NOURIANZ is indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off" episodes.
The recommended dosage of NOURIANZ is 20 mg administered orally once daily. The dosage may be increased to a maximum of 40 mg once daily, based on individual need and tolerability. Initial dose titration is not required.
NOURIANZ can be taken with or without food [see Clinical Pharmacology (12.3)].
The maximum recommended dosage of NOURIANZ with concomitant use of strong CYP3A4 inhibitors is 20 mg once daily [see Drug Interactions (7.1)].
Avoid use of NOURIANZ with strong CYP3A4 inducers [see Drug Interactions (7.1)].
The maximum recommended dosage of NOURIANZ in patients with moderate hepatic impairment (Child-Pugh Class B) is 20 mg once daily. Closely monitor patients with moderate hepatic impairment for adverse reactions when on NOURIANZ treatment [see Adverse Reactions (6.1)]. Avoid use of NOURIANZ in patients with severe hepatic impairment (Child-Pugh Class C) [see Use in Specific Populations (8.7)].
The recommended dosage of NOURIANZ in patients who use tobacco in amounts of 20 or more cigarettes per day (or the equivalent of another tobacco product) is 40 mg once daily [see Use in Specific Populations (8.8) and Clinical Pharmacology (12.3)].
Risk Summary
There are no adequate data on the developmental risk associated with the use of NOURIANZ in pregnant women. In animal studies (see Data), oral administration of istradefylline during pregnancy resulted in teratogenicity (increased incidences of fetal structural abnormalities, embryofetal and offspring mortality and growth deficits) at clinically relevant exposures and in the absence of maternal toxicity. The teratogenic effects of istradefylline in pregnant rabbits were substantially greater when administered in combination with levodopa/carbidopa than when administered alone.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2-4% and 15-20%, respectively.
Data
Animal Data
Oral administration of istradefylline (0, 40, 200, or 1000 mg/kg/day) to pregnant rats throughout organogenesis resulted in decreased fetal body weight and increased fetal skeletal and visceral variations at the highest dose tested. Plasma exposure (AUC) at the no-effect dose for adverse effects on embryofetal development in rats (200 mg/kg/day) is approximately 4 times that in humans at the maximum recommended human dose (MRHD) of 40 mg.
Oral administration of istradefylline (0, 50, 200, or 800 mg/kg/day) to pregnant rabbits throughout organogenesis resulted in increased embryofetal mortality at the mid and high doses, increased fetal malformations (external, visceral, skeletal) at all doses, and reduced fetal body weight at the highest dose tested. A no-effect dose for adverse effects on embryofetal development in rabbits was not identified. Plasma exposure (AUC) at the lowest dose tested (50 mg/kg/day) is less than that in humans at the MRHD.
In pregnant rabbits, oral administration of istradefylline (0, 50, 200, or 400 mg/kg/day) alone or in combination with oral levodopa/carbidopa (80/20 mg/kg/day) throughout the period of organogenesis resulted in an increase in embryofetal mortality and an increase (marked at the high dose) in malformations (including limb reduction, craniofacial, and cardiovascular) in fetuses from rats administered istradefylline at all doses in combination with levodopa/carbidopa. Istradefylline alone resulted in an increase in embryofetal mortality and visceral malformations; no increase in fetal malformations was observed with levodopa/carbidopa alone. Fetal body weight was reduced by istradefylline alone (400 mg/kg/day) and in combination (200 and 400 mg/kg/day) with levodopa/carbidopa. A no-effect dose for adverse effects on embryofetal development in rabbits when istradefylline was administered in combination with levodopa/carbidopa was not identified. Plasma exposure (AUC) at the lowest dose of istradefylline tested (50 mg/kg/day) in combination with levodopa/carbidopa is less than that in humans at the MRHD.
Oral administration of istradefylline (0, 6, 25, 100, or 400 mg/kg/day) to female rats throughout gestation and lactation resulted in decreased pup survival and reduced pup body weight (which persisted into adulthood) at all but the lowest dose tested. Exposure to drug in the milk may have contributed to these effects, as demonstrated in pups of untreated (control) dams reared by dams receiving istradefylline (400 mg/kg/day). No adverse effects were observed on physical or neurobehavioral development, or reproductive function. Plasma exposure at the no-effect dose for adverse effects on pre- and postnatal development in rats (6 mg/kg/day) is less than that in humans at the MRHD.
