Combination gemcitabine, platinum, and bevacizumab for the treatment of recurrent ovarian cancer

Phase II study of gemcitabine, cisplatin, and bevacizumab for first recurrent and refractory ovarian clear cell carcinoma Kansai Clinical Oncology Group-G1601

Patients with advanced ovarian clear cell carcinoma (CCC) have a poor prognosis in the absence of an effective standard treatment. Combination therapy with gemcitabine, cisplatin, and bevacizumab (GPBev) is promising for ovarian CCC. Thus, we conducted a multi-institutional, phase II trial in Japan to examine the efficacy and safety of GPBev for CCC. This is the first study on the use of GPBev for CCC. Eighteen patients (median age, 56.5 years) with pathologically confirmed first recurrent or refractory CCC and having evaluable regions, as assessed using RECIST, were recruited between January 2017 and May 2019. Gemcitabine (1000 mg/m2), cisplatin (40 mg/m2), and bevacizumab (10 mg/kg) were administered intravenously on days 1 and 15, every 28 days, for 6-10 cycles, until disease progression or intolerable toxicity. The primary endpoint was overall response rate (ORR). The secondary endpoints included disease control rate (DCR) and adverse events (AEs). Fifteen patients (83.3%) completed 6-10 cycles of treatment; three patients (two with AEs and one with progressive disease) did not. The ORR was 61.1% [complete response (CR) 3 and partial response (PR) 8] and DCR was 88.9% (CR 3, PR 8, and stable disease 5). Grade 3 and 4 hematological AEs were observed in 16.7 and 5.6% of the patients, respectively. Nonhematological AEs of grades 3 and 4 were observed in 27.8 and 5.6% of the patients, respectively. GPBev is a promising therapy for CCC owing to the high ORR and acceptable toxicity for the first recurrence and refractory CCC.

Functional Genomics Approaches to Elucidate Vulnerabilities of Intrinsic and Acquired Chemotherapy Resistance

Drug resistance is a commonly unavoidable consequence of cancer treatment that results in therapy failure and disease relapse. Intrinsic (pre-existing) or acquired resistance mechanisms can be drug-specific or be applicable to multiple drugs, resulting in multidrug resistance. The presence of drug resistance is, however, tightly coupled to changes in cellular homeostasis, which can lead to resistance-coupled vulnerabilities. Unbiased gene perturbations through RNAi and CRISPR technologies are invaluable tools to establish genotype-to-phenotype relationships at the genome scale. Moreover, their application to cancer cell lines can uncover new vulnerabilities that are associated with resistance mechanisms. Here, we discuss targeted and unbiased RNAi and CRISPR efforts in the discovery of drug resistance mechanisms by focusing on first-in-line chemotherapy and their enforced vulnerabilities, and we present a view forward on which measures should be taken to accelerate their clinical translation.

Treatment of epithelial ovarian cancer

Ovarian cancer is the third most common gynecologic malignancy worldwide but accounts for the highest mortality rate among these cancers. A stepwise approach to assessment, diagnosis, and treatment is vital to appropriate management of this disease process. An integrated approach with gynecologic oncologists as well as medical oncologists, pathologists, and radiologists is of paramount importance to improving outcomes. Surgical cytoreduction to R0 is the mainstay of treatment, followed by adjuvant chemotherapy. Genetic testing for gene mutations that affect treatment is the standard of care for all women with epithelial ovarian cancer. Nearly all women will have a recurrence, and the treatment of recurrent ovarian cancer continues to be nuanced and requires extensive review of up to date modalities that balance efficacy with the patient's quality of life. Maintenance therapy with poly ADP-ribose polymerase inhibitors, bevacizumab, and/or drugs targeting homologous recombination deficiency is becoming more widely used in the treatment of ovarian cancer, and the advancement of immunotherapy is further revolutionizing treatment targets.

