Maintenance therapy in advanced ovarian cancer: progression-free survival and clinical benefit

Maintenance of pegylated liposomal doxorubicin/carboplatin in patients with advanced ovarian cancer: randomized study of an Asian Gynecologic Oncology Group

Objectives

An Asian Gynecologic Oncology Group phase III randomized trial was conducted to determine whether maintenance chemotherapy could improve progression-free survival (PFS) in stages III/IV ovarian cancer.

Methods

Between 2007 and 2014, 45 newly-diagnosed ovarian cancer patients were enrolled after complete remission and randomized (1:1) to arm A (4-weekly carboplatin area under the curve 4 and pegylated liposomal doxorubicin [PLD] 30 mg/m², n=24) for 6 cycles or arm B (observation, n=21). The primary end-point was PFS. A post hoc translational study was conducted to deep sequence BRCA/homologous recombination deficiency (HRD) genes, because BRCA/HRD mutations (BRCA/HRDm) are known to be associated with better prognosis.

Results

Enrollment was slow, accrual was closed when 7+ years had passed. With a median follow-up of 88.9 months, the median PFS was significantly better in arm A (55.5 months) than arm B (9.2 months) (hazard ratio [HR]=0.40; 95% confidence interval [CI]=0.19–0.87; p=0.020), yet the median overall survival was not significantly different in arm A (not reached) than arm B (95.1 months) (p=0.148). Overall grade 3/4 adverse events were more frequent in arm A than arm B (60.9% vs 0.0%) (p<0.001). Quality of life was generally not significantly different. Distribution of BRCA1/2m or BRCA/HRDm was not significantly biased between the two arms. Wild-type BRCA/non-HRD subgroup seemed to fare better with maintenance therapy (HR=0.35; 95% CI=0.11–1.18; p=0.091).

Conclusions

Despite limitations in small sample size, it suggests that maintenance carboplatin-PLD chemotherapy could improve PFS in advanced ovarian cancer.

Strengthening the AntiTumor NK Cell Function for the Treatment of Ovarian Cancer

The crosstalk between cancer cells and host cells is a crucial prerequisite for tumor growth and progression. The cells from both the innate and adaptive immune systems enter into a perverse relationship with tumor cells to create a tumor-promoting and immunosuppressive tumor microenvironment (TME). Epithelial ovarian cancer (EOC), the most lethal of all gynecological malignancies, is characterized by a unique TME that paves the way to the formation of metastasis and mediates therapy resistance through the deregulation of immune surveillance. A characteristic feature of the ovarian cancer TME is the ascites/peritoneal fluid, a malignancy-associated effusion occurring at more advanced stages, which enables the peritoneal dissemination of tumor cells and the formation of metastasis. The standard therapy for EOC involves a combination of debulking surgery and platinum-based chemotherapy. However, most patients experience disease recurrence. New therapeutic strategies are needed to improve the prognosis of patients with advanced EOC. Harnessing the body’s natural immune defenses against cancer in the form of immunotherapy is emerging as an innovative treatment strategy. NK cells have attracted attention as a promising cancer immunotherapeutic target due to their ability to kill malignant cells and avoid healthy cells. Here, we will discuss the recent advances in the clinical application of NK cell immunotherapy in EOC.

Deep obturator lymph node dissection in gynaecological cancer patients: Is it feasible and useful?

Our aim was to investigate the feasibility and outcomes of deep obturator lymph node (DOLN) dissection in gynaecological cancer patients. A prospective study included 62 patients with a diagnosis of ovarian, endometrial or cervical cancer who underwent surgery. In the study group, 36 patients underwent obturator lymph node dissection above and under the obturator nerve, while 26 control group patients underwent routine obturator lymph node dissection above the obturator nerve. Groups were compared with respect to dissected lymph node count, intraoperative characteristics and early postoperative complications. Total lymph node count in the DOLN dissected group was greater than that in the control group, and the difference was statistically significant. No statistically significant difference was found between the groups, regarding postoperative complications and intraoperative characteristics. The total number of lymph nodes dissected by using DOLN dissection increased without an increase in intra- and postoperative complications in gynaecological cancer patients.

