Maintenance treatment with interferon for advanced ovarian cancer: results of the Northern and Yorkshire gynaecology group randomised phase III study

Ubiquitination network in the type I IFN-induced antiviral signaling pathway

Type I IFN (IFN-I) is the body's first line of defense against pathogen infection. IFN-I can induce cellular antiviral responses and therefore plays a key role in driving antiviral innate and adaptive immunity. Canonical IFN-I signaling activates the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, which induces the expression of IFN-stimulated genes and eventually establishes a complex antiviral state in the cells. Ubiquitin is a ubiquitous cellular molecule for protein modifications, and the ubiquitination modifications of protein have been recognized as one of the key modifications that regulate protein levels and/or signaling activation. Despite great advances in understanding the ubiquitination regulation of many signaling pathways, the mechanisms by which protein ubiquitination regulates IFN-I-induced antiviral signaling have not been explored until very recently. This review details the current understanding of the regulatory network of ubiquitination that critically controls the IFN-I-induced antiviral signaling pathway from three main levels, including IFN-I receptors, IFN-I-induced cascade signals, and effector IFN-stimulated genes.

Monocytes: A Promising New TRAIL in Ovarian Cancer Cell Therapy

Adoptive cell transfer of IFN-activated monocytes administered intraperitoneally to patients with platinum-resistant ovarian cancer demonstrated antitumor effects and acceptable tolerability. The exposure of monocytes to IFNα and IFNγ upregulated TRAIL, which triggered caspase 8 and direct cell-to-cell contact-dependent apoptosis of ovarian cancer cells. See related article by Green et al., p. 349.

Maintenance therapy for newly diagnosed epithelial ovarian cancer- a review

Epithelial ovarian cancer (EOC) is the most lethal gynaecological cancer among women worldwide, with the 5-year survival rate ranging between 30 and 40%. Due to the asymptomatic nature of the condition, it is more likely to be diagnosed at an advanced stage, requiring an aggressive therapeutic approach. Cytoreductive surgery (CRS) along with systemic chemotherapy with paclitaxel and carboplatin has been the mainstay of the treatment in the frontline management of EOC. In recent years, neo-adjuvant chemotherapy, followed by interval CRS has become an important strategy for the management of advanced EOC. Due to the high rate of recurrence, the oncology community has begun to shift its focus to molecular-targeted agents and maintenance therapy in the frontline settings. The rationale for maintenance therapy is to delay the progression or relapse of the disease, as long as possible after first-line treatment, irrespective of the amount of residual disease. Tumours with homologous recombination deficiency (HRD) including BReast CAncer gene (BRCA) mutations are found to be sensitive to polyadenosine diphosphate-ribose polymerase (PARP) inhibitors and understanding of HRD status has become important in the frontline setting. PARP inhibitors are reported to provide a significant improvement in progression-free survival and have an acceptable safety profile. PARP inhibitors have also been found to act regardless of BRCA status. Recently, PARP inhibitors as maintenance therapy in the frontline settings showed encouraging results in EOC; however, the results from further trials and survival data from ongoing trials are awaited for understanding the role of this pathway in treatment of EOC. This review discusses an overview of maintenance strategies in newly diagnosed EOC along with considerations for maintenance therapy in EOC with a focus on PARP inhibitors.

Efficacy and Safety of Placebo During the Maintenance Therapy of Ovarian Cancer in Randomized Controlled Trials: A Systematic Review and Meta-analysis

Introduction

This meta-analysis evaluated the efficacy and safety of placebo during the maintenance therapy of ovarian cancer (OC) patients in randomized controlled trials (RCTs).

Methods

A comprehensive literature review was performed for RCTs published up to and including August 2020 from four electronic databases. We analyzed the efficacy and safety in the control arms of the maintenance therapy in advanced OC patients. Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) of progression-free survival (PFS) and overall survival (OS) were estimated in the placebo arms and the observation arms, respectively, using the Frequency Framework method. We also calculated the incidences of common adverse effects (AEs) in the placebo arms.

Results

In total, 41 articles with 20,099 (4,787 in the placebo arms, 3,420 in the observation arms, and 11,892 in the experiment arms) patients were included in this meta-analysis. Compared with observation, placebo did not improve or reduce PFS (HR, 1.02; 95% CI, 0.87–1.20; P = 0.81) and OS (HR, 1.02; 95% CI, 0.89–1.16; P = 0.76) of OC patients, while other treatments, except for radiotherapy, significantly improved PFS and OS (all P < 0.05). The incidences of AEs produced by placebo were 94.03% in all grades and 20.22% in grade ≥3. The incidences of AEs were 29.75% in fatigue, 26.38% in nausea, 24.34% in abdominal pain, 18.92% in constipation, 16.65% in diarrhea, 14.55% in vomiting, 13.89% in hypertension, and 13.14% in headache.

Conclusions

Placebo did not improve or reduce the PFS and OS benefits of OC patients in RCTs but increased the incidences of AEs.

Frontline Maintenance Treatment for Ovarian Cancer

Purpose of Review

Advanced epithelial ovarian cancer remains the most lethal gynaecological cancer. Most patients with advanced disease will relapse within 3 years after primary treatment with surgery and chemotherapy. Recurrences become increasing difficult to treat due to the emergence of drug resistance and 5-year survival has changed little over the last decade. Maintenance treatment, here defined as treatment given beyond primary chemotherapy, can both consolidate the response and prolong the control of disease which is an approach to improve survival.

Recent Findings

Here we review maintenance strategies such as targeting angiogenesis, interference of DNA repair through inhibition of PARP, combinations of targeting agents, and immunotherapy and hormonal therapy.

