Pirfenidone 267 mg Tablet, Film Coated, 270-count — NDC 70954-869-30 (Billing 70954-0869-30)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action The mechanism of action of pirfenidone in the treatment of IPF has not been established.

12.2Pharmacodynamics Cardiac Electrophysiology: The effect of pirfenidone on QT interval was evaluated in a randomized, placebo, and positive controlled parallel study in 160 healthy adult volunteers. Volunteers received pirfenidone 2,403 mg/day (recommended dose) and 4,005 mg/day (1.6 times recommended dose) or placebo for 10 days or a single dose of 400 mg moxifloxacin (active control). Relative to placebo, the maximum mean change from baseline in study-specific QT interval was 3.2 milliseconds (ms) and 2.2 ms for pirfenidone 2,403 mg/day and 4,005 mg/day, respectively.

No volunteer had a QTc interval greater than 480 ms or change from baseline greater than 60 ms. Although there was no evidence that pirfenidone prolonged the QTc interval in this study, a definitive conclusion may not be drawn as the positive control (moxifloxacin) did not perform as expected in this study, and pirfenidone at 4,005 mg/day (1.7 times the maximum recommended dose) did not cover the maximum pirfenidone exposure increase with co-administration of fluvoxamine, a strong CYP1A2 inhibitor.

12.3Pharmacokinetics Absorption: After single oral-dose administration of 801 mg pirfenidone (three 267 mg capsules), the maximum observed plasma concentration (C max ) was achieved between 30 minutes and 4 hours (median time of 0.5 hours). Food decreased the rate and extent of absorption. Median T max increased from 0.5 hours to 3 hours with food.

Maximum plasma concentrations (C max ) and AUC 0 to inf decreased by approximately 49% and 16% with food, respectively. Bioequivalence was demonstrated in the fasted state when comparing the 801 mg tablet to three 267 mg capsules. The effect of food on pirfenidone exposure was consistent between the tablet and capsule formulations.

A reduced incidence of adverse reactions was observed in the fed group when compared to the fasted group. In controlled studies with IPF patients, pirfenidone was taken with food [see Dosage and Administration (2) and Clinical Studies (14) ] . The absolute bioavailability of pirfenidone has not been determined in humans.

Distribution: Pirfenidone binds to human plasma proteins, primarily to serum albumin, in a concentration-independent manner over the range of concentrations observed in clinical trials. The overall mean binding was 58% at concentrations observed in clinical studies (1 to 10 mcg/mL). Mean apparent oral volume of distribution is approximately 59 to 71 liters.

Metabolism: In vitro profiling studies in hepatocytes and liver microsomes have shown that pirfenidone is primarily metabolized in the liver by CYP1A2 and multiple other CYPs (CYP2C9, 2C19, 2D6, and 2E1). Oral administration of pirfenidone results in the formation of four metabolites. In humans, only pirfenidone and 5-carboxy-pirfenidone are present in plasma in significant quantities.

The mean metabolite-to-parent ratio ranged from approximately 0.6 to 0.7. No formal radiolabeled studies have assessed the metabolism of pirfenidone in humans. In vitro data suggests that metabolites are not expected to be pharmacologically active at observed metabolite concentrations.

Elimination: The mean terminal half-life is approximately 3 hours in healthy subjects. Pirfenidone is excreted predominantly as metabolite 5-carboxy-pirfenidone, mainly in the urine (approximately 80% of the dose). The majority of pirfenidone was excreted as the 5-carboxy metabolite (approximately 99.6% of that recovered).

Specific Populations: Hepatic Impairment The pharmacokinetics of pirfenidone and the 5-carboxy-pirfenidone metabolite were studied in 12 subjects with moderate hepatic impairment (Child Pugh Class B) and in 12 subjects with normal hepatic function. Results showed that the mean exposure, AUC 0 to inf and C max of pirfenidone increased approximately 1.6- and approximately 1.4-fold in subjects with moderate… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action The mechanism of action of pirfenidone in the treatment of IPF has not been established.

12.3Pharmacokinetics Absorption: After single oral-dose administration of 801 mg pirfenidone (three 267 mg capsules), the maximum observed plasma concentration (C max ) was achieved between 30 minutes and 4 hours (median time of 0.5 hours). Food decreased the rate and extent of absorption. Median T max increased from 0.5 hours to 3 hours with food.

Maximum plasma concentrations (C max ) and AUC 0 to inf decreased by approximately 49% and 16% with food, respectively. Bioequivalence was demonstrated in the fasted state when comparing the 801 mg tablet to three 267 mg capsules. The effect of food on pirfenidone exposure was consistent between the tablet and capsule formulations.

A reduced incidence of adverse reactions was observed in the fed group when compared to the fasted group. In controlled studies with IPF patients, pirfenidone was taken with food [see Dosage and Administration (2) and Clinical Studies (14) ] . The absolute bioavailability of pirfenidone has not been determined in humans.