Anti-Tumor Effect of Pinus massoniana Bark Proanthocyanidins on Ovarian Cancer through Induction of Cell Apoptosis and Inhibition of Cell Migration

Pinus massoniana bark proanthocyanidins (PMBPs), an active component isolated from Pinus massoniana bark, has been reported to possess a wide range of biochemical properties. Here, we investigated the anti-tumor effect of PMBPs on ovarian cancer. The results indicated that PMBPs significantly reduced the growth of ovarian cancer cells and induced dose-dependent apoptosis. The underlying mechanisms involved were elucidated to include the loss of mitochondrial membrane potential, down-regulation of the anti-apoptotic protein Bcl-2 and the activation of Caspase 3/9, suggesting that PMBPs triggered apoptosis through activation of mitochondria-associated apoptotic pathway. In addition, wound healing and transwell chamber assays revealed that PMBPs could suppress migration and invasion of ovarian cancer cells. PMBPs dramatically inhibited MMP-9 activity and expression, blocked the activity of NFκB and the activation of ERK1/2 and p38 MAPK. Our findings suggest that PMBPs has the potential to be developed as an anti-tumor drug for ovarian cancer treatment and/ or disease management.

Design Issues in Randomized Clinical Trials of Maintenance Therapies

A potential therapeutic strategy for patients who respond (or have stable disease) on a fixed-duration induction therapy is to receive maintenance therapy, typically given for a prolonged period of time. To enable patients and clinicians to make informed treatment decisions, the designs of phase III randomized clinical trials (RCTs) assessing maintenance strategies need to be such that their results will provide clear assessment of the relevant risks and benefits of these strategies. We review the key aspects of maintenance RCT designs. Important design considerations include choice of first-line and second-line therapies, minimizing between-arm differences in follow-up schedules, and choice of the primary endpoint. In order to change clinical practice, RCTs should be designed to accurately isolate and quantify the clinical benefit of maintenance as compared with the standard approach of fixed-duration induction followed by the second-line treatment at progression. To accomplish this, RCTs need to utilize an overall survival (or quality of life) endpoint or, in settings where this is not feasible, endpoints that incorporate the effects of the subsequent line of therapy (eg, time from randomization to second progression or death). Toxicity and symptom information over both the study treatment (maintenance) and the second-line treatment should also be collected and reported.

Perioperative and Maintenance Therapy After First-Line Therapy as Paradigms for Drug Discovery in Urothelial Carcinoma

Perioperative chemotherapy provided to increase the chance of cure for localized disease and maintenance therapy for metastatic disease represent 2 distinct aspects of the urothelial cancer disease treatment spectrum. The ability to access both pre- and postchemotherapy tissue in the neoadjuvant setting provides important opportunities for translational research to test novel therapies and identify predictors of response to therapy. The maintenance setting may be more complex, and study design and endpoints need to be determined on the basis of the candidate drugs' mechanisms of action and toxicity.

The impact of perioperative packed red blood cell transfusion on survival in epithelial ovarian cancer

OBJECTIVE

Perioperative packed red blood cell transfusion (PRBCT) has been implicated as a negative prognostic marker in surgical oncology. There is a paucity of evidence on the impact of PRBCT on outcomes in epithelial ovarian cancer (EOC). We assessed whether PRBCT is an independent risk factor of recurrence and death from EOC.

METHODS

Perioperative patient characteristics and process-of-care variables (defined by the National Surgical Quality Improvement Program) were retrospectively abstracted from 587 women who underwent primary EOC staging between January 2, 2003, and December 29, 2008. Associations with receipt of PRBCT were evaluated using univariate logistic regression models. The associations between receipt of PRBCT and disease-free survival and overall survival were evaluated using multivariable Cox proportional hazards models and using propensity score matching and stratification, respectively.

RESULTS

The rate of PRBCT was 77.0%. The mean ± SD units transfused was 4.1 ± 3.1 U. In the univariate analysis, receipt of PRBCT was significantly associated with older age, advanced stage (≥ IIIA), undergoing splenectomy, higher surgical complexity, serous histologic diagnosis, greater estimated blood loss, longer operating time, the presence of residual disease, and lower preoperative albumin and hemoglobin. Perioperative packed red blood cell transfusion was not associated with an increased risk for recurrence or death, in an analysis adjusting for other risk factors in a multivariable model or in an analysis using propensity score matching or stratification to control for differences between the patients with and without PRBCT.

CONCLUSIONS

Perioperative packed red blood cell transfusion does not seem to be directly associated with recurrence and death in EOC. However, lower preoperative hemoglobin was associated with a higher risk for recurrence. The need for PRBCT seems to be a stronger prognostic indicator than the receipt of PRBCT.