Risk Summary
There are no data on the presence of istradefylline in human milk, the effects of istradefylline on the breastfed infant, or the effects of istradefylline on milk production. Istradefylline was present in the milk of lactating rats at concentrations up to 10 times that in maternal plasma.
The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for NOURIANZ, and any potential adverse effects on the breastfed infant from NOURIANZ or from the underlying maternal condition.
Contraception
Use of NOURIANZ during pregnancy is not recommended. Women of childbearing potential should be advised to use contraception during treatment with NOURIANZ [see Use in Specific Populations (8.1)].
Safety and effectiveness in pediatric patients have not been established.
No adjustment of NOURIANZ dosage is recommended on the basis of age. Of the total number of PD patients who received NOURIANZ in clinical trials, 53% were ≥65 years and 13% were ≥75 years of age. No overall differences in effectiveness were observed between these patients and younger patients.
No adjustment of NOURIANZ dosage is needed in patients with mild renal impairment (estimated creatinine clearance (CrCL) by Cockcroft-Gault equation: 60-89 mL/min), moderate renal impairment (CrCL 30-59 mL/min), or severe renal impairment (CrCL 15-29 mL/min). NOURIANZ has not been evaluated in patients with end-stage renal disease (ESRD) (CrCL <15 mL/min) or ESRD requiring hemodialysis [see Clinical Pharmacology (12.3)].
No adjustment of NOURIANZ dosage is needed in patients with mild hepatic impairment (Child-Pugh Class A).
In patients with moderate hepatic impairment (Child-Pugh Class B), the steady-state exposures (AUC0-24h) were predicted to be 3.3-fold higher than in healthy subjects, based on the estimated mean terminal half-life. Therefore, the maximum recommended dosage of NOURIANZ in patients with moderate hepatic impairment (Child-Pugh Class B) is 20 mg once daily [see Clinical Pharmacology (12.3)]. Closely monitor patients with moderate hepatic impairment for adverse events when on NOURIANZ treatment [see Adverse Reactions (6.1)].
NOURIANZ has not been studied in patients with severe hepatic impairment (Child-Pugh Class C). Avoid use of NOURIANZ in patients with severe hepatic impairment [see Clinical Pharmacology (12.3)].
Tobacco smoking decreased NOURIANZ steady-state systemic exposures by 38% to 54% [see Clinical Pharmacology (12.3)], which may decrease efficacy. Therefore, the recommended NOURIANZ dosage in patients who smoke 20 or more cigarettes per day (or the equivalent amount of another tobacco product) is 40 mg once daily.
None.
NOURIANZ in combination with levodopa may cause dyskinesia or exacerbate pre-existing dyskinesia.
In controlled clinical trials (Studies 1, 2, 3, and 4) [see Clinical Studies (14)], the incidence of dyskinesia was 15% for NOURIANZ 20 mg, 17% for NOURIANZ 40 mg, and 8% for placebo, in combination with levodopa. One percent of patients treated with either NOURIANZ 20 mg or 40 mg discontinued treatment because of dyskinesia, compared to 0% for placebo.
Because of the potential risk of exacerbating psychosis, patients with a major psychotic disorder should not be treated with NOURIANZ. Consider dosage reduction or discontinuation if a patient develops hallucinations or psychotic behaviors while taking NOURIANZ.
In controlled clinical trials (Studies 1, 2, 3, and 4) [see Clinical Studies (14)], the incidence of hallucinations was 2% for NOURIANZ 20 mg, 6% for NOURIANZ 40 mg, and 3% for placebo. In patients treated with NOURIANZ 40 mg, 1% discontinued because of hallucinations, compared to 0% for placebo and 0% for patients treated with NOURIANZ 20 mg. The incidence of "abnormal thinking and behavior" (paranoid ideation, delusions, confusion, mania, disorientation, aggressive behavior, agitation, or delirium) reported as an adverse reaction was 1% for NOURIANZ 20 mg, 2% for NOURIANZ 40 mg, and 1% for placebo.
