A randomised, double-blind, phase II study of two doses of pemetrexed in the treatment of platinum-resistant, epithelial ovarian or primary peritoneal cancer

Optimizing regional chemotherapy for epithelial ovarian cancer

AIM

The response with intravenous chemotherapy using cisplatin and paclitaxel in patients with advanced ovarian cancer is often substantial. However, this regression of the malignancy is not durable, and a majority of patients succumb to this disease process. It is possible that alternative types of chemotherapy and alternative routes of chemotherapy administration can improve the results of treatment and perhaps, reduce the morbidity and mortality that patients experience.

METHODS

Regional chemotherapy treatments previously presented in the ovarian cancer literature were reviewed and critically analyzed. New methods for chemotherapy delivery for both advanced primary and recurrent ovarian cancer were reviewed. This included hyperthermic intraperitoneal chemotherapy (HIPEC), early postoperative intraperitoneal chemotherapy (EPIC), and normothermic intraperitoneal chemotherapy (NIPEC) long-term.

RESULTS

An important addition to perioperative chemotherapy delivery is the simultaneous use of heat with intraperitoneal drug delivery after a complete cytoreductive surgery. Drugs to be considered for HIPEC are cisplatin, gemcitabine, and melphalan. For EPIC, chemotherapy agents to consider include paclitaxel, pemetrexed, gemcitabine, and liposomal doxorubicin. For NIPEC, paclitaxel is the drug of choice usually combined with a systemic agent as bidirectional chemotherapy. Also, pemetrexed, gemcitabine, and liposomal doxorubicin are drugs to be considered for NIPEC in phase I/II trials.

CONCLUSIONS

Innovative regimens of regional chemotherapy may improve the outcome of patients with advanced ovarian cancer. These chemotherapy treatments must be integrated with complete cytoreductive surgery and the availability of peritoneal access for repeated delivery of chemotherapy solutions.

Platinum-Pemetrexed Chemotherapy for Recurrent Ovarian Cancer (ROC): A Single Center Experience

In this retrospective analysis of 36 patients with recurrent ovarian cancer (ROC) treated with platinum pemetrexed doublet ± bevacizumab, the median age was 54.5 years (47-60) and 33 (91.7%) had serous histology. The overall response rate [ORR = complete (CR)+partial (PR) response] was 83.3%. At a median follow-up of 16 months, the median PFS was 13.8 months (95% CI: 10.849-20.580) and median OS 30.6 months, (95% CI: 21.46 months-NR). The incidence of Grade 3/4 anemia, thrombocytopenia, neutropenia and non-hematological toxicity was 19.4%, 3.9%, 16.6%, and 8.3%. Platinum pemetrexed chemotherapy in ROC is safe and effective treatment option.

Translational Theragnosis of Ovarian Cancer: where do we stand?

BACKGROUND

Ovarian cancer is the second most common gynecologic malignancy, accounting for approximately 220,000 deaths annually worldwide. Despite radical surgery and initial high response rates to platinum- and taxane-based chemotherapy, most patients experience a relapse, with a median progression-free survival of only 18 months. Overall survival is approximately 30% at 5 years from the diagnosis. In comparison, patients out from breast cancer are more than 80 % after ten years from the disease discovery. In spite of a large number of published fundamental and applied research, and clinical trials, novel therapies are urgently needed to improve outcomes of the ovarian cancer. The success of new drugs development in ovarian cancer will strongly depend on both fully genomic disease characterization and, then, availability of biomarkers able to identify women likely to benefit from a given new therapy.

METHODS

In this review, the focus is given to describe how complex is the diseases under the simple name of ovarian cancer, in terms of cell tumor types, histotypes, subtypes, and specific gene mutation or differently expressed in the tumor with respect the healthy ovary. The first- and second-line pharmacological treatment clinically used over the last fifty years are also described. Noteworthy achievements in vitro and in vivo tested new drugs are also summarized. Recent literature related to up to date ovarian cancer knowledge, its detection by biomarkers and chemotherapy was searched from several articles on Pubmed, Google Scholar, MEDLINE and various Governmental Agencies till April 2019.