Recommended patient-reported core set of symptoms and quality-of-life domains to measure in ovarian cancer treatment trials

There is no consensus as to what symptoms or quality-of-life (QOL) domains should be measured as patient-reported outcomes (PROs) in ovarian cancer clinical trials. A panel of experts convened by the National Cancer Institute reviewed studies published between January 2000 and August 2011. The results were included in and combined with an expert consensus-building process to identify the most salient PROs for ovarian cancer clinical trials. We identified a set of PROs specific to ovarian cancer: abdominal pain, bloating, cramping, fear of recurrence/disease progression, indigestion, sexual dysfunction, vomiting, weight gain, and weight loss. Additional PROs identified in parallel with a group charged with identifying the most important PROs across cancer types were anorexia, cognitive problems, constipation, diarrhea, dyspnea, fatigue, nausea, neuropathy, pain, and insomnia. Physical and emotional domains were considered to be the most salient domains of QOL. Findings of the review and consensus process provide good support for use of these ovarian cancer-specific PROs in ovarian cancer clinical trials.

Randomized, Phase II, Placebo-Controlled, Double-Blind Study With and Without Enzastaurin in Combination With Paclitaxel and Carboplatin As First-Line Treatment Followed by Maintenance Treatment in Advanced Ovarian Cancer

Purpose

Enzastaurin is an oral serine/threonine kinase inhibitor antitumor agent. Our phase II trial tested the efficacy and safety of enzastaurin added to a standard carboplatin/paclitaxel chemotherapy regimen in patients with newly diagnosed advanced ovarian cancer.

Patients and Methods

This was a randomized, placebo-controlled study in patients with International Federation of Gynecology and Obstetrics stage IIB to IV ovarian, fallopian tube, or peritoneal epithelial carcinoma. Patients were randomly assigned to six cycles of chemotherapy (paclitaxel/carboplatin ± enzastaurin [PCE/PC]) followed by maintenance therapy (enzastaurin/placebo). Primary end point was progression-free survival (PFS). Secondary measures included response rate, safety assessment, and translational research.

Results

A total of 142 patients were randomly assigned to PCE (n = 69) or PC (n = 73). Patients in the PCE group had a 3.7-month longer median PFS compared with patients in the PC group; this was not statistically significant (hazard ratio [HR], 0.80; 95% CI, 0.50 to 1.29; P = .37). Safety profiles of the treatment arms were comparable. Frequency of discontinuation because of adverse events was similar (PCE, 11.9%; PC, 9.7%). Multivariate analyses confirmed the importance of optimal debulking with regard to PFS (debulking optimal v suboptimal: HR, 0.51; 95% CI, 0.30 to 0.85; P = .009). HR for covariate stage (stage IIB to IIIB v IIIC to IV) was not statistically significant (0.75; 95% CI, 0.38 to 1.47; P = .40). Translational research of immunohistochemistry protein assays did not identify any markers significantly associated with treatment difference regarding PFS.

Conclusion

The PCE combination increased PFS, but it was not significantly superior to PC in this phase II study.

Phase I trial of a formulated IL-12 plasmid in combination with carboplatin and docetaxel chemotherapy in the treatment of platinum-sensitive recurrent ovarian cancer

OBJECTIVES

The primary objective of this study was to evaluate the safety and tolerability of a formulated IL-12 plasmid administered intraperitoneally (IP) in conjunction with intravenous (IV) carboplatin/docetaxel in platinum-sensitive ovarian cancer patients.

METHODS

Escalating doses of IL-12 plasmid (phIL-12) formulated with the lipopolymer PEG-PEI-Cholesterol (PPC) were administered IP every 10-11 days for a total of four treatments and the highest dose was expanded to eight treatments. Patients also received IV carboplatin (AUC 5) and docetaxel (75 mg/m(2)) every 21 days. Patients were followed for safety, biological activity and antitumor activity after phIL-12/PPC treatment.

