DNA damaging agents in ovarian cancer

Epithelial ovarian cancer (EOC) is very sensitive to upfront chemotherapy. This condition is attributable to defects in the DNA damage repair system. Agents that damage DNA are the main drugs used for its treatment. Many EOC cells have DNA repair deficiencies that confer susceptibility to these agents. Platinum is the most important agent for first-line and also for relapses, together with other drugs that can be given as monotherapy or along with platinum or other drugs. Lately, the emerging role of PARP inhibitors has changed the landscape of opportunities for patients with EOC. All these strategies will be reviewed in this article.

Bevacizumab as maintenance treatment in BRCA mutated patients with advanced ovarian cancer: A large, retrospective, multicenter case-control study

OBJECTIVE

The aim of this study was to investigate the correlation between BRCA mutational status and response to bevacizumab in a large advanced ovarian cancer (AOC) series.

METHODS

This is a multicenter, retrospective case-control study including upfront AOC treated between January 2015 and June 2019. The main inclusion criteria were: having received three weekly carboplatin-paclitaxel as first-line treatment, with or without Bevacizumab maintenance, knowledge of the BRCA mutational status.

RESULTS

Overall, 441 patients were included; 183 (41.5%) patients received bevacizumab (Cases), and 258 (58.5%) did not receive it (Controls). The BRCA mutated patients (BRCAmut) were 58 (39%) in the Cases group and 90 (34.9%) in the Controls group (p = .77). Patients who received bevacizumab had a significant 4-months increase in median progression free survival (mPFS: 21 vs. 17 months, p = .033). Concerning BRCAmut patients, no differences were shown between those who received bevacizumab or not in terms of mPFS (24 vs. 22 months, p = .3). Conversely, in BRCA wild-type (BRCAwt) population bevacizumab administration significantly prolonged mPFS (20 vs 15 months, p = .019). At multivariate analysis, independent factors of prolonged PFS were BRCA status (OR = 0.60), having received PDS (OR = 0.69), and complete cytoreduction (OR = 0.50), but not the bevacizumab administration (OR = 0.83, p = .22).

CONCLUSIONS

No evidence of oncological benefit in terms of PFS and OS related to bevacizumab maintenance therapy was found in BRCAmut patients. Differently, BRCAwt patients seem to benefit from antiangiogenic treatment in terms of mPFS.

Targeting cervical cancer: Is there a role for poly (ADP-ribose) polymerase inhibition?

Patients with metastatic and recurrent cervical cancer (CC) have a poor prognosis with limited palliative treatment options. Increasing understanding of the cellular aberrations inherent to cancer cells has allowed the development of therapies to target biological pathways, an important step toward the individualization of cancer therapy. The poly (ADP-ribose) polymerase (PARP) family of enzymes is important in several DNA repair pathways. Drugs that inhibit these PARP enzymes have been investigated in many types of cancer and their application in the treatment of gynecologic malignancies has rapidly evolved. Although the majority of data for PARPi in gynecologic malignancies has been specifically regarding ovarian cancer, their role in the treatment of uterine and CC is currently being investigated. This review will examine PARP inhibitors in CC, summarizes the critical clinical trials of PARP inhibitors that have been completed, provides an overview of the on-going trials, presents the confirmed conclusions and notes the issues that need to be addressed in future studies.

Ovarian cancer relapse: From the latest scientific evidence to the best practice

Ovarian cancer (OC) is the fifth most common cause of cancer death in women worldwide. Despite treatment options have continued to improve in recent years, the recurrence rate is still high; in fact around 80% of patients relapses within 18 months. Recently, the scientific landscape is agree in asserting that the ovarian cancer is not a single disease but the outcome of patients depends from the molecular and biological characterization of tumor tissue. In this scenario, molecular targeted therapy given alone or in combination with chemotherapy is showing significant results. We review the different options for the treatment of ovarian cancer recurrence, including the role of surgery, in order to try outlining a possible treatment algorithm evaluating the recent scientific literature and the most important trials.

[Hereditary ovarian carcinomas: clinico-biological features and treatment]

Hereditary ovarian cancers account for 10% of all cases. Two major syndromes with dominant autosomal transmission are identified. The most common one is breast-ovarian cancer syndrome due to BRCA1 and BRCA2 genes mutations, and the Lynch syndrome with mutated MMR genes is the other. Alterations in homologous recombination specifically observed in ovarian cancer with BRCA defects associated to Parp inhibition create a synthetic lethality of special interest. Numerous studies are in progress to explore this promising new approach. Furthermore, it seems that carcinogenesis of these two syndromes are different, suggesting alternative therapeutic options in the near future in order to improve prognosis of ovarian carcinomas.

Is there an epigenetic component underlying the resistance of triple-negative breast cancers to parp inhibitors?

Poly(ADP-ribose) polymerase (Parp) is an enzyme responsible for catalyzing post-translational modifications through the addition of poly(ADP-ribose) chains (known as PARylation). Modification by PARylation modulates numerous cellular processes including transcription, chromatin remodeling, apoptosis, and DNA damage repair. In particular, the role of Parp activation in response to DNA damage has been intensely studied. Tumors bearing mutations of the breast cancer susceptibility genes, Brca1/2, are prone to DNA breakages whose restoration into functional double-strand DNA is Parp dependent. This concept has been exploited therapeutically in Brca mutated breast and ovarian tumors, where acute sensitivity to Parp inhibitors is observed. Based on in vitro and clinical studies it remains unclear to what extent Parp inhibitors can be utilized beyond treating Brca mutated tumors. This review will focus on the often overlooked roles of PARylation in chromatin remodeling, epigenetics, and transcription to explain why some cancers may be unresponsive to Parp inhibition. We predict that understanding the impact of PARylation on gene expression will lead to alternative approaches to manipulate the Parp pathway for therapeutic benefit.