Peginterferon alfa-2a

12.1 Mechanism of Action Pegylated recombinant human interferon alfa-2a is an inducer of the innate antiviral immune response [see Microbiology (12.4) ] .

1 INDICATIONS AND USAGE PEGASYS is an inducer of the innate immune response indicated for the treatment of Chronic Hepatitis C (CHC) ( 1.1 ) Adult Patients: In combination therapy with other hepatitis C virus drugs for adults with compensated liver disease. PEGASYS monotherapy is indicated only if patient has contraindication or significant intolerance to other HCV drugs. Pediatric Patients: In combination with ribavirin for pediatric patients 5 years of age and older with compensated liver disease Chronic Hepatitis B (CHB) ( 1.2 ) Adult Patients: Treatment of adults with HBeAg-positive and HBeAg-negative chronic hepatitis B (CHB) infection who have compensated liver disease and evidence of viral replication and liver inflammation Pediatric Patients: Treatment of non-cirrhotic pediatric patients 3 years of age and older with HBeAg-positive CHB and evidence of viral replication and elevations in serum alanine aminotransferase (ALT) 1.1 Chronic Hepatitis C (CHC) Adult Patients: PEGASYS, as part of a combination regimen with other hepatitis C virus (HCV) antiviral drugs, is indicated for the treatment of adults with CHC and compensated liver disease. For information about the safe and effective use of other HCV antiviral drugs to be used in combination with PEGASYS, refer to their prescribing information. PEGASYS monotherapy is only indicated for the treatment of patients with CHC and compensated liver disease if there are contraindications or significant intolerance to other HCV antiviral drugs. Pediatric Patients: PEGASYS in combination with ribavirin is indicated for the treatment of pediatric patients 5 years of age and older with CHC and compensated liver disease. Limitations of Use : PEGASYS alone or in combination with ribavirin without additional HCV antiviral drugs is not recommended for treatment of patients with CHC who previously failed therapy with an interferon-alfa. PEGASYS is not recommended for treatment of patients with CHC who have had solid organ tr

2 DOSAGE AND ADMINISTRATION PEGASYS is administered by subcutaneous injection ( 2 ) In adult patients with CHC, PEGASYS is dosed as 180 mcg per week and the duration of treatment depends on indication, genotype, and whether it is administered with other HCV antiviral drugs ( 2.2 ). In adult patients with CHB, PEGASYS is dosed as 180 mcg per week for 48 weeks ( 2.4 ). In pediatric patients with CHC, PEGASYS is dosed as 180 mcg/1.73 m 2 × BSA per week, in combination with ribavirin, and the duration of treatment depends on genotype ( 2.3 ) In pediatric patients with CHB, PEGASYS is dosed as 180 mcg/1.73 m 2 × BSA per week for 48 weeks ( 2.5 ): Dosage modification is recommended in patients experiencing certain laboratory abnormalities, adverse reactions or renal impairment ( 2.6 , 12.3 ) 2.1 Dosage Overview Administer PEGASYS by subcutaneous injection once weekly in the abdomen or thigh for the treatment of: Adult patients with CHC without or with HIV coinfection [see Dosage and Administration (2.2) ]; Pediatric patients with CHC [see Dosage and Administration (2.3) ] ; Adult patients with CHB [see Dosage and Administration (2.4) ] ; and Pediatric patients with CHB [see Dosage and Administration (2.5) ]. For treatment of CHC, use PEGASYS in combination with other HCV antiviral drugs. For information about the recommended dosage and administration and the safe and effective use of these other HCV antiviral drugs, refer to their prescribing information. PEGASYS monotherapy is only indicated in the treatment of CHC if there are contraindications to or significant intolerance to other HCV antiviral drugs. For dosage modifications in patients with CHC or CHB: Due to neutropenia, thrombocytopenia, ALT elevation, and depression [see Dosage and Administration (2.6) ] . In patients with severe renal impairment (creatinine clearance less than 30 mL/minute) and in patients with creatinine clearance between 30 and 50 mL/minute [see Dosage and Administration (2.6) ] . For important administration instructions for all the PEGASYS injection presentations (i.e., vial and prefilled syringe) [ see Dosage and Administration (2.7) ]. 2.2 Recommended Dosage for Adults with CHC Dosage in Adults with CHC without HIV Coinfection Table 1 displays the recommended dosage and duration of PEGASYS and other HCV antiviral drugs in adults with CHC (without HIV coinfection) based on HCV genotype. For treatment of HCV genotype 1 with PEGASYS in combination with ribavirin or alone, discontinuation of treatment is recommended if at least a 2 log 10 reduction from baseline in HCV RNA has not been demonstrated by 12 weeks of therapy or if undetectable HCV RNA has not been achieved after 24 weeks of therapy [see Clinical Studies (14) ] . Refer to the prescribing information for specific HCV antiviral drugs used in combination with PEGASYS for information on stopping therapy based on treatment response. Immediately discontinue PEGASYS for hepatic decompensation (Child-Pugh score greater than 6 [class B and C]). Table 1 Recommended Dosage for PEGASYS for Adults with CHC Infection If PEGASYS is used in combination with other antiviral drugs for CHC, refer to the prescribing information of the other HCV antiviral drugs for the recommended dosage of the other HCV antiviral drugs and duration of the entire treatment regimen. Hepatitis C Virus Genotype PEGASYS Dosage PEGASYS Duration Genotypes 1, 4 If PEGASYS and ribavirin are used without other HCV antiviral drugs the recommended duration of therapy is 48 weeks. 180 mcg subcutaneous injection in thigh or abdomen once weekly Refer to the prescribing information of HCV antiviral drugs. Genotypes 2, 3 If PEGASYS and ribavirin are used without other HCV antiviral drugs the recommended duration of therapy is 24 weeks. Genotypes 5, 6 There are insufficient data for dosage recommendations If PEGASYS monotherapy is used for treatment of CHC, the recommended PEGASYS dosage is 180 mcg via subcutaneous injection in thigh or abdomen once weekly for 48 weeks. Dosage in Adults with CHC with HIV Coinfection The recommended PEGASYS dosage in adults with CHC and HIV coinfection is 180 mcg subcutaneously once weekly in the thigh or abdomen. If PEGASYS is used in combination with other antiviral drugs, refer to the prescribing information of the other HCV antiviral drugs for the recommended dosage of the other HCV antiviral drugs and duration of the entire treatment regimen (including PEGASYS). If PEGASYS and ribavirin are used without other HCV antiviral drugs, the recommended duration of therapy is 48 weeks (regardless of HCV genotype). 2.3 Recommended Dosage for Pediatric Patients with CHC PEGASYS is administered as 180 mcg/1.73 m 2 × BSA subcutaneously once weekly, to a maximum dose of 180 mcg, and should be given in combination with ribavirin. The recommended treatment duration for pediatric patients with HCV genotype 2 or 3 is 24 weeks and for other HCV genotypes is 48 weeks. Patients who initiate treatment prior to