RESULTS

The papers referenced by this review allow a deep analysis of status of the art in the classification of the several types of ovarian cancer, the present knowledge of diagnosis based on biomarkers and imaging techniques, and the therapies developed over the past five decades.

CONCLUSION

This review aims at stimulating more multi-disciplinary efforts to identify a panel of novel and more specific biomarkers to be used to screen patients for a very early diagnosis, to have prognosis and therapy efficacy indications. The desired final goal would be to have available tools allowing to reduce the recurrence rate, increase both the disease progression free interval and of course the overall survival at five years from the diagnosis that today is still very low.

Evaluation of a Simple and Safe Tumor Drilling Technique to Potentiate the Effect of Intraperitoneal Chemotherapy in the Treatment of Recurrent Epithelial Ovarian, Tubal, and Peritoneal Cancer: A Matched Retrospective Cohort Study

Frontline intraperitoneal chemotherapy (IPCT) in the treatment of epithelial ovarian cancer has been well established. However, the role of second-line IPCT is yet to be confirmed. With a view to implementing IPCT to treat recurrent disease, a prerequisite is to perform a cytoreductive procedure to minimize residual tumor size. However, the role of cytoreductive procedure is still in debate due to a higher chance of complications. A matched retrospective cohort study was conducted. From 2008 to 2015, we adopted a relatively simple and safe tumor drilling technique to maximize tumor exposure to second-line IPCT. Patients who received tumor drilling followed by second-line IPCT constituted the cohort group. Concurrently, patients who received standard second-line systemic chemotherapy were selected as the comparison group. After propensity score matching, 85 patients in each group entered into the final analysis. The median progression-free survival was 7.3 months (95% confidence interval [CI], 6.2-7.8) for the cohort group versus 4.1 months (95% CI, 4.0-4.3) for the comparison group (hazard ratio = 0.25 [95% CI, 0.17-0.36]; P < .001, by log-rank test). The median overall survival was 33.6 months (32.1-36.6) for the cohort group versus 25.9 months (20.5-26.9) for the comparison group (hazard ratio = 0.33 [95% CI, 0.23-0.48]; P < .001, by log-rank test). Toxicities in the cohort group were not different from those that were published in reports of IPCT for ovarian cancer. The most commonly observed toxicity was gastrointestinal origin (51.7%), and it may be attributed to the intraperitoneal pharmacokinetic clearance of cisplatin and taxol and we also discussed the mechanism of gastrointestinal toxicity. Tumor drilling followed by second-line IPCT may confer a survival advantage over standard second-line systemic chemotherapy in the treatment of recurrent ovarian cancer.

One-Carbon Metabolism: Biological Players in Epithelial Ovarian Cancer

Metabolism is deeply involved in cell behavior and homeostasis maintenance, with metabolites acting as molecular intermediates to modulate cellular functions. In particular, one-carbon metabolism is a key biochemical pathway necessary to provide carbon units required for critical processes, including nucleotide biosynthesis, epigenetic methylation, and cell redox-status regulation. It is, therefore, not surprising that alterations in this pathway may acquire fundamental importance in cancer onset and progression. Two of the major actors in one-carbon metabolism, folate and choline, play a key role in the pathobiology of epithelial ovarian cancer (EOC), the deadliest gynecological malignancy. EOC is characterized by a cholinic phenotype sustained via increased activity of choline kinase alpha, and via membrane overexpression of the alpha isoform of the folate receptor (FRα), both of which are known to contribute to generating regulatory signals that support EOC cell aggressiveness and proliferation. Here, we describe in detail the main biological processes associated with one-carbon metabolism, and the current knowledge about its role in EOC. Moreover, since the cholinic phenotype and FRα overexpression are unique properties of tumor cells, but not of normal cells, they can be considered attractive targets for the development of therapeutic approaches.

