Peginterferon Alfa-2a

Indications

Peginterferon Alfa-2a is used for: Chronic hepatitis C, Chronic hepatitis B

Adult Dose

Subcutaneous Chronic hepatitis C Adult: 180 mcg SC once weekly for 48 weeks Treatment duration Monotherapy: 48 weeks Dual therapy with Ribavirin Hepatitis C (Genotype 1 & 4): 48 weeks Hepatitis C (Genotype 2 & 3): 24 weeks Chronic Hepatitis B Adult: 180 mcg SC once weekly for 48 weeks Dosage Modifications Neutropenia ANC <750 cells/mm³: Reduce dose to 135 mcg SC once weekly ANC <500 cells/mm³: Discontinue treatment until ANC values return to >1000 cells/mm³ and then reinstitute at 90 mcg SC once weekly; monitor ANC Thrombocytopenia Platelet <50,000 cells/mm³: Reduce dose to 90 mcg SC once weekly Platelets <25,000 cells/mm³: Discontinue Hepatic impairment: Alanine transaminase (ALT) progressively rising above baseline: Decrease dose to 135 mcg/wk. If ALT continues to rise or is accompanied by increased bilirubin or hepatic decompensation, discontinue immediately.

Child Dose

Chronic Hepatitis C Indicated in combination with ribavirin for treatment of chronic hepatitis C of children aged >5 yr with CHC and compensated liver disease <5 years: Safety and efficacy not established >5 years: 180 mcg/1.73 m² SC qWeek with daily ribavirin Treatment duration Genotypes 2, 3: 24 weeks Genotypes 1, 4: 48 weeks

Renal Dose

Renal impairment CrCl 30-50 mL/min: 180 mcg once weekly CrCl <30 mL/min (including patients on hemodialysis): 135 mcg once weekly If severe adverse reactions or laboratory abnormalities develop, dose can be reduced to 90 mcg once weekly until adverse reactions abate If intolerance persists after dosage adjustment, discontinued

Administration

Administer by SC injection once weekly in abdomen or thigh

Contra Indications

Hypersensitivity to any component of the product. Autoimmune hepatitis; decompensated liver disease in cirrhotic patients (Child-Pugh score >6); decompensated liver disease (Child-Pugh score >6, class B and C) in chronic hepatitis C coinfected with HIV; neonates and infants; in combination with ribavirin in pregnant women.

Precautions

Neuropsychiatric disorders, discontinue treatment with worsening or persistently severe signs/symptoms; myelosuppresion; anemia (spherocytosis, history of GI bleeding); pulmonary disease; autoimmune disease; cardiovascular disease; DM; infectious disorders; ischaemic disorders; renal impairment; thyroid disorders; patients who have failed other alpha interferon therapy, received organ transplants, been coinfected with Hepatis B or C virus or HIV; or with Hepatitis C virus and HIV with a CD4+ cell count <100 cells/microliter, or been treated for >48 wk. Elderly. Safety and efficacy not been established in children. Do not change brands of interferon without the concurrence of healthcare provider (product variability). More frequent monitoring of LFTs and dose reduction in Hepatitis B. Hazardous agent, handle and dispose appropriately. May affect ability to drive or operate machinery. Lactation: Unknown if distributed in human breast milk; because of the potential for adverse reactions from the drugs in nursing infants, a decision must be made whether to discontinue nursing or discontinue the drug

Pregnancy-Lactation

Pregnancy There are no adequate and well-controlled studies in pregnant women to inform a drug-associated risk; based on animal reproduction studies, therapy can cause fetal harm and should be assumed to have abortifacient potential; non-pegylated interferon alfa-2a treatment caused abortion when given to pregnant rhesus monkeys Combination treatment with ribavirin is contraindicated in women who are pregnant and in the male partners of women who are pregnant; significant teratogenic and/or embryocidal effects demonstrated in all animal species exposed to ribavirin Pregnancy testing Females of reproductive potential must undergo pregnancy testing before initiation of treatment as monotherapy or in combination with ribavirin or with other HCV drugs; females of reproductive potential receiving therapy in combination with ribavirin must have a routine pregnancy test performed monthly during treatment and for at least 6 months following treatment; female partners of male patients receiving treatment in combination with ribavirin must have a routine pregnancy test performed monthly during treatment and for at least 6 months posttherapy Contraception Because of abortifacient potential of therapy, females of reproductive potential should be advised to use effective contraception during therapy; however, when receiving treatment in combination with ribavirin, women of reproductive potential and their partners must use effective contraception during treatment and for at least 6 months after the last dose Infertility Based on mechanism of action and studies in female monkeys, treatment can cause disruption of menstrual cycle; no female fertility study has been performed Lactation There is no information regarding presence of peginterferon alfa-2a in human milk, effects on breastfed infant, or on milk production; because of potential for adverse reactions from drugs in nursing infants, a decision must be made whether to discontinue nursing or discontinue treatment; the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for therapy and any potential adverse effects on breastfed child from treatment or from underlying maternal condition The Centers for Disease Control and Prevention recommends that HIV-infected mothers not breastfeed their infants to avoid potential transmission of HIV; therefore, CHC- and CHB-infected mothers coinfected with HIV should not breastfeed their infants

Interactions

Increased risk of haemolytic anemia, birth defects and/or foetal mortality, genotoxicity, mutagenicity, and may possibly be carcinogenic with ribavirin; decreases metabolism of theophylline; enhances adverse/toxic effects of zidovudine, decreases metabolism of zidovudine. Avoid ethanol in hepatitis C virus patients.

Side Effects

Side effects of Peginterferon Alfa-2a : >10% Fatigue (24% to 67% ), Headache (27% to 54% ), Fever (24% to 54% ), Myalgia (26% to 51% ), Influenza-like illness (25% to 47% ), Rigor (25% to 47% ), Neutropenia (21% to 40% ), Anxiety (19% to 33% ), Feeling nervous (19% to 33% ), Irritability (19% to 33% ), Diarrhea (11% to 31% ), Injection site inflammation (10% to 31% ), Insomnia (19% to 30% ), Arthralgia (22% to 28% ), Alopecia (18% to 28% ), Abdominal pain (8% to 26% ), Nausea and vomiting (5% to 25% ), Loss of appetite (16% to 24% ), Injection site reaction (22% to 23% ), Dizziness (13% to 23% ), Depression (18% to 20% ), Pruritus (12% to 19% ), Dermatitis (8% to 16% ), Weight decreased (4% to 16% ), Lymphocytopenia (Severe) (5% to 14% ), Anemia (2% to 14%), Lymphocyte count abnormal (3% to 14% ), Dyspnea (4% to 13% ) 1-10% Reduced concentration (8% to 10% ), Cough (4% to 10% ), Dry skin (4% to 10% ), Rash (5% to 8% ), Thrombocytopenia (5% to 8% ), Bacterial infectious disease (3% to 5%), Severe bacterