oparib-induced cytotoxicity may involve inhibition of PARP enzymatic activity and increased formation of PARP-DNA complexes resulting in DNA damage, decreased cell proliferation, and apoptosis. Talazoparib anti-tumor activity was observed in human patient-derived xenograft breast cancer tumor models that expressed mutated or wild-type BRCA 1 and 2.
12.2 Pharmacodynamics
Cardiac Electrophysiology
The effect of talazoparib on cardiac repolarization was eva luated in 37 patients with advanced solid tumors. Talazoparib had no large QTc prolongation (i.e., >20 ms) at the recommended dose.
12.3 Pharmacokinetics
After oral administration of 1 mg TALZENNA once daily in patients, the recommended dose, the geometric mean [% coefficient of variation (CV%)] of AUC and maximum observed plasma concentration (Cmax) of talazoparib at steady-state was 208 (37%) ng.hr/mL and 16.4 (32%) ng/mL, respectively. The pharmacokinetics (PK) of talazoparib is linear from 0.025 mg to 2 mg (2 times the recommended dose). The median accumulation ratio of talazoparib following repeated oral administration of 1 mg once daily was in the range of 2.3 to 5.2. Talazoparib plasma concentrations reached steady-state within 2 to 3 weeks.
Absorption
Following oral administration of talazoparib, the median time to Cmax (Tmax) was generally between 1 to 2 hours after dosing.
Food Effect
Following a single oral dose of 0.5 mg TALZENNA with high-fat, high-calorie food (approximately 800 to 1000 calories with 150, 250, and 500 to 600 calories from protein, carbohydrate, and fat, respectively), the mean Cmax of talazoparib was decreased by 46%, the median Tmax was delayed from 1 to 4 hours, and AUCinf was not affected.
Distribution
The mean apparent volume of distribution of talazoparib is 420 L. In vitro, protein binding of talazoparib is 74% and is independent of talazoparib concentration.
Elimination
The mean terminal plasma half-life (±standard deviation) of talazoparib is 90 (±58) hours, and the mean apparent oral clearance (inter-subject variability) is 6.45 L/h (31.1%) in cancer patients.
Metabolism
Talazoparib undergoes minimal hepatic metabolism. The identified metabolic pathways of talazoparib in humans include mono-oxidation, dehydrogenation, cysteine conjugation of mono-desfluoro-talazoparib, and glucuronide conjugation.
Excretion
Excretion of talazoparib in urine was the major route of elimination. Approximately 68.7% (54.6% unchanged) of the total administered radioactive dose [14C]talazoparib was recovered in urine, and 19.7% (13.6% unchanged) was recovered in feces.
Specific Populations
Age (18 to 88 years), sex, race (361 White, 41 Asian, 16 Black, 9 Others, and 63 Not Reported), and body weight (36 to 162 kg) had no clinically relevant effect on the PK of talazoparib.
Pediatric Patients
The pharmacokinetics of talazoparib have not been eva luated in patients <18 years of age.
Patients with Renal Impairment
Talazoparib CL/F was decreased by 14.4% in patients with mild renal impairment (CLcr 60 – 89 mL/min) and 37.1% in patients with moderate renal impairment (CLcr 30 – 59 mL/min), when compared to patients with normal renal function (CLcr ≥ 90 mL/min). The PK of talazoparib have not been studied in patients with severe renal impairment (CLcr < 30 mL/min) or in patients requiring hemodialysis.
Patients with Hepatic Impairment
Mild hepatic impairment (total |