Proteomic and Bioinformatic Studies for the Characterization of Response to Pemetrexed in Platinum Drug Resistant Ovarian Cancer

Proteomics and bioinformatics are a useful combined technology for the characterization of protein expression level and modulation associated with the response to a drug and with its mechanism of action. The folate pathway represents an important target in the anticancer drugs therapy. In the present study, a discovery proteomics approach was applied to tissue samples collected from ovarian cancer patients who relapsed after the first-line carboplatin-based chemotherapy and were treated with pemetrexed (PMX), a known folate pathway targeting drug. The aim of the work is to identify the proteomic profile that can be associated to the response to the PMX treatment in pre-treatement tissue. Statistical metrics of the experimental Mass Spectrometry (MS) data were combined with a knowledge-based approach that included bioinformatics and a literature review through ProteinQuest™ tool, to design a protein set of reference (PSR). The PSR provides feedback for the consistency of MS proteomic data because it includes known validated proteins. A panel of 24 proteins with levels that were significantly different in pre-treatment samples of patients who responded to the therapy vs. the non-responder ones, was identified. The differences of the identified proteins were explained for the patients with different outcomes and the known PMX targets were further validated. The protein panel herein identified is ready for further validation in retrospective clinical trials using a targeted proteomic approach. This study may have a general relevant impact on biomarker application for cancer patients therapy selection.

Human Thymidylate Synthase Inhibitors Halting Ovarian Cancer Growth

Human thymidylate synthase (hTS) has an important role in DNA biosynthesis, thus it is essential for cell survival. TS is involved in the folate pathways, specifically in the de novo pyrimidine biosynthesis. Structure and functions are intimately correlated, account for cellular activity and, in a broader view, with in vivo mechanisms. hTS is a target for anticancer agents, some of which are clinical drugs. The understanding of the detailed mechanism of TS inhibition by currently used drugs and of the interaction with the mechanism of action of other anticancer agents can suggest new perspective of TS inhibition able to improve the anticancer effect and to overcome drug resistance. TS-targeting drugs in therapy today are inhibitors that bind at the active site and that mostly resemble the substrates. Nonsubstrate analogs offer an opportunity for allosteric binding and novel mode of inhibition in the cancer cells. This chapter illustrates the relationship among the large number of hTS actions at molecular and clinical levels, its role as a target for ovarian cancer therapy, in particular in cases of overexpression of hTS and other folate proteins such as those induced by platinum drug treatments, and address the potential combination of TS inhibitors with other suitable anticancer agents.

Prognostic values of excision repair cross-complementing genes mRNA expression in ovarian cancer patients

Excision repair cross-complementing (ERCC) genes, key components of the nucleotide excision repair pathway, are regarded as crucial factors for DNA repair capacity. Previous studies have investigated prognostic values of ERCC genes in a number of malignancies. However, the relationship between ERCC genes and prognosis of ovarian cancer patients remains controversial. Therefore, in the current study, we systematically analyze the prognostic values of ERCC genes in ovarian cancer by the Kaplan-Meier plotter, which includes updated gene expression data and survival information of 1656 ovarian cancer patients. Our results showed that high expression of ERCC1 and ERCC8 mRNA was related to a worse overall survival among ovarian cancer patients, especially in late stage and poor differentiation serous ovarian patients. Increased ERCC4 mRNA expression indicated a better overall survival among serous ovarian cancer patients. The other ERCC genes were uncorrelated with prognosis in ovarian cancer. These results indicate that some ERCC genes have critical prognostic values in ovarian cancer.

The role of pemetrexed in recurrent epithelial ovarian cancer: A scoping review

Ovarian cancer is the leading cause of mortality among gynecologic malignancies, with most cases diagnosed at an advanced stage. Despite an initial response, most develop a recurrence and subsequent resistance to standard therapies. Pemetrexed (AlimtaTM) is a new generation multi-targeted antifolate initially approved for the treatment of malignant pleural mesothelioma. In recent years, it has shown promise in the treatment of recurrent epithelial ovarian cancer. In this review, we outline the current literature and discuss the future of pemetrexed in the setting of recurrent epithelial ovarian cancer.

Chemotherapy for epithelial ovarian, fallopian tube and primary peritoneal cancer

Chemotherapy plays a key role in the management of women with epithelial ovarian, fallopian tube and primary peritoneal cancer (EOC). Platinum- and taxane-based regimens are the standard of care for adjuvant treatment in early-stage EOC and first-line therapy for advanced stage disease. Efforts to define the optimal scheduling, timing and route of administration are ongoing. The majority of women with EOC will develop recurrent disease, and treatment options for these women are depend on the time that has elapsed from first-line therapy. Platinum-based doublet chemotherapy is preferred for women with platinum-sensitive recurrent cancer. In platinum-resistant relapsed EOC, options are much more limited, and careful consideration of symptoms, performance status, anticipated toxicity and quality of life is essential when recommending chemotherapy for these women.

Precision targeted therapy of ovarian cancer

The review is aimed at describing modern approaches to detection as well as precision and personalized treatment of ovarian cancer. Modern methods and future directions of nanotechnology-based targeted and personalized therapy are discussed.

Role of the folate receptor in ovarian cancer treatment: evidence, mechanism, and clinical implications

Folate can be transported into the cell by the reduced folate carrier (RFC), the proton-coupled folate transporter (PCFT), or the folate receptor (FR), of which various isoforms exist. While the RFC and PCFT are expressed by many normal cells, the FR is present only in a small proportion of normal tissues. In these tissues, the FR expression level is often low and restricted to the apical surface of polarized epithelial cells. In contrast, FR is expressed on the blood-accessible basal and lateral membranes of many types of epithelial cancer. Considering that FR is expressed in few nonmalignant cell types on luminal membranes generally not accessible for molecules transported in the blood, FR is considered a promising antitumor target. As FR expression seems associated with tumor progression and prognosis, anticancer therapies targeting FR are currently being developed, such as farletuzumab (Morphotek, Exton, PA, USA), IMGN853 (ImmunoGen, Waltham, MA, USA), vintafolide, and EC1456 (both Endocyte Inc., West Lafayette, IN, USA). FR expression could be used as a response-predictive biomarker for these treatments. The ability to identify patients and treat them with an effective therapy based on the known expression of the tumor marker would, indeed, be the next step in predictive medicine for these patients. This review summarizes the role of FR in ovarian cancer and the value of FR as a prognostic biomarker for ovarian cancer and a response-predictive biomarker for folate-targeted therapeutics.

Inside the biochemical pathways of thymidylate synthase perturbed by anticancer drugs: Novel strategies to overcome cancer chemoresistance

Our current understanding of the mechanisms of action of antitumor agents and the precise mechanisms underlying drug resistance is that these two processes are directly linked. Moreover, it is often possible to delineate chemoresistance mechanisms based on the specific mechanism of action of a given anticancer drug. A more holistic approach to the chemoresistance problem suggests that entire metabolic pathways, rather than single enzyme targets may better explain and educate us about the complexity of the cellular responses upon cytotoxic drug administration. Drugs, which target thymidylate synthase and folate-dependent enzymes, represent an important therapeutic arm in the treatment of various human malignancies. However, prolonged patient treatment often provokes drug resistance phenomena that render the chemotherapeutic treatment highly ineffective. Hence, strategies to overcome drug resistance are primarily designed to achieve either enhanced intracellular drug accumulation, to avoid the upregulation of folate-dependent enzymes, and to circumvent the impairment of DNA repair enzymes which are also responsible for cross-resistance to various anticancer drugs. The current clinical practice based on drug combination therapeutic regimens represents the most effective approach to counteract drug resistance. In the current paper, we review the molecular aspects of the activity of TS-targeting drugs and describe how such mechanisms are related to the emergence of clinical drug resistance. We also discuss the current possibilities to overcome drug resistance by using a molecular mechanistic approach based on medicinal chemistry methods focusing on rational structural modifications of novel antitumor agents. This paper also focuses on the importance of the modulation of metabolic pathways upon drug administration, their analysis and the assessment of their putative roles in the networks involved using a meta-analysis approach. The present review describes the main pathways that are modulated by TS-targeting anticancer drugs starting from the description of the normal functioning of the folate metabolic pathway, through the protein modulation occurring upon drug delivery to cultured tumor cells as well as cancer patients, finally describing how the pathways are modulated by drug resistance development. The data collected are then analyzed using network/netwire connecting methods in order to provide a wider view of the pathways involved and of the importance of such information in identifying additional proteins that could serve as novel druggable targets for efficacious cancer therapy.