Summary

Much has been learnt from the success and challenges of these treatments that have in the last few years which led to significant reduction in disease recurrence, changed the guidelines for treatment, and established a new paradigm for the treatment of ovarian cancer.

Consolidation or maintenance systemic therapy for newly diagnosed stage II, III, or IV epithelial ovary, fallopian tube, or primary peritoneal carcinoma: A systematic review

BACKGROUNDS

To systematically review the effectiveness and harm of consolidation or maintenance therapy in patients with newly diagnosed stage II-IV EOC.

METHODS

MEDLINE, EMBASE, PubMed, Cochrane Library, and PROSPERO databases, and four relevant conferences were systematically searched. We adhered to PRISMA guidelines, and used the GRADE approach to aggregate data.

RESULTS

Among 12,675 citations, 28 comprising 16,310 patients were analyzed. The certainty of aggregated study evidence ranged from high to low.

CONCLUSIONS

The existing evidence does not find overall survival benefit for consolidation therapy with chemotherapy. For maintenance therapy, comparing with placebo, olaparib, niraparib, veliparib, and bevacizumab are effective as maintenance therapy for certain patients with newly diagnosed stage III-IV epithelial ovarian, fallopian tube, or primary peritoneal carcinoma respectively without reducing quality of life. Longer follow-up with more mature results of overall survival will better define the effect of these agents.

An Ontario Health (Cancer Care Ontario) Clinical Practice Guideline: Consolidation or Maintenance Systemic Therapy for Newly Diagnosed Stage II, III, or IV Epithelial Ovary, Fallopian Tube, or Primary Peritoneal Carcinoma

OBJECTIVE

To provide recommendations on systemic therapy options in consolidation or maintenance therapy for women with newly diagnosed stage II, III, or IV epithelial ovary, fallopian tube, or primary peritoneal carcinoma including all histological types.

METHODS

Consistent with the Program in Evidence-based Program's standardized approach, MEDLINE, EMBASE, PubMed, Cochrane Library, and PROSPERO (the international prospective register of systematic reviews) databases, and four relevant conferences were systematically searched. The Working Group drafted recommendations and revised them based on the comments from internal and external reviewers.

RESULTS

We have one recommendation for consolidation therapy and eight recommendations for maintenance therapy. Overall, consolidation therapy with chemotherapy should not be recommended in the target population. For maintenance therapy, we recommended olaparib (Recommendation), niraparib (Weak Recommendation), veliparib (Weak Recommendation), and bevacizumab (Weak Recommendation) for certain patients with newly diagnosed stage III-IV epithelial ovarian, fallopian tube, or primary peritoneal carcinoma, respectively. We do not recommend some agents as maintenance therapy in four recommendations. We are unable to specify the patient population by histological types for different maintenance therapy recommendations. When new evidence that can impact the recommendations is available, the recommendations will be updated as soon as possible.

Opposing Roles of Type I Interferons in Cancer Immunity

The immune system is tasked with identifying malignant cells to eliminate or prevent cancer spread. This involves a complex orchestration of many immune cell types that together recognize different aspects of tumor transformation and growth. In response, tumors have developed mechanisms to circumvent immune attack. Type I interferons (IFN-Is) are a class of proinflammatory cytokines produced in response to viruses and other environmental stressors. IFN-Is are also emerging as essential drivers of antitumor immunity, potently stimulating the ability of immune cells to eliminate tumor cells. However, a more complicated role for IFN-Is has arisen, as prolonged stimulation can promote feedback inhibitory mechanisms that contribute to immune exhaustion and other deleterious effects that directly or indirectly permit cancer cells to escape immune clearance. We review the fundamental and opposing functions of IFN-Is that modulate tumor growth and impact immune function and ultimately how these functions can be harnessed for the design of new cancer therapies.

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.

Blocking autophagy flux promotes interferon-alpha-mediated apoptosis in head and neck squamous cell carcinoma

Despite multiple antitumor activities, interferon-alpha (IFNα) therapy alone is less effective in solid tumors. Autophagy has been reported to play a key role in tumor chemoresistance. Therefore, it is meaningful to explore whether autophagy can be activated by IFNα in head and neck squamous cell carcinoma (HNSCC) and serve as a potential target to improve efficacy of IFNα therapy. In this study, we report that IFNα not only exhibits anti-proliferation activity and induces apoptosis, but also activates autophagy in HNSCC cells. Moreover, silencing autophagy-related protein 5 (ATG5) and signal transducer and activator of transcription 1 (STAT1) suppresses autophagy flux. Furthermore, IFNα and autophagy inhibitors (hydroxychloroquine and wortmannin) show clear synergistic effects on inhibiting growth and promoting apoptosis in HNSCC cells and xenograft models. Our findings indicate that IFNα-induced autophagy plays a cytoprotective role and blocking autophagy flux promotes IFNα-mediated apoptosis in HNSCC. These results suggest that the combination of IFNα and autophagy inhibitors represents a novel strategy for HNSCC treatment.

Type I Interferon in Chronic Virus Infection and Cancer

Type I interferons (IFN-Is) are emerging as key drivers of inflammation and immunosuppression in chronic infection. Control of these infections requires IFN-I signaling; however, prolonged IFN-I signaling can lead to immune dysfunction. IFN-Is are also emerging as double-edged swords in cancer, providing necessary inflammatory signals, while initiating feedback suppression in both immune and cancer cells. Here, we review the proinflammatory and suppressive mechanisms potentiated by IFN-Is during chronic virus infections and discuss the similar, newly emerging dichotomy in cancer. We then discuss how this understanding is leading to new therapeutic concepts and immunotherapy combinations. We propose that, by modulating the immune response at its foundation, it may be possible to widely reshape immunity to control these chronic diseases.

