Trial Outcomes & Findings for A Trial of Niraparib in Platinum-Sensitive Castration-Resistant Prostate Cancer With DNA Repair Defects (NCT NCT04288687)

Last Updated: 2026-03-04

Results Overview

Proportion of participants alive without radiographic progression (per PCWG2 criteria), clinical deterioration (as assessed by the investigator), or death from any cause, measured from the start of maintenance niraparib therapy using Kaplan-Meier analysis.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

11 participants

Primary outcome timeframe

6 months from initiation of maintenance niraparib therapy

Results posted on

2026-03-04

Participant Flow

Participant milestones

Participant milestones
Measure	Niraparib Arm (Only Arm) Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Overall Study STARTED	11
Overall Study COMPLETED	11
Overall Study NOT COMPLETED	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

A Trial of Niraparib in Platinum-Sensitive Castration-Resistant Prostate Cancer With DNA Repair Defects

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Niraparib Arm (Only Arm) n=11 Participants Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Age, Categorical <=18 years	0 Participants n=41 Participants
Age, Categorical Between 18 and 65 years	5 Participants n=41 Participants
Age, Categorical >=65 years	6 Participants n=41 Participants
Age, Continuous	68 years n=41 Participants
Sex: Female, Male Female	0 Participants n=41 Participants
Sex: Female, Male Male	11 Participants n=41 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=41 Participants
Race (NIH/OMB) Asian	0 Participants n=41 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=41 Participants
Race (NIH/OMB) Black or African American	3 Participants n=41 Participants
Race (NIH/OMB) White	8 Participants n=41 Participants
Race (NIH/OMB) More than one race	0 Participants n=41 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=41 Participants
Region of Enrollment United States	11 participants n=41 Participants

PRIMARY outcome

Timeframe: 6 months from initiation of maintenance niraparib therapy

Population: All participants who received at least one dose of maintenance niraparib and were evaluable for radiographic progression (N=11) were included in this analysis.

Outcome measures

Outcome measures
Measure	Niraparib Arm (Only Arm) n=11 Participants Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
6-Month Radiographic Progression-Free Survival (rPFS6)	6 Participants

SECONDARY outcome

Timeframe: From baseline until end of treatment, or up to 24 months

Population: All patients receiving at least one dose of maintenance niraparib, however, participants with baseline PSA \<0.5 ng/mL will be excluded from this analysis.

Number of participants achieving a ≥50% decline in serum PSA from baseline while on maintenance niraparib therapy. Participants with baseline PSA \<0.5 ng/mL will be excluded from this analysis.

Outcome measures

Outcome measures
Measure	Niraparib Arm (Only Arm) n=7 Participants Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Number of Participants With PSA50 Response	3 Participants

SECONDARY outcome

Timeframe: From baseline until end of treatment, or up to 24 months

Population: All participants who received at least one dose of maintenance niraparib and had baseline PSA ≥0.5 ng/mL were included in this analysis (N=7). Participants with baseline PSA \<0.5 ng/mL were excluded.

Number of participants achieving a ≥30% decline in serum PSA from baseline while on maintenance niraparib therapy. Participants with baseline PSA \<0.5 ng/mL will be excluded from this analysis.

Outcome measures

Outcome measures
Measure	Niraparib Arm (Only Arm) n=7 Participants Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Number of Participants With PSA30 Response	3 Participants

SECONDARY outcome

Timeframe: From baseline until end of treatment, or up to 24 months

Population: All participants who received at least one dose of maintenance niraparib and had baseline PSA ≥0.5 ng/mL were included (N=7). Participants with baseline PSA \<0.5 ng/mL were excluded from this PSA-based analysis.

Time from initiation of maintenance niraparib therapy to the first PSA increase \>25% and ≥2 ng/mL from nadir, per PCWG2 criteria. Participants with baseline PSA \<0.5 ng/mL were not evaluable. Participants without an event were censored at the last PSA assessment.

Outcome measures

Outcome measures
Measure	Niraparib Arm (Only Arm) n=7 Participants Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Time to PSA Progression	11.2 Months Interval 4.7 to 12.0

SECONDARY outcome

Timeframe: From initiation of maintenance niraparib therapy until death from any cause, up to 36 months

Population: All patients receiving at least one dose of maintenance niraparib were included in the safety analysis (N=11).

Time from initiation of maintenance niraparib therapy to death from any cause, estimated by Kaplan-Meier analysis.

Outcome measures

Outcome measures
Measure	Niraparib Arm (Only Arm) n=11 Participants Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Overall Survival (OS)	24.6 Months Interval 7.2 to Upper CI not reached

Adverse Events

Niraparib Arm (Only Arm)

Serious events: 5 serious events

Other events: 11 other events

Deaths: 9 deaths

Serious adverse events

Serious adverse events
Measure	Niraparib Arm (Only Arm) n=11 participants at risk Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Blood and lymphatic system disorders Anemia (Grade 3)	18.2% 2/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Blood and lymphatic system disorders Lymphopenia (Grade 3)	18.2% 2/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Blood and lymphatic system disorders Neutropenia (Grade 3)	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Blood and lymphatic system disorders Thrombocytopenia (Grade 4)	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Respiratory, thoracic and mediastinal disorders Hypertension (Grade 3)	18.2% 2/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Respiratory, thoracic and mediastinal disorders Thromboembolic Event (Grade 3)	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Blood and lymphatic system disorders Acute Myeloid Leukemia	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.

Other adverse events

Other adverse events
Measure	Niraparib Arm (Only Arm) n=11 participants at risk Niraparib 200 mg by mouth daily (2 x 100 mg pills) on a 28 day cycle Niraparib Pill: Niraparib 200 mg by mouth daily (2 x 100 mg pills)
Blood and lymphatic system disorders Leukopenia	54.5% 6/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Blood and lymphatic system disorders Thrombocytopenia	27.3% 3/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Blood and lymphatic system disorders Anemia	27.3% 3/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Gastrointestinal disorders Nausea	54.5% 6/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Gastrointestinal disorders Anorexia	27.3% 3/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Gastrointestinal disorders Constipation	45.5% 5/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
General disorders Fatigue	36.4% 4/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Vascular disorders Hypertension	72.7% 8/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Renal and urinary disorders Creatinine Increased	36.4% 4/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Gastrointestinal disorders Emesis	18.2% 2/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Gastrointestinal disorders Mucositis	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Gastrointestinal disorders Dry Mouth	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Gastrointestinal disorders Weight Loss	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Nervous system disorders Headache	18.2% 2/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Skin and subcutaneous tissue disorders Rash	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Psychiatric disorders Insomnia	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Cardiac disorders Tachycardia	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Hepatobiliary disorders AST Elevation	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Metabolism and nutrition disorders Hyponatremia	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.
Metabolism and nutrition disorders Hypomagnesemia	9.1% 1/11 • Toxicity and adverse event monitoring occurred at screening, at each treatment phase study visit, at the end of treatment visit, and at the 30-day and 90-day follow-up visits. All-cause Mortality was assessed up to 40 months through study completion. Adverse events were assessed and graded according to the NCI CTCAE v5.0. Patients were systematically evaluated through physical examination, laboratory assessments, and patient-reported symptoms. All treatment-emergent adverse events were collected and categorized as serious or non-serious. The safety analysis population included all patients who received at least one dose of niraparib.

Additional Information

Camilo Henao

Abramson Cancer Center

Phone: 215-220-9671

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place