An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is defined as any untoward medical occurrence that, at any dose resulted in death, is life threatening, required hospitalization or prolongation of existing hospitalization, resulted in disability/incapacity, is a congenital anomaly/birth defect, other situations and is associated with liver injury or impaired liver function. SAEs are subsets of AEs. TEAE is an event that emerged during treatment having been absent pretreatment or worsened relative to the pretreatment state. AESI is any AE (serious or nonserious) that is of scientific and medical concern specific to niraparib for which ongoing monitoring and rapid communication by the Investigator to the Sponsor is warranted. AEs were coded using the Medical Dictionary for Regulatory Activities (MedDRA) coding system.

Safety population included all randomized participants who received at least 1 dose of study treatment (niraparib or placebo).

An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. TEAE is an event that emerged during treatment having been absent pretreatment or worsened relative to the pretreatment state.Number of participants with TEAEs leading to death were reported.

Safety population

An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. TEAE is an event that emerged during treatment having been absent pretreatment or worsened relative to the pretreatment state. Number of participants with TEAEs leading to dose modifications (reduction and interruption/delay) and permanent discontinuation of study treatment were reported.

Safety population

Number of participants with ECOG Performance Status was reported and was measured on 6-point grade scale 0: Fully active, able to carry on all pre-disease performance without restriction. Grade 1: Restricted in physically strenuous activity but ambulatory & able to carry out work of light or sedentary nature; Grade 2 - Ambulatory & capable of all self-care but unable to carry out any work activities. Up and about more than (>) 50% of waking hours; Grade 3 -Capable of only limited self-care, confined to bed or chair > 50% of waking hours; Grade 4 -Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair; Grade 5 -Dead. Data is presented as baseline grade, best case on-therapy, and worst-case on-therapy for the available participants.

Safety population. Only those participants with data available at specified time points have been analyzed.

Blood samples were collected for the analysis of hematology parameters. The summaries of worst-case change from baseline with respect to normal range was analyzed for only those laboratory tests that were not gradable by Common Terminology Criteria for Adverse Events (CTCAE) version (v) 5. The number of participants with decreases to low from baseline, changes to normal or no changes from baseline, and increases to high values have been presented. Baseline is defined as the latest non-missing pre-dose value, including those from unscheduled visits.

Safety population. Only those participants with data available for specified parameter have been analyzed. Participants whose lab value category was unchanged (e.g., High to High), or whose value became normal, are recorded in the "To Normal or No Change" category. Participants are counted twice if the participant has values that changed 'To Low' and 'To High', so the percentages may not add to 100%.

Blood samples were collected for evaluation of clinical chemistry parameters. The summaries of worst case change from Baseline with respect to normal range have been presented for only those laboratory tests that are gradable by CTCAE v5.0. The number of participants with decreases to low, changes to normal or no changes from Baseline, and increases to high values have been presented. Baseline is defined as the latest non-missing pre-dose value, including those from unscheduled visits.

Safety population. Only those participants with data available for specified parameter have been analyzed.Participants whose lab value category was unchanged (e.g., High to High), or whose value became normal, are recorded in the "To Normal or No Change" category. Participants are counted twice if the participant has values that changed 'To Low' and 'To High', so the percentages may not add to 100%.

The abnormal vital sign ranges are: Pulse Rate (PR): Low [<60 beats per minute (bpm)], Normal (60 bpm to 100 bpm), High (>100 bpm); Temperature: Low (<35 degree Celsius (°C)), Normal (35 C and 38 C), High (>38 C); Systolic Blood Pressure (SBP): Low (<90 millimeter of mercury (mmHg)), Normal (>90 mmHg to <120 mmHg), High (>120 mmHg); Diastolic Blood Pressure (DBP): Low (<60 mmHg), Normal (60 mmHg to 79 mmHg), High (>80 mmHg). Participants were counted in the maximum worst case increase category that their value changes to (low, normal or high), unless there is no change in their category. Participants whose value category was unchanged (e.g., High to High), or whose value became normal, are recorded in the "To Normal or No Change" category.

Safety population. Only those participants with data available for specified parameter have been analyzed.

Number of participants who used concomitant medications is presented.

Intent-To-Treat Population included all participants randomized into the study.