The goal of this clinical trial is to learn about the safety profile of niraparib in adult female participants for the treatment of advanced or relapsed epithelial ovarian cancer.

Inclusion Criteria:

• Female participants with ≥18 years of age, able to understand the study procedures and agree to participate in the study by providing written informed consent.

• Histologically confirmed epithelial ovarian cancer.

  • Eligible for active study drug treatment according to the approved label - as monotherapy for the maintenance treatment of adult participants with advanced epithelial (International Federation of Gynecology and Obstetrics [FIGO] stage III and IV) high-grade ovarian, fallopian tube or primary peritoneal cancer who are in response (complete or partial) following completion of first-line platinum-based chemotherapy.
  • as monotherapy for the maintenance treatment of adult participants with platinum-sensitive relapsed high grade serious epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in response (complete or partial) to platinum-based chemotherapy.

• Laboratory complete blood count (CBC) criteria (Absolute neutrophil count ≥1,500/microliters [μL]; Platelets ≥100,000/μL; Hemoglobin ≥9 grams per decilitre [g/dL]).

• Adequately controlled hypertension basis on investigator's discretion.

• Women of childbearing potential must be ready to use contraceptive measures to avoid pregnancy during study period and until 180 days after the last dose.

Exclusion Criteria:

• Participant is pregnant, breastfeeding, or expecting to conceive children while receiving study treatment and for up to 180 days after the last dose of study treatment.
• Participant had known, active hepatic disease, known case of end-stage renal disease (ESRD), known case of serious, uncontrolled medical disorder, any known history or current diagnosis of Myelodysplastic syndrome (MDS) or Acute myeloid leukemia (AML).
• Any previous polymerases inhibitor (PARPi) treatment.
• Participant with concomitant serious uncontrolled medical illness.
• Participant is receiving niraparib for use that is not according to the approved label.
• Participant with either the history of hypersensitivity to excipients of the study drug or to drugs with a similar chemical structure or class to the study drug.
• Participant with a previously or currently diagnosed MDS/ AML or pneumonitis.
• Participants who have not recovered sufficiently from prior surgery or anticancer treatment.
• Participants who have known history of hepatitis B or hepatitis C.
• Participant with active infection such as tuberculosis (TB) Prior/concurrent clinical study experience.
• Participation in another clinical study with a study drug administered in the last 3 months.
• Judgment by the investigator that the participant should not take part in the study if the participant is unlikely to comply with study procedures, restrictions and requirements.
• Previous enrolment in the present study.

Qualified researchers may request access to anonymized individual patient-level data (IPD) and related study documents of the eligible studies via the Data Sharing Portal. Details on GSK's data sharing criteria can be found at: https://www.gsk.com/en-gb/innovation/trials/data-transparency/

Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or terminated asset(s) across all indications.

Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension may be granted, when justified, for up to 6 months.