Maintenance Therapy In Ovarian Cancer Research Articles

Where do Antiangiogenic Agents Belong in the Treatment Algorithm for Ovarian Cancer?

Although epithelial ovarian cancer responds well to chemotherapy, patients presenting with advanced disease still have a poor prognosis. The clear role of angiogenesis in the development and progression of ovarian tumorigenesis has led to the development of several novel antiangiogenic agents; however, questions remain as how to best incorporate such agents into current treatment algorithms. Searches of PubMed (terms: angiogenesis, VEGF, tyrosine kinase inhibitor, bevacizumab and ovarian cancer) and of recent results from key oncology congresses (terms: drug names and ovarian cancer) were performed to identify relevant articles and abstracts. Clinical trials are ongoing to evaluate investigational antiangiogenic agents as a component of first-line chemotherapy, as a treatment option for recurrent disease, and as maintenance therapy for ovarian cancer. The antiangiogenic monoclonal antibody bevacizumab has demonstrated a progression-free survival benefit in combination with first-line paclitaxel/carboplatin and continued as maintenance therapy, and phase II data suggest therapeutic potential for several multitargeted tyrosine kinase inhibitors in ovarian cancer, with phase III results forthcoming for BIBF 1120, cediranib, and pazopanib. Antiangiogenic therapy remains a promising strategy for ovarian cancer, and it is hoped that results from ongoing trials will inform their optimal placement in the treatment paradigm.

Treatment with Paclitaxel Orotate and Carboxyamidotriazole Orotate in SC-Implanted OVCAR-5 Human Ovarian Tumor Xenografts

Background: Paclitaxel (PTX) is approved for the treatment of refractory ovarian cancer and breast cancer, but is problematic due to severe, dose-dependent, potentially irreversible neurotoxicity. Alternative formulations using nanoparticles and liposomes have been developed to avoid solvent-related toxicity. These formulations allow improved delivery; however, toxicity, compensatory signaling, and drug resistance still pose challenges. Conversion of cytotoxic agents to their orotate compounds offers a potentially improved approach by increasing bioavailability and reducing toxicity. Orotate salts are neutral and acquire lipophilic properties, easing diffusion through lipid membranes. The orotate salt of PTX (PTXO) may yield an improved safety profile. Combination therapy with cytotoxic drugs, antiangiogenics and/or signal transduction pathway inhibitors has shown better efficacy than cytotoxic monotherapy. The combination of carboxyamidotriazole orotate (CTO, a calcium signal transduction pathway inhibitor) and PTX may be more effective than PTX alone at non-toxic doses. Materials and Methods: PTXO alone, and combinations of CTO with PTX and PTXO were first tested in female athymic NCr-nu/nu mice to evaluate tolerance of the combinations. The tolerated combinations, PTX monotherapy, and PTXO monotherapy were then tested to evaluate their antitumor activity in female athymic NCr-nu/nu mice with subcutaneously implanted OVCAR-5 human ovarian tumor. Antitumor activity was measured by median time to doubling, median tumor growth delay, and mean percent body weight loss. Results: CTO, PTX, and PTXO showed significant inhibition of growth of the human OVCAR-5 ovarian tumor xenografts. The combination of low PTX and CTO, or high PTXO monotherapy, had significant efficacy and it was less toxic than high PTX as measured by body weight loss. Conclusions: Low-dose CTO is effective and has low toxicity, suggesting the potential for maintenance therapy for ovarian cancer. PTXO offers efficacy and a strategy for minimizing body weight loss, and may improve outcomes for patients who demonstrate toxicity to PTX.

Olaparib as maintenance therapy for ovarian cancer

Olaparib as maintenance therapy for ovarian cancer

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.

The rationale for mTOR inhibition in epithelial ovarian cancer

The AKT/mTOR signaling pathway is frequently overexpressed in human epithelial ovarian cancer and an attractive target for therapy. In vivo mouse models were confirmative for in vitro findings, where the administration of mTOR inhibitors in ovarian cancer xenografts showed antitumoral as well as antiangiogenic effects. Phase I – II trials are now ongoing with mTOR inhibitors in ovarian cancer patients, some in combination with conventional cytotoxic agents. If further development of mTOR inhibition in ovarian cancer is pursued, studying combinations of mTOR inhibitors with other new targeted therapies would be of interest. mTOR inhibitors in the adjuvant setting could have potential, since, for the moment, there is no standard maintenance therapy in ovarian cancer. A crucial challenge will be to identify strong predictive biomarkers. This review highlights the rationale for the use of mTOR inhibitors in ovarian cancer and summarizes the available preclinical findings.

A randomized phase II placebo-controlled trial using maintenance therapy to evaluate the vascular targeting agent BIBF 1120 following treatment of relapsed ovarian cancer (OC)

5501 Background: BIBF 1120 is a new targeted therapeutic agent for maintenance therapy in OC. It is a unique triple angiokinase inhibitor, targeting 3 receptor classes involved in the formation of blood vessels (VEGFR, PDGFR, and FGFR). Methods: Continuous BIBF 1120 (250 mg, oral, twice daily) for up to 9 months (mo) was compared with placebo in a novel application of a randomized double-blind trial in pts who responded to their last (at least second line) chemotherapy. The primary endpoint, progression-free survival at 36 weeks, was confirmed by CT assessment, performed at 12-week intervals. Results: 84 pts were randomized (44 BIBF 1120; 40 placebo), mean age 60y (range 27–76). All had responded according to GCIG criteria. Treatment-free interval before prior chemotherapy was <6 mo for 41% and 6–12 mo for 59% of pts. Median treatment duration was 116 days (d), range, 2–281d (BIBF 1120) and 101 d, 2–239d (placebo). Five BIBF 1120 pts completed 9 mo of treatment vs 0 placebo pts. The 36-wk PFS rates (95% confidence interval [CI]) were 15.6% (3.8, 27.3) for BIBF 1120 and 2.9% (0.0, 8.4) for placebo. Although the trial was not powered for a direct comparison, the PFS hazard ratio was 0.68 (95% CI: 0.42, 1.09). Median time to RECIST progression (mo) was 4.8 for BIBF 1120, and 2.8 for placebo. There were no deaths during treatment. Grade 3 and 4 adverse events (AE) were seen in 54 and 7% (BIBF 1120) and 25 and 3% (placebo) of pts. Expected gastrointestinal toxicities occurred slightly more frequently in the BIBF 1120 arm (16 vs 10%, all gd 3; no gd 4 events). Elevated liver enzymes occurred in 43% (BIBF 1120) vs. 6.3% (placebo). Conclusions: Our trial suggests that maintenance BIBF 1120 could delay disease progression in OC pts who had previously responded to chemotherapy. A large phase III trial is needed to confirm the efficacy of this drug. [Table: see text]

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.