Continuous Low-Dose Oral Cyclophosphamide and Methotrexate as Maintenance Therapy in Patients With Advanced Ovarian Carcinoma After Complete Clinical Response to Platinum and Paclitaxel Chemotherapy

PURPOSE

The aim of this study was to evaluate efficacy and safety of continuous, low dose of oral, metronomic chemotherapy as maintenance therapy in patients with advanced ovarian carcinoma after complete clinical response to platinum and paclitaxel chemotherapy.

PATIENTS AND METHODS

In this nonrandomized study, patients older than 18 years, with Eastern Cooperative Oncology Group performance status less than 2, with advanced ovarian carcinoma after complete clinical response to platinum and paclitaxel chemotherapy were enrolled in 2 arms--arm A (maintenance arm), treated with continuous low-dose oral cyclophosphamide 50 mg and methotrexate 2.5 mg, and arm B (observation arm). Both arms were followed up for progression-free survival and toxicity.

RESULTS

Thirty patients were accrued in each arm from January 2009 to December 2010 in Ain Shams University Hospitals, where they received the treatment and followed up for disease progression and toxicity. Patients had a median age of 53 years in maintenance arm and 52.5 years in the observational arm, respectively. Over 80% had papillary serous adenocarcinoma, and over 40% of them had a stage IV disease in both arms. After median follow-up of 27 months, patients achieved median progression-free survival of 18 months in maintenance arm (A) and 15.5 months in observational arm (B), respectively. Toxicity profile was excellent with no grade 3 or 4 toxicity reported.

CONCLUSIONS

Current study may provide an evidence of efficacy and tolerability of continuous low-dose oral cyclophosphamide and methotrexate as a maintenance therapy in patients with advanced ovarian carcinoma after complete clinical response to platinum and paclitaxel chemotherapy.

Frontline treatment of epithelial ovarian cancer

This is a contemporaneous review of the frontline treatment of epithelial ovarian cancer (EOC), specifically on the importance of optimal surgical cytoreductive surgery, the pivotal role of platinum-based adjuvant chemotherapy (which encompasses intraperitoneal and dose-dense regimens) and the emergence of neo-adjuvant chemotherapy. Additionally, the benefit of concurrent and maintenance bevacizumab in the suboptimally debullked stage III and stage IV EOC setting is also reviewed. The article also discusses the increasing importance of prognostic and predictive molecular biomarkers in the future management of EOC.

Leveraging immunotherapy for the treatment of gynecologic cancers in the era of precision medicine

During the past decade significant progress in the understanding of stimulatory and inhibitory signaling pathways in immune cells has reinvigorated the field of immuno-oncology. In this review we outline the current immunotherapy based approaches for the treatment of gynecological cancers, and focus on the emerging clinical data on immune checkpoint inhibitors, adoptive cell therapies, and vaccines. It is anticipated that in the coming years biomarker-guided clinical trials, will provide for a better understanding of the mechanisms of response and resistance to immunotherapy, and guide combination treatment strategies that will extend the benefit from immunotherapy to patients with gynecologic cancers.

Maintenance chemotherapy in the management of epithelial ovarian cancer

The fundamental goal of maintenance therapy of cancer is to extend a clinically meaningful survival endpoint (overall, symptom-free, progression-free) while at the same time not substantially interfering with a patient's quality of life. Several phase 3 randomized trials in ovarian cancer involving different anti-neoplastics (e.g., paclitaxel, anti-angiogenic agents, olaparib) have revealed an improvement in progression-free survival with generally acceptable side effect profiles, and as a result represent in appropriately selected patients a rational therapeutic strategy.

First-line and maintenance therapy for ovarian cancer: current status and future directions

Paclitaxel and carboplatin combination chemotherapy has remained the standard of care in the frontline therapy of advanced epithelial ovarian carcinoma during the last decade. Maintenance chemotherapy or immunotherapy has not been proven to impact on overall survival and only one clinical trial that explored the administration of monthly paclitaxel for 1 year showed a benefit in terms of progression-free survival (PFS), but at the cost of maintained alopecia and increased peripheral neuropathy. This scenario may be changing with the incorporation of targeted therapy to the frontline therapy of ovarian cancer. In particular, anti-angiogenic therapy has been identified as the most promising targeted therapy, and the addition of bevacizumab to first-line chemotherapy followed by a maintenance period of bevacizumab in monotherapy has shown to prolong PFS. This was considered the proof of concept of the value of anti-angiogenic therapy in the frontline of ovarian cancer, and the results of two additional clinical trials with anti-angiogenic tyrosine-kinase inhibitors have shown results in the same direction.

Maintenance therapy in ovarian cancer

PURPOSE OF REVIEW

Targeted therapies are being used as maintenance therapy to improve the outcome of ovarian cancer following standard treatment in the first-line setting and in recurrent disease. We review the different approaches being used, trial design, and the impact of maintenance treatment on survival and quality of life.