Patients treated with NOURIANZ and one or more medication(s) for the treatment of Parkinson's disease (including levodopa) may experience intense urges to gamble, increased sexual urges, intense urges to spend money, binge or compulsive eating, and/or other intense urges, and the inability to control these urges. In controlled clinical trials (Studies 1, 2, 3 and 4) [see Clinical Studies (14)], one patient treated with NOURIANZ 40 mg was reported to have impulse control disorder, compared to no patient on placebo or NOURIANZ 20 mg.
In some postmarketing cases, these urges were reported to have stopped when the dose was reduced, or the medication was discontinued. Because patients may not recognize these behaviors as abnormal, it is important for prescribers to specifically ask patients or their caregivers about the development of new or increased gambling urges, sexual urges, uncontrolled spending, binge or compulsive eating, or other urges while being treated with NOURIANZ. Consider dose reduction or discontinuation if a patient develops such urges while taking NOURIANZ [see Adverse Reactions (6.2)].
The following clinically significant adverse reactions are discussed in greater detail in other sections of the labeling:
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
The safety of NOURIANZ was evaluated in 734 patients with Parkinson's disease (PD) taking a stable dose of levodopa and a DOPA decarboxylase inhibitor, with or without other PD medications, in four randomized, multicenter, double-blind, placebo-controlled trials 12 weeks in duration (Studies 1, 2, 3 and 4) [see Clinical Studies (14)]. Of the patient population exposed to NOURIANZ, 50% were male, 32% White, 67% Asian, and the mean age was 65 years (range: 33 to 84 years). Of these patients, 356 received NOURIANZ 20 mg and 378 received NOURIANZ 40 mg.
Adverse Reactions Leading to Discontinuation of Treatment
The incidence of patients discontinuing for any adverse reaction was 5% for NOURIANZ 20 mg, 6% for NOURIANZ 40 mg, and 5% for placebo. The most frequently reported adverse reaction causing study discontinuation was dyskinesia [see Warnings and Precautions (5.1)].
Common Adverse Reactions in Pooled Placebo-Controlled Trials
Table 1 shows adverse reactions with a frequency of at least 2% in patients treated with NOURIANZ 20 mg or 40 mg once daily. The most common adverse reactions in which the frequency for NOURIANZ was at least 5%, and greater than the incidence on placebo, were dyskinesia, dizziness, constipation, nausea, hallucination, and insomnia.
| Adverse Reactions | NOURIANZ 20 mg/day (N=356) % | NOURIANZ 40 mg/day (N=378) % | Placebo N=426 (%) |
|---|---|---|---|
| |||
| Nervous system disorders | |||
| Dyskinesia | 15 | 17 | 8 |
| Dizziness | 3 | 6 | 4 |
| Gastrointestinal disorders | |||
| Constipation | 5 | 6 | 3 |
| Nausea | 4 | 6 | 5 |
| Diarrhea | 1 | 2 | 1 |
| Psychiatric disorders | |||
| Hallucination * | 2 | 6 | 3 |
| Insomnia | 1 | 6 | 4 |
| Metabolism and nutrition disorders | |||
| Decreased appetite | 1 | 3 | 1 |
| Investigations | |||
| Blood alkaline phosphatase increased | 1 | 2 | 1 |
| Blood glucose increased | 1 | 2 | 0 |
| Blood urea increased | 1 | 2 | 0 |
| Respiratory, thoracic and mediastinal disorders | |||
| Upper Respiratory Tract Inflammation | 1 | 2 | 0 |
| Skin and subcutaneous tissue disorders | |||
| Rash | 1 | 2 | 1 |
The following adverse reaction has been identified during post approval use of istradefylline outside of the United States. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure: increased libido.
