DNA-repair pathway inhibitors for the treatment of ovarian cancer

Abstract

BACKGROUND: Ovarian cancer is the sixth most common cancer and seventh most common cause of cancer death in women world-wide.Three-quarters of women present when the disease has spread through-put the abdomen (stage III or IV) and treatment consists of a combination of debulking surgery and platinum-based chemotherapy, with or without taxanes. Although initial responses to chemotherapy are often good, most women will relapse and require further chemotherapy and will eventually develop resistance to chemotherapy agents. Increased understanding about the molecular basis of ovarian cancer has lead to the development of novel agents, which work in different ways to conventional chemotherapy. These include DNA-repair pathway inhibitors, the commonest of which are the PARP (poly (ADP-ribose) polymerase) inhibitors. It is therefore important to compare their effectiveness and side effects of these novel agents to assess their role in the treatment of advanced ovarian cancer, especially as treatment of advanced disease is aiming to improve length of survival and quality of life (QoL). OBJECTIVES: To compare the effectiveness and harmful effects of interventions, which inhibit DNA-repair pathways, in the treatment of ovarian cancer. SEARCH STRATEGY: RCTs were identified by searching The Cochrane Central Register of Controlled Trials (CENTRAL, Issue 2, 2009), The Cochrane Gynaecological Cancer Collaborative Review Group's Trial Register, MEDLINE (1990 to June 2009), EMBASE (1990 to June 2009), ongoing trials on www.controlled-trials.com/rct, www.clinicaltrials.gov, www.cancer.gov/clinicaltrials and the National Research Register (NRR), the FDA database and pharmaceutical industry biomedical literature. SELECTION CRITERIA: Adult women with histologically proven ovarian cancer who were randomised to treatment groups which either compared DNA-repair pathway inhibitors with no treatment or DNA-repair pathway inhibitors together with conventional chemotherapy compared with conventional chemotherapy alone. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed whether potentially relevant studies met the inclusion criteria. Searches for additional data and information were also performed by two independent review authors. No trials were found and therefore no data were analysed, so only information on excluded references was collected. MAIN RESULTS: The search strategy identified 473 unique references of which 461 were excluded on the basis of title and abstract. The remaining 12 articles were retrieved in full, but none satisfied the inclusion criteria. However, two ongoing randomised phase II clinical trials were identified from the clinical trials databases that met our inclusion criteria, but no preliminary data were available. AUTHORS' CONCLUSIONS: There are to date no published RCT data on the effectiveness and side effects of DNA-repair pathways inhibitors used alone or in association with conventional chemotherapy in the treatment of ovarian cancer. On-going trials have been identified and results are awaited and will be included in future updates of this review.