RESULTS

All 13 patients enrolled in the study received both phIL-12/PPC and chemotherapy treatment. There were 49 plasmid-associated adverse events (AEs). The most common AEs were abdominal pain, transient hypotension, low grade fever, catheter site pain, chills, dysgeusia, infusion-related reaction, and nausea. These AEs appeared to be plasmid dose related. Grade 3 AEs included manageable abdominal pain and cytokine release syndrome. There were no dose limiting toxicities and the plasmid treatment did not augment the chemotherapy-associated AEs. The best overall antitumor response (17% CR, 33% PR, 42% SD and 8% PD) was typical of the patient population enrolled for the study. Translational studies showed rise in IFN-γ and TNF-α concentrations in a dose dependent manner.

CONCLUSIONS

The escalating doses and cycles of intraperitoneal phIL-12/PPC when combined with carboplatin/docetaxel chemotherapy in recurrent ovarian cancer patients were well tolerated and did not appear to exacerbate the side effects or attenuate the efficacy of the chemotherapy treatment.

Sensitization of ovarian carcinoma cells to Bcl-xL-targeting strategies through indirect modulation of Mcl-1 activity by MR22388, a molecule of the tripentone family

Background

Our work has been carried out in the context of the therapeutic failure in ovarian carcinoma, which remains the leading cause of death by gynecologic malignancy. In these tumours, recurrence and subsequent acquired chemoresistance constitute major hurdles to successful therapy. Here we studied the interest of a member of the tripentone chemical family, MR22388, for the treatment of chemoresistant ovarian cancer cells.

Findings

MR22388 activity has been assessed in vitro on cisplatin-resistant (SKOV3 and IGROV1-R10) ovarian cancer cell lines by conventional analysis, alone or combined to a BH3-mimetic molecule, ABT-737. MR22388 exerts its activity on cisplatin resistant cells, and we showed that it induces a decrease of the Mcl-1 anti-apoptotic protein expression. Considering our previous work demonstrating that the efficiency of Bcl-x_L targeting strategies is conditioned to the concomitant inhibition of Mcl-1 we studied the interest of the association of this MR22388 with ABT-737, and showed that this combination was highly cytotoxic in chemoresistant cells.

Conclusions

This work thus opens new perspectives for the use of this promising molecule for the treatment of highly chemoresistant ovarian cancer cells and for sensitization of emerging Bcl-x_L targeting strategies such as the use of BH3-mimetic molecules.

Distinct genetic alterations occur in ovarian tumor cells selected for combined resistance to carboplatin and docetaxel

BACKGROUND

Current protocols for the treatment of ovarian cancer include combination chemotherapy with a platinating agent and a taxane. However, many patients experience relapse of their cancer and the development of drug resistance is not uncommon, making successful second line therapy difficult to achieve. The objective of this study was to develop and characterize a cell line resistant to both carboplatin and docetaxel (dual drug resistant ovarian cell line) and to compare this cell line to cells resistant to either carboplatin or docetaxel.

METHODS

The A2780 epithelial endometrioid ovarian cancer cell line was used to select for isogenic carboplatin, docetaxel and dual drug resistant cell lines. A selection method of gradually increasing drug doses was implemented to avoid clonal selection. Resistance was confirmed using a clonogenic assay. Changes in gene expression associated with the development of drug resistance were determined by microarray analysis. Changes in the expression of selected genes were validated by Quantitative Real-Time Polymerase Chain Reaction (QPCR) and immunoblotting.

RESULTS

Three isogenic cell lines were developed and resistance to each drug or the combination of drugs was confirmed. Development of resistance was accompanied by a reduced growth rate. The microarray and QPCR analyses showed that unique changes in gene expression occurred in the dual drug resistant cell line and that genes known to be involved in resistance could be identified in all cell lines.

CONCLUSIONS

Ovarian tumor cells can acquire resistance to both carboplatin and docetaxel when selected in the presence of both agents. Distinct changes in gene expression occur in the dual resistant cell line indicating that dual resistance is not a simple combination of the changes observed in cell lines exhibiting single agent resistance.

The value of progression-free survival to patients with advanced-stage cancer

Progression-free survival (PFS) is frequently used as a primary end point in oncology clinical trials. Employing PFS instead of overall survival as the primary outcome has the advantage that trial completion can be quicker with fewer patients required, and it is cheaper. PFS is sensitive to cytostatic as well as cytotoxic mechanisms of therapeutic intervention and directly measures the effect of the investigational treatment. Despite these practical advantages, it is unclear whether or not extending PFS provides discernable clinical benefit. New treatments that increase PFS may not be of sufficient value to patients with advanced-stage cancer unless accompanied by tangible quantity or quality of life advantages. Any symptom relief that patients gain from treatment resulting in tumor shrinkage or stabilization must be balanced against the toxic effects that drug therapy itself creates. Consequently, improved assessment of new treatments using patient-reported outcomes alongside PFS is crucial to enable communication between clinicians and patients and optimal decision-making about therapeutic options.