Inhibiting DNA Polymerases as a Therapeutic Intervention against Cancer

Inhibiting DNA synthesis is an important therapeutic strategy that is widely used to treat a number of hyperproliferative diseases including viral infections, autoimmune disorders, and cancer. This chapter describes two major categories of therapeutic agents used to inhibit DNA synthesis. The first category includes purine and pyrmidine nucleoside analogs that directly inhibit DNA polymerase activity. The second category includes DNA damaging agents including cisplatin and chlorambucil that modify the composition and structure of the nucleic acid substrate to indirectly inhibit DNA synthesis. Special emphasis is placed on describing the molecular mechanisms of these inhibitory effects against chromosomal and mitochondrial DNA polymerases. Discussions are also provided on the mechanisms associated with resistance to these therapeutic agents. A primary focus is toward understanding the roles of specialized DNA polymerases that by-pass DNA lesions produced by DNA damaging agents. Finally, a section is provided that describes emerging areas in developing new therapeutic strategies targeting specialized DNA polymerases.

Safety of bevacizumab in clinical practice for recurrent ovarian cancer: A retrospective cohort study

The poor outcome of patients with recurrent ovarian cancer constitutes a continuous challenge for decision-making in clinical practice. In this setting, molecular targets have recently been identified, and novel compounds are now available. Bevacizumab has been introduced for the treatment of patients with ovarian cancer and is, to date, the most extensively investigated targeted therapy in this setting. However, potential toxicities are associated with the use of this monoclonal antibody. These toxicities have been reported in clinical trials, and can also be observed outside of trials. As limited data is currently available regarding the safety of bevacizumab treatment in daily clinical practice, the current retrospective study was designed to evaluate this. Data from 156 patients with recurrent ovarian cancer who had received bevacizumab treatment between January 2006 and June 2009 were retrospectively identified from the institutional records of five French centers. In contrast to clinical trials, the patients in the present study were not selected and had a heterogeneous profile according to their prior medical history, lines of treatment prior to bevacizumab introduction and number of relapses. The results first confirm the effect of heavy pretreatment on the occurrence of serious and fatal adverse events in clinical practice, as previously reported for clinical trials and for other retrospective cohort studies. Importantly, the data also demonstrates, for the first time, that medical history of hypertension is an independent predictive risk factor for the development of high-grade hypertension during bevacizumab treatment. These results thus suggest that treating physicians must consider all risk factors for managing bevacizumab toxicity prior to its introduction. Such risk factors include the time of bevacizumab introduction, a patient's history of hypertension and a low incidence of pre-existing obstructive disease.

Emerging therapies: angiogenesis inhibitors for ovarian cancer

INTRODUCTION

Patients with epithelial ovarian cancer (EOC) have a high rate of recurrence, and overall survival remains at ∼ 25%. There is a need for new treatments that can increase progression free survival and quality of life. Recent clinical trials focus on angiogenesis, VEGFs, and tyrosine kinase inhibitors that play a role in recurrence, metastasis, and ascites in EOC.

AREAS COVERED

This review summarizes clinical rationale, mechanisms of action, and clinical data for angiogenesis inhibitors under evaluation in Phase II and III trials for EOC. Anti-angiogenesis agents reviewed in this paper include aflibercept, bevacizumab, cediranib, fosbretabulin, imatinib, nintedanib, pazopanib, saracatinib, sorafenib, sunitinib, and trebananib.

EXPERT OPINION

These agents have particular rationale for potential use in EOC due to the molecular changes associated with EOC tumorigenesis, namely a significant increase in angiogenic activity. Due to the costs and toxicities associated with anti-angiogenics, biomarker or molecular signature selection strategy for patients who will most benefit would be ideal but no such strategy has been validated to date.

The redox-active nanomaterial toolbox for cancer therapy

Advances in nanomaterials science contributed in recent years to develop new devices and systems in the micro and nanoscale for improving the diagnosis and treatment of cancer. Substantial evidences associate cancer cells and tumor microenvironment with reactive oxygen species (ROS), while conventional cancer treatments and particularly radiotherapy, are often mediated by ROS increase. However, the poor selectivity and the toxicity of these therapies encourage researchers to focus efforts in order to enhance delivery and to decrease side effects. Thus, the development of redox-active nanomaterials is an interesting approach to improve selectivity and outcome of cancer treatments. Herein, we describe an overview of recent advances in redox nanomaterials in the context of current and emerging strategies for cancer therapy based on ROS modulation.