Strong CYP3A4 Inhibitors
Coadministration of NOURIANZ with a strong CYP3A4 inhibitor (ketoconazole) increased istradefylline AUCinf by 2.5-fold [see Clinical Pharmacology (12.3)]. Therefore, the recommended maximum dosage of NOURIANZ in patients concomitantly using strong CYP3A4 inhibitors (e.g., itraconazole, ketoconazole, clarithromycin) is 20 mg once daily [see Dosage and Administration (2.2)].
Strong CYP3A4 Inducers
Coadministration of NOURIANZ with a strong CYP3A4 inducer (rifampin) decreased istradefylline Cmax and AUCinf by 45% and 81%, respectively [see Clinical Pharmacology (12.3)]. Therefore, it is recommended to avoid use of NOURIANZ with strong CYP3A4 inducers (e.g., carbamazepine, rifampin, phenytoin, St. John's wort) [see Dosage and Administration (2.3)].
CYP3A4 Substrates
Coadministration of NOURIANZ 20 mg with a CYP3A4 substrate (midazolam) did not affect the CYP3A4 substrate exposure, while concomitant administration of NOURIANZ 40 mg increased the CYP3A4 substrate (atorvastatin) Cmax and AUCinf by 1.5-fold [see Clinical Pharmacology (12.3)]. Monitor for an increase in adverse reactions of concomitant drugs that are CYP3A4 substrates when coadministering with NOURIANZ 40 mg.
P-glycoprotein (P-gp) Substrates
Coadministration of NOURIANZ with a P-gp substrate (digoxin) increased the P-gp substrate Cmax and AUCinf by 33% and 21%, respectively [see Clinical Pharmacology (12.3)]. Monitor for an increase in adverse reactions of concomitant drugs that are P-gp substrates when coadministering with NOURIANZ.
NOURIANZ contains istradefylline, an adenosine receptor antagonist, which has a xanthine derivative structure. The chemical name is (E)-8-(3,4-dimethoxystyryl)-1,3-diethyl-7-methyl-3,7-dihydro-1H-purine-2,6-dione. Its molecular formula is C20H24N4O4. The molecular weight is 384.43. Istradefylline has the following structural formula:
Istradefylline is a light yellow-green crystalline powder. Istradefylline has a dissociation constant (pKa) of 0.78. The aqueous solubility of istradefylline is ~0.5 µg/mL across the physiological pH range and 0.6 µg/mL in water.
NOURIANZ tablets are intended for oral administration only. Each tablet contains 20 mg or 40 mg of istradefylline and the following inactive ingredients: crospovidone, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and polyvinyl alcohol. The film coating contains hypromellose, lactose monohydrate, polyethylene glycol 3350, titanium dioxide, triacetin, and the following dyes: iron oxide red and iron oxide yellow. Carnauba wax is used for polishing.
The precise mechanism by which istradefylline exerts its therapeutic effect in Parkinson’s disease is unknown. In in vitro studies and in in vivo animal studies, istradefylline was demonstrated to be an adenosine A2A receptor antagonist.
Cardiac Electrophysiology
The effect of NOURIANZ (40 mg or 160 mg [4 times the maximum recommended dosage] once daily for 14 days) on the QTc interval was evaluated in a randomized, placebo and moxifloxacin-controlled, multiple-dose, blinded, parallel group study. There was no clinically significant prolongation of QTc interval or relationship between changes in QTc and concentrations of istradefylline.
Istradefylline exhibits dose-proportional pharmacokinetics after multiple oral doses from 20 mg to 80 mg (2 times the maximum recommended dosage). Steady-state was reached within 2 weeks of once-daily dosing. The pharmacokinetics of istradefylline were similar in PD patients and healthy subjects.
Absorption
The median time to reach the maximum concentration (Tmax) for istradefylline was about 4 hours under fasted dosing conditions.
Effect of Food
Istradefylline exposure, represented by the area under the curve over time to infinity (AUCinf), increased 1.25-fold when NOURIANZ was coadministered with a standard high-fat meal, compared with administration in a fasted state. Istradefylline maximum plasma concentrations (Cmax) increased by 1.64-fold and Tmax was shortened by 1 hour when NOURIANZ was administered with a high-fat meal. These differences in pharmacokinetic parameters are not expected to be clinically significant [see Dosage and Administration (2.1)].