Potential application of curcumin and its analogues in the treatment strategy of patients with primary epithelial ovarian cancer

Recent findings on the molecular basis of ovarian cancer development and progression create new opportunities to develop anticancer medications that would affect specific metabolic pathways and decrease side systemic toxicity of conventional treatment. Among new possibilities for cancer chemoprevention, much attention is paid to curcumin—A broad-spectrum anticancer polyphenolic derivative extracted from the rhizome of Curcuma longa L. According to ClinicalTrials.gov at present there are no running pilot studies, which could assess possible therapeutic benefits from curcumin supplementation to patients with primary epithelial ovarian cancer. Therefore, the goal of this review was to evaluate potential preclinical properties of curcumin and its new analogues on the basis of in vivo and in vitro ovarian cancer studies. Curcumin and its different formulations have been shown to display multifunctional mechanisms of anticancer activity, not only in platinum-resistant primary epithelial ovarian cancer, but also in multidrug resistant cancer cells/xenografts models. Curcumin administered together with platinum-taxane chemotherapeutics have been reported to demonstrate synergistic effects, sensitize resistant cells to drugs, and decrease their biologically effective doses. An accumulating body of evidence suggests that curcumin, due to its long-term safety and an excellent profile of side effects should be considered as a beneficial support in ovarian cancer treatment strategies, especially in patients with platinum-resistant primary epithelial recurrent ovarian cancer or multidrug resistant disease. Although the prospect of curcumin and its formulations as anticancer agents in ovarian cancer treatment strategy appears to be challenging, and at the same time promising, there is a further need to evaluate its effectiveness in clinical studies.

Development of nanoscale approaches for ovarian cancer therapeutics and diagnostics

Ovarian cancer is the deadliest of all gynecological cancers and the fifth leading cause of death due to cancer in women. This is largely due to late-stage diagnosis, poor prognosis related to advanced-stage disease, and the high recurrence rate associated with development of chemoresistance. Survival statistics have not improved significantly over the last three decades, highlighting the fact that improved therapeutic strategies and early detection require substantial improvements. Here, we review and highlight nanotechnology-based approaches that seek to address this need. The success of Doxil, a PEGylated liposomal nanoencapsulation of doxorubicin, which was approved by the FDA for use on recurrent ovarian cancer, has paved the way for the current wave of nanoparticle formulations in drug discovery and clinical trials. We discuss and summarize new nanoformulations that are currently moving into clinical trials and highlight novel nanotherapeutic strategies that have shown promising results in preclinical in vivo studies. Further, the potential for nanomaterials in diagnostic imaging techniques and the ability to leverage nanotechnology for early detection of ovarian cancer are also discussed.

Treatment options in recurrent ovarian cancer: latest evidence and clinical potential

Ovarian cancer (OC) is the fifth most common cause of cancer death in women. Although significant progress has been made in the treatment of OC, the majority of patients experience disease recurrence and receive second-line and sometimes several lines of treatment. Here we review the options available for the treatment of recurrent disease and discuss how different agents are selected, combined and offered in a rationale sequence in the context of multidisciplinary care. We reviewed published work between 1990 and 2013 and meeting abstracts related to the use of chemotherapy and surgery in patients with recurrent ovarian cancer. We discuss treatment regimens, efficacy endpoints and safety profiles of the different therapies. Platinum-based drugs are the most active agents and are selected on the basis of a probability of response to retreatment. Nonplatinum-based chemotherapy regimens are usually given in the 'platinum-resistant' setting and have a modest effect on outcome. Molecular targeted therapy of ovarian cancer given alone or integrated with chemotherapy is showing promising results. Many patients are now receiving more than one line of therapy for recurrent disease, usually platinum based until platinum resistance emerges. The sequential use of chemotherapy regimens and the incorporation of molecularly targeted treatments, either alone or in combination with chemotherapy, have over the last decade significantly extended the median survival of patients with ovarian cancer.

