Activity of bevacizumab (rhuMAB VEGF) in advanced refractory epithelial ovarian cancer

Emerging drugs for ovarian cancer

BACKGROUND

Long-term survival of patients with ovarian cancer remains poor and therapy disappointing despite decades of experience with various chemotherapies, including the current gold standard, carboplatin/paclitaxel (TC).

OBJECTIVE

To review current and emerging therapies for ovarian cancer in search of ways to improve outcome, reduce toxicity, and maintain quality of life.

METHODS

This is a review of the current status of chemotherapy for ovarian cancer, the ongoing clinical studies, emerging therapies, and proposals for future research.

RESULTS/CONCLUSION

Novel chemotherapeutic agents are needed to reduce toxicity and improve efficacy. Effective biological agents must be found and tested, either in combination with TC or as maintenance therapy after TC. An appropriate regimen and number of repeat treatment cycles for intraperitoneal chemotherapy is urgently needed, and an effective regimen must be established for patients with clear cell/mucinous adenocarcinoma. The main strategy for recurrent ovarian cancer is to find the gene related to drug resistance, then treat the cancer based on its molecular biology.

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 promise and perils of 'targeted therapy' of advanced ovarian cancer

For several reasons, ovarian cancer is an excellent malignancy to consider the use of 'targeted' therapeutic strategies. However, to date, despite considerable effort, there remains limited evidence that such approaches are clinically relevant in the malignancy. The one important exception is the delivery of anti-angiogenic anti-neoplastic agents, which actually appear to be more biologically active as single drugs in ovarian cancer than in other solid tumors where they have been examined. It is anticipated that future trials of 'targeted' therapy in ovarian cancer will focus on molecular targets of documented relevance in the malignancy.

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.

Preoperative radiotherapy and bevacizumab for angiosarcoma of the head and neck: Two case studies

BACKGROUND

Angiosarcoma of the face is a vascular tumor with poor local control and short median survival despite standard treatment. Bevacizumab is a humanized monoclonal antibody to vascular endothelial growth factor (VEGF), which can inhibit tumor growth. It is synergistic with radiotherapy in gastrointestinal malignancies. Given the vascular nature of angiosarcoma and the need for better treatment of this disease, we investigated the concurrent use of bevacizumab with preoperative radiotherapy for head and neck angiosarcoma.

METHODS

Two patients diagnosed with angiosarcoma of the nose were treated preoperatively with bevacizumab (5-10 mg/kg) and concurrent radiotherapy (50 Gy), followed by resection of the tumor bed.

RESULTS

Both patients had a complete pathologic response with no residual disease. Neither has developed recurrence, with follow-up of 8.5 months and 2.1 years.

CONCLUSIONS

The neoadjuvant combination of bevacizumab and radiation therapy is promising and should be further studied in the setting of vascular malignancies.

Ginger inhibits cell growth and modulates angiogenic factors in ovarian cancer cells

Background

Ginger (Zingiber officinale Rosc) is a natural dietary component with antioxidant and anticarcinogenic properties. The ginger component [6]-gingerol has been shown to exert anti-inflammatory effects through mediation of NF-κB. NF-κB can be constitutively activated in epithelial ovarian cancer cells and may contribute towards increased transcription and translation of angiogenic factors. In the present study, we investigated the effect of ginger on tumor cell growth and modulation of angiogenic factors in ovarian cancer cells in vitro.

Methods

The effect of ginger and the major ginger components on cell growth was determined in a panel of epithelial ovarian cancer cell lines. Activation of NF-κB and and production of VEGF and IL-8 was determined in the presence or absence of ginger.

Results

Ginger treatment of cultured ovarian cancer cells induced profound growth inhibition in all cell lines tested. We found that in vitro, 6-shogaol is the most active of the individual ginger components tested. Ginger treatment resulted in inhibition of NF-kB activation as well as diminished secretion of VEGF and IL-8.