Functional Characterization of a Fluorescent Highly Tumorigenic Ovarian Cancer Line to Test Cellular Therapy in Experimental Models

Objectives

The objective of this study was to functionally characterize a fluorescent highly tumorigenic ovarian cancer line to test cellular therapy in combination with cytokines or chemotherapies in experimental models.

Methods

A fluorescent highly tumorigenic subline (SKOV3-AF2) was derived from the SKOV3 ovarian cancer cell line. Peripheral blood mononuclear cell (PBMC)-mediated cytotoxicity of SKOV3-AF2 in the presence of interleukin 2 (IL-2) and interferon α-2b (IFNα-2b) was assayed by lactate dehydrogenase release. Sensitivity of SKOV3-AF2 cells to polyethylene glycol-IFNα-2b and IL-2 was assayed in a xenograph nude mouse model. Histopathology was performed to determine necrosis and tumor-infiltrating lymphocytes in the solid tumors. Reverse transcriptase-polymerase chain reaction was used for gene expression analyses ofE-cadherinandcysteine-rich 61(CCN1).

Results

The SKOV3-AF2 subline exhibits increased cytotoxicity (up to 70%), mediated by PBMCs, IL-2, and IFNα-2b, compared with parental SKOV3-red fluorescent protein (RFP) cells. SKOV3-AF2 cells are more tumorigenic in vivo as indicated by tumor incidence, time to sacrifice, tumor weight, and ascitic fluid production. SKOV3-AF2 tumor growth was inhibited by polyethylene glycol-IFNα-2b but not low-dose IL-2. Histopathology revealed that the tumors consisted of poorly differentiated surface epithelial carcinoma. SKOV3-RFP, and -AF2 cell lines as well as -AF2 tumors expressedE-cadherin.SKOV3-AF2 derived tumors expressedCCN1; however, the SKOV3-RFP and SKOV3-AF2 cell lines did not.

Conclusions

Characterization of SKOV3-AF2 cells revealed that it is more susceptible to PBMC-mediated cytotoxicity than SKOV3-RFP and highly tumorigenic in a xenograph model, and AF-2 tumors express genes that promote aggressive behavior. Collectively, our data suggest that the SKOV3-AF2 subline will be a useful tool to test cellular therapy for the treatment of ovarian cancer utilizing experimental models.

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.

Current status of maintenance therapy for advanced ovarian cancer

Even after countered with and responding to maximal surgical and chemotherapy efforts, advanced ovarian cancer usually ultimately recurs. One strategy employed to forestall recurrence is maintenance chemotherapy, an extension of treatment following a complete response to conventional measures. Many agents have been studied and many more are currently under investigation in maintenance regimens. While phase III data suggest that taxane maintenance prolongs progression-free survival, no overall survival benefit has been established. This article reviews the current status of maintenance therapy for advanced ovarian cancer, including phase III evidence and new and upcoming trials.

A review of the current evidence for maintenance therapy in ovarian cancer

OBJECTIVES

Ovarian cancer (OC) typically is diagnosed at advanced stages, in which the primary goal of therapy is to prolong progression-free survival (PFS) and overall survival (OS). In recent years, maintenance therapy has been tested for this purpose in advanced OC (AOC). Literature on maintenance therapy in AOC was systematically reviewed to assess current knowledge regarding the impact of this therapeutic approach.

METHODS

A MEDLINE search was performed 2/2009 for articles published 1/2001-1/2009 pertaining to OC maintenance therapy guidelines, patterns, and outcomes. A second search used keywords specific to maintenance and included primary studies published in the last 10 years. Of 406 sources identified, 36 primary studies and 16 review articles were included in this systematic review. A third search used the keyword "consolidation" to find maintenance articles not identified through other searches; of 48 additional sources, 13 primary studies and 6 reviews were included. A fourth search of non-MEDLINE-indexed sources yielded 14 additional relevant publications from the same time period.