Distribution
The plasma protein binding of istradefylline was approximately 98%. The apparent volume of distribution (Vd/F) of istradefylline is approximately 557 liters.
Elimination
The total clearance of istradefylline is approximately 4.6 L/hour. The mean terminal half-life (t1/2) for istradefylline at steady-state is approximately 83 hours.
Metabolism
In humans, istradefylline is exclusively eliminated via metabolism. In vitro studies indicate that istradefylline is primarily metabolized via CYP1A1 and CYP3A4, with minor contribution from CYP1A2, 2B6, 2C8, CYP2C9, CYP2C18, and 2D6. Six metabolites have been identified in human plasma. These metabolites each account for less than 10% of the exposure of the parent drug.
Excretion
Approximately 48% of a 40-mg oral dose of 14C-istradefylline was eliminated in feces, and 39% in urine. Unchanged istradefylline was not detected in urine.
Specific Populations
In patients with moderate hepatic impairment (Child-Pugh Class B), the steady-state exposure (AUC0-24) of istradefylline is predicted to be 3.3-fold higher relative to healthy subjects, based on the estimated mean terminal half-life [see Use in Specific Populations (8.7)]. Based on population pharmacokinetic analyses, no clinically relevant changes in the pharmacokinetics of istradefylline were observed based on age, sex, weight, or race. No clinically relevant changes in istradefylline exposure were observed in patients with severe renal impairment (CrCL 15-29 mL/min) or mild hepatic impairment. NOURIANZ has not been studied in patients with ESRD (CrCL < 15 mL/min), ESRD patients requiring hemodialysis, or severe hepatic impairment (Child-Pugh Class C) [see Use in Specific Populations (8.6, 8.7)].
Steady-state systemic exposure to istradefylline (40 mg) is 38% to 54% lower in tobacco smokers (who smoke 20 or more cigarettes per day) when compared with non-smokers matched for age, gender, and body weight [see Specific Populations (8.8)].
Drug Interaction Studies
In Vitro Assessment of Drug Interactions
Drug-Metabolizing Enzyme Inhibition
Istradefylline is a weak inhibitor of CYP3A4, but not an inhibitor of CYP1A2, 2B6, 2C9, 2C19, or 2D6 in vitro.
Drug-Metabolizing Enzyme Induction
Istradefylline was a weak inducer of CYP3A4 but not an inducer of CYP1A2 and 2B6 when tested in vitro. However, clinical drug-drug interaction studies with a CYP3A4 substrate (i.e., midazolam) showed no induction of CYP3A4.
Transporters
Istradefylline was not a substrate for drug transporters P-gp, BCRP, OATP1B1, or OATP1B3 when tested in vitro. Istradefylline was a weak inhibitor for P-gp, BCRP, OATP1B1, OATP1B3, OAT1, OCT2, MATE1, and MATE2-K, but not an inhibitor of OAT3 when tested in vitro.
In Vivo Assessment of Drug Interactions
Effect of Other Drugs on Istradefylline
Strong CYP3A4 Inhibitors
Coadministration of ketoconazole (200 mg twice daily for 4 days) with a single dose of istradefylline (40 mg) increased the AUCinf of istradefylline by 2.5-fold, but had no effect on Cmax [see Drug Interactions (7.1)].
Strong CYP3A4 Inducers
Coadministration of rifampin (600 mg daily for 20 days) with a single dose of istradefylline (40 mg) reduced the Cmax and AUCinf of istradefylline by 45% and 81% respectively, when compared with istradefylline administered alone [see Drug Interactions (7.1)].
Effect of Istradefylline on Other Drugs
CYP3A4 Substrates
Coadministration of istradefylline at higher than the recommended doses (80 mg for 14 days) with a single dose of midazolam (10 mg) increased midazolam AUCinf 2.4-fold, and Cmax by 1.6-fold, when compared with midazolam administered alone. Coadministration of lower doses of istradefylline (5 mg and 20 mg) with midazolam (7.5 mg) did not have these effects [see Drug Interactions (7.2)].