RECENT FINDINGS

The greatest experience of maintenance therapy is with antiangiogenic agents. Several trials targeting vascular endothelial growth factor with bevacizumab or vascular endothelial growth factor receptor with oral tyrosine kinase inhibitors have demonstrated a prolongation in progression-free survival (PFS) following first or second-line treatment. Maintenance therapy with olaparib, a poly ADP ribose polymerase inhibitor given post-platinum therapy for recurrent disease, has led to a prolongation in PFS, particularly, in patients with a BRCA mutation. The results of immunotherapy maintenance studies, based on using cancer antigen 125 as an antigen, have been disappointing. A benefit in PFS often does not translate into overall survival improvement, largely because of crossover and postprogression therapies. This makes clinical interpretation of results more difficult.

SUMMARY

The principle of using molecular targeted therapy to prolong the control of ovarian cancer has been clearly demonstrated. The greatest effect is on prolongation of PFS and, by adding to the effects of standard treatments, maintenance therapy is likely to help incrementally extend the 5-year survival of women with ovarian cancer.

Incorporation of Pazopanib in Maintenance Therapy of Ovarian Cancer

Purpose

Pazopanib is an oral, multikinase inhibitor of vascular endothelial growth factor receptor (VEGFR) -1/-2/-3, platelet-derived growth factor receptor (PDGFR) -α/-β, and c-Kit. Preclinical and clinical studies support VEGFR and PDGFR as targets for advanced ovarian cancer treatment. This study evaluated the role of pazopanib maintenance therapy in patients with ovarian cancer whose disease did not progress during first-line chemotherapy.

Patients and Methods

Nine hundred forty patients with histologically confirmed cancer of the ovary, fallopian tube, or peritoneum, International Federation Gynecology Obstetrics (FIGO) stages II-IV, no evidence of progression after primary therapy consisting of surgery and at least five cycles of platinum-taxane chemotherapy were randomized 1:1 to receive pazopanib 800 mg once per day or placebo for up to 24 months. The primary end point was progression-free survival by RECIST 1.0 assessed by the investigators.

Results

Maintenance pazopanib prolonged progression-free survival compared with placebo (hazard ratio [HR], 0.77; 95% CI, 0.64 to 0.91; P = .0021; median, 17.9 v 12.3 months, respectively). Interim survival analysis based on events in 35.6% of the population did not show any significant difference. Grade 3 or 4 adverse events of hypertension (30.8%), neutropenia (9.9%), liver-related toxicity (9.4%), diarrhea (8.2%), fatigue (2.7%), thrombocytopenia (2.5%), and palmar-plantar erythrodysesthesia (1.9%) were significantly higher in the pazopanib arm. Treatment discontinuation related to adverse events was higher among patients treated with pazopanib (33.3%) compared with placebo (5.6%).

Conclusion

Pazopanib maintenance therapy provided a median improvement of 5.6 months (HR, 0.77) in progression-free survival in patients with advanced ovarian cancer who have not progressed after first-line chemotherapy. Overall survival data to this point did not suggest any benefit. Additional analysis should help to identify subgroups of patients in whom improved efficacy may balance toxicity (NCT00866697).

Estimation of expectedness: predictive accuracy of standard therapy outcomes in randomized phase 3 studies in epithelial ovarian cancer

BACKGROUND

The anticipated clinical outcome of the standard/control arm is an important parameter in the design of randomized phase 3 (RP3) trials to properly calculate sample size, power, and study duration. Changing patterns of care or variation in the study population enrolled may lead to a deviation from the initially anticipated outcome. The authors hypothesized that recent changes in patterns of care in epithelial ovarian cancer (EOC) have led to challenges in correctly estimating the outcome of control groups.

METHODS

A systematic review of the literature was conducted for RP3 trials of EOC published between January 2000 and December 2010. The expected outcome of the control arm as well as the actual outcome achieved by this cohort was collected and a ratio (actual‐over‐expected ratio) was calculated. The estimation of outcome was deemed accurate if the outcome of the control arm was between 0.75 to 1.25 times the anticipated outcome.

RESULTS

A total of 35 trials were eligible for analysis. Fifteen trials had survival as the primary endpoint whereas 20 had a progression‐based primary endpoint. In total, 12 of 15 trials with a survival‐based endpoint significantly underestimated the outcome of the control arm, whereas only 4 of 20 trials with a progression‐based endpoint did. Studies with a survival endpoint underestimated outcome more frequently than those with a progression endpoint (P<.001).

CONCLUSIONS

Survival of the control arm has frequently been underestimated in recent EOC RP3 trials. This underestimation means that the initial statistical assumptions of these trials may have been inaccurate. Underestimating the outcome of the control arm may result in trials being underpowered to demonstrate the absolute benefit they were designed to show. Cancer 2015;121:413–422. © 2014 American Cancer Society.

The anticipated clinical outcome of the standard/control arm is an important parameter in the design of randomized phase 3 trials for the accurate calculation of sample size, power, and study duration but is often underestimated in ovarian cancer trials. Changing patterns of care and variations in enrolled study populations may result in a deviation from the anticipated outcome and subsequent inaccurate statistical assumptions.

Ovarian cancer from an immune perspective

Despite major advances in the treatment of ovarian cancer over the past two decades, it is still an incurable disease and requires the development of better treatment strategies. In recent years, we have developed a greater understanding of tumor immunology and the interactions between tumors and the immune system. This has led to the emergence of cancer immunotherapy as the fourth treatment modality in cancer. In this article, we address the principles of immunotherapy and different approaches that have been investigated over the past decade and discuss the future of immune therapy in ovarian cancer.

Interferon after surgery for women with advanced (Stage II-IV) epithelial ovarian cancer

BACKGROUND

Epithelial ovarian cancer (EOC) is a life-threatening disease. Most often women become symptomatic only in the advanced stages of the disease, increasing the difficulty of treatment. Whilst the disease responds well to surgery and chemotherapy, the relapse rate is high. New treatments to prevent disease recurrence or progression, prolong survival, and increase the quality of life are needed.