Angiogenesis inhibitors in the treatment of epithelial ovarian cancer

Treatment of epithelial ovarian cancer involves surgical management with staging or debulking surgery and chemotherapy with a platinum and taxane-containing regimen. Despite achieving a 70-80 % complete remission, patients often will recur. Novel therapies are needed to improve the treatment of ovarian cancers. Tumor angiogenesis is a critical process involved in the growth and metastasis of ovarian cancer. Numerous phase II trials with angiogenesis inhibitors have been reported and have led to the development and completion of several recent phase III trials in both upfront and recurrent ovarian cancers. Future studies will need to focus on how and when to incorporate angiogenesis inhibitors in the treatment armamentarium for ovarian cancers.

Anti-VEGFA Therapy Reduces Tumor Growth and Extends Survival in a Murine Model of Ovarian Granulosa Cell Tumor

Although angiogenesis has been proposed as a therapeutic target for the treatment of ovarian granulosa cell tumor (GCT), its potential has not been evaluated in controlled studies. To do so, we used the Pten (tm1Hwu/tm1Hwu); Ctnnb1 (tm1Mmt/+);Amhr2 (tm3(cre)Bhr/+) (PCA) mouse model, which develops GCTs that mimic the advanced disease in women. A monoclonal anti-vascular endothelial growth factor A (VEGFA) antibody was administered weekly to PCA mice beginning at 3 weeks of age. By 6 weeks of age, anti-VEGFA therapy significantly decreased tumor weights relative to controls (P < .05) and increased survival, with all treated animals but none of the controls surviving to 8 weeks of age. Analyses of PCA tumors showed that anti-VEGFA treatment resulted in significant decreases in tumor cell proliferation and microvessel density relative to controls (P < .05). However, treatment did not have a significant effect on apoptosis or tumor necrosis. The VEGFA receptor 2 (VEGFR2) signaling effector p44/p42 mitogen-activated protein kinase (MAPK), whose activity is associated with cell proliferation, was significantly less phosphorylated (i.e., activated) in tumors from the treated group (P < .05). Conversely, no significant difference was found in the activation of protein kinase B, a VEGFR2 signaling effector associated with cell survival. Together, these results suggest that anti-VEGFA therapy is effective at inhibiting GCT growth in the PCA model and acts by reducing microvascular density and cell proliferation through inhibition of the VEGFR2-MAPK pathway. Findings from this preclinical model therefore support the investigation of targeting VEGFA for the adjuvant treatment of GCT in women.

Should Bevacizumab Be Continued After Progression on Bevacizumab in Recurrent Ovarian Cancer?

Objective

The optimal role of bevacizumab (Bev) in the treatment of ovarian cancer has not yet been established. Furthermore, it is unclear whether there is a benefit of Bev after progression on a Bev-containing regimen in ovarian cancer. The objective of this study was to compare response rates, progression-free survival (PFS), and overall survival between patients who were treated with chemotherapy and Bev after progression on Bev (BAB) versus patients who were treated with chemotherapy without Bev (CWOB).

Methods

We conducted a retrospective chart review of all patients who received treatment with Bev (with or without cytotoxic chemotherapy) for recurrent ovarian cancer at a single institution. Patients who received additional therapy after progression while on Bev were included.

Results

Forty-six patients were included (16 CWOB group and 30 BAB). The median number of previous chemotherapy regimens was 2.5 for CWOB compared with 4 for BAB (P= 0.11). Fifty-two percent of patients had an objective response to the first Bev regimen before progressing on Bev. Response rates for the regimen after progression on Bev were 19% (3/16) in the CWOB group and 23% (7/30) in the BAB group (P= 1). Twenty-five percent of the patients who responded to the first Bev regimen and 18% of those who did not respond to the first Bev regimen responded to the second Bev regimen (P= 0.72). The median PFS for patients in the CWOB group was 2.6 months (95% confidence interval [CI], 1.3–5 months), compared with 5.0 months (95% CI, 3.5–7.3 months) for patients in the BAB group (P= 0.01). Overall survival was similar, 9.4 months (95% CI, 5.0–12.0 months) for CWOB versus 8.6 months (95% CI, 5.8–15.5 months) for BAB (P= 0.19). One patient in the BAB group died of a bowel perforation.

Conclusions

In patients previously treated with Bev for recurrent ovarian cancer, the subsequent addition of Bev to cytotoxic chemotherapy increased the PFS compared with patients not receiving a second course of Bev, but did so without an impact on overall survival. The response to the first Bev regimen did not predict whether a patient would respond again to the next Bev regimen. Randomized, larger studies will have to be performed to confirm this observation.

