Updated Overall Survival Analysis in Oceans, a Randomized Phase 3 Trial of Gemcitabine (G) + Carboplatin (C) and Bevacizumab (BV) or Placebo (PL) Followed by BV or PL in Platinum-Sensitive Recurrent Epithelial Ovarian (ROC), Primary Peritoneal (PPC), or Fallopian Tube Cancer (FTC)

Biological Pathways Involved in Tumor Angiogenesis and Bevacizumab Based Anti-Angiogenic Therapy with Special References to Ovarian Cancer

The creation of new blood vessels from existing ones, which is a mechanism called “angiogenesis”, is essential in cancer to supply cancerous growth. Moreover, the development and the progression of the tumor and its metastases are the result of an efficient vascular response. Cancer cells release and activate different angiogenic growth factors and their receptors in the tumor microenvironment to promote the angiogenic process. The most important pro-angiogenic factor is the “Vascular Endothelial Growth Factor” (VEGF) because of its mitogen activity on vascular endothelium. Bevacizumab is a monoclonal antibody that obstructs the binding of circulating vascular endothelial growth factor to its receptors and has been approved for the treatment of primary and recurrent ovarian cancer but also for many other solid tumors.

Improvements in progression-free and overall survival due to the use of anti-angiogenic agents in gynecologic cancers

OPINION STATEMENT

In ovarian cancer (OC), the best established anti-angiogenic drug, bevacizumab, has demonstrated only modest prolonged progression free survival (PFS) and no increased overall survival (OS). The unanswered question is in which clinical situation bevacizumab might benefit ovarian cancer patients most. The cost-benefit analysis in the primary treatment was found not to be favorable but the use in the recurrent OC setting might be more compelling. Multi-targeted anti-angiogenic tyrosine kinase inhibitors (TKI) such as cediranib and pazopanib have shown some therapeutic benefits with improvements of PFS and OS in patients with platinum-sensitive as well as resistant OC, in whom there is a major need for novel therapies. Very promising is also the observed improvement of PFS in recurrent OC in patients when combining cediranib with the PARP inhibitor olaparib without giving additional chemotherapy. The anti-angiogenic agent trebananib has achieved similar results like TKI, but has a favorable toxicity profile which does not overlap with those of VEGF inhibitors. In cervical cancer the addition of bevacizumab to combination chemotherapy in patients with recurrent, persistent or metastatic chemotherapy-naive disease results in a significant increase in OS. Considering the lack of therapeutic options in this difficult clinical setting, the inclusion of bevacizumab most likely will become a new standard for recurrent cervical cancer. In uterine sarcomas as very aggressive malignancies with a substantial need for better therapies the observed improved PFS with sorafenib warrants further investigation. No data showing a convincing improvement of survival in endometrial cancer have been presented yet. In view of the limited PFS and OS benefit observed with anti-angiogenics in gynecologic oncology, increased morbidity due to side effects of this treatment resulting in loss of quality of life and also substantial costs have to be taken into consideration. Thorough case selection based on molecular subgrouping of gynecologic cancers will therefore be a prerequisite for future anti-angiogenic therapy. This will require the integration of molecular diagnostics which still have to be developed and standardized.

Final overall survival and safety analysis of OCEANS, a phase 3 trial of chemotherapy with or without bevacizumab in patients with platinum-sensitive recurrent ovarian cancer

OBJECTIVE

OCEANS is a randomized, placebo (PL)-controlled, phase 3 trial evaluating the efficacy and safety of bevacizumab combined with gemcitabine+carboplatin (GC) for patients with platinum-sensitive recurrent ovarian cancer (ROC). The study met its primary endpoint, demonstrating improved progression-free survival with GC+bevacizumab compared with GC+PL. Herein, we describe results of final overall survival (OS) and updated safety.

METHODS

Patients with recurrent platinum-sensitive ROC (recurring ≥6months after first-line platinum-based therapy) and measurable disease at baseline were randomized to receive GC+bevacizumab or GC+PL for 6-10cycles; PL or bevacizumab was then continued until disease progression. In this updated analysis, a Cox proportional hazards model was used to compare OS between the 2 treatment arms.