Conclusion

Ginger inhibits growth and modulates secretion of angiogenic factors in ovarian cancer cells. The use of dietary agents such as ginger may have potential in the treatment and prevention of ovarian cancer.

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.

Antiangiogenic and antitumor effects of SRC inhibition in ovarian carcinoma

Src, a nonreceptor tyrosine kinase, is a key mediator for multiple signaling pathways that regulate critical cellular functions and is often aberrantly activated in a number of solid tumors, including ovarian carcinoma. The purpose of this study was to determine the role of activated Src inhibition on tumor growth in an orthotopic murine model of ovarian carcinoma. In vitro studies on HeyA8 and SKOV3ip1 cell lines revealed that Src inhibition by the Src-selective inhibitor, AP23846, occurred within 1 hour and responded in a dose-dependent manner. Furthermore, Src inhibition enhanced the cytotoxicity of docetaxel in both chemosensitive and chemoresistant ovarian cancer cell lines, HeyA8 and HeyA8-MDR, respectively. In vivo, Src inhibition by AP23994, an orally bioavailable analogue of AP23846, significantly decreased tumor burden in HeyA8 (P = 0.02), SKOV3ip1 (P = 0.01), as well as HeyA8-MDR (P < 0.03) relative to the untreated controls. However, the greatest effect on tumor reduction was observed in combination therapy with docetaxel (P < 0.001, P = 0.002, and P = 0.01, for the above models, respectively). Proliferating cell nuclear antigen staining showed that Src inhibition alone (P = 0.02) and in combination with docetaxel (P = 0.007) significantly reduced tumor proliferation. In addition, Src inhibition alone and in combination with docetaxel significantly down-regulated tumoral production of vascular endothelial growth factor and interleukin 8, whereas combination therapy decreased the microvessel density (P = 0.02) and significantly affected vascular permeability (P < 0.05). In summary, Src inhibition with AP23994 has potent antiangiogenic effects and significantly reduces tumor burden in preclinical ovarian cancer models. Thus, Src inhibition may be an attractive therapeutic approach for patients with ovarian carcinoma.

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.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its therapeutic potential in breast and gynecologic cancers

OBJECTIVE

The relationship between the apoptotic pathway and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising area of scientific interest for cancer researchers. TRAIL-receptor-activating agents have demonstrated favorable in vitro and in vivo activity for the treatment of several malignancies including breast and gynecologic cancers.

METHODS

This article reviews the available peer-reviewed literature and our own institution's experience with specific TRAIL-receptor-activating agents. Emphasis was placed on the apoptotic/TRAIL mechanism, preclinical evaluation, and phase I studies in various malignancies.

RESULTS

Preclinical and early phase I studies indicate that these novel agents are safe with enhanced target specificity for malignancy. When these targeted agents are combined with conventional chemotherapy drugs or radiation therapy, they appear to increase cell death over single-agent modalities.

CONCLUSIONS

TRAIL-receptor-activating agents represent an exciting new class of targeted therapies that hold promise to improve the treatment of women with breast and gynecologic malignancies.

Phase II testing of sunitinib: the National Cancer Institute of Canada Clinical Trials Group IND Program Trials IND.182-185

Sunitinib (SU11248) is an orally bioavailable inhibitor that affects the receptor tyrosine kinases involved in tumour proliferation and angiogenesis, including vascular endothelial growth factor (VEGF) receptors 1, 2, 3, and platelet-derived growth factor receptors alpha (PDGFRA) and beta (PDGFRB). Because angiogenesis is necessary for the growth and metastasis of solid tumours, and VEGF is believed to have a pivotal role in that process, SUNITINIB treatment may have broad-spectrum clinical utility. In the present article, we discuss the biologic and clinical rationales that have recently led the Investigational New Drug Program of the National Cancer Institute of Canada Clinical Trials Group to initiate four phase ii trials testing this agent in the following four different tumour types: relapsed diffuse large cell lymphoma, malignant pleural mesothelioma, locally advanced or metastatic cervical cancer and recurrent epithelial ovarian, fallopian tube, or primary peritoneal carcinoma.