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.

Significance of vascular endothelial growth factor in growth and peritoneal dissemination of ovarian cancer

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis which drives endothelial cell survival, proliferation, and migration while increasing vascular permeability. Playing an important role in the physiology of normal ovaries, VEGF has also been implicated in the pathogenesis of ovarian cancer. Essentially by promoting tumor angiogenesis and enhancing vascular permeability, VEGF contributes to the development of peritoneal carcinomatosis associated with malignant ascites formation, the characteristic feature of advanced ovarian cancer at diagnosis. In both experimental and clinical studies, VEGF levels have been inversely correlated with survival. Moreover, VEGF inhibition has been shown to inhibit tumor growth and ascites production and to suppress tumor invasion and metastasis. These findings have laid the basis for the clinical evaluation of agents targeting VEGF signaling pathway in patients with ovarian cancer. In this review, we will focus on VEGF involvement in the pathophysiology of ovarian cancer and its contribution to the disease progression and dissemination.

Targeted molecular therapies for ovarian cancer: an update and future perspectives (Review)

Identification of the potential gene expression profiles of epithelial ovarian cancer and the arrival of newly targeted therapies have advanced the strategies used for treatment of this disease. This review focuses on the design of ongoing and planned clinical trials and offers a synopsis of the English-language literature for preclinical and clinical targeted therapies for epithelial ovarian cancer. Among many targeted agents, a promising, novel class of targeted drugs for special patient populations expected to improve the effectiveness of current therapy include inhibitors of angiogenesis, poly (ADP ribose) polymerase (PARP) and DNA repair mechanisms. Inhibition of PARP or homologous recombination (HR) repair mediated by Chk1 (checkpoint kinase 1) would selectively sensitize p53 mutation, BRCAness phenotype (serous type ovarian cancer) or HNF (hepatocyte nuclear factor)-1β-overexpressing tumor cells (clear cell type ovarian cancer) to chemotherapeutic agents. The therapeutic response is likely to be limited to a targeted patient, but not to the broad population. This review discusses some of the key current developments and existing challenges.

CK2 inhibitor CX-4945 suppresses DNA repair response triggered by DNA-targeted anticancer drugs and augments efficacy: mechanistic rationale for drug combination therapy

Drug combination therapies are commonly used for the treatment of cancers to increase therapeutic efficacy, reduce toxicity, and decrease the incidence of drug resistance. Although drug combination therapies were originally devised primarily by empirical methods, the increased understanding of drug mechanisms and the pathways they modulate provides a unique opportunity to design combinations that are based on mechanistic rationale. We have identified protein kinase CK2 as a promising therapeutic target for combination therapy, because CK2 regulates not just one but many oncogenic pathways and processes that play important roles in drug resistance, including DNA repair, epidermal growth factor receptor signaling, PI3K/AKT/mTOR signaling, Hsp90 machinery activity, hypoxia, and interleukin-6 expression. In this article, we show that CX-4945, a clinical stage selective small molecule inhibitor of CK2, blocks the DNA repair response induced by gemcitabine and cisplatin and synergizes with these agents in models of ovarian cancer. Mechanistic studies show that the enhanced activity is a result of inactivation of XRCC1 and MDC1, two mediator/adaptor proteins that are essential for DNA repair and that require phosphorylation by CK2 for their function. These data position CK2 as a valid pharmacologic target for intelligent drug combinations and support the evaluation of CX-4945 in combination with gemcitabine and platinum-based chemotherapeutics in the clinical setting.

Utility of vascular endothelial growth factor inhibitors in the treatment of ovarian cancer: from concept to application

Despite recent advances in the management of ovarian cancer, it remains the most lethal gynecologic malignancy. Vascular endothelial growth factor (VEGF) has been shown to play a pivotal role in the progression of ovarian cancer leading to the eventual development of malignant ascites. On this basis, agents rendering VEGF ineffective by neutralizing VEGF (bevacizumab), blocking its receptors (aflibercept), or interfering with the postreceptor signaling pathways (sunitinib) provide us with the rational treatment options. These agents are generally used in combination with the standard chemotherapeutic drugs. Here, we discuss the basis of and the logic behind the use of these agents in the treatment of epithelial ovarian cancer, as well as their evaluation in different preclinical and clinical studies.