OBJECTIVES

To assess the effectiveness and safety of interferon after surgery in the treatment of advanced (stage II-IV) EOC.

SEARCH METHODS

The Cochrane Gynaecological Cancer Review Group Specialized Register, Cochrane Central Register of Controlled Trials (CENTRAL) Issue 1, 2012, MEDLINE and EMBASE were searched to January 2012. Handsearching of conference proceedings was also undertaken. Reference lists of reviews and included trials were screened and experts in the field were contacted for additional trials. Clinical trials registers were searched for ongoing trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) involving participants with advanced EOC that compared post-operative chemotherapy alone with post-operative interferon therapy in combination with chemotherapy or post-operative chemotherapy followed by interferon or observation alone

DATA COLLECTION AND ANALYSIS

Two review authors (AL and AM) independently screened the search results for relevant trials and extracted pre-specified information from each included trial. Data were managed using Review Manager 5.1. Hazard ratios (HR) were calculated for time-to-event outcomes and risk ratios (RR) for dichotomous outcomes, with corresponding 95% confidence intervals (CI).

MAIN RESULTS

Five trials, including 1476 participants, were included in the review. Two trials compared interferon with observation alone and three trials compared interferon plus chemotherapy with chemotherapy alone. A meta-analysis of two trials involving 370 participants found no significant difference in both overall survival (HR 1.14, 95% CI 0.84 to 1.55) and progression free survival (HR 0.99, 95% CI 0.79 to 1.24) between the interferon and observation alone groups in post-surgical women who had undergone first-line chemotherapy for advanced EOC. One trial with 293 participants found that while no significant difference was observed in incidence of nausea or vomiting between the two treatment groups, significantly more flu-like symptoms (RR 2.25, 95% CI 1.73 to 2.91) and fatigue (RR 1.54, 95% CI 1.27 to 1.88) were reported in the interferon group. For the second comparison, a meta-analysis of two trials comprising 244 participants found that although there was no significant difference in overall survival between the interferon plus chemotherapy and the chemotherapy alone group (HR 1.14, 95% CI 0.74 to 1.76), women in the interferon plus chemotherapy group had worse progression free survival than those in the chemotherapy alone group (HR 1.43, 95% CI 1.02 to 2.00). Compared to chemotherapy alone, adding interferon to chemotherapy did not alter the incidence of adverse events in post-surgical women with advanced EOC.

AUTHORS' CONCLUSIONS

Implications for practice Based on low quality evidence, the addition of interferon to first-line chemotherapy did not alter the overall survival in post-surgical women with advanced EOC compared with chemotherapy alone. There is low quality evidence to suggest that interferon in combination with chemotherapy worsened the progression free survival in post-surgical women with advanced EOC compared with chemotherapy alone. There is not enough evidence that interferon therapy alone alters overall survival or progression free survival compared to observation alone in post-surgical women who have undergone first-line chemotherapy.

IMPLICATIONS FOR RESEARCH

Three of the five trials included in this review were stopped early and were, therefore, underpowered to detect any true effect of the intervention. The trials did not report the results of important outcomes in a uniform manner, preventing statistical aggregation of the results. Trial methodology was poorly reported resulting in unclear risk of bias. For clear recommendations to be made regarding the effectiveness of interferon in the treatment of advanced EOC, long-term, well conducted and adequately powered RCTs would be needed. However, the available data do not suggest that interferon has an adequately advantageous effect to warrant further investigation.

Abagovomab as maintenance therapy in patients with epithelial ovarian cancer: a phase III trial of the AGO OVAR, COGI, GINECO, and GEICO--the MIMOSA study

PURPOSE

To determine whether abagovomab maintenance therapy prolongs recurrence-free (RFS) and overall survival (OS) in patients with ovarian cancer in first clinical remission.

PATIENTS AND METHODS

Patients with International Federation of Gynecology and Obstetrics stage III to IV ovarian cancer in complete clinical remission after primary surgery and platinum- and taxane-based chemotherapy were randomly assigned at a ratio of 2:1 in a phase III, double-blind, placebo-controlled, multicenter study. Abagovomab 2 mg or placebo was administered as 1-mL suspension once every 2 weeks for 6 weeks (induction phase) and then once every 4 weeks (maintenance phase) until recurrence or up to 21 months after random assignment of the last patient. The primary end point was RFS; secondary end points were OS and immunologic response.

RESULTS

Characteristics of the 888 patients included: mean age, 56.3 years; Eastern Cooperative Oncology Group performance status, ≤ 1 in > 99% of patients; serous papillary subtype, 81.5%; stage III, 85.9%; and cancer antigen 125 ≤ 35 U/mL after third cycle, 80.9%. Mean exposure to study treatment (± standard deviation) was 449.7 ± 333.08 days. Hazard ratio (HR) of RFS for the treatment group using tumor size categorization (≤ 1 cm, > 1 cm) was 1.099 (95% CI, 0.919 to 1.315; P = .301). HR of OS using tumor size categorization (≤ 1 cm, > 1 cm) was 1.150 (95% CI, 0.872 to 1.518; P = .322). The most frequently reported type of adverse event was an injection site reaction in 445 patients (50.2%), followed by injection site erythema and fatigue in 227 (25.6%) and 212 patients (23.9%), respectively. By the final visit, median anti-anti-idiotypic antibody level was 493,000.0 ng/mL, indicating a robust response.