RESULTS

Among practice guidelines identified, only the National Comprehensive Cancer Network (NCCN) 2008 guidelines provide recommendations regarding maintenance therapy, assigning it a category 2B recommendation. No studies were identified that reported current treatment patterns or economic outcomes in maintenance therapy; quality of life data were reported in one study. A variety of agents have been tested for maintenance, with paclitaxel the most commonly evaluated. The Southwest Oncology Group-Gynecologic Oncology Group 178 trial has found that 12 cycles of paclitaxel extend PFS (by 7 months) compared to 3 months paclitaxel, but could not adequately evaluate OS.

CONCLUSIONS

Maintenance therapy may improve clinical outcomes in AOC, but additional research is needed to demonstrate an OS advantage. Future studies should investigate the long-term clinical benefit of maintenance treatment and its impact on resource utilization and health-related quality of life.

Challenges for chemotherapy in ovarian cancer

BACKGROUND

Ovarian cancer is treated with surgery followed by combination chemotherapy with paclitaxel plus carboplatin. In an effort to improve outcomes, clinical trials are evaluating the following strategies: maintenance therapy; intraperitoneal drug administration; new combinations; novel cytotoxics; combination chemotherapy for recurrent disease; and molecular-targeted therapies.

PATIENTS AND METHODS

Clinical trials evaluating the above strategies are being performed in ovarian cancer in patients with: (1) previously untreated advanced ovarian cancer; (2) platinum-sensitive recurrent disease; and (3) platinum-resistant recurrent disease.

RESULTS

Combination chemotherapy regimens are superior to single-agent therapy in recurrent ovarian cancer. Molecular-targeted therapy has produced objective responses in previously treated patients. Maintenance therapy of any type has not been shown to prolong survival. Intraperitoneal therapy has resulted in improved survival with considerable toxicity in patients with small-volume stage III disease.

CONCLUSIONS

Numerous novel clinical strategies are being evaluated in ovarian cancers that have the potential to improve outcomes compared to standard therapy.

Pegylated liposomal doxorubicin HCL (PLD; Caelyx/Doxil): experience with long-term maintenance in responding patients with recurrent epithelial ovarian cancer

BACKGROUND

We hypothesized that a response to pegylated liposomal doxorubicin (PLD, Caelyx/Doxil) followed by maintenance is beneficial and safe in recurrent ovarian cancer.

PATIENTS AND METHODS

Sixteen patients have received PLD for more than 1 year for recurrent ovarian (14) or fallopian tube (2) cancer. All had stable disease or better responses to PLD + carboplatin (5) or topotecan (9) doublets or to PLD alone (2). PLD maintenance therapy 30-40 mg/m(2) was given every 4-8 weeks. This analysis focuses on cardiac status, overall tolerance, and time to recurrence.

RESULTS

Termination of PLD was due to progression in all patients. Noteworthy was the lack of cumulative myelosuppression and, with one exception, clinical cardiac toxicity. This patient was hospitalized with cardiogenic shock and fever complicating grade 4 pancytopenia from topotecan ten months after discontinuation of PLD. Seven patients continue to receive PLD after a median of 1680 mg/m(2) (1180-2460 mg/m(2)). Four of these had documented relapses after 3-6 years on maintenance occurring in the setting of lengthening of the treatment interval. Maintenance PLD was reinstituted after 'reinduction' with a platinum.

CONCLUSIONS

PLD appears to be safe as long-term maintenance in ovarian cancer and may be important for a continued response.

Alpha v beta 3 integrin-targeting of intraperitoneally growing tumors with a radiolabeled RGD peptide