Platinum-based adjuvant chemotherapy on moderate- and high-risk stage I and II epithelian ovarian cancer patients. Long-term single institution experience and literature review

BACKGROUND

Although the optimal management of women with FIGO stages I and II epithelial ovarian cancer (EOC) is still controversial, platinum-based adjuvant chemotherapy (CT) is the mainstay of treatment. Suboptimal survival results have led to major efforts to identify prognostic factors, improve surgical staging and develop adjuvant therapies to improve patients' outcomes.

PATIENTS AND METHODS

We evaluate in a retrospective study clinical efficacy and the toxicity profile of a platinum-based adjuvant CT in FIGO stages I and II EOC treated at our institution from March 1984 to December 2006. Grade I FIGO stages IA-IB were excluded from the analysis. In the first period (1984-1997), patients received a platinum-based regimen without taxanes. In the second period from 1997 onwards, patients were treated with carboplatin and paclitaxel. Four to six cycles of adjuvant CT were administered. Potential predictive factors of efficacy and the role of paclitaxel addition were also analysed.

RESULTS

One hundred and fifty-eight patients (60 treated with paclitaxel) met inclusion criteria and were evaluable. Median age at diagnosis was 53.7 years (range 19-81) and most patients had an Eastern Cooperative Oncology Group performance status score (ECOG) of 0-1 (91.8%); 82.9% patients had pathological stage I and 17.1% pathological stage II. With a median follow up of 8.34 years (range 4.4-11.6), 103 patients (74.1%) were free of disease and 110 of them were alive (79.1%). Median relapse-free survival (RFS) and median overall survival (OS) had not been reached at the time of the analysis. No survival difference was found between paclitaxel and carboplatin combination or non-paclitaxel-containing regimens. Statistically significant prognostic factors for better RFS in the multivariate analysis were: ECOG 0 (p=0.023; HR 0.32; 95% CI 0.17-0.57); FIGO I stage (p<0.001; HR 0.30; 95% CI 0.15-0.58); I-II histological grade (p=0.005; HR 0.38; 95% CI 0.19-0.75); mucinous histology (p=0.013; HR 0.28; 95% CI 0.13-0.53); non-surgical adherences (p<0.002, HR 0.32; 95% CI 0.15-0.54); paracolic gutters inspection (p=0.033; HR 0.50; 95% CI 0.26-0.95) and liver surface biopsies (p=0.048; HR 0.64; 95% CI 0.41-0.98).Toxicity was generally mild and non-haematologic events were the most commonly found (62.9% of the total). The most frequent haematologic toxicities were neutropenia (41.7% in all grades, 9.5% grade 3-4) and anaemia (29.1% in all grades, 3.2% grade 3-4).

CONCLUSIONS

The long-term outcome of this series is comparable to the published evidence and reflects the limited activity of platinum-based CT in the adjuvant setting. The potential survival advantage of the addition of paclitaxel to carboplatin cannot be definitively answered due to the small number of patients, the limited follow-up and the retrospective nature of the study. More effective and specific treatments are clearly required, in particular for those patients with stage II and undifferentiated tumours. Quality of surgery entails prognostic value.

A uniform procedure for reimbursing the off-label use of antineoplastic drugs according to the value-for-money approach

National healthcare systems as well as local institutions generally reimburse numerous off-label uses of anticancer drugs, but an explicit framework for managing these payments is still lacking. As in the case of on-label uses, an optimal management of off-label uses should be aimed at a direct proportionality between cost and clinical benefit. Within this framework, assessing the incremental cost/effectiveness ratio becomes mandatory, and measuring the magnitude of the clinical benefit (e.g. gain in overall survival or progression-free survival) is essential.This paper discusses how the standard principles of cost-effectiveness and value-for-money can be applied to manage the reimbursement of off-label treatments in oncology. It also describes a detailed operational scheme to appropriately implement this aim. Two separate approaches are considered: a) a trial-based approach, which is designed for situations where enough information is available from clinical studies about the expected effectiveness of the off-label treatment; b) an individualized payment-by-results approach, which is designed for situations in which adequate information on effectiveness is lacking; this latter approach requires that each patient receiving off-label treatment is followed-up to determine individual outcomes and tailor the extent of payment to individual results.Some examples of application of both approaches are presented in detail, which have been extracted from a list of 184 off-label indications approved in 2010 by the Region of tuscany in italy. these examples support the feasibility of the two methods proposed.In conclusion, the scheme described in this paper represents an operational solution to an unsettled problem in the area of oncology drugs.

