Effect of P-gp Inhibitors
Coadministration with P-gp inhibitors may increase talazoparib exposure.
In patients with advanced solid tumors, coadministration of a P-gp inhibitor (itraconazole) increased talazoparib plasma exposure by 56%. In the clinical studies, coadministration with P-gp inhibitors including amiodarone, carvedilol, clarithromycin, itraconazole, and verapamil resulted in an approximate 45% increase in talazoparib exposure and an increase in the rate of TALZENNA dose reduction. If coadministration of TALZENNA with these P-gp inhibitors cannot be avoided, reduce the TALZENNA dose [see Dosage and Administration (2.5)]. When the P-gp inhibitor is discontinued, increase the TALZENNA dose (after 3–5 half-lives of the inhibitor) to the dose used prior to the initiation of the P-gp inhibitor [see Dosage and Administration (2.5), Clinical Pharmacology (12.3)].
Effect of BCRP inhibitors
Coadministration with BCRP inhibitors may increase talazoparib exposure. If coadministration cannot be avoided, monitor patients for potential increased adverse reactions when coadministering [see Clinical Pharmacology (12.3)].
Based on findings from animal studies and its mechanism of action [see Clinical Pharmacology (12.1)] , TALZENNA can cause embryo-fetal harm when administered to a pregnant woman. There are no available data on TALZENNA use in pregnant women to inform a drug-associated risk. In an animal reproduction study, the administration of talazoparib to pregnant rats during the period of organogenesis caused fetal malformations and structural skeletal variations and embryo-fetal death at maternal exposures that were 0.24 times the AUC in patients receiving the recommended dose of 1 mg daily (see Data). Apprise pregnant women and females of reproductive potential of the potential risk to a fetus.
The background risk of major birth defects and miscarriage for the indicated population is unknown. In the general U.S. population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2% to 4% and 15% to 20%, respectively.
In an embryo-fetal development toxicity study, pregnant rats received oral doses of 0.015, 0.05, and 0.15 mg/kg/day talazoparib during the period of organogenesis. Talazoparib caused embryo-fetal death at doses ≥0.015 mg/kg/day (approximately 0.24 times the AUC in patients at the recommended dose). A dose of 0.015 mg/kg/day caused decreased fetal body weights and an increased incidence of fetal malformations (depressed eye bulge, small eye, split sternebra, and fused cervical vertebral arch) and structural variations including misshapen or incomplete ossification of the sternebra, skull, rib, and vertebra.
There are no data on the presence of talazoparib in human milk, the effects of the drug on milk production, or the effects of the drug on the breastfed child. Because of the potential for serious adverse reactions in a breastfed child from talazoparib, advise lactating women not to breastfeed during treatment with TALZENNA and for at least 1 month after the final dose.
A pregnancy test is recommended for females of reproductive potential prior to initiating TALZENNA treatment.
TALZENNA can cause fetal harm when administered to pregnant women [see Use in Specific Populations (8.1)]. Advise females of reproductive potential to use effective contraception during treatment and for at least 7 months following the last dose of TALZENNA.
Based on genotoxicity and animal reproduction studies, advise male patients with female partners of reproductive potential and pregnant partners to use effective contraception during treatment with TALZENNA and for at least 4 months following the last dose [see Use in Specific Populations (8.1), Nonclinical Toxicology (13.1)].
Based on animal studies, TALZENNA may impair fertility in males of reproductive potential [see Nonclinical Toxicology (13.1)].
The safety and effectiveness of TALZENNA have not been established in pediatric patients.
In clinical trials of TALZENNA enrolling 494 patients with advanced solid tumors who received TALZENNA 1 mg daily as monotherapy, 85 (17%) patients were ≥65 years of age, and this included 19 (4%) patients who were ≥75 years old. There were 5 patients ≥85 years old. No overall differences in safety or effectiveness of TALZENNA were observed between these patients and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
Patients with moderate or severe renal impairment have a higher exposure to TALZENNA than patients with normal renal function. Reduce the recommended dose of TALZENNA in patients with moderate (CLcr 30 – 59 mL/min) and severe (CLcr 15 – 29 mL/min) renal impairment. Monitor patients with severe renal impairment for potential increased adverse reactions and adjust dosing accordingly [see Dosage and Administration (2.4), Clinical Pharmacology (12.3)]. No dose adjustment is required for patients with mild renal impairment (CLcr 60 – 89 mL/min). TALZENNA has not been studied in patients requiring hemodialysis [see Clinical Pharmacology (12.3)].
TALZENNA has not been studied in patients with moderate hepatic impairment (total bilirubin >1.5 to 3.0 × upper limit of normal [ULN] and any aspartate aminotransferase [AST]) or severe hepatic impairment (total bilirubin >3.0 × ULN and any AST). No dose adjustment is required for patients with mild hepatic impairment (total bilirubin ≤1 × ULN and AST > ULN, or total bilirubin >1.0 to 1.5 × ULN and any AST) [see Clinical Pharmacology (12.3)].
There is no specific treatment in the event of TALZENNA overdose, and symptoms of overdose have not been established. In the event of overdose, discontinue treatment with TALZENNA, consider gastric decontamination, follow general supportive measures, and treat symptomatically.