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.

A phase II study of outpatient first-line paclitaxel, carboplatin, and bevacizumab for advanced-stage epithelial ovarian, peritoneal, and fallopian tube cancer

The purpose of this study was to assess the response rate and toxicity of paclitaxel, carboplatin, and bevacizumab (PCB) primary induction therapy for the treatment of advanced-stage ovarian carcinoma. Twenty patients were treated with paclitaxel (175 mg/m(2)), carboplatin (AUC of 5 IV), and bevacizumab (15 mg/kg) of body weight; q21 days for six cycles. Bevacizumab was administered at cycles two through six. Patients received 116 cycles of PCB chemotherapy (median = 6, range 2-6) and were evaluable for toxicity assessment. Grade 3 and 4 neutropenia developed in 23.3% and 25% of cycles, with no incidence of grades 3/4 thrombocytopenia or anemia. Prior to cycle six, one patient was removed from the study due to grade 3 neuropathy and another patient was excluded due to clinical deterioration. There was no incidence of gastrointestinal perforations, and only two patients demonstrated grade 3 hypertension (HTN). No grade 4 HTN was observed. Eighteen patients were evaluated for response following induction therapy. Six demonstrated a complete response (30%) and ten exhibited a partial response (50%), resulting in a total response rate of 80%. One patient exhibited stable disease (5%), and one demonstrated disease progression (5%). The lack of bowel perforations and wound complications should mitigate some concerns regarding these side effects. This study suggests that first-line treatment with PCB can be safely administered to previously untreated advanced-stage ovarian carcinoma patients. The favorable toxicity results and reasonable response rate warrant additional study in a larger patient population.

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.

Efficacy of anti-death receptor 5 (DR5) antibody (TRA-8) against primary human ovarian carcinoma using a novel ex vivo tissue slice model

OBJECTIVES

The purpose of this study was to evaluate the cytotoxicity of a death receptor 5 (DR5) targeting monoclonal antibody (TRA-8) in primary ovarian cancer specimens utilizing a tissue slice technique that allows for assessment of anti-tumor activity in a three-dimensional ex vivo model.

METHODS

Nineteen primary ovarian tumor specimens were obtained at the time of cytoreductive surgery and tumor slices were prepared with the Krumdieck tissue slicer. Tumor slices were incubated with TRA-8 for 24 h and a dose-response curve was established for each specimen using non-linear modeling, with IC50 values used as the parameter of TRA-8 sensitivity. In parallel with ATP viability assays, TRA-8 treated and untreated tumor slices were assessed by immunohistochemistry (IHC) and western blot analysis to confirm apoptosis induction.

RESULTS

Incubation with 0-1000 ng/ml TRA-8 resulted in a dose response with maximum killing observed at 1000 ng/ml compared to untreated control slices. IC50 values of 6.0 to >1000 ng/ml were calculated for individual tumor specimens. H&E, IHC, and western blot specimens demonstrated TRA-8-induced cellular death in a dose-dependent fashion via apoptosis and activation of caspases 3, 8, and 9. The apoptosis produced by varying concentrations of TRA-8 was confirmed using the TUNEL technique. Treatment with TRA-8 markedly reduced proliferation in the ovarian cancer cells as measured by expression of Ki-67/SP6.

CONCLUSIONS

This study demonstrates that targeting DR5 with TRA-8 decreases cellular proliferation, increases caspase activation, and induces apoptosis in this novel three-dimensional ex vivo model of primary ovarian cancer.

Copper-67 radioimmunotherapy and growth inhibition by anti-L1-cell adhesion molecule monoclonal antibodies in a therapy model of ovarian cancer metastasis

PURPOSE

We examined the tumor-targeting and therapeutic effects of (67)Cu-labeled single amino acid mutant forms of anti-L1 monoclonal antibody chCE7 in nude mice with orthotopically implanted SKOV3ip human ovarian carcinoma cells.

