Investigational agents for epithelial ovarian cancer

Emerging drugs for ovarian cancer

IMPORTANCE OF THE FIELD

Ovarian cancer has the highest mortality of all female reproductive tract cancers, which reflects both the absence of proven ovarian cancer screening tests and the development of drug-resistant cancer cell. Apart from varying the dosages, schedules, mode of delivery and combinations of existing drugs, efforts must continue to identify signaling pathways in tumor cells sufficiently different from normal cells that can be a target for maximizing tumor kill and minimizing toxicity.

AREAS COVERED IN THIS REVIEW

Some of the most important cellular pathways are analyzed and discussed and the most interesting clinical trials, both closed and ongoing, described.

WHAT THE READER WILL GAIN

The reader will gain a panoramic vision of all the most active drugs in clinical investigations in ovarian cancer. The reader will also better understand what the unresolved problems of molecular research are and how complicated the process 'from the bench to the bedside' is.

TAKE HOME MESSAGE

It is only with a strong commitment, cooperation and collaboration from the international ovarian cancer community that significant improvement in patient outcomes can be attained beyond the marginal gains achieved so far.

Visualization of hypoxia in microscopic tumors by immunofluorescent microscopy

Tumor hypoxia is commonly observed in primary solid malignancies but the hypoxic status of subclinical micrometastatic disease is largely unknown. The distribution of hypoxia in microscopic tumors was studied in animal models of disseminated peritoneal disease and intradermal (i.d.) growing tumors. Tumors derived from human colorectal adenocarcinoma cell lines HT29 and HCT-8 ranged in size from a few hundred microns to several millimeters in diameter. Hypoxia was detected by immunofluorescent visualization of pimonidazole and the hypoxia-regulated protein carbonic anhydrase 9. Tumor blood perfusion, cellular proliferation, and vascularity were visualized using Hoechst 33342, bromodeoxyuridine, and CD31 staining, respectively. In general, tumors of <1 mm diameter were intensely hypoxic, poorly perfused, and possessed little to no vasculature. Larger tumors (approximately 1-4 mm diameter) were well perfused with widespread vasculature and were not significantly hypoxic. Patterns of hypoxia in disseminated peritoneal tumors and i.d. tumors were similar. Levels of hypoxia in microscopic peritoneal tumors were reduced by carbogen breathing. Peritoneal and i.d. tumor models are suitable for studying hypoxia in microscopic tumors. If the patterns of tumor hypoxia in human patients are similar to those observed in these animal experiments, then the efficacy of systemic treatments of micrometastatic disease may be compromised by hypoxic resistance.

Survival Benefits With Diverse Chemotherapy Regimens for Ovarian Cancer: Meta-analysis of Multiple Treatments

BACKGROUND

Numerous randomized trials have compared different chemotherapy regimens in women with ovarian cancer. Although ovarian cancer survival has improved in recent years, the magnitude of these incremental benefits across diverse regimens is unclear.

METHODS

We used multiple-treatment meta-analysis methodology to combine information from direct and indirect comparisons of all chemotherapy regimens used in randomized trials of ovarian cancer in the last 40 years. Chemotherapy was categorized by the use or not of platinum and/or taxanes, combinations of agents, and intraperitoneal administration. Monte Carlo simulations were used to determine which regimen most improved survival. Analyses of trials that examined first- and second-line treatments were also performed separately.

RESULTS

We found 198 trials (N = 38,440 women) involving 120 different chemotherapy regimens published in 1971-2006. Eighty-two trials compared different types of chemotherapy, among which 60 had usable survival information (N = 15,609 women). Monte Carlo simulations showed a 92% probability that the regimen that best prolonged survival is a platinum and taxane combination with intraperitoneal administration; this regimen resulted in a 55% relative risk reduction (95% confidence interval [CI] = 39% to 67%) for mortality as compared with nonintraperitoneal monotherapy using neither platinum nor taxane. Against that same monotherapy comparator, platinum-based combinations with and without intraperitoneal administration achieved 40% (95% CI = 21% to 54%) and 30% (95% CI = 20% to 38%) relative risk reductions for mortality, respectively, and combinations involving platinum and taxane without intraperitoneal administration achieved a 42% (95% CI = 31% to 51%) relative risk reduction. Results were similar when analyses were limited to first-line treatment. Data on second-line treatment were consistent with the superiority of platinum and taxane combinations.

CONCLUSIONS

Distinct incremental improvements in survival have been achieved for ovarian cancer chemotherapy over time, with the possibility to achieve a doubling or more of time to mortality with platinum and taxane combinations, especially when intraperitoneal administration is used.

Participation of patients with gynecological cancer in phase I clinical trials: two years experience in a major cancer center

OBJECTIVES

This study aims at analyzing the clinico-demographic features that influence the recruitment of gynecological cancer (GC) patients to phase I trials. The possible clinical benefit to patients resulting from the participation in these trials has been also investigated.

METHODS

We performed a retrospective analysis of GC patients referred to the Phase I Unit of the Royal Marsden Hospital in Sutton (Surrey, UK), over 2 years.

RESULTS

Overall 68 GC patients were referred, and subsequently 32 (47.1%) enrolled. The percentage of patients enrolled increased as the distance to travel between the patient's residence and the hospital shortened (8.3% through 47.8% to 60.8%, for travel time >2, 1-2 or < or =1 h, respectively; p=0.008). Better performance status (PS) was found to be associated with higher enrollment rate with percentages increasing from 0 through 51.2 to 58.8 in cases with PS> or =2, PS=1, PS=0, respectively (p=0.015). Among the biochemical parameters, only hepatobiliary dysfunction was found to be associated with lower enrollment (p=0.012). Minimal response/disease stabilization was observed in 11 patients (34.4%). An increased median survival following the first visit was observed in patients enrolled compared to those not enrolled (8 versus 4 months, respectively, p=0.0055). In the multivariate analysis, only PS and enrollment in trials retained an independent prognostic role (p=0.031 and p=0.040, respectively).

CONCLUSIONS

This study, suggesting liver function and PS as important factors influencing the recruitment of GC patients to phase I trials could guide referral of patients to phase I Units. Moreover, the practical limitations imposed by long distance travel, together with the potential clinical benefit due to the participation to these trials, should encourage more investigators to develop phase I units in major cancer centers.