Ovarian cancer is the fourth most common cause of cancer deaths among females in the western world after cancer of the breast, colon and lung. The inability to control the disease within the peritoneal cavity is the major cause of treatment failure in patients with ovarian cancer. The majority of ovarian carcinomas express the alpha(v)beta(3) integrin. Here we studied the tumor targeting potential of an (111)In-labeled cyclic RGD peptide in athymic BALB/c mice with intraperitoneally (i.p.) growing NIH:OVCAR-3 human ovarian carcinoma tumors. The cyclic RGD peptide, c(RGDfK)E, was synthesized, conjugated with DOTA and radiolabeled with (111)In. The targeting potential of (111)In-DOTA-E-c(RGDfK) was studied in athymic mice with i.p. growing NIH:OVCAR-3 xenografts and the optimal dose of this compound was determined (0.01 microg up to 10 microg). The biodistribution at optimal peptide dose was determined at various time points (0.5 up to 72 hr). Furthermore, the therapeutic potential of (177)Lu-DOTA-E-c(RGDfK) was studied in this model. Two hours after i.p. administration, (111)In-DOTA-E-c(RGDfK) showed high and specific uptake in the i.p. growing tumors. Optimal uptake in the i.p. growing tumors was observed at a 0.03-0.1 microg dose range. Tumor uptake of (111)In-DOTA-E-c(RGDfK) peaked 4 hr p.i. [(38.8 +/- 2.7)% ID/g], gradually decreasing at later time points [(24.0 +/- 4.1)% ID/g at 48 hr p.i.]. Intraperitoneal growth of OVCAR-3 could be significantly delayed by injecting 37 MBq (177)Lu-labeled peptide i.p. Radiolabeled DOTA-E-c(RGDfK) is suitable for targeting of i.p. growing tumors and potentially can be used for peptide receptor radionuclide therapy of these tumors.

Maintenance or consolidation therapy in advanced ovarian cancer

Most patients with advanced epithelial ovarian cancer (EOC) achieve a clinical complete response (CR) or have no clinical evidence of disease after aggressive cytoreductive surgery and 6 cycles of platinum-/taxane-based chemotherapy. From the reported randomized trials using different durations or different cycles of chemotherapy, none of these showed improvement in survival beyond 6 cycles. Data from the literature do not support a relationship between the number of cycles and response or between the cumulative dose and response. In addition, no benefit in survival was detected with high-dose and intensity chemotherapy administered for a short time compared with standard-dose chemotherapy given for a longer time. However, statistically significant differences in progression-free survival were found in patients who achieved a clinically defined CR to a platinum (CDDP)-/paclitaxel-based chemotherapy and who continued single-agent paclitaxel for an extended time period. Notably, this randomized trial most likely did not offer any survival advantage, as it was closed prematurely by the Data Safety Monitoring Committee in accordance with the guidelines planned for interim analysis of primary end-points.

The role of maintenance therapy and novel taxanes in ovarian cancer

OBJECTIVES

Despite several studies reporting various degrees of success, the role of maintenance chemotherapy in ovarian cancer remains controversial. This article reviews the available data and the controversy surrounding maintenance therapy. In addition, the role of novel taxanes, which may offer an improved therapeutic index and reduced toxicity relative to conventional therapies in this setting, is discussed.

METHODS

The available randomized clinical data on extended or maintenance therapy in ovarian cancer are reviewed.

RESULTS

Available data indicate that patients with ovarian cancer undergoing taxane maintenance chemotherapy exhibit a reduced recurrence rate and a longer progression-free survival.

CONCLUSIONS

While an additional randomized trial is needed to confirm these benefits and establish maintenance therapy as the standard of care, the authors conclude that maintenance therapy is a valuable option that should be discussed with patients until further data are available. The Gynecologic Oncology Group 212 trial is a randomized clinical trial that is designed to answer whether taxane maintenance therapy offers a survival advantage as well as to determine the impact of such a therapeutic regimen on a patient's quality of life. This trial is also designed to address some of the questions regarding the role of a novel taxane in maintenance therapy in ovarian cancer.

Systemic therapy for ovarian cancer: current status and new treatments

Current systemic therapy for ovarian cancer consists of a combination of carboplatin and paclitaxel. While the majority of patients achieve clinical complete remission after six cycles of chemotherapy, the relapse rate stands at over 50%. Median survival time for patients after recurrence is approximately 2 years. New treatment approaches for patients with advanced ovarian cancer include consolidation and maintenance therapy, intraperitoneal administration of cytotoxic agents, new combination chemotherapy regimens, the development of new cytotoxic agents, and molecular-targeted therapies. These agents will be evaluated either singularly or with chemotherapy. Currently, the Gynecologic Oncology Group is evaluating a combination of bevacizumab together with paclitaxel and carboplatin in previously untreated patients with advanced ovarian cancer. This trial is based on phase II data that suggest that bevacizumab as a single agent has significant activity in patients with recurrent ovarian cancer. In addition, the Gynecologic Oncology Group will be conducting phase II trials of different combinations of intraperitoneal chemotherapy in an effort to decrease toxicity associated with current intraperitoneal regimens that have shown an improvement in survival in patients with small-volume stage III disease. The Gynecologic Oncology Group will also be conducting a trial of maintenance therapy in patients who enter clinical complete remission with paclitaxel plus carboplatin, comparing observation with monthly paclitaxel or monthly paclitaxel poliglumex. Novel new cytotoxic and biologic agents are also being evaluated as single agents in phase II trials in patients with recurrent ovarian cancer.