Talazoparib is an inhibitor of mammalian polyadenosine 5′-diphosphoribose polymerase (PARP) enzyme. The chemical name of talazoparib tosylate is (8S ,9R)-5-Fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H -1,2,4-triazol-5-yl)-2,7,8,9-tetrahydro-3H -pyrido[4,3,2-de ]phthalazin-3-one 4-methylbenzenesulfonate (1:1). The chemical formula of talazoparib tosylate is C26 H22 F2 N6 O4 S, and the relative molecular mass is 552.56 Daltons. The chemical structure of talazoparib tosylate is shown below:
Talazoparib tosylate is a white to yellow solid. TALZENNA capsules for oral use are available as a 0.25 mg hard hypromellose (HPMC) capsule that contains 0.363 mg talazoparib tosylate equivalent to 0.25 mg talazoparib free base or as a 1 mg HPMC capsule that contains 1.453 mg talazoparib tosylate equivalent to 1 mg talazoparib free base.
Inactive ingredients: silicified microcrystalline cellulose (sMCC). The white/ivory and white/light red opaque capsule shells contain HPMC, yellow iron oxide, red iron oxide and titanium dioxide; and the printing ink contains shellac, black iron oxide, potassium hydroxide, ammonium hydroxide, and propylene glycol.
Talazoparib is an inhibitor of poly (ADP-ribose) polymerase (PARP) enzymes, including PARP1 and PARP2, which play a role in DNA repair. In vitro studies with cancer cell lines that harbored defects in DNA repair genes, including BRCA 1 and 2, have shown that talazoparib-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.
The effect of talazoparib on cardiac repolarization was evaluated in 37 patients with advanced solid tumors. Talazoparib had no large QTc prolongation (i.e., >20 ms) at the recommended dose.
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.
Following oral administration of talazoparib, the median time to Cmax (Tmax ) was generally between 1 to 2 hours after dosing.
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.
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.
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.
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 of talazoparib in urine was the major route of elimination. Approximately 68.7% (54.6% unchanged) of the total administered radioactive dose [14 C]talazoparib was recovered in urine, and 19.7% (13.6% unchanged) was recovered in feces.
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.
The PK of talazoparib have not been evaluated in patients <18 years of age.
Patients with Renal Impairment
Talazoparib steady-state total exposure (AUC0–24 ) increased by 12%, 43%, and 163% in patients with mild (eGFR 60 – 89 mL/min/1.73 m2), moderate (eGFR 30 – 59 mL/min/1.73 m2), and severe (eGFR 15 – 29 mL/min/1.73 m2) renal impairment, respectively, relative to patients with normal renal function (eGFR ≥ 90 mL/min/1.73 m2). Talazoparib steady-state peak concentration (Cmax ) increased by 11%, 32%, and 89% in patients with mild, moderate, and severe renal impairment, respectively, relative to patients with normal renal function. The PK of talazoparib has not been studied in patients requiring hemodialysis. There was no evidence of a relationship between the protein binding of talazoparib and renal function.
Patients with Hepatic Impairment
Mild hepatic impairment (total bilirubin ≤1.0 × ULN and AST > ULN, or total bilirubin >1.0 to 1.5 × ULN and any AST) had no effect on the PK of talazoparib. The PK of talazoparib have not been studied in patients with moderate (total bilirubin >1.5 to 3.0 × ULN and any AST) or severe hepatic impairment (total bilirubin >3.0 × ULN and any AST).
Drug Interaction Studies
Effect of Other Drugs on Talazoparib
Effect of P-gp inhibitors: In patients with advanced solid tumors, coadministration of a P-gp inhibitor (multiple 100 mg twice-daily doses of itraconazole) with a single 0.5 mg talazoparib dose increased talazoparib AUCinf and Cmax by approximately 56% and 40%, respectively. Population PK analysis showed that coadministration with P-gp inhibitors including amiodarone, carvedilol, clarithromycin, itraconazole, and verapamil in clinical studies increased talazoparib exposure by 45% [see Dosage and Administration (2.5), Drug Interactions (7.1)].
Coadministration with P-gp inhibitors including azithromycin, atorvastatin, diltiazem, felodipine, fluvoxamine, and quercetin in clinical studies increased talazoparib exposure by 8% [see Dosage and Administration (2.5), Drug Interactions (7)].
Effect of P-gp inducers: In patients with advanced solid tumors, coadministration of a P-gp inducer (multiple 600 mg once-daily doses of rifampin) with a single 1 mg talazoparib dose increased talazoparib Cmax by 37% with no effect on talazoparib exposure.
Effect of BCRP inhibitors: The effect of BCRP inhibitors on PK of talazoparib has not been studied. Coadministration with BCRP inhibitors may increase talazoparib exposure [see Drug Interactions (7)].
Effect of acid-reducing agents on talazoparib: Coadministration of acid-reducing agents including proton pump inhibitors (PPI), histamine receptor 2 antagonists (H2 RA), or other acid reducing agents has no effect on the absorption of talazoparib.
In Vitro Studies
Talazoparib is a substrate of P-gp and BCRP transporters.
Talazoparib is not a substrate of organic anion transporting polypeptide [OATP]1B1, OATP1B3, organic cationic transporter [OCT]1, OCT2, organic anion transporter [OAT]1, OAT3, bile salt export pump [BSEP], multidrug and toxin extrusion [MATE]1, and MATE2-K.
Talazoparib is not an inhibitor of cytochrome (CYP)1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4/5, or inducer of CYP1A2, CYP2B6, or CYP3A4.
Talazoparib is not an inhibitor of transporters including P-gp, BCRP, OATP1B1, OATP1B3, OCT1, OCT2, OAT1, OAT3, BSEP, MATE1, and MATE2-K.
Talazoparib is not an inhibitor of uridine-diphosphate glucuronosyltransferase (UGT) isoforms (1A1, 1A4, 1A6, 1A9, 2B7, and 2B15).
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