Pemetrexed for ovarian cancer: a systematic review of the published literature and a consecutive series of patients treated in a nonclinical trial setting

Objective

To gain a better understanding of the role of pemetrexed in ovarian cancer patients, we conducted a systematic review of the published literature and evaluated a consecutive, single-institution series of non-study pemetrexed-treated patients.

Methods/Results

Thirteen published articles met this study's eligibility criteria, providing a total of 376 unique and evaluable ovarian cancer patients. This systematic review demonstrated tumor response rates with pemetrexed-based chemotherapy from 9 to 84%; the agent appeared to be well tolerated. Similarly, 13 consecutive patients with ovarian, fallopian tube, or primary peritoneal cancer were treated with pemetrexed at the Mayo Clinic, Rochester, Minn., USA, from 2004 through 2013. The median number of previous chemotherapy regimens was 4; most patients received single-agent pemetrexed (n = 9). Patients received a median of 2 cycles of pemetrexed-based chemotherapy; 1 patient received 10 cycles (7 months’ worth) with treatment ongoing at the time of this report. The median survival from the start of pemetrexed was 4.8 months (95% confidence interval 1.2, 15 months). Two patients manifested a 50% drop in Ca-125 levels. Again, pemetrexed was relatively well tolerated.

Conclusion

Pemetrexed has antineoplastic activity in patients with ovarian cancer – even among those who have been heavily pretreated – and therefore merits further study.

Pemetrexed and cisplatin for the treatment of advanced, persistent, or recurrent carcinoma of the cervix: a limited access phase II trial of the gynecologic oncology group

PURPOSE

To estimate the antitumor activity of pemetrexed and cisplatin with objective tumor response (partial and complete) in patients with advanced, persistent, or recurrent carcinoma of the cervix and to determine the nature and degree of toxicity of this regimen. Secondarily, this study will determine the effects of this regimen on progression-free survival and overall survival.

PATIENTS AND METHODS

Eligible, consenting patients received pemetrexed 500 mg/m(2) and cisplatin 50 mg/m(2) intravenously repeated every 21 days until disease progression or adverse events prohibited further therapy. Patients received no prior therapeutic chemotherapy, except when administered concurrently with primary radiation therapy. Subsequent doses were adjusted according to observed toxicity and protocol guidelines. Adverse events were assessed with Common Terminology Criteria for Adverse Events v 3.0. The primary measure of efficacy was tumor response according to Response Evaluation Criteria in Solid Tumors. The study was stratified by prior radiation therapy.

RESULTS

From September 2008 to November 2011, 55 patients were enrolled by five Gynecologic Oncology Group member institutions; of those, 54 patients were eligible and assessable. The regimen was well tolerated with 26% receiving more than nine cycles. The most common greater than grade 2 toxicities were neutropenia 35%, leukopenia 28%, and metabolic 28%. The overall response rate was 31% (one complete and 16 partial). The median progression-free survival was 5.7 months, and overall survival was 12.3 months.

CONCLUSION

Pemetrexed in combination with cisplatin demonstrates activity in the treatment of advanced, persistent, or recurrent carcinoma of the cervix.

Patient selection and targeted treatment in the management of platinum-resistant ovarian cancer

Ovarian cancer (OC) has the highest mortality rate of any gynecologic cancer, and patients generally have a poor prognosis due to high chemotherapy resistance and late stage disease diagnosis. Platinum-resistant OC can be treated with cytotoxic chemotherapy such as paclitaxel, topotecan, pegylated liposomal doxorubicin, and gemcitabine, but many patients eventually relapse upon treatment. Fortunately, there are currently a number of targeted therapies in development for these patients who have shown promising results in recent clinical trials. These treatments often target the vascular endothelial growth factor pathway (eg, bevacizumab and aflibercept), DNA repair mechanisms (eg, iniparib and olaparib), or they are directed against folate related pathways (eg, pemetrexed, farletuzumab, and vintafolide). As many targeted therapies are only effective in a subset of patients, there is an increasing need for the identification of response predictive biomarkers. Selecting the right patients through biomarker screening will help tailor therapy to patients and decrease superfluous treatment to those who are biomarker negative; this approach should lead to improved clinical results and decreased toxicities. In this review the current targeted therapies used for treating platinum-resistant OC are discussed. Furthermore, use of prognostic and response predictive biomarkers to define OC patient populations that may benefit from specific targeted therapies is also highlighted.