EXPERIMENTAL DESIGN

For radioimmunotherapy, chCE7 antibodies with a mutation of histidine 310 to alanine (chCE7H310A) and a mutation of asparagine 297 to glutamine (chCE7agl) were generated to achieve more rapid blood clearance. Biodistributions of (67)Cu-4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methyl benzoic acid tetrachloride (CPTA)-labeled mutant antibodies were measured in nude mice bearing SKOV3ip human ovarian cancer metastases. The effects of single i.v. injections of (67)Cu-chCE7agl alone on tumor reduction and survival were investigated. In addition, a combination of low-dose (67)Cu-radioimmunotherapy with unlabeled anti-L1 antibody L1-11A on survival was investigated.

RESULTS

(67)Cu-CPTA-chCE7agl showed high (up to 49% ID/g) and persistent (up to 168 h) uptake in SKOV3ip metastases, with low levels in normal tissues. (67)Cu-CPTA-chCE7H310A revealed a shorter half-life in the blood and a lower tumor uptake and retention. A single low dose of 4 MBq of (67)Cu-chCE7agl reduced tumor growth but did not prolong survival significantly, whereas a single 10.5 MBq dose of (67)Cu-chCE7agl reduced tumor growth and prolonged survival significantly. The combination of unlabeled monoclonal antibody L1-11A with a subtherapeutic dose of (67)Cu-radioimmunotherapy also prolonged survival significantly.

CONCLUSION

The results show improved pharmacokinetics and biodistributions as well as the therapeutic effect of the (67)Cu-labeled single amino acid mutant chCE7agl. Therapeutic data indicate, for the first time, the feasibility of combining anti-L1-directed growth inhibition and (67)Cu-radioimmunotherapy, thereby increasing the efficiency of antibody treatment of metastatic ovarian carcinoma.

Tumor vascular proteins as biomarkers in ovarian cancer

PURPOSE

This study aimed to identify novel ovarian cancer biomarkers and potential therapeutic targets through molecular analysis of tumor vascular cells.

METHODS

Immunohistochemistry-guided laser-capture microdissection and genome-wide transcriptional profiling were used to identify genes that were differentially expressed between vascular cells from human epithelial ovarian cancer and healthy ovaries. Tumor vascular markers (TVMs) were validated through quantitative real-time polymerase chain reaction (qRT-PCR) of immunopurified tumor endothelial cells, in situ hybridization, immunohistochemistry, and Western blot analysis. TVM expression in tumors and noncancerous tissues was assessed by qRT-PCR and was profiled using gene expression data.

RESULTS

We identified a tumor vascular cell profile of ovarian cancer that was distinct from the vascular profile of normal ovary and other tumors. We validated 12 novel ovarian TVMs. These were expressed by immunopurified tumor endothelial cells and localized to tumor vasculature. Select TVMs were found to be specifically expressed in ovarian cancer and were absent in all normal tissues tested, including female reproductive tissues with physiologic angiogenesis. Many ovarian TVMs were expressed by a variety of other solid tumors. Finally, overexpression of any one of three ovarian TVMs by vascular cells was associated with decreased disease-free interval (all P < .005).

CONCLUSION

We have identified for the first time the molecular profile of ovarian tumor vasculature. We demonstrate that TVMs may serve as potential biomarkers and molecular targets for ovarian cancer and a variety of other solid tumors.

Novel targeted therapies in epithelial ovarian cancer: from basic research to the clinic