Coadministration of istradefylline (40 mg daily for 17 days) with a single dose of atorvastatin (40 mg) increased the Cmax and AUCinf of atorvastatin by 1.5-fold, compared with atorvastatin alone [see Drug Interactions (7.2)].
P-glycoprotein Substrates
Coadministration of istradefylline (40 mg daily for 21 days) with a single dose of digoxin (0.4 mg) increased the Cmax and AUCinf of digoxin by 33% and 21%, respectively, when compared with digoxin alone [see Drug Interactions (7.2)].
Carbidopa/Levodopa
Coadministration of istradefylline (80 mg [two times the recommended maximum dosage] daily for 14 days) with a single dose of carbidopa/levodopa (50/200 mg) did not affect the pharmacokinetics of carbidopa/levodopa. Also, coadministration of istradefylline (20 mg or 40 mg daily for 14 days) with carbidopa/levodopa (25/100 mg three times a day for 14 days) did not affect the systemic exposure of carbidopa/levodopa.
Carcinogenesis
In lifetime oral carcinogenicity studies, there was no evidence of carcinogenicity in mouse (0, 25, 125, or 250 mg/kg) or rat (0, 30, 100, or 320 mg/kg). Plasma exposures (AUC) at the highest doses tested were approximately 20 (mouse) and 10 (rat) times that in humans at the maximum recommended human dose (MRHD) of 40 mg/day.
Mutagenesis
Istradefylline was negative in in vitro (bacterial reverse mutation assay, chromosomal aberration in mammalian cells) and in vivo (mouse bone marrow micronucleus) assays.
Impairment of Fertility
Oral administration of istradefylline (0, 160, 360, or 800 mg/kg/day) to male and female rats prior to and during mating and continuing in females to gestation day 7 resulted in a decrease in fertility at the highest dose tested and an increase in preimplantation loss at the mid and high doses. Sperm motility was reduced at the highest dose tested. Plasma exposure (AUC) at the no-effect dose (160 mg/kg) for adverse effects on reproductive function is approximately 3 times that in humans at the MRHD.
Oral administration of istradefylline (0, 30, 100, or 320 mg/kg/day) to rats for two years resulted in an increase in the incidence and severity of vascular mineralization in the brain (including in the caudate/putamen, globus pallidus, thalamus, and nucleus accumbens) at all doses tested. The vascular mineralization was composed of calcium and phosphorus and, at higher doses, were reported to partially or completely occlude the blood vessels. There was no evidence of neuronal degeneration, inflammation, or glial response associated with the foci of mineralization.
Brain mineralization was not detected in mice administered istradefylline (0, 25, 125, or 250 mg/kg/day) orally for two years or in dogs administered istradefylline (0, 10, 30, or 100 mg/kg/day) orally for 52 weeks.
The efficacy of NOURIANZ for the adjunctive treatment to levodopa/carbidopa in patients with Parkinson's disease experiencing "off" episodes was shown in four randomized, multicenter, double-blind, 12-week, placebo-controlled studies (Study 1, NCT00456586; Study 2, NCT00199407; Study 3, NCT00455507; and Study 4, NCT00955526). The studies enrolled patients with a mean duration of Parkinson's disease of 9 years (range: 1 month to 37 years) that were Hoehn and Yahr Stage II to IV, experiencing at least 2 hours (mean approximately 6 hours) of "off" time per day, and were treated with levodopa for at least one year, with stable dosage for at least 4 weeks before screening (mean total daily dosage range: 416 to 785 mg). Patients continued levodopa treatment with or without concomitant PD medications, including dopamine agonists (85%), COMT inhibitors (38%), MAO-B inhibitors (40%), anticholinergics (13%), and/or amantadine (33%), provided the medications were stable for at least 4 weeks before screening and throughout the study period. The studies excluded patients who had received a neurosurgical treatment for PD (e.g., pallidotomy, thalamotomy, deep brain stimulation).
