Clinical trials in gynecological cancer

Novel approaches to improve the treatment of rare gynecologic cancers: research opportunities and challenges

More than 50% of all gynecologic cancers can be classified as rare tumors (defined as an incidence of fewer than six per 100,000). Improved understanding of the molecular pathogenesis of tumors increases the proportion of rare tumors and creates challenges in optimizing the design of clinical trials. Novel trial designs are needed to take forward the development of new treatments in rare tumors. This requires international partnerships, harmonization of treatment, and collaboration to overcome the regulatory barriers to conducting international trials. Although randomized trials can be done in many tumor types, there are some for which conducting even single-arm studies may be challenging. For these tumors, robust collection of data through national and/or international registries could lead through audit to improvements in the treatment of rare tumors.

RNA interference of human papillomavirus type 16 E7 increases HLA class I antigen expression in HaCaT-E7 cells

BACKGROUND

High-risk human papillomaviruses (HPVs) are the major causative agents of cervical cancer. The E7 protein of high-risk HPV disturbs cell cycle control and down-regulates components of the antigen presentation pathway, suggesting an ideal target for development of the immunotherapy in HPV-positive cervical cancers. We previously reported that HPV16 E7 could down-regulate cell-surface HLA class I antigen accompanying decreased expression of transporter associated with antigen processing 1 (TAP-1). The purpose of this study was to determine whether knockdown of HPV16 E7 could up-regulate surface HLA class I antigen expression in HPV16 E7 expressing HaCaT cells (HaCaT-E7).

METHODS

An E7-specific small interfering RNA (siRNA) was transfected into the HaCaT-E7 cells, and the expression of HPV16 E7 was measured by real-time reverse transcriptase polymerase chain reaction and Western blot. With the use of flow cytometry analysis, the levels of cell surface HLA class I antigen and intracellular TAP-1 expression were detected.

RESULTS

It was found that transfection of HPV16 E7-siRNA reduced HPV16 E7 expression as measured on messenger RNA and protein levels. The flow cytometry analysis showed that, compared with mock transfection, a statistically significant increase of approximately 75% in surface HLA class I levels was observed in HaCaT-E7 cells at 72 hours after transfection of E7 siRNA. Moreover, he knockdown of E7 in HaCaT-E7 cells could result in an increase of intracellular TAP-1 expression, which is essential for the expression of HLA class I at cell surface.

CONCLUSIONS

Our study showed that the knockdown of HPV16 E7 could increase cell surface HLA class I antigen expression in HaCaT-E7 cells. In addition, for HPV-positive human cervical cancer, our observations indicate that the HPV E7 gene is a target of choice.

Evaluation of new platinum-based treatment regimens in advanced-stage ovarian cancer: a Phase III Trial of the Gynecologic Cancer Intergroup

PURPOSE

To determine if incorporation of an additional cytotoxic agent improves overall survival (OS) and progression-free survival (PFS) for women with advanced-stage epithelial ovarian carcinoma (EOC) and primary peritoneal carcinoma who receive carboplatin and paclitaxel.

PATIENTS AND METHODS

Women with stages III to IV disease were stratified by coordinating center, maximal diameter of residual tumor, and intent for interval cytoreduction and were then randomly assigned among five arms that incorporated gemcitabine, methoxypolyethylene glycosylated liposomal doxorubicin, or topotecan compared with carboplatin and paclitaxel. The primary end point was OS and was determined by pairwise comparison to the reference arm, with a 90% chance of detecting a true hazard ratio of 1.33 that limited type I error to 5% (two-tail) for the four comparisons.

RESULTS

Accrual exceeded 1,200 patients per year. An event-triggered interim analysis occurred after 272 events on the reference arm, and the study closed with 4,312 women enrolled. Arms were well balanced for demographic and prognostic factors, and 79% of patients completed eight cycles of therapy. There were no improvements in either PFS or OS associated with any experimental regimen. Survival analyses of groups defined by size of residual disease also failed to show experimental benefit in any subgroup.

CONCLUSION

Compared with standard paclitaxel and carboplatin, addition of a third cytotoxic agent provided no benefit in PFS or OS after optimal or suboptimal cytoreduction. Dual-stage, multiarm, phase III trials can efficiently evaluate multiple experimental regimens against a single reference arm. The development of new interventions beyond surgery and conventional platinum-based chemotherapy is required to additionally improve outcomes for women with advanced EOC.

First-line randomized trials: revisiting the Ptolemaic universe

Epithelial ovarian cancer is initially a chemosensitive neoplasm, with overall response rates to systemic platinum-based therapy exceeding 80% in conjunction with cytoreductive surgery. However, long-term survival remains poor due to eventual tumor recurrence and emergence of drug resistance. While platinum (cisplatin or carboplatin) and taxanes remain at the core of primary treatment, there has been increased interest in the evaluation of doublet and triplet combinations with diverse cytotoxic agents, including docetaxel, topotecan, gemcitabine, and PEG-liposomal doxorubicin. This has been prompted by single-agent activity in the setting of recurrent platinum-resistant disease and encouraging data from nonrandomized phase I-II trials. As a result, beginning in 1998, the international cooperative groups collaborated on a series of phase III trials to improve long-term outcomes through the development of new platinum-based combinations. More than 10,000 women have been randomized on these trials, and preliminary data from several studies have been reported. Although final data are pending, there is not currently any evidence to recommend adopting a new two- or three-drug combination, and carboplatin with paclitaxel remains the standard regimen of choice. Rapid developments in molecular-targeted therapy are challenging our paradigm for future clinical trials, and our priorities need to be carefully considered.