Current status of bevacizumab in advanced ovarian cancer

Ovarian cancer is the most lethal gynecological cancer, mainly because of the delay in diagnosis. Recently, much effort has been put into investigating and introducing novel targeted agents into clinical practice, with the aim of improving prognosis and quality of life. Angiogenesis is a possible target. The aim of this review is to investigate the most common molecular pathways of angiogenesis, which have provided novel targets for tailored therapy in patients with ovarian cancer. These therapeutic strategies include monoclonal antibodies and tyrosine-kinase inhibitors. These drugs have as molecular targets vascular endothelial growth factor, vascular endothelial growth factor receptors, platelet-derived growth factor, fibroblast growth factor, and angiopoietin. Bevacizumab was investigated in several Phase III studies, with interesting results. Today, there is strong evidence for introducing bevacizumab in the treatment of patients with advanced and recurrent ovarian cancer. Nevertheless, further investigations and large clinical trials are needed to understand the safety and effectiveness of bevacizumab, the optimal duration and timing of treatment, and activity in association with other chemotherapeutic and targeted agents. It also is necessary to identify biologic factors predictive of efficacy to choose the most appropriate antiangiogenic agent in the integrated treatment of epithelial ovarian cancer.

Clinical utility of targeted treatments in the management of epithelial ovarian cancer

Epithelial ovarian cancer is typically found in its advanced stages, where a combination of surgical debulking and platinum/taxane-based chemotherapy is recommended. Although over 70%-80% of patients achieve remission, a significant proportion develop recurrence of their disease. Additional cytotoxic chemotherapy, as well as surgery, is typically used to manage disease recurrence. Therapies that target specific pathways in cancer cells are rapidly developing in the laboratory and are increasingly being studied in patients with ovarian cancer. We review the current status of novel therapies in the management of epithelial ovarian cancer.

Comparison of ERCC1/XPF genetic variation, mRNA and protein levels in women with advanced stage ovarian cancer treated with intraperitoneal platinum

OBJECTIVE

Approximately 20% of patients receiving platinum-based chemotherapy for epithelial ovarian cancer (EOC) are refractory or develop early recurrence. Identifying these patients early could reduce treatment-associated morbidity and allow quicker transfer to more effective therapies. Much attention has focused on ERCC1 as a potential predictor of response to therapy because of its essential role in the repair of platinum-induced DNA damage. The purpose of this study was to accurately measure protein levels of ERCC1 and its essential binding partner XPF from patients with EOC treated with platinum-based therapy and determine if protein levels correlate with mRNA levels, patient genotypes or clinical outcomes.

METHODS

ERCC1 and XPF mRNA and protein levels were measured in frozen EOC specimens from 41 patients receiving intraperitoneal platinum-based chemotherapy using reverse transcription polymerase chain reaction and western blots. Genotypes of common nucleotide polymorphisms were also analyzed. Patient outcomes included progression free (PFS) and overall survival (OS).

RESULTS

Expression of ERCC1 and XPF were tightly correlated with one another at both the mRNA and protein level. However, the mRNA and protein levels of ERCC1 were not positively correlated. Likewise, none of the SNPs analyzed correlated with ERCC1 or XPF protein levels. There was an inverse correlation between mRNA levels and patient outcomes.

CONCLUSION

Neither genotype nor mRNA levels are predictive of protein expression. Despite this, low ERCC1 mRNA significantly correlated with improved PFS and OS.

Phase I trial of intraperitoneal pemetrexed, cisplatin, and paclitaxel in optimally debulked ovarian cancer

PURPOSE

This phase I trial evaluated intraperitoneal (i.p.) pemetrexed, cisplatin, and paclitaxel in optimally debulked ovarian cancer.