Maintenance therapy in ovarian cancer: Molecular basis and therapeutic approach

Ovarian cancer has the highest mortality rate among gynaecological tumours despite the fact that the majority of patients with advanced disease achieve complete remission after first-line surgery and chemotherapy. Unfortunately, disease recurrence occurs in the majority of patients and second-line treatments are not curative. Clearly, the persistence of dormant and drug-resistant cells after front-line treatments results in the inability to cure the disease. The identification of cancer-initiating cells or cancer stem cells as key players in the development of recurrence has opened up a novel field of research aimed at identifying additional innovative therapeutic approaches. Strategies of maintenance therapy to extend the survival of patients have been studied, but to date no overall survival benefit has been detected. Currently, numerous clinical trials have just been completed or are ongoing involving patients achieving a complete clinical response after first-line chemotherapy in order to evaluate the efficacy of different therapeutic approaches in terms of disease-free survival and overall survival. At the 2010 ASCO meeting, the first positive results of a phase III clinical trial in this setting were presented: bevacizumab (15 mg/kg i.v. every 21 days) added to first-line chemotherapy and continued for an additional 15 cycles was found to prolong progression-free survival of 3.8 months in comparison to 6 cycles of chemotherapy alone or only 6 cycles of chemotherapy plus bevacizumab. In addition, positive results were announced for a second phase III trial testing bevacizumab in the same setting, but at half dose. The final assessment of the overall clinical benefit and the approval of bevacizumab in maintenance therapy by regulatory agencies is expected to be positive, as are the final results of abagovomab phase III trial MIMOSA, another antibody-based therapy tested as a maintenance treatment for advanced ovarian cancer patients. Encouraging preliminary results confirming the safety profile and the immunogenic activity of abagovomab were presented at the last ASCO meeting. The final results are expected to be released in the first half of 2011.

Overexpression of tumor vascular endothelial growth factor A may portend an increased likelihood of progression in a phase II trial of bevacizumab and erlotinib in resistant ovarian cancer

PURPOSE

This phase II trial evaluated bevacizumab plus erlotinib in platinum-resistant ovarian cancer; exploratory biomarker analyses, including that of tumor vascular endothelial growth factor A (VEGF-A), were also done.

EXPERIMENTAL DESIGN

Forty heavily pretreated patients received erlotinib (150 mg/d orally) and bevacizumab (10 mg/kg i.v.) every 2 weeks until disease progression. Primary end points were objective response rate and response duration; secondary end points included progression-free survival (PFS), toxicity, and correlations between angiogenic protein levels, toxicity, and efficacy.

RESULTS

Grade 3 toxicities included skin rash (n = 6), diarrhea (n = 5), fatigue (n = 4), and hypertension (n = 3). Grade 4 toxicities were myocardial infarction (n = 1) and nasal septal perforation (n = 1). Only one grade 3 fistula and one grade 2 bowel perforation were observed. Nine (23.1%) of 39 evaluable patients had a response (median duration, 36.1+ weeks; one complete response), and 10 (25.6%) patients achieved stable disease, for a disease control rate of 49%. Median PFS was 4 months, and 6-month PFS was 30.8%. Biomarker analyses identified an association between tumor cell VEGF-A expression and progression (P = 0.03); for every 100-unit increase in the VEGF-A score, there was a 3.7-fold increase in the odds of progression (95% confidence interval, 1.1-16.6).

CONCLUSIONS

Bevacizumab plus erlotinib in heavily pretreated ovarian cancer patients was clinically active and well tolerated. Erlotinib did not seem to contribute to efficacy. Our study raises the intriguing possibility that high levels of tumor cell VEGF-A, capable of both autocrine and paracrine interactions, are associated with resistance to bevacizumab, emphasizing the complexity of the tumor microenvironment.