6 ADVERSE REACTIONS In clinical trials, a broad variety of serious adverse reactions were observed in 1,010 subjects who received PEGASYS at doses of 180 mcg for 48 weeks, alone or in combination with ribavirin [see Boxed Warning and Warnings and Precautions (5) ] . The most common life-threatening or fatal events induced or aggravated by PEGASYS and ribavirin include depression, suicide, relapse of drug abuse/overdose, and bacterial infections, each occurring at a frequency of less than 1%. Hepatic decompensation occurred in 2% (10/574) of CHC/HIV subjects [see Warnings and Precautions (5.9) ] . Adult subjects: The most common adverse reactions (incidence greater than 40%) are fatigue/asthenia, pyrexia, myalgia, and headache ( 6.1 ) Pediatric subjects: The most common adverse reactions are similar to those seen in adults ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact pharma& agent at 1-888-814-7734 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying and controlled conditions, adverse reaction rates observed in 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 clinical practice. Chronic Hepatitis C Adult Subjects In all hepatitis C studies, one or more serious adverse reactions occurred in 10% of CHC monoinfected subjects and in 19% of CHC/HIV subjects receiving PEGASYS alone or in combination with ribavirin. The most common serious adverse reactions (3% in CHC and 5% in CHC/HIV) was bacterial infection (e.g., sepsis, osteomyelitis, endocarditis, pyelonephritis, pneumonia). Other SAEs occurred at a frequency of less than 1% and included: suicide, suicidal ideation, aggression, anxiety, drug abuse and drug overdose, angina, hepatic dysfunction, fatty liver, cholangitis, arrhythmia, diabetes mellitus, autoimmune phenomena (e.g., hyperthyroidism, hypothyroidism, sarcoidosis, systemic lupus erythematosus, rheumatoid arthritis), peripheral neuropathy, aplastic anemia, peptic ulcer, gastrointestinal bleeding, pancreatitis, colitis, corneal ulcer, pulmonary embolism, coma, myositis, cerebral hemorrhage, thrombotic thrombocytopenic purpura, psychotic disorder, and hallucination. In clinical trials, 98 to 99 percent of subjects experienced one or more adverse reactions. For hepatitis C subjects, the most commonly reported adverse reactions were psychiatric reactions, including depression, insomnia, irritability, anxiety, and flu-like symptoms such as fatigue, pyrexia, myalgia, headache, and rigors. Other common reactions were anorexia, nausea and vomiting, diarrhea, arthralgias, injection site reactions, alopecia, and pruritus. Table 7 displays pooled rates of adverse reactions occurring in greater than 5% of subjects in the PEGASYS monotherapy and PEGASYS/ribavirin combination therapy clinical trials. Overall, 11% of CHC monoinfected subjects receiving 48 weeks of therapy with PEGASYS either alone or in combination with ribavirin discontinued therapy; 16% of CHC/HIV coinfected subjects discontinued therapy. The most common reasons for discontinuation of therapy were psychiatric, flu-like syndrome (e.g., lethargy, fatigue, headache), dermatologic and gastrointestinal disorders, and laboratory abnormalities (thrombocytopenia, neutropenia, and anemia). Overall, 39% of subjects with CHC or CHC/HIV required modification of PEGASYS and/or ribavirin therapy. The most common reasons for dose modification of PEGASYS in CHC and CHC/HIV subjects was for neutropenia (20% and 27%, respectively) and thrombocytopenia (4% and 6%, respectively). The most common reason for dose modification of ribavirin in CHC and CHC/HIV subjects was anemia (22% and 16%, respectively). PEGASYS dose was reduced in 12% of subjects receiving 1000 mg to 1200 mg ribavirin for 48 weeks and in 7% of subjects receiving 800 mg ribavirin for 24 weeks. Ribavirin dose was reduced in 21% of subjects receiving 1000 mg to 1200 mg ribavirin for 48 weeks and in 12% of subjects receiving 800 mg ribavirin for 24 weeks. Chronic hepatitis C monoinfected subjects treated for 24 weeks with PEGASYS and 800 mg ribavirin were observed to have lower incidence of serious adverse reactions (3% vs. 10%), Hgb less than 10 g/dL (3% vs. 15%), dose modification of PEGASYS (30% vs. 36%) and ribavirin (19% vs. 38%) and of withdrawal from treatment (5% vs. 15%) compared to subjects treated for 48 weeks with PEGASYS and 1000 mg or 1200 mg ribavirin. The overall incidence of adverse reactions appeared to be similar in the two treatment groups. Table 7 Adverse Reactions Occurring in Greater Than or Equal to 5% of Subjects in Chronic Hepatitis C Clinical Trials (Pooled Studies 1, 2, 3, and Study 4) CHC Monotherapy (Pooled Studies 1-3) CHC Combination Therapy (Study 4) Body System PEGASYS 180 mcg 48 week Pooled studies 1, 2, and 3 ROFERON-A Either 3 MIU An induction dose of 6 million international unit

7 DRUG INTERACTIONS Drugs metabolized by CYP1A2: monitor for increased serum levels of theophylline and adjust dose accordingly ( 7.2 ) Methadone: monitor for signs and symptoms of methadone toxicity ( 7.3 ) Nucleoside analogues: closely monitor for toxicities. Reduce or discontinue the dose of PEGASYS or ribavirin or both should the events worsen ( 7.4 ) Zidovudine: monitor for worsening neutropenia and/or anemia with PEGASYS and/or ribavirin ( 7.4 ) 7.1 Drugs Metabolized by Cytochrome P450 There was no effect on the pharmacokinetics of representative drugs metabolized by CYP 2C9, CYP 2C19, CYP 2D6 or CYP 3A4. Treatment with PEGASYS once weekly for 4 weeks in healthy subjects was associated with an inhibition of P450 1A2 and a 25% increase in theophylline AUC. 7.2 Theophylline Treatment with PEGASYS once weekly for 4 weeks in healthy subjects was associated with an inhibition of P450 1A2 and a 25% increase in theophylline AUC. Theophylline serum levels should be monitored and appropriate dose adjustments considered for patients given both theophylline and PEGASYS. 7.3 Methadone In a PK study of HCV subjects concomitantly receiving methadone, treatment with PEGASYS once weekly for 4 weeks was associated with methadone levels that were 10% to 15% higher than at baseline. The clinical significance of this finding is unknown; however, patients should be monitored for the signs and symptoms of methadone toxicity. The pharmacokinetics of concomitant administration of methadone and PEGASYS were evaluated in 24 PEGASYS naïve CHC subjects (15 male, 9 female) who received 180 mcg PEGASYS subcutaneously weekly. All subjects were on stable methadone maintenance therapy (median dose 95 mg, range 30 mg to 150 mg) prior to receiving PEGASYS. Mean methadone PK parameters were 10% to 15% higher after 4 weeks of PEGASYS treatment as compared to baseline. Methadone did not significantly alter the PK of PEGASYS as compared to a PK study of 6 chronic hepatitis C subjects not receiving methadone. 7.4 Nucleoside Analogues NRTIs In Study 7 among the CHC/HIV coinfected cirrhotic subjects receiving NRTIs cases of hepatic decompensation (some fatal) were observed [see Warnings and Precautions (5.9) ] . Patients receiving PEGASYS/ribavirin in combination with other HCV antiviral drugs and NRTIs should be closely monitored for treatment associated toxicities. Physicians should refer to prescribing information for other HCV antiviral drugs and the respective NRTIs for guidance regarding toxicity management. In addition, dose reduction or discontinuation of PEGASYS, ribavirin or both, should also be considered if worsening toxicities are observed [see Warnings and Precautions (5.3 , 5.9) and Dosage and Administration (2.6) ] . Zidovudine In Study 7, subjects who were administered zidovudine in combination with PEGASYS/ribavirin developed severe neutropenia (ANC less than 500 cells/mm 3 ) and severe anemia (hemoglobin less than 8 g/dL) more frequently than similar subjects not receiving zidovudine (neutropenia 15% vs. 9%) (anemia 5% vs. 1%). Discontinuation of zidovudine should be considered as medically appropriate. Dose reduction or discontinuation of PEGASYS, ribavirin or both should also be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh greater than 6). Refer to the prescribing information for specific HCV antiviral drugs used in combination with PEGASYS for information on drug interaction potential.