CONCLUSION

Abagovomab administered as repeated monthly injections is safe and induces a measurable immune response. Administration as maintenance therapy for patients with ovarian cancer in first remission does not prolong RFS or OS.

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.

Maintenance chemotherapy: an evolving and increasingly acceptable strategy in cancer management

Individual randomized phase 3 trials and meta-analyses of previously published studies have provided support for the general concept of the clinical utility of extending the duration of antineoplastic drug therapy in an effort to prolong ("maintain") a favorable clinical state. This commentary briefly reviews data from several of these reports.

Abagovomab: an anti-idiotypic CA-125 targeted immunotherapeutic agent for ovarian cancer

Ovarian cancer remains the leading cause of death due to gynecologic malignancies. Most patients present with advanced disease at the time of diagnosis. Although many have a good initial response to surgical debulking and platinum-based chemotherapy, relapse is common, with the eventual development of chemotherapy resistance. Innovative treatments are needed in the remission setting to prolong the disease-free interval or prevent recurrence. Abagovomab is a murine monoclonal anti-idiotypic antibody (molecular weight: 165-175 kDa) that functionally imitates the tumor-associated antigen, CA-125. It has been shown to be well tolerated and to induce a sustained immune response in initial Phase I and II clinical trials. An ongoing, double-blind, placebo-controlled, multicenter, Phase III trial (MIMOSA) completed its double-blind period in December 2010 and will compare abagovomab maintenance therapy to placebo, which will definitively determine the efficacy of this immunotherapeutic approach in patients with ovarian cancer.

Immune response in ovarian cancer: how is the immune system involved in prognosis and therapy: potential for treatment utilization

Ovarian cancer is one of the leading causes of cancer-related death among women. Resistance to the disease occurs in more than 70% of the cases even after treated with chemotherapy agents such as paclitaxel- and platinum-based agents. The immune system is increasingly becoming a target for intense research in order to study the host's immune response against ovarian cancer. T cell populations, including NK T cells and Tregs, and cytokines have been associated with disease outcome, indicating their increasing clinical significance, having been associated with prognosis and as markers of disease progress, respectively. Harnessing the immune system capacity in order to induce antitumor response remains a major challenge. This paper examines the recent developments in our understanding of the mechanisms of development of the immune response in ovarian cancer as well as its prognostic significance and the existing experience in clinical studies.

Continued chemotherapy after complete response to primary therapy among women with advanced ovarian cancer: a meta-analysis

BACKGROUND

Ovarian cancer (OC) is associated with a >75% risk of recurrence after completion of primary therapy. Several clinical trials have explored the role of continued therapy after complete response to primary adjuvant therapy to reduce the risk of recurrence; however, these trials have largely been underpowered, leading to inconclusive results.

METHODS

A systematic search strategy was initiated to identify all clinical trials involving consolidation or maintenance therapy regimens for OC in first complete remission. A meta-analysis was conducted to evaluate toxicity and progression-free (PFS) and overall survival (OS).

RESULTS

There were 37 publications meeting all eligibility criteria, representing 20 consolidation and 9 maintenance therapy trials. Consolidation and maintenance therapies were associated with improved PFS (hazard ratio [HR], 0.79 [P = .003] and HR, 0.82 [P = .02], respectively) and OS (HR, 0.68 [P = .0008] and HR, 0.68 [P = .007], respectively). This relationship remained statistically significant when the analysis was limited to randomized trials and across other sensitivity analyses.

CONCLUSIONS

Although individual studies have not yet convincingly shown a survival advantage with maintenance chemotherapy in OC, this meta-analysis demonstrates that continued chemotherapy after completion of primary therapy for OC improves PFS and OS. Benefits are greatest in patients with advanced stage OC who reach complete clinical or pathologic response after primary therapy.

First-line systemic treatment of ovarian cancer: a critical review of available evidence and expectations for future directions

PURPOSE OF REVIEW

Epithelial ovarian cancer (EOC) is a prevalent gynecologic malignancy whose prognosis in most cases remains poor despite advances in therapy. In this article, we critically review the available clinical evidence for the choice of first-line chemotherapy in EOC and discuss promising therapeutic strategies.

RECENT FINDINGS

In the last 25 years, first-line chemotherapy regimens and the indication of systemic treatment for early-stage disease have been better established. Significant progress has been made in the treatment of advanced EOC with the optimization of the carboplatin plus paclitaxel regimen and the use of intraperitoneal chemotherapy for selected patients. Targeted therapies may be approved for EOC in the near future and this would bring more specific treatments and improve outcomes for patients. Validated biomolecular signatures to better define prognosis and to predict response to therapeutic agents are still lacking.

SUMMARY

The standard first-line chemotherapy in EOC is based on the doublet carboplatin plus paclitaxel. It may be possible to improve the efficacy of treatment by means of a more intensive dose-dense regimen or by the intraperitoneal delivery of chemotherapy. Significant improvements in the treatment of EOC are expected from the development of antiangiogenic and other targeted agents and from better patient selection.

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.

The role of interferons in the treatment of osteosarcoma

Interferons, a group of cytokines with antiangiogenic, direct antitumour and immunostimulating properties, have shown significant activity against osteosarcoma in vitro and in xenograft models. They have also been used in osteosarcoma clinical trials as a single adjuvant to surgery, with an apparent increase in relapse-free survival. In the ongoing EURAMOS 1 clinical trial, interferon alpha-2b is evaluated as an adjuvant treatment in osteosarcoma. This article reviews the rationale for the use of interferon in cancer with special reference to the treatment of osteosarcoma, including all published data of clinical efficacy in this disease.