The development of new molecularly targeted therapies represents a high priority for the treatment of epithelial ovarian cancer. P-glycoprotein overexpression has been associated with multidrug resistance, and the use of multidrug resistance modulators, such as valspodar, is being explored in combination with chemotherapy. Human epidermal receptor (HER) family members are attractive targets for biological therapies. The addition of erlotinib or cetuximab to first-line paclitaxel- plus carboplatin-based chemotherapy is feasible and well tolerated. Gefitinib is able to inhibit the proliferation of ovarian clear-cell carcinoma in in vitro and in vivo experimental models. Single-agent trastuzumab has a limited value for recurrent epithelial ovarian cancer owing to the low frequency of HER2 overexpression and the low rate of objective responses among HER2-overexpressing patients. A Gynecologic Oncology Group Phase II trial of the proteasome inhibitor bortezomib in recurrent epithelial ovarian cancer is currently ongoing, and the combination of bortezomib and chemotherapeutic agents should be assessed. The mammalian target of rapamycin (mTOR) plays an important role in stimulating the translation of mRNAs encoding key proteins for cell growth and angiogenesis, and mTOR inhibitors, such as AP-23573 (ARIAD), deserve to be tested in selected epithelial ovarian cancer patients. The addition of intraperitoneal treatment with adenovirus containing human wild-type p53 to standard paclitaxel- plus carboplatin-based chemotherapy failed to improve the clinical outcome of patients with mutated p53 epithelial ovarian cancer. The Gynecologic Oncology Group is conducting a Phase II trial of single-agent bevacizumab (antivascular endothelial growth factor monoclonal antibody) in platinum-resistant disease. In conclusion, emerging drugs for epithelial ovarian cancer include agents designed to overcome chemoresistance, HER-targeting agents, proteasome inhibitors, mTOR inhibitors and angiogenesis inhibitors. A new paradigm of treatment could consist of chemotherapy combined with a biological agent for six cycles, and followed by chronic maintenance therapy with the biological agent alone. Advances in genomics and proteomics will elucidate the molecular mechanisms of ovarian carcinogenesis, which will hopefully lead to individualized molecular medicine in the next years.

New, Expanded, and Modified Use of Approved Antineoplastic Agents in Ovarian Cancer

Over the past several years, clinical research efforts in ovarian cancer employing a number of U.S. Food and Drug Administration (FDA)-approved antineoplastic agents have permitted the development of approaches that both improve the effectiveness and decrease the toxicities of systemic therapy of ovarian cancer. These initiatives, including prospective trials and retrospective examinations of large clinical experience, have involved agents previously approved by the FDA for use in ovarian cancer (e.g., cisplatin, paclitaxel, topotecan, and liposomal doxorubicin) and the development of new strategies for drugs approved for other malignant conditions (e.g., gemcitabine, docetaxel, etoposide, irinotecan, vinorelbine, and bevacizumab). It can be anticipated that future studies involving novel approved agents will further expand the oncologist's weapons against ovarian cancer.

Relevant molecular markers and targets

Ovarian cancer is a heterogeneous disease with extensive cytogenetic and molecular heterogeneity including aneuploidy, chromosomal alterations, mutations and overexpression as well as a natural propensity to disseminate and spread, making it difficult to diagnose at an early stage. Insights into the molecular mechanisms operative in cancer development, progression and metastasis have uncovered a wide array of targets for therapeutic intervention. In the absence of a common driving oncogene in ovarian cancer, single targeted therapy for this disease is unlikely to yield significant clinical benefit. Tailored approaches that combine molecular targeting agents with cytotoxic regimens hold great promise when used in primary treatment, during consolidation and maintenance therapy, and in the treatment of persistent or recurrent disease. The most promising treatment strategies are those that target the drivers of tumorigenesis and enhance the activity of cytotoxic agents. Receptor tyrosine kinases, non-receptor tyrosine kinases, serine/threonine kinases, transferases, proteases and deacetylases are among the relevant molecular markers and targets for ovarian cancer that are discussed. Collaboration, coordination, creativity and aggressive outreach to patients and their advocates are essential for success in running the concurrent trials with multiple clinical end points and embedded translational research that are needed to evaluate the array of promising targeted therapeutics and combinations. Validated biomarkers, surrogate specimens and end points, and additional clinically relevant in vitro and in vivo models for ovarian cancer are needed to facilitate the drug development and evaluation process, and ultimately to make meaningful improvements in the diagnosis, prevention and management of ovarian cancer.

