancer from Austria and Germany using pyrosequencing. Results were correlated with clinical data.

RESULTS

The three investigated polymorphisms did not correlate with any of the investigated clinicopathologic variables. In univariate and multivariate models, no significant correlations between any polymorphism and patients' overall survival were ascertained. Simultaneous carriage of the three homozygous genotypes (i.e., VEGF -634C/C, VEGF -1154G/G, VEGF -2578C/C) known to be associated with increased VEGF expression in an individual patient, however, was independently associated with a shortened overall survival (hazard ratio, 2.1; 95% confidence interval, 1.1-3.9; P=0.02).

CONCLUSIONS

We present the first data on VEGF gene polymorphisms in ovarian cancer. Simultaneous carriage of the three investigated homozygous genotypes was shown to be an independent adverse prognosticator of overall survival.

Investigational agents against platinum-resistant ovarian cancer

Ovarian cancer is still the fourth cause of death by cancer among women and is the most fatal among gynaecological tumours. The goal of treatment for patients with recurrent, platinum-resistant (platinum-free interval < 6 months) ovarian cancer is the palliation of symptoms because no evidence indicates that present therapies may prolong survival in this setting of patients. Successful management of these patients depends on the identification of agents that are not cross-resistant with platinum compounds. The development of molecular biology is providing us with new information on the molecular basis of cancer, its mechanism of initiation and progression, and supply the need of a more patient-tailored therapy where specific tumours are treated with specific drugs. This paper reports and discusses new developments in the treatment of platinum-resistant ovarian cancer patients. The authors present proteomic advances, including the HER kinases, the 26S proteasome and the angiogenesis pathway. The opportunities to change the treatment of ovarian cancer will require creative clinical trial design but the next 10 years promise to be filled with therapeutic advances for patients with ovarian cancer.

[Experimental animal models of diabetes mellitus]

Vascular endothelial growth factor (VEGF) plays a critical role in angiogenesis, which is required for tumor growth and metastasis. In this article, a review of the functional and biological roles of the VEGF pathway in driving angiogenesis and growth of gynecologic malignancies was performed. Based on the biological functions of VEGF, multiple approaches for targeting the VEGF/VEGF-receptor complex have been developed and many of these have demonstrated substantial activity in preclinical models. These promising data have led to rapid clinical development of VEGF-targeted agents. Therefore, we also assessed the status of VEGF-targeted therapies and associated toxicities in gynecologic malignancies. However, many questions remain related to optimal dosing, sequencing of therapies, management of toxicities, appropriate patient selection, and assessment of response, which will require further studies. Nevertheless, VEGF-targeted therapies offer hope for improving the outcome of cancer patients.