Treatment goals in ovarian cancer

Ovarian cancer remains the number one gynecological killer in the Western world. Most ovarian cancer patients present with advanced-stage disease and are treated with cytoreductive surgery followed by combination chemotherapy. While the majority of patients respond to treatment, most will relapse such that the 5-year survival rates for advanced disease are approximately 20-25%. Overall survival and progression-free survival (PFS) are the primary endpoints in clinical trials in patients with advanced ovarian cancer. In patients with early-stage ovarian cancer, PFS may be the preferred trial endpoint, whereas in patients with recurrent ovarian cancer, the primary goal of therapy remains palliation and control of symptoms. Recent studies in recurrent disease have demonstrated that chemotherapy can improve the endpoints of PFS and overall survival, and so they are being used as the primary endpoints for comparing new regimens in phase III trials in relapsed patients. However, it would be easier to compare new treatment modalities if a uniformly accepted instrument was available that could evaluate quality of life and symptom control.

First-line therapy for ovarian carcinoma: what's next?

Based on results from large, randomized trials conducted over the last 25 years, the current standard of care for newly diagnosed advanced (FIGO stage III-IV) ovarian carcinoma is surgical bulk reduction followed by six cycles of paclitaxel plus carboplatin. This approach has resulted in an enhanced response rate and clinical complete response rate, an improved progression-free survival, an increase in survival, and more long-term survivors. Despite these results, the overall frequency of relapse and hence need for second-line therapy is 62%. Ongoing and future studies focus or will focus on four major themes: dose intensity through the use of intraperitoneal chemotherapy in selected patients, addition of a third cytotoxic agent to front line therapy, addition of a targeted or biologic agent to front-line therapy, and the development of effective maintenance or consolidation therapy. The current standard of care for patients who present with limited (FIGO stage I-II) ovarian carcinoma is the use of prognostic factors to classify the patient as at low risk or high risk for recurrence. High risk features include: grade 2 or 3 disease, disease on the surface of the ovary, disease outside the ovary, positive peritoneal cytology, or the presence of ascites. Any one high risk feature makes the patient high risk for recurrence. Patients at low risk require surgical resection only, whereas those at high risk for recurrence require adjuvant therapy. Ongoing studies evaluate the duration of therapy and the potential value of anti-angiogenic agents in those patients at high risk for recurrence. Future directions point to the evaluation of targeted or biologic agents in high risk patients. At present, there is no evidence that any approach constitutes an effective screening test. Studies of serum markers, transvaginal sonography, and serum proteomic profiles have failed to establish any of these techniques as an effective tool for early diagnosis. An overview of current management and its basis will be followed by a discussion of the rationale for both current and potential future trials.

Update on Gynecologic Oncology Group (GOG) Trials in Ovarian Cancer

The Gynecologic Oncology Group (GOG) has conducted a series of randomized trials in advanced ovarian cancer patients, both with early-stage disease (FIGO stages I and II) and advanced-stage disease (FIGO stages III and IV). In patients with early-stage disease, the current standard of therapy is three cycles of paclitaxel and carboplatin-based combination chemotherapy. In patients with advanced-stage ovarian cancer, the GOG standard is six cycles of the same regimen. The GOG has also performed prospective randomized trials of consolidation and maintenance therapy with intraperitoneal (IP) radioisotomes and additional cycles of paclitaxel, respectively. Neither of these modalities has shown improvement in survival. In addition, the GOG has performed randomized trials of IP chemotherapy, and while it has been demonstrated that the regimens that included IP cisplatin led to improved outcomes, the toxicity of this approach has precluded widespread acceptance of this modality. Currently, the GOG is performing additional pilot studies to evaluate less toxic IP regimens. The GOG has also been at the forefront of developing new combination chemotherapy regimens based on the activity of second-line agents, such as topotecan, gemcitabine, and encapsulated doxorubicin. The GOG is also exploring molecular-targeted therapies in phase II trials with the goal of ultimately incorporating biological therapies in newly diagnosed patients with advanced disease.