Addition of bevacizumab to weekly paclitaxel significantly improves progression-free survival in heavily pretreated recurrent epithelial ovarian cancer

OBJECTIVE

Weekly paclitaxel has been shown to be an effective cytotoxic regimen for recurrent epithelial ovarian cancer (EOC), and may act through inhibition of angiogenesis. Bevacizumab, a potent angiogenesis inhibitor, has also been shown to have activity in patients with EOC. Therefore, we sought to determine if the addition of bevacizumab to weekly paclitaxel led to an increased survival compared to weekly paclitaxel alone.

METHODS

A single institutional review was conducted for patients with recurrent EOC treated with weekly paclitaxel (60-70mg/m(2)) on days 1, 8, 15, and 22 of a 28day cycle and those treated with weekly paclitaxel and bevacizumab (10-15mg/kg on day 1 and 15). Response rates (RR) were calculated, and progression-free survival (PFS), and overall survival (OS) were compared using Kaplan-Meier survival analysis.

RESULTS

Twenty-nine patients treated with weekly paclitaxel and 41 patients treated with paclitaxel/bevacizumab were identified. The groups were similar in demographics, initial optimal cytoreduction, stage, histology, grade, platinum sensitivity, and median number of previous regimens (4 vs. 4, p=0.69).The overall response rate (ORR) was 63% (complete response (CR) 34% and partial response (PR) 29%) for paclitaxel/bevacizumab and 48% (CR 17% and PR 31%) for weekly paclitaxel (p=0.23). Improvement in PFS was seen in those treated with paclitaxel/bevacizumab in comparison to weekly paclitaxel alone (median PFS 13.2 vs. 6.2months, p<.01). There was a trend towards improved OS for paclitaxel/bevacizumab (median OS 20.6 vs. 9.1months; p=0.12). Toxicities were similar between the two regimens although more bowel perforations (2 vs. 0) were seen in the paclitaxel/bevacizumab group.

CONCLUSION

A significant increase in PFS with a trend towards improved OS was demonstrated in this heavily pretreated population treated with paclitaxel/bevacizumab as compared to weekly paclitaxel alone. This data should be helpful in guiding future trials to determine the optimal care for women with recurrent EOC.

Receptor mediated uptake of paclitaxel from a synthetic high density lipoprotein nanocarrier

The purpose of these studies was to determine the mechanism(s) whereby paclitaxel (PTX), is taken up by cancer cells, once encapsulated into synthetic/reconstituted high density lipoprotein (rHDL). The uptake of PTX was found to be facilitated by the scavenger receptor type B-1 (SR-B1) when drug-loaded rHDL particles were incubated with cells that express the SRB1 receptor. Studies with double-labeled, PTX containing rHDL nanoparticles showed that prostate cancer (PC-3) cells incorporated PTX primarily via a selective (SR-B1 type) uptake mechanism. In the presence of a 10-fold excess of plasma HDL, PTX uptake decreased to 30% of the control. These findings suggest that the incorporation of lipophilic drugs by cancer cells from rHDL nanoparticles is facilitated by a receptor mediated (SR-B1) mechanism.

The thrombospondin-1 mimetic ABT-510 increases the uptake and effectiveness of cisplatin and paclitaxel in a mouse model of epithelial ovarian cancer

Epithelial ovarian cancer (EOC) comprises approximately 90% of ovarian cancers and arises from the surface epithelium. Typical treatment of EOC involves cytoreductive surgery combined with chemotherapy. More recent therapies have targeted the tumor vasculature using antiangiogenic compounds such as thrombospondin-1 (TSP-1). TSP-1 mimetic peptides such as ABT-510 have been created and have been in various clinical trials. We have previously shown that ABT-510 reduces abnormal vasculature associated with tumor tissue and increases the presence of mature blood vessels. It has been hypothesized that treatment with antiangiogenic compounds would allow increased delivery of cytotoxic agents and enhance treatment. In this study, we evaluated the potential role of ABT-510 and various chemotherapeutics (cisplatin and paclitaxel) on tumor progression, angiogenesis, and the benefits of combinational treatments on tissue uptake and perfusion using an orthotopic syngeneic mouse model of EOC. Animals were treated with ABT-510 (100 mg/kg per day) alone or in combination with cisplatin (2 mg/kg per 3 days) or paclitaxel (10 mg/kg per 2 days) at 60 days after tumor induction. Radiolabeled and fluorescently labeled paclitaxel demonstrated a significant increase in tumor uptake after ABT-510 treatment. Combined treatment with ABT-510 and cisplatin or paclitaxel resulted in a significant increase in tumor cell and tumor endothelial cell apoptosis and a resultant decrease in ovarian tumor size. Combined treatment also regressed secondary lesions and eliminated the presence of abdominal ascites. The results from this study show that through vessel normalization, ABT-510 increases uptake of chemotherapy drugs and can induce regression of advanced ovarian cancer.

