End of inclusion period.

Ovarian cancer is the seventh most common cancer in women worldwide and is the leading cause of gynecologic cancer deaths in high-income countries.

Standard treatment for newly diagnosed advanced ovarian cancer consist of cytoreductive surgery and platinum-based chemotherapy with or without concurrent and maintenance bevacizumab, a vascular endothelial growth factor (VEGF) inhibitor.

A majority of women with epithelial ovarian cancer respond well to first-line platinum-based chemotherapy. There is however a high rate of relapse/recurrence (disease progression ranging from 10 to 26 months).

Poly ADP ribose polymerase inhibitors (PARPi), a new class of therapeutic molecules have recently revolutionized this paradigm, demonstrating progression-free survival (PFS) advantages in several trials.

The PARPi molecule Niraparib has obtained its market authorization after the NOVA trial as second maintenance treatment line, irrespectively of patients' BRCA-mutated gene or HR status.

Since, results of the Phase III trial PRIMA, have demonstrated that Niraparib can also provided a significant PFS increase as first line maintenance treatment, for adult patients with platinum-sensitive, relapsed, high grade serous epithelial ovarian cancer who are in response (complete response or partial response) to platinum-based chemotherapy, irrespectively of their BRCA-mutated gene or HR status.

However, despite its high therapeutic potential, Niraparib at standard dose (200 or 300mg/day) is known to lead to hematologic toxicity and/or nephrotoxicity. This was demonstrated during the NOVA trial (the dose of Niraparib having to be reduced in 80% of the patients to reduce toxicity).

A retrospective study of the NOVA trial indicates that 2 predictive factors leading to hematologic toxicity were a weight <77kg and an initial platelet count <175 G/L. However, it seems more complex as 50% of patients with an initial weight between 58 and 77kg have not reported thrombocytopenia. Same for platelet count. Creatinine clearance below 60ml/min and an hypoalbuminemia <35 g/l have also been identified in another study as predictive factors to thrombocytopenia.

The inter-individual heterogeneity in terms of toxicity regarding Niraparib is high and still not well understood.

The aim of our study is therefore to better identify which clinical, biological and pharmacokinetic metrics can be considered as toxicity induction causes when Niraparib is used as maintenance treatment (200 or 300mg/day) for ovarian cancer patients.

Inclusion Criteria:

• Patient Study Information and written informed consent
• Social Security Affiliation
• Patient > 18 years old.
• Ovarian, tubular or peritoneal high-grade epithelial carcinoma, histologically proven. Recommendation of a maintenance treatment with Niraparib at standard dose (200-300mg/day)
• Glomerular filtration rate with standardized serum creatinine values using CKD-EPI formula ≥ 30ml/min/1.73m2 (https://www.kidney.org/professionals/kdoqi/gfr\_calculator)
• Normal liver function with bilirubin < 1.5N
• 6-8 weeks break between last chemotherapy and Niraparib treatment initiation.
• Patient with an effective birth control

Exclusion Criteria:

• Minor patient
• Patient not able to understand the aim of the study or under curatorship
• Low grade carcinoma
• Pregnant or breastfeeding patient
• Hypersensivity to an active substance present in niraparib

The target population for this study is adult patients over 18 years of age with primary high-grade serous epithelial ovarian, tubal or peritoneal cancers