RESULTS

At the data cutoff date (July 19, 2013), 353 patients (72.9%) had died. Median follow-up for OS was 58.2months in the experimental arm and 56.4months in the control arm. Consistent with interim analyses, median OS was comparable between arms (GC+bevacizumab: 33.6months; GC+PL: 32.9months; hazard ratio=0.95; log-rank p=0.65), and was consistent across all examined patient subgroups. The frequency and severity of adverse events were consistent with previous analyses; no new safety concerns were identified.

CONCLUSIONS

Results from final OS analysis of the phase 3 OCEANS study showed no significant difference in OS for patients treated with GC+bevacizumab compared with GC+PL.

Paclitaxel/carboplatin with or without sorafenib in the first-line treatment of patients with stage III/IV epithelial ovarian cancer: a randomized phase II study of the Sarah Cannon Research Institute

This trial compared the efficacy and toxicity of standard first-line treatment with paclitaxel/carboplatin versus paclitaxel/carboplatin plus sorafenib in patients with advanced ovarian carcinoma. Patients with stage 3 or 4 epithelial ovarian cancer with residual measurable disease or elevated CA-125 levels after maximal surgical cytoreduction were randomized (1:1) to receive treatment with paclitaxel (175 mg/m², 3 h infusion, day 1) and carboplatin (AUC 6.0, IV, day 1) with or without sorafenib 400 mg orally twice daily (PO BID). Patients were reevaluated for response after completing 6 weeks of treatment (two cycles); responding or stable patients received six cycles of paclitaxel/carboplatin. Patients receiving the sorafenib-containing regimen continued sorafenib (400 PO BID) for a total of 52 weeks. Eighty-five patients were randomized and received treatment.Efficacy was similar for patients receiving paclitaxel/carboplatin/sorafenib versus paclitaxel/carboplatin: overall response rates 69% versus 74%; median progression-free survival 15.4 versus 16.3 months; 2 year survival 76% versus 81%. The addition of sorafenib added substantially to the toxicity of the regimen; rash, hand–foot syndrome, mucositis, and hypertension were significantly more common in patients treated with sorafenib. The addition of sorafenib to standard paclitaxel/carboplatin did not improve efficacy and substantially increased toxicity in the first-line treatment of advanced epithelial ovarian cancer. Based on evidence from this study and other completed trials, sorafenib is unlikely to have a role in the treatment of ovarian cancer.

Increasing the chances for platinum-sensitive ovarian cancer patients

Ovarian carcinoma is still one of the most common causes of death from cancer in the western world. Despite high sensitivity to chemotherapy, the majority of patients will relapse within 3 years. In this article the focus is centered on patients who have a late relapse (>12 months). Carboplatin-based regimens are the backbone of treatment for this group, producing clinical benefit with higher rates for progression-free and overall survival. However, not all patients can continue with platinum owing to loss of activity or toxicity (hypersensitivity, neurotoxicity and ototoxicity). In particular, hypersensitivity reactions to carboplatin are a concern and have been reported in approximately 15–20% of women receiving the drug. When expectations for a positive outcome with carboplatin are good, desensitization protocols may be useful so as to continue treatment. If platinum-based regimens are not possible then alternative forms of treatment are required; additional research efforts are being directed towards the development of nonplatinum-based therapies. Promising results have been obtained with the combination of trabectedin plus pegylated liposomal doxorubicin, providing encouragement that it will be a viable option for patients with recurrent ovarian cancer who cannot be treated with a platinum-based chemotherapeutic option.

Contemporary use of bevacizumab in ovarian cancer

INTRODUCTION

Ovarian cancer remains the most lethal gynecologic malignancy. Although standard platinum-based chemotherapy results in high response rates, more than 70% of patients with advanced disease will experience recurrence within 5 years. Therefore, novel treatment strategies to increase primary efficacy, decrease recurrence after primary treatment and improve the response rate for recurrent disease are needed.

AREAS COVERED

This review covers antiangiogenesis therapy and the efficacy of bevacizumab as primary treatment and in platinum-sensitive and resistant recurrent disease.

EXPERT OPINION

The evidence provided from Phase III trials has supported the efficacy of bevacizumab in primary and recurrent ovarian cancer management. Future investigation is needed to improve clinical performance (via biomarkers of efficacy, early discontinuation, additional agents, etc.), as well as, more sensitive tools to assess direct patient impact.