EXPERIMENTAL DESIGN

Dose escalation of day 1 i.p. pemetrexed accrued three patients to each of five dose levels (60-1,000 mg/m(2)), along with day 2 i.p. cisplatin (75 mg/m(2)) and day 8 i.p. paclitaxel (60 mg/m(2)). The goals were to determine maximum tolerated dose (MTD), 18-month progression-free survival (PFS), and pharmacokinetics of i.p. pemetrexed.

RESULTS

Cycles, given every 21 days, had an 80% 6-cycle completion rate. There was minimal grade III toxicity in the first 4 dose levels and remarkably an almost complete absence of peripheral neuropathy and alopecia. At the highest dose level, two of three patients experienced ≥ grade III and dose-limiting toxicity (DLT; hematologic, infection, gastrointestinal). There was a pharmacokinetic advantage for i.p. pemetrexed with an intraperitoneal:plasma area under the concentration-time curve ratio of 13-fold. Neither analysis of pharmacokinetic nor homocysteine levels explains the unexpected severity of toxicity in those two patients. On the basis of plasma C(24h) levels, the 42 cycles at ≥ 500 mg/m(2) i.p. pemetrexed without DLT, the MTD appears to be 500 mg/m(2). Median PFS is 30.1 months; 18-month PFS is 78.6% (median follow-up 22.4 months).

CONCLUSIONS

This i.p.-only regimen in front-line ovarian cancer is feasible with PFS in line with recent literature. We suggest phase II trials of this regimen in this population with i.p. pemetrexed at 500 mg/m(2). The favorable toxicity profile at doses <1,000 mg/m(2), which needs to be confirmed, appears to compare well with standard combination i.v./i.p. platinum/taxane chemotherapy in this disease.

Protein-protein interface-binding peptides inhibit the cancer therapy target human thymidylate synthase

Human thymidylate synthase is a homodimeric enzyme that plays a key role in DNA synthesis and is a target for several clinically important anticancer drugs that bind to its active site. We have designed peptides to specifically target its dimer interface. Here we show through X-ray diffraction, spectroscopic, kinetic, and calorimetric evidence that the peptides do indeed bind at the interface of the dimeric protein and stabilize its di-inactive form. The "LR" peptide binds at a previously unknown binding site and shows a previously undescribed mechanism for the allosteric inhibition of a homodimeric enzyme. It inhibits the intracellular enzyme in ovarian cancer cells and reduces cellular growth at low micromolar concentrations in both cisplatin-sensitive and -resistant cells without causing protein overexpression. This peptide demonstrates the potential of allosteric inhibition of hTS for overcoming platinum drug resistance in ovarian cancer.

Overcoming platinum resistance in ovarian carcinoma

IMPORTANCE OF THE FIELD

Ovarian cancer remains a deadly malignancy because most patients develop recurrent disease that is resistant to chemotherapy, including platinum. Because response rates for current treatment regimens are relatively similar and unfortunately low, no standard chemotherapy for platinum-resistant ovarian cancer exists.

AREAS COVERED IN THIS REVIEW

A systematic literature review of clinical studies published between January 2005 and March 2010 was conducted using search engines, PubMed and MEDLINE with the entry keywords 'ovarian cancer' and 'platinum resistance'. This search revealed 40 clinical trials (1793 patients).

WHAT THE READER WILL GAIN

Gemcitabine was the most common drug used in clinical trials reporting higher response rates, ≥ +1 SD of overall response rate (5 out of 8). Gemcitabine-based combination therapy showed an average response rate of 27.2% (95% CI, 22.4-32.0). Combination of gemcitabine and pegylated liposomal doxorubicin (PLD) was the most common regimen (n = 3) and was associated with possible additive effects in platinum-resistant ovarian cancer patients: response rate, gemcitabine alone 6.1%, PLD alone 19.8%, and gemcitabine with PLD 28.7% (95% CI, 20.4-37.0), respectively.

TAKE HOME MESSAGE

Analysis of recent clinical trials showed that gemcitabine-based combination chemotherapy was associated with the highest antitumor effects in platinum-resistant ovarian cancer patients during the study period.

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.

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.