The primary efficacy endpoint was the change from baseline in the daily awake percentage of "off" time, or the change from baseline in total daily "off" time, based on 24-hour diaries completed by patients. A change from baseline in "on" time without troublesome dyskinesia (i.e., "on" time without dyskinesia plus "on" time with non-troublesome dyskinesia) was a secondary efficacy endpoint.
Study 1 was conducted in the U.S. and Canada, and Study 2 was conducted in the U.S. In these studies, patients were randomized to once-daily treatment with NOURIANZ 20 mg, 40 mg, or placebo. Patients treated with NOURIANZ 20 mg or NOURIANZ 40 mg once daily experienced a statistically significant decrease from baseline in percentage of daily awake "off" time, compared with patients on placebo, as summarized in Table 2.
| Baseline | Change from Baseline to Endpoint | |||
|---|---|---|---|---|
| N | (mean ± SD) % of awake "off" hours | N | (LSMD * vs. placebo), % awake "off" hours, (p-value) | |
| SD: Standard Deviation | ||||
| ||||
| Study 1 | ||||
| Placebo | 66 | 37.2 ± 13.8 | 65 | -- |
| NOURIANZ 40 mg | 129 | 38.4 ± 16.2 | 126 | - 6.78 (p=0.007) |
| Study 2 | ||||
| Placebo | 113 | 38.7 ± 11.6 | 113 | -- |
| NOURIANZ 20 mg | 112 | 39.8 ± 14.0 | 112 | - 4.57 (p=0.025) |
Compared with patients on placebo, patients treated with NOURIANZ experienced an additional increase from baseline in "on" time without troublesome dyskinesia of 0.96 hours (nominal p=0.026) in Study 1, and of 0.55 hours (nominal p=0.135) in Study 2.
Study 3 and Study 4 were conducted in Japan. In these studies, patients were randomized equally to treatment with NOURIANZ 20 mg, 40 mg, or placebo. Patients treated with NOURIANZ 20 mg or NOURIANZ 40 mg once daily experienced a statistically significant decrease from baseline in "off" time compared with patients on placebo, as summarized in Table 3.
| Baseline | Change from Baseline to Endpoint | |||
|---|---|---|---|---|
| N | (mean ± SD) hours | N | (LSMD * vs. placebo) hours ( p-value) | |
| SD: Standard Deviation | ||||
| ||||
| Study 3 | ||||
| Placebo | 118 | 6.4 ± 2.7 | 118 | -- |
| NOURIANZ 20 mg | 115 | 6.8 ± 2.9 | 115 | -0.65 (p=0.028) |
| NOURIANZ 40 mg | 124 | 6.6 ± 2.5 | 124 | -0.92 (p=0.002) |
| Study 4 | ||||
| Placebo | 123 | 6.3 ± 2.5 | 123 | -- |
| NOURIANZ 20 mg | 120 | 6.6 ± 2.7 | 120 | -0.76 (p=0.006) |
| NOURIANZ 40 mg | 123 | 6.0 ± 2.5 | 123 | -0.74 (p=0.008) |
In Study 3, compared with placebo, an additional increase from baseline in "on" time without troublesome dyskinesia of 0.57 hours (nominal p=0.085) and of 0.65 hours (nominal p=0.048), respectively, were observed in patients treated with NOURIANZ 20 mg or NOURIANZ 40 mg. In Study 4, the corresponding increases in "on" time without troublesome dyskinesia were 0.83 hours (nominal p=0.008) for NOURIANZ 20 mg and 0.81 hours (nominal p=0.008) for NOURIANZ 40 mg.
NOURIANZ (istradefylline) tablets are available as:
20 mg Tablets:
Peach-colored, pillow-shaped, film-coated tablets with "20" debossed on one side.
Bottle of 90: NDC 42747-602-90
40 mg Tablets:
Peach-colored, almond-shaped, film-coated tablets with "40" debossed on one side.
Bottle of 90: NDC 42747-604-90
Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F to 86°F) [see USP Controlled Room Temperature].
The precise mechanism by which istradefylline exerts its therapeutic effect in Parkinson’s disease is unknown. In in vitro studies and in in vivo animal studies, istradefylline was demonstrated to be an adenosine A2A receptor antagonist.