The use of bevacizumab to palliate symptomatic ascites in patients with refractory ovarian carcinoma

OBJECTIVE

To evaluate our experience with the use of bevacizumab in patients with heavily pretreated recurrent ovarian carcinoma who have symptomatic ascites.

METHODS

Four patients were identified who were previously heavily pretreated for recurrent ovarian carcinoma. Each had symptomatic ascites and required frequent therapeutic paracenteses. Each was treated with bevacizumab with the intent to palliate symptomatic ascites. Clinical data including demographic data and clinicopathologic variables was abstracted.

RESULTS

The four patients demonstrated symptomatic relief of ascites. Toxicity was manageable in all patients with no grade 3/4 toxicity observed. In addition to symptomatic relief of ascites, no therapeutic paracenteses were required after initiation of therapy with bevacizumab.

CONCLUSIONS

Bevacizumab may be a viable palliative option in patients with end stage ovarian carcinoma who have symptomatic ascites.

Bevacizumab combination therapy in recurrent, platinum-refractory, epithelial ovarian carcinoma: A retrospective analysis

BACKGROUND

The study was undertaken to determine the safety and efficacy of the monoclonal, antivascular endothelial growth factor antibody bevacizumab in combination with cytotoxic chemotherapy for women with platinum-refractory ovarian cancer.

METHODS

A retrospective analysis of women who received bevacizumab in combination with a cytotoxic agent was performed. Response was determined by measurable disease or assessment of serial cancer antigen (CA) 125 measurements.

RESULTS

Twenty-three patients were identified. The patients were heavily pretreated with a median of 7 prior regimens including a median of 3 prior platinum regimens. The combination regimen included cyclophosphamide in 15 (65%), 5-fluorouracil (5-FU) in 6 (26%), docetaxel in 1 (4%), and gemcitibine/liposomal doxorubicin in 1 (4%). Two (9%) women developed chylous ascites during treatment. CTC Grade 4-5 toxicities occurred in 4 (17%) subjects. Gastrointestinal perforation occurred in 2 (9%) patients. Measurable disease was present in 22. The overall best response rate was 35% and all 8 were partial responses (PRs). Stable disease was found in a further 10 (44%) women, whereas progressive disease was observed in 5 (22%). The median time to progression was 5.6 months in patients with a PR and 2.3 months in subjects with stable disease. Three (13%) women experienced a progression-free interval (PFI) of >6 months. At last follow-up, 8 (35%) subjects had died of disease, whereas 15 (65%) women were alive with disease.

CONCLUSIONS

Combination bevacizumab therapy demonstrated activity in heavily pretreated women with ovarian cancer. Gastrointestinal perforations were identified in 9%. Despite the toxicity of the regimen, prospective studies, particularly in less heavily pretreated patients, are warranted.

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

OBJECTIVES

Bevacizumab (BEV) is a humanized monoclonal antibody against vascular endothelial growth factor. We reviewed our experience with BEV in patients with recurrent advanced epithelial ovarian cancer who had failed multiple prior chemotherapeutic regimens.

METHODS

Thirty-two patients not participating in an ongoing clinical trial were treated with BEV (15 mg/kg every 3 weeks IV). Demographic and clinicopathologic data, clinical outcomes, and adverse events were extracted from patient charts. RECIST and CA-125 Rustin criteria were retrospectively applied to evaluate response and progression. Median progression-free survival (PFS) and overall survival (OS) were determined using Kaplan-Meier methods. Adverse events were retrospectively categorized using the common terminology criteria for adverse events version 3.