Consolidation strategies in ovarian cancer: observations for future clinical trials

PURPOSE.: To describe the characteristics of a series of study populations of ovarian cancer patients with identical eligibility criteria in second or subsequent clinical remission (cCR) and to propose endpoint benchmarks for future consolidation studies. PATIENTS AND METHODS.: The patient populations consisted of those (1) untreated (U; observed until progression; n=35, (2) receiving imatinib (G; n=32), (3) receiving goserelin and bicalutamide (A; n=32), and (4) receiving vaccine (V; n=68; total=167). The endpoint of the combined analysis was progression-free survival in second remission (PFS 2). Patient characteristics were compared by chi-square test, and factors predicting PFS 2 evaluated in multivariate Cox model. RESULTS.: Groups were comparable for age, stage, grade, and debulking. Multivariate model to predict PFS 2 duration included histology, stage, optimal debulking, PFS 1 duration, and the type of intervention. As a benchmark for future studies, the median PFS 2 of the combined population of G, A, and U (removing V which had the most impact in prolonging PFS 2, n=68) was 11.3 months (95% CI: 10.4-12.5 months). The percent of patients with PFS 2>PFS 1 was 14/90 (16%). At 12 months, 43% remain progression-free. CONCLUSION.: Preliminary benchmarks for efficacy endpoints are suggested for future consolidation trials of patients in cCR. However, the suggested strategies will require validation in randomized trials and larger data sets.

Consolidation Therapy in Ovarian Cancer: A Clinical Update

Objectives:

To evaluate current strategies under investigation for use as consolidation or maintenance treatment in patients with ovarian cancer.

Patients with epithelial ovarian cancer often enter a complete remission after primary treatment. Many relapse, unfortunately, but some can return to remission after additional treatment. Outcomes can be improved by applying effective consolidation or maintenance approaches to patients in a complete primary or subsequent remission.

Methods:

A selective review of the literature is undertaken to consider strategies that are being or will likely be evaluated in randomized trials while we assess whether consolidation or maintenance will have a place in the treatment of patients with ovarian cancer.

Results:

The application of extended standard cytotoxic agents has been generally disappointing, and no strategy applied in the first remission setting has prolonged overall survival.

Conclusions:

As treatment options move beyond classic chemotherapy to novel hormones, immune interventions, and biologic agents, the consolidation strategy is regaining interest. This is particularly attractive in that many of these agents have stable disease as best outcome, and this is most appropriate to evaluate in patients with minimal volume disease. A consideration of toxicity is paramount, and any strategy to be considered in an otherwise asymptomatic patient in remission must be well tolerated. In addition, patients in second or third complete remission are also being considered as an appropriate group in which to evaluate new agents. Numerous other phase 2 trials with novel agents not considered here are underway, and it is to be hoped that some will emerge as contenders for randomized trials. Participation in these trials remains a priority for patients who otherwise must pursue a difficult watch-and-wait strategy.

Ovarian cancer

The standard initial management of epithelial ovarian cancer consists of surgical staging, operative tumour debulking including total abdominal hysterectomy and bilateral salpingo-oophorectomy, and administration of six cycles of intravenous chemotherapy with carboplatin and paclitaxel. Extensive and largely retrospective experience has shown that optimum surgical debulking to leave residual tumour deposits that are less than 1 cm in size is associated with improved patient outcomes. However, 75% of patients present with advanced (stage III or IV) disease and, although more than 80% of these women benefit from first-line therapy, tumour recurrence occurs in almost all these patients at a median of 15 months from diagnosis. Second-line treatments can improve survival and quality of life but are not curative. Advances in screening and understanding of molecular pathogenesis of ovarian cancer and development of novel targeted therapies (eg, bevacizumab) and practical intraperitoneal techniques for drug delivery are most likely to improve patient outcomes.

Phase III Trial of Observation Versus Six Courses of Paclitaxel in Patients With Advanced Epithelial Ovarian Cancer in Complete Response After Six Courses of Paclitaxel/Platinum-Based Chemotherapy: Final Results of the After-6 Protocol 1

Purpose

To assess whether six courses of paclitaxel are effective as consolidation treatment in patients with advanced epithelial ovarian cancer who are in complete response after first-line paclitaxel/platinum–based chemotherapy.

Patients and Methods

Patients with stages IIb to IV disease in clinical or pathologic complete response after six courses of paclitaxel/platinum–based chemotherapy were randomly allocated to either observation (ie, control) or six courses of paclitaxel 175 mg/m2 every 3 weeks (ie, maintenance).

Results

Two hundred patients were randomly assigned from March 1999 to July 2006. Because of the low accrual rate, an unplanned interim analysis of futility according to the Bayesian approach was performed. Grade 2 or greater motor neurotoxicity and sensory neurotoxicity were reported in 11.3% and 28.0% of the paclitaxel-arm patients, respectively. After a median follow-up of 43.5 months, 107 patients (53%) had experienced relapse, and 48 patients (24%) had died. Two-year progression-free survival rates were 54% (95% CI, 43% to 64%) and 59% (95% CI, 49% to 69%; P = not significant) in the control and maintenance arms, respectively. Corresponding 2-year overall survival rates were 90% (95% CI, 84% to 97%) and 87% (95% CI, 80% to 94%; P = not significant), respectively. The Cox model showed that residual disease after initial surgery (macroscopic v no macroscopic residuum; hazard ratio [HR], 1.91; 95%CI, 1.21 to 3.03) and stage (IIIc to IV v others; HR, 3.10; 95% CI, 1.13 to 8.48) were independent prognostic factors for progression-free survival, whereas the treatment arm (maintenance v control) had no prognostic relevance.

