Pirfenidone Drug Information

Pirfenidone capsules are indicated for the treatment of idiopathic pulmonary fibrosis (IPF). Pirfenidone is a pyridone indicated for the treatment of idiopathic pulmonary fibrosis (IPF).

Clinical Trials Experience

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 pirfenidone has been evaluated in more than 1,400 subjects with over 170 subjects exposed to pirfenidone for more than 5 years in clinical trials. Pirfenidone was studied in 3 randomized, double-blind, placebo-controlled trials (Studies 1, 2, and 3) in which a total of 623 patients received 2,403 mg/day of pirfenidone and 624 patients received placebo.

Subjects ages ranged from 40 to 80 years (mean age of 67 years). Most patients were male (74%) and Caucasian (95%). The mean duration of exposure to pirfenidone was 62 weeks (range: 2 to 118 weeks) in these 3 trials. At the recommended dosage of 2,403 mg/day, 14.6% of patients on pirfenidone compared to 9.6% on placebo permanently discontinued treatment because of an adverse event. The most common (> 1%) adverse reactions leading to discontinuation were rash and nausea.

The most common (> 3%) adverse reactions leading to dosage reduction or interruption were rash, nausea, diarrhea, and photosensitivity reaction. The most common adverse reactions with an incidence of ≥ 10% and more frequent in the pirfenidone than placebo treatment group are listed in Table 2. Table 2: Adverse Reactions Occurring in ≥ 10% of Pirfenidone-Treated Patients and More Commonly Than Placebo in Studies 1, 2, and 3 Adverse Reaction % of Patients (0 to 118 Weeks) Pirfenidone 2,403 mg/day (N = 623) Placebo (N = 624) Nausea 36% 16% Rash 30% 10% Abdominal Pain 1 24% 15% Upper Respiratory Tract Infection 27% 25% Diarrhea 26% 20% Fatigue 26% 19% Headache 22% 19% Decreased Appetite 21% 8% Dyspepsia 19% 7% Dizziness 18% 11% Vomiting 13% 6% Gastro-esophageal Reflux Disease 11% 7% Sinusitis 11% 10% Insomnia 10% 7% Weight Decreased 10% 5% Arthralgia 10% 7% 1 Includes abdominal pain, upper abdominal pain, abdominal distension, and stomach discomfort. Adverse reactions occurring in ≥ 5% to < 10% of pirfenidone-treated patients and more commonly than placebo are photosensitivity reaction (9% vs. 1%), pruritus (8% vs. 5%), asthenia (6% vs. 4%), dysgeusia (6% vs. 2%), and non-cardiac chest pain (5% vs. 4%).

Post-marketing Experience

In addition to adverse reactions identified from clinical trials the following adverse reactions have been identified during post-approval use of pirfenidone. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency. Blood and Lymphatic System Disorders: Agranulocytosis Hepatobiliary Disorders: Drug-induced liver injury Immune System Disorders: Angioedema Skin and Subcutaneous Tissue Disorders: Severe Cutaneous Adverse Reactions (SCAR)

CYP1A2 Inhibitors Pirfenidone is metabolized primarily (70% to 80%) via

CYP1A2 with minor contributions from other CYP isoenzymes including CYP2C9, 2C19, 2D6 and 2E1. Strong CYP1A2 Inhibitors The concomitant administration of pirfenidone and fluvoxamine or other strong CYP1A2 inhibitors (e.g., enoxacin) is not recommended because it significantly increases exposure to pirfenidone. Use of fluvoxamine or other strong CYP1A2 inhibitors should be discontinued prior to administration of pirfenidone and avoided during pirfenidone treatment. In the event that fluvoxamine or other strong CYP1A2 inhibitors are the only drug of choice, dosage reductions are recommended.

Monitor for adverse reactions and consider discontinuation of pirfenidone as needed . Moderate CYP1A2 Inhibitors Concomitant administration of pirfenidone and ciprofloxacin (a moderate inhibitor of CYP1A2) moderately increases exposure to pirfenidone . If ciprofloxacin at the dosage of 750 mg twice daily cannot be avoided, dosage reductions are recommended. Monitor patients closely when ciprofloxacin is used at a dosage of 250 mg or 500 mg once daily. Concomitant CYP1A2 and other CYP Inhibitors Agents or combinations of agents that are moderate or strong inhibitors of both CYP1A2 and one or more other CYP isoenzymes involved in the metabolism of pirfenidone (i.e.

CYP2C9, 2C19, 2D6, and 2E1) should be discontinued prior to and avoided during pirfenidone treatment.

CYP1A2 Inducers

The concomitant use of pirfenidone and a CYP1A2 inducer may decrease the exposure of pirfenidone and this may lead to loss of efficacy. Therefore, discontinue use of strong CYP1A2 inducers prior to pirfenidone treatment and avoid the concomitant use of pirfenidone and a strong CYP1A2 inducer .

Pregnancy Risk Summary The data with pirfenidone use in pregnant women are insufficient to inform on drug associated risks for major birth defects and miscarriage. In animal reproduction studies, pirfenidone was not teratogenic in rats and rabbits at oral doses up to 3 and 2 times, respectively, the maximum recommended daily dose (MRDD) in adults . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data Animal reproductive studies were conducted in rats and rabbits.

In a combined fertility and embryofetal development study, female rats received pirfenidone at oral doses of 0, 50, 150, 450, and 1,000 mg/kg/day from 2 weeks prior to mating, during the mating phase, and throughout the periods of early embryonic development from gestation days (GD) 0 to 5 and organogenesis from GD 6 to 17. In an embryofetal development study, pregnant rabbits received pirfenidone at oral doses of 0, 30, 100, and 300 mg/kg/day throughout the period of organogenesis from GD 6 to 18. In these studies, pirfenidone at doses up to 3 and 2 times, respectively, the maximum recommended daily dose (MRDD) in adults (on mg/m 2 basis at maternal oral doses up to 1,000 mg/kg/day in rats and 300 mg/kg/day in rabbits, respectively) revealed no evidence of impaired fertility or harm to the fetus due to pirfenidone. In the presence of maternal toxicity, acyclic/irregular cycles (e.g., prolonged estrous cycle) were seen in rats at doses approximately equal to and higher than the MRDD in adults (on a mg/m 2 basis at maternal doses of 450 mg/kg/day and higher). In a pre- and post-natal development study, female rats received pirfenidone at oral doses of 0, 100, 300, and 1,000 mg/kg/day from GD 7 to lactation day 20. Prolongation of the gestation period, decreased numbers of live newborn, and reduced pup viability and body weights were seen in rats at an oral dosage approximately 3 times the MRDD in adults (on a mg/m 2 basis at a maternal oral dose of 1,000 mg/kg/day).

Pediatric Use Safety and effectiveness of pirfenidone in pediatric patients have not been established.

There is limited clinical experience with overdosage. Multiple-dosages of pirfenidone up to a maximum tolerated dose of 4,005 mg per day were administered as five 267 mg capsules three times daily to healthy adult volunteers over a 12-day dose escalation. In the event of a suspected overdosage, appropriate supportive medical care should be provided, including monitoring of vital signs and observation of the clinical status of the patient.