Current Pharmaceutical Design - Volume 18, Issue 25, 2012

The standard treatment for advanced ovarian cancer consists in complete cytoreductive surgery (CRS) and intravenous combination chemotherapy with a platinum compound and a taxane. Although response rates to initial therapy are high, many patients will recur and die of peritoneal carcinomatosis. The addition of Hyperthermic IntraPEritoneal Chemotherapy (HIPEC) to the standard therapy aims at increasing survival by reducing peritoneal recurrence. This review describes the survival results of HIPEC at the different time-points of the treatment of ovarian cancer: at upfront CRS, at interval CRS, at consolidation CRS after complete response to initial therapy, at secondary CRS after incomplete response, at salvage CRS for recurrence and as palliative treatment without CRS for unresectable ovarian cancer with chemotherapy resistant ascites. The available evidence suggests that a potential survival benefit of adding HIPEC may be largest in the settings of secondary CRS for stage III ovarian cancer and salvage CRS for recurrent ovarian cancer, two time-points representing failure of initial standard therapy. There is much less evidence for a potential benefit of HIPEC for less advanced stages (I-II) and for earlier time-points in the treatment of ovarian cancer (upfront, interval and consolidation). Postoperative mortality is not higher after CRS and HIPEC (0.7%) than after CRS only (1.4%). Four randomised trials are ongoing and their results are eagerly awaited. Palliative HIPEC without CRS might be used more in patients with incapacitating ascites due to recurrent ovarian cancer which has become resistant to systemic chemotherapy.

Immunotherapy for ovarian cancer is one of the new treatment strategies currently investigated in epithelial ovarian cancer. This review discusses the results of different immunization strategies, identifies possible drawbacks in study design and provides potential solutions for augmentation of clinical efficacy. A potential target for cancer immunotherapy is p53, as approximately 50% of ovarian cancer cells carry p53 mutations. Therefore we review the immunological and clinical responses observed in ovarian cancer patients vaccinated with p53 targeting vaccines in particular. In most studies antigen-specific vaccine-induced immunological responses were observed. Unfortunately, no clinical responses with significant reduction of tumor-burden have been reported. Based on the currently available results we emphasize the necessity of multimodality treatment of ovarian cancer, combining classical cytoreductive surgery, (neo) adjuvant chemotherapy, immunotherapy and/or targeted therapy.

Epithelial ovarian cancer (EOC) is the most lethal of the gynecologic malignancies, largely due to the advanced stage at diagnosis in most patients. Standard treatment for EOC is surgical debulking followed by platinum-based chemotherapy. While the majority of ovarian cancer patients will respond to initial chemotherapy, most will ultimately relapse. The major focus of current clinical trials for treatment of recurrent ovarian cancer is the use of targeted biologic agents. Folate receptor alpha (FRα) is upregulated in majority of EOC and correlated with tumor stage and grade. It is hypothesized that the presence of overexpressed FRα correlates with the propagation rate of the tumors. FRα is largely absent from normal tissue, making it an attractive therapeutic target. Farletuzumab (MORAb-003), a humanized monoclonal antibody against FRα, has shown antitumor activity in preclinical xenograft models. A Phase 1 dose escalation study did not demonstrate dose-limiting toxicities, or severe adverse effects. A phase 2 efficacy and safety study of farletuzumab with carboplatin and taxane in patients with platinum-sensitive EOC in first relapse, have shown an improved response rate and time to progression compared with historical controls. Recently, preliminary safety data from a phase 1 trial reported that the combination of farletuzumab, carboplatin and PLD has an acceptable safety profile in patients with platinum- sensitive EOC following first or second relapse. Two randomized, double-blind, placebo-controlled Phase 3 studies with farletuzumab plus chemotherapy have been done. A trial of: farletuzumab with weekly paclitaxel in platinum-resistant EOC closed in December 2011 with full report pending. A second trial of farletuzumab with carboplatin and taxane in platinum-sensitive EOC in first relapse is slated to complete accrual in early 2012. Results from these trials will help define the role of farletuzumab in EOC.

Epithelial ovarian cancer is a major problem as about 75% of patients develop recurrence after initial primary treatment and tumors are often chemoresistant. This article reviews the role of the interleukin-6 (IL-6) in chemoresistance and suppression of tumor immunity in ovarian cancer and provides the rationale for modulating the IL-6/ IL-6 receptor (IL-6R) induced pathway as a potential new target for the treatment of ovarian cancer. IL-6 is elevated in serum and ascites of ovarian cancer patients and increased IL-6 levels correlate with chemoresistance and poor prognosis in these patients. IL-6 induced Jak/Stat3, Ras/MEK/ERK and PI3K/Ras signaling pathways lead to cell survival, proliferation, angiogenesis, and confers resistance to apoptosis induced by conventional therapies. Furthermore, IL-6 induces tumor-promoting macrophages which are known to foster tumor growth and suppress local immunity. However, direct proof of the clinical impact of IL-6 blocking on disease progression is missing necessiting further studies in which the IL-6(R) pathway is modulated and its clinical impact on (epithelial) ovarian cancer is tested.