RESULTS

The median patient age was 57 years (range 35-80) with 84% being Caucasian and 50% having a GOG performance status of 2. FIGO stages included 80% stage III and 10% stage IV. The tumors were mostly grades 2 (29%) and 3 (64%) and serous histological subtype (69%). All patients had failed multiple prior cytotoxic chemotherapies (median of 5 (range 2-10)) prior to BEV. The median duration of follow-up was 4.8 months (range 0.4-16.3). Twenty-three patients were treated with BEV alone, 2 received BEV with another chemotherapy regimen (5-FU/lecovorin plus oxaliplatin, cyclophosphamide), and 8 initially received BEV alone, followed by BEV with capcitabine, cyclophosphamide, docetaxel, carboplatin, or weekly paclitaxel. A median of 6 cycles (range 1-20) with 196 total doses of BEV was administered. One patient was lost to follow-up after cycle 1. We observed a 16% response rate (all in those treated with BEV alone) with 62.5% of patients demonstrating stable disease. Median OS was 6.9 months, and the median PFS was 5.5 months. Three grade 3 and no grade 4 adverse events were observed. Grade 3 toxicities included hypertension, proteinuria, and enterocutaneous fistula. The fistula occurred after 5 cycles of BEV in a patient who had undergone 7 debulking surgeries prior to BEV.

CONCLUSIONS

BEV is generally well tolerated after multiple prior cytotoxic regimens and results in significant clinical benefit among women with recurrent ovarian cancer.

Sustained response to bevacizumab in refractory well-differentiated ovarian neoplasms

BACKGROUND

Bevacizumab has demonstrated activity against a variety of solid tumors, including ovarian carcinoma. However, there have not been reproducible prognostic features associated with its activity.

CASES

One patient each with recurrent, refractory well-differentiated serous-endometrioid ovarian carcinoma, micropapillary serous carcinoma of the ovary, and primary peritoneal micropapillary serous carcinoma were treated with single agent bevacizumab (15 mg/kg [DOSAGE ERROR CORRECTED] intravenously every 3 weeks). All three have had dramatic sustained responses of 15, 15, and 22 months' duration.

CONCLUSION

Bevacizumab may have significant activity against well-differentiated ovarian carcinoma and micropapillary serous carcinomas of the ovary or peritoneum. Since these tumors are generally indolent and not responsive to adjuvant therapy, further investigation is warranted.

Bevacizumab and weekly taxane chemotherapy demonstrates activity in refractory ovarian cancer

OBJECTIVE

To determine the ability of patients to be treated with biweekly bevacizumab and weekly taxane chemotherapy in women with advanced, refractory ovarian cancer.

METHODS

Ten patients with advanced, recurrent, and refractory ovarian cancer who were treated with biweekly bevacizumab (10 mg/kg) and weekly taxane (paclitaxel or docetaxel) chemotherapy days 1, 8, 15, and 22 every 28 days were identified retrospectively. All patients were followed with serial CA125 measurements prior to each cycle of therapy; cross-sectional imaging was not used to follow response to therapy. Toxicities were assessed prior to each cycle of treatment.

RESULTS

Of the 10 patients treated with weekly taxane and biweekly bevacizumab therapy, all 9 that were evaluable had a decrease in CA125. Five patients have had an increase in CA125 after therapy after a median of three cycles (range 1-4), while 3 patients experienced normalization of CA125 and another with continued improvement in CA125. All symptomatic patients experienced rapid palliation of pain, nausea, and ascites. Side effects have been mild, with no grade 3 or 4 toxicities noted. No treatment delays or discontinuations have been necessary.

CONCLUSION

Treatment of advanced, recurrent, refractory epithelial ovarian cancer with bevacizumab and weekly taxane chemotherapy leads to significant, albeit temporary, improvement in the cancer-related symptoms in women treated on this regimen, and short-term exposure to these agents is not associated with significant toxicity. Thus, continued investigation of bevacizumab with weekly scheduling of cytotoxic chemotherapy is imperative.

New agents for the treatment of ovarian cancer: the next generation

Ovarian cancer shares many important characteristics with more common malignancies including breast, lung, and colon cancer. The relative chemosensitivity of ovarian cancer and other aspects of its unique biology provide opportunities for novel interventions. In this brief summary, some of the potential targets in ovarian cancer are discussed, including the HER kinases, heat shock protein, 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 decade promises to be filled the therapeutic advances for patients with ovarian cancer.