The OVAREX study: Establishment of ex vivo ovarian cancer models to validate innovative therapies and to identify predictive biomarkers.

BACKGROUND: Ovarian cancer is the first cause of death from gynecological malignancies mainly due to development of chemoresistance. Despite the emergence of PARP inhibitors, which have revolutionized the therapeutic management of some of these ovarian cancers, the 5-year overall survival rate remains around 45%. Therefore, it is crucial to develop new therapeutic strategies, to identify predictive biomarkers and to predict the response to treatments. In this context, functional assays based on patient-derived tumor models could constitute helpful and relevant tools for identifying efficient therapies or to guide clinical decision making. METHOD: The OVAREX study is a single-center non-interventional study which aims at investigating the feasibility of establishing in vivo and ex vivo models and testing ex vivo models to predict clinical response of ovarian cancer patients. Patient-Derived Xenografts (PDX) will be established from tumor fragments engrafted subcutaneously into immunocompromised mice. Explants will be generated by slicing tumor tissues and Ascites-Derived Spheroids (ADS) will be isolated following filtration of ascites. Patient-derived tumor organoids (PDTO) will be established after dissociation of tumor tissues or ADS, cell embedding into extracellular matrix and culture in specific medium. Molecular and histological characterizations will be performed to compare tumor of origin and paired models. Response of ex vivo tumor-derived models to conventional chemotherapy and PARP inhibitors will be assessed and compared to results of companion diagnostic test and/or to the patient's response to evaluate their predictive value. DISCUSSION: This clinical study aims at generating PDX and ex vivo models (PDTO, ADS, and explants) from tumors or ascites of ovarian cancer patients who will undergo surgical procedure or paracentesis. We aim at demonstrating the predictive value of ex vivo models for their potential use in routine clinical practice as part of precision medicine, as well as establishing a collection of relevant ovarian cancer models that will be useful for the evaluation of future innovative therapies. TRIAL REGISTRATION: The clinical trial has been validated by local research ethic committee on January 25th 2019 and registered at ClinicalTrials.gov with the identifier NCT03831230 on January 28th 2019, last amendment v4 accepted on July 18, 2023.

Efficacy and safety of bevacizumab-containing neoadjuvant therapy followed by interval debulking surgery in advanced ovarian cancer: Results from the ANTHALYA trial.

AIM: To investigate whether adding bevacizumab to neoadjuvant carboplatin-paclitaxel (CP) helps achieve optimal debulking, measured by complete resection rate (CRR) at interval debulking surgery (IDS), in patients with initially unresectable International Federation of Gynecology and Obstetrics stage IIIC/IV ovarian, tubal or peritoneal adenocarcinoma. METHODS: Multicentre, open-label, non-comparative phase II study. Ninety-five patients randomised (2:1) to receive four cycles of neoadjuvant CP ±3 concomitant cycles of bevacizumab 15 mg/kg (BCP) followed by IDS. Primary objective is to evaluate the CRR at IDS in the BCP group (reference CRR rate defined as 45% CRR). A stopping rule based on bevacizumab-related adverse events (AEs) of special interest was implemented. RESULTS: In the BCP group (N = 58), IDS was performed in 40 (69%) patients, of whom 85% had a complete resection. The CRR of this group was therefore 58.6% (34 patients), statistically over pre-defined 45%. The CRR in the CP group was 51.4%: 22 (60%) patients underwent IDS (85% had a complete resection). Grade ≥3 adverse events occurred in 62% of the BCP-treated patients and 63% of the CP-treated patients: mainly blood and lymphatic, gastrointestinal and vascular disorders, without more toxicity with BCP. Postoperative complications (mainly wound, infectious and gastrointestinal complications) occurred in 28% and 36% of the patients, respectively. The pre-specified safety stopping rule was not reached. CONCLUSION: The primary objective was met as the CRR with BCP was significantly higher than the reference rate. Bevacizumab may be safely added to a preoperative program in patients deemed non-optimally resectable, whatever the final surgical decision. Bevacizumab's role in this setting should be further investigated.