Practical considerations in ovarian cancer chemotherapy

Epithelial ovarian cancer remains the most lethal gynecologic malignancy despite advances in treatment. The standard management generally involves a combination of surgical tumor debulking and chemotherapy. Over the decades, chemotherapy for ovarian cancer has evolved and currently involves a combination of intravenous platinum and taxane chemotherapy. Over the past decade, three randomized phase III trials have been reported, and all have demonstrated a significant survival advantage for intraperitoneal compared with intravenous chemotherapy. However, there are potential barriers and controversies related to the administration of intraperitoneal chemotherapy in ovarian cancer patients. In this review, we discuss the evolution and current management considerations of chemotherapy for the treatment of 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.

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.

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.

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.

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.

Carboplatin—gemcitabine in the therapy of advanced ovarian cancer: dose reduction consideration

Carboplatin—gemcitabine doublet is an important therapeutic option for patients with both previously treated and untreated ovarian cancer (OC). At the currently recommended dosing, its main toxicity is hematological, consisting of thrombocytopenia, neutropenia, including febrile neutropenia, and/or anemia. The use of platelet transfusions, G-CSF and/ or packed red blood cells is often necessary, in order to avoid treatment delays or omission of doses. We report here on the high efficacy of lower doses of gemcitabine at 750 mg/m2 on days 1 and 8 in combination with carboplatin AUC = 4 on day 1, repeated in 21-day cycles, in a small series of patients with advanced/metastatic OC. Using the above dose regimen, durable complete remissions were achieved in all patients in our cohort within 9—12 weeks, with no growth factor support, and no transfusions of blood components being necessary. We believe that lowering the doses of both carboplatin and gemcitabine from the start of therapy would ensure their timely delivery and steady-state plasma drug levels. In conclusion, administration of carboplatin AUC = 4 and gemcitabine 750 mg/m2 appears to be a safe and effective combination for the therapy of advanced/metastatic OC, with clinically tolerable hematological toxicity.

Synthetic lethal RNAi screening identifies sensitizing targets for gemcitabine therapy in pancreatic cancer

Background

Pancreatic cancer retains a poor prognosis among the gastrointestinal cancers. It affects 230,000 individuals worldwide, has a very high mortality rate, and remains one of the most challenging malignancies to treat successfully. Treatment with gemcitabine, the most widely used chemotherapeutic against pancreatic cancer, is not curative and resistance may occur. Combinations of gemcitabine with other chemotherapeutic drugs or biological agents have resulted in limited improvement.

Methods

In order to improve gemcitabine response in pancreatic cancer cells, we utilized a synthetic lethal RNAi screen targeting 572 known kinases to identify genes that when silenced would sensitize pancreatic cancer cells to gemcitabine.

Results

Results from the RNAi screens identified several genes that, when silenced, potentiated the growth inhibitory effects of gemcitabine in pancreatic cancer cells. The greatest potentiation was shown by siRNA targeting checkpoint kinase 1 (CHK1). Validation of the screening results was performed in MIA PaCa-2 and BxPC3 pancreatic cancer cells by examining the dose response of gemcitabine treatment in the presence of either CHK1 or CHK2 siRNA. These results showed a three to ten-fold decrease in the EC₅₀ for CHK1 siRNA-treated cells versus control siRNA-treated cells while treatment with CHK2 siRNA resulted in no change compared to controls. CHK1 was further targeted with specific small molecule inhibitors SB 218078 and PD 407824 in combination with gemcitabine. Results showed that treatment of MIA PaCa-2 cells with either of the CHK1 inhibitors SB 218078 or PD 407824 led to sensitization of the pancreatic cancer cells to gemcitabine.

Conclusion

These findings demonstrate the effectiveness of synthetic lethal RNAi screening as a tool for identifying sensitizing targets to chemotherapeutic agents. These results also indicate that CHK1 could serve as a putative therapeutic target for sensitizing pancreatic cancer cells to gemcitabine.