Distribution: Pirfenidone binds to human plasma proteins, primarily to serum albumin, in a concentration-independent manner over the range of concentrations observed in clinical trials. The overall mean binding was 58% at concentrations observed in clinical studies (1 to 10 mcg/mL). Mean apparent oral volume of distribution is approximately 59 to 71 liters.

Metabolism: In vitro profiling studies in hepatocytes and liver microsomes have shown that pirfenidone is primarily metabolized in the liver by CYP1A2 and multiple other CYPs (CYP2C9, 2C19, 2D6, and 2E1). Oral administration of pirfenidone results in the formation of four metabolites. In humans, only pirfenidone and 5-carboxy-pirfenidone are present in plasma in significant quantities.

The mean metabolite-to-parent ratio ranged from approximately 0.6 to 0.7. No formal radiolabeled studies have assessed the metabolism of pirfenidone in humans. In vitro data suggests that metabolites are not expected to be pharmacologically active at observed metabolite concentrations.

Elimination: The mean terminal half-life is approximately 3 hours in healthy subjects. Pirfenidone is excreted predominantly as metabolite 5-carboxy-pirfenidone, mainly in the urine (approximately 80% of the dose). The majority of pirfenidone was excreted as the 5-carboxy metabolite (approximately 99.6% of that recovered).

Specific Populations: Hepatic Impairment The pharmacokinetics of pirfenidone and the 5-carboxy-pirfenidone metabolite were studied in 12 subjects with moderate hepatic impairment (Child Pugh Class B) and in 12 subjects with normal hepatic function. Results showed that the mean exposure, AUC 0 to inf and C max of pirfenidone increased approximately 1.6- and approximately 1.4-fold in subjects with moderate hepatic impairment, respectively. The exposure of 5-carboxy-pirfenidone did not change significantly in subjects with moderate hepatic impairment.

Renal Impairment The pharmacokinetics of pirfenidone and the 5-carboxy-pirfenidone metabolite were studied in 18 subjects with mild (CL cr 50 to 80 mL/min), moderate (CL cr 30 to 50 mL/min), and severe (CL cr less than 30 mL/min) renal impairment (n=6/group) and in 6 subjects with normal CL cr (greater than or equal to 80 mL/min) renal function. Results showed that systemic exposure (AUC 0 to inf ) to pirfenidone increased approximately 1.4, 1.5, and 1.2-fold in subjects with mild, moderate and severe renal impairment, respectively.

The corresponding AUC 0 to inf of 5-carboxy-pirfenidone increased 1.7, 3.4, and 5.6-fold, although the change in the patients with mild renal impairment was not statistically significant. The renal clearance of 5-carboxy-pirfenidone decreased significantly in patients with moderate to severe renal impairment. The pharmacokinetics and safety of pirfenidone has not been studied in subjects with end-stage renal disease requiring dialysis.

Geriatric Results of population pharmacokinetic analysis suggest that no dosage adjustment is ne… [Excerpted — this section continues on DailyMed.]

12.2Pharmacodynamics Cardiac Electrophysiology: The effect of pirfenidone on QT interval was evaluated in a randomized, placebo, and positive controlled parallel study in 160 healthy adult volunteers. Volunteers received pirfenidone 2,403 mg/day (recommended dose) and 4,005 mg/day (1.6 times recommended dose) or placebo for 10 days or a single dose of 400 mg moxifloxacin (active control). Relative to placebo, the maximum mean change from baseline in study-specific QT interval was 3.2 milliseconds (ms) and 2.2 ms for pirfenidone 2,403 mg/day and 4,005 mg/day, respectively.

No volunteer had a QTc interval greater than 480 ms or change from baseline greater than 60 ms. Although there was no evidence that pirfenidone prolonged the QTc interval in this study, a definitive conclusion may not be drawn as the positive control (moxifloxacin) did not perform as expected in this study, and pirfenidone at 4,005 mg/day (1.7 times the maximum recommended dose) did not cover the maximum pirfenidone exposure increase with co-administration of fluvoxamine, a strong CYP1A2 inhibitor.

14 CLINICAL STUDIES The efficacy of pirfenidone was evaluated in patients with IPF in three phase 3, randomized, double-blind, placebo-controlled, multicenter trials (Studies 1, 2, and 3). Study 1 was a 52-week trial comparing pirfenidone 2,403 mg/day (n=278) versus placebo (n=277) in patients with IPF. Study 2 and Study 3 were nearly identical to each other in design, with few exceptions, including an intermediate dose treatment arm in Study 2.

Study 2 compared treatment with either pirfenidone 2,403 mg/day (n=174) or pirfenidone 1,197 mg/day (n=87) to placebo (n=174), while Study 3 compared pirfenidone 2,403 mg/day (n=171) to placebo (n=173). Study drug was administered three times daily with food for a minimum of 72 weeks. Patients continued on treatment until the last patient completed 72 weeks of treatment, which included observations to approximately 120 weeks of study treatment.

The primary endpoint was the change in percent predicted forced vital capacity (%FVC) from baseline to study end, measured at 52 weeks in Study 1, and at 72 weeks in Studies 2 and 3. Studies 1, 2 and 3 enrolled adult patients who had a clinical and radiographic diagnosis of IPF (with or without accompanying surgical lung biopsy), without evidence or suspicion of an alternative diagnosis for interstitial lung disease. Eligible patients were to have %FVC greater than or equal to 50% at baseline and a percent predicted diffusing capacity of the lungs for carbon monoxide (%DL CO ) greater than or equal to 30% (Study 1) or 35% (Studies 2 and 3) at baseline.

In all three trials, over 80% of patients completed study treatment. A total of 1,247 patients with IPF were randomized to receive pirfenidone 2,403 mg/day (n=623) or placebo (n=624) in these three trials. Baseline characteristics were generally balanced across treatment groups.

The study population ranged from 40 to 80 years of age (mean age 67 years). Most patients were male (74%), white (95%), and current or former smokers (65%). Approximately 93% of patients met criteria for definite IPF on high resolution computed tomography (HRCT).

Baseline mean %FVC and %DL CO were 72% and 46%, respectively. Approximately 15% subjects discontinued from each treatment group. Change from Baseline in Percent Predicted Forced Vital Capacity In Study 1, the primary efficacy analysis for the change in %FVC from baseline to Week 52 demonstrated a statistically significant treatment effect of pirfenidone 2,403 mg/day (n=278) compared with placebo (n=277) using a rank ANCOVA with the lowest rank imputation for missing data due to death.

In Study 2, there was a statistically significant difference at Week 72 for the change in %FVC from baseline. In Study 3, there was no statistically significant difference at Week 72 for the change in %FVC from baseline. Figure 1 presents the cumulative distribution for all cut-offs for the change from baseline in %FVC at Week 52 for Study 1.

For all categorical declines in lung function, the proportion of patients declining was lower on pirfenidone than on placebo. Study 2 showed similar results. Figure 1.

Cumulative Distribution of Patients by Change in Percent Predicted FVC from Baseline to Week 52 (Study 1). The Dashed Lines Indicate ≥10% Decline or ≥0% Decline. Mean Change from Baseline in FVC (mL) In Study 1, a reduction in the mean decline in FVC (in mL) was observed in patients receiving pirfenidone 2,403 mg/day (-235 mL) compared to placebo (-428 mL) (mean treatment difference 193 mL) at Week 52 (see Figure 2).

In Study 2, a reduction in the decline in FVC volume was also observed in patients receiving pirfenidone 2,403 mg/day compared with placebo (mean treatment difference 157 mL) at Week 72. There was no statistically significant difference in decline in FVC volume seen in Study 3. Figure 2.

Mean Change from Baseline in Forced Vital Capacity (Study 1) Survival Survival was evaluated for pirfenidone compared to placebo in Studies 1, 2, and 3 as an exploratory analysis to s… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis & Mutagenesis & Impairment Of Fertility Carcinogenesis Long-term studies were conducted in mice and rats with admixture of pirfenidone to the diet to evaluate its carcinogenic potential. In a 24-month carcinogenicity study in B6C3F1 mice, pirfenidone caused statistically significant dose-related increases of the combination of hepatocellular adenoma and carcinoma and hepatoblastoma in male mice at doses of 800 mg/kg and above (AUC exposure approximately 0.4 times adult exposure at the MRDD). There were statistically significant dose-related increases of the combination of hepatocellular adenoma and carcinoma in female mice at doses of 2,000 mg/kg and above (AUC exposure approximately 0.7 times adult exposure at the MRDD).

In a 24-month carcinogenicity study in Fischer rats, pirfenidone caused statistically significant dose-related increases of the combination of hepatocellular adenoma and carcinoma in male rats at doses of 750 mg/kg and above (AUC exposure approximately 1.9 times adult exposure at the MRDD). There were statistically significant increases of the combination of hepatocellular adenoma and carcinoma and the combination of uterine adenocarcinoma and adenoma at a dose of 1,500 mg/kg/day (AUC exposure approximately 3.0 times adult exposure at the MRDD).

The relevance of these tumor findings in rodents to humans is unknown. Mutagenesis Pirfenidone was not mutagenic or clastogenic in the following tests: mutagenicity tests in bacteria, a chromosomal aberration test in Chinese hamster lung cells, and a micronucleus test in mice. Impairment of Fertility Pirfenidone had no effects on fertility and reproductive performance in rats at dosages up to 1,000 mg/kg/day (approximately 3 times the MRDD in adults on a mg/m 2 basis).