oxide, gelatin in the white capsule body; and FD&C Blue #1, FD&C Red #3, FD&C Yellow #5 and gelatin in the purple capsule cap. The black printing ink consists of shellac, dehydrated alcohol, isopropyl alcohol, butyl alcohol, propylene glycol, purified water, strong ammonia solution, potassium hydroxide and black iron oxide. The white printing ink consists of shellac, dehydrated alcohol, isopropyl alcohol, butyl alcohol, propylene glycol, sodium hydroxide, povidone and titanium oxide.
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
Niraparib is an inhibitor of poly(ADP-ribose) polymerase (PARP) enzymes, PARP-1 and PARP-2, which play a role in DNA repair. In vitro studies have shown that niraparib-induced cytotoxicity may involve inhibition of PARP enzymatic activity and increased formation of PARP-DNA complexes resulting in DNA damage, apoptosis and cell death. Increased niraparib-induced cytotoxicity was observed in tumor cell lines with or without deficiencies in BRCA1/2. Niraparib decreased tumor growth in mouse xenograft models of human cancer cell lines with deficiencies in BRCA1/2 and in human patient-derived xenograft tumor models with homologous recombination deficiency that had either mutated or wild type BRCA1/2.
12.2 Pharmacodynamics
The pharmacodynamic response of niraparib has not been characterized.
Cardiovascular Effects
Niraparib has the potential to cause effects on pulse rate and blood pressure in patients receiving the recommended dose, which may be related to pharmacological inhibition of the dopamine transporter (DAT), norepinephrine transporter (NET) and serotonin transporter (SERT) [see NONCLINICAL TOXICOLOGY (13.2)].
In the NOVA study, mean pulse rate and blood pressure increased over baseline in the niraparib arm relative to the placebo arm at all on-study assessments. Mean greatest increases from baseline in pulse rate on treatment were 24.1 and 15.8 beats/min in the niraparib and placebo arms, respectively. Mean greatest increases from baseline in systolic blood pressure on treatment were 24.5 and 18.3 mmHg in the niraparib and placebo arms, respectively. Mean greatest increases from baseline in diastolic blood pressure on treatment were 16.5 and 11.6 mmHg in the niraparib and placebo arms, respectively.
Cardiac Electrophysiology
The potential for QTc prolongation with niraparib was eva luated in a randomized, placebo-controlled trial in cancer patients (367 patients on niraparib and 179 patients on placebo). No large changes in the mean QTc interval (>20 ms) were detected in the trial following the treatment of niraparib 300 mg once daily.
12.3 Pharmacokinetics
Following a single-dose administration of 300 mg niraparib, the mean (±SD) peak plasma concentration (Cmax) was 804 (± 403) ng/mL. The systemic exposures (Cmax and AUC) of niraparib increased in a dose proportional manner with daily doses ranging 30 mg (0.1 times the approved recommended dosage) to 400 mg (1.3 times the approved recommended dosage). The accumulation ratio of niraparib exposure following 21 days of repeated daily doses was approximately 2 fold for doses ranging from 30 mg to 400 mg.
Absorption
The absolute bioavailability of niraparib is approximately 73%. Following oral administration of niraparib, peak plasma concentration, Cmax, is reached within 3 hours.
Concomitant administration of a high fat meal (800-1,000 calories with approximately 50% of total caloric |