Conclusion

A consolidation treatment with six cycles of paclitaxel does not prolong progression-free survival or overall survival in patients in complete response after first-line paclitaxel/platinum–based regimens.

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.

The side population of ovarian cancer cells is a primary target of IFN-alpha antitumor effects

The side population (SP), recently identified in several normal tissues and in a variety of tumors based on its ability to extrude some fluorescent dyes, may comprise cells endowed with stem cell features. In this study, we investigated the presence of SP in epithelial ovarian cancer and found it in 9 of 27 primary tumor samples analyzed, as well as in 4 of 6 cultures from xenotransplants. SP cells from one xenograft bearing a large SP fraction were characterized in detail. SP cells had higher proliferation rates, were much less apoptotic compared with non-SP cells, and generated tumors more rapidly than non-SP cells. We also investigated the effects of IFN-alpha, a cytokine that has widely been used to treat solid tumors, on epithelial ovarian cancer cells and observed that IFN-alpha exerted marked antiproliferative and proapoptotic effects on primary cultures containing high numbers of SP cells. In vitro, IFN-alpha treatment invariably caused a dramatic reduction in SP size in tumor cell lines of different origins; moreover, IFN-alpha treatment of purified SP cells was associated with a distinctive change in their transcriptional profile. Gene therapy with human IFN-alpha resulted in regression of established tumors bearing a large SP fraction, which was not observed when tumors bearing low SP levels were treated. These findings could have relevant clinical implications because they imply that tumors bearing large SP numbers, albeit rare, could be sensitive to IFN-alpha treatment.

Radiation therapy and biological compounds for consolidation therapy in advanced ovarian cancer

Consolidation therapy is used in order to maximize the benefit of first-line therapy and to improve the progression-free and overall survival of patients. In women with advanced epithelial ovarian cancer, tested maintenance and consolidation strategies following first-line chemotherapy include high-dose chemotherapy, radiation therapy, intraperitoneal radionuclides including those linked to an antibody, and biological and immunologic agents. This review focuses on the current understanding of the benefit of radiation therapy and biological agents used as consolidation in women with advanced ovarian cancer. Whole abdominal radiation has given promising results only in the subgroup of patients with pathologic complete response. However, this treatment modality is associated with considerable intestinal toxicity. Single treatment with intraperitoneal radionuclides, either alone (32P) or in combination with an antibody (90Y-muHMFG1) has not improved survival. Biological agents used for consolidation include, eg, alpha- and gamma-interferon, tanomastat, a matrix metalloprotease inhibitor and oregovomab, a murine antibody that targets CA125. Randomized trials with these agents have not demonstrated any significant improvement in the overall survival of ovarian cancer patients. Currently, two ongoing studies (GOG 218, ICON7) are examining the potential of bevacizumab in the maintenance therapy of advanced epithelial ovarian cancer. Evaluation of new agents is indicated in order to achieve long-term disease-free survival in these patients. Toxicity and ease of administration must be reflected against the benefits of therapy.

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.

Current management strategies for ovarian cancer

Epithelial ovarian cancer originates in the layer of cells that covers the surface of the ovaries. The disease spreads readily throughout the peritoneal cavity and to the lymphatics, often before causing symptoms. Of the cancers unique to women, ovarian cancer has the highest mortality rate. Most women are diagnosed as having advanced stage disease, and efforts to develop new screening approaches for ovarian cancer are a high priority. Optimal treatment of ovarian cancer begins with optimal cytoreductive surgery followed by combination chemotherapy. Ovarian cancer, even in advanced stages, is sensitive to a variety of chemotherapeutics. Although improved chemotherapy has increased 5-year survival rates, overall survival gains have been limited because of our inability to eradicate all disease. Technologic advances that allow us to examine the molecular machinery that drives ovarian cancer cells have helped to identify numerous therapeutic targets within these cells. In this review, we provide an overview of ovarian cancer with particular emphasis on recent advances in operative management and systemic therapies.

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.

Novel therapeutic agents in ovarian cancer

AIMS

Epithelial ovarian cancer is responsible for 4% of all cancer deaths in women, and the five-year overall survival of patients with advanced disease is 30-40%. Treatment currently comprises a combination of surgery and chemotherapy with carboplatin and paclitaxel. The main reason for treatment failure is that the majority of patients present with advanced disease, and current drugs are unable to effect a cure even in chemosensitive patients. This article systematically reviews novel therapeutic strategies that have been evaluated in patients with ovarian cancer in the last 5 years.

METHODS

Pubmed (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed) and American Society of Clinical Oncology Annual conference abstracts were searched using the terms "(phase I OR phase II OR phase III OR phase 1 OR phase 2 OR phase 3) AND (ovary OR ovarian) AND (cancer OR carcinoma)" from January 2000 to May 2005 to identify studies for potential inclusion in this review. Reviews of novel therapies in ovarian cancer were also used to identify additional clinical trials.

FINDINGS

A wide range of therapeutic strategies are currently being evaluated in ovarian cancer. These include novel cytotoxics, small molecule inhibitors, monoclonal antibodies, gene therapy and immuno-therapy strategies. The rationale for the development of these agents includes enhancement of efficacy by targeting novel biological pathways, re-sensitisation to existing drugs, simplification of drug administration and/or reduction of drug-toxicity.

CONCLUSIONS

Current developments have the potential to result in substantial improvements in the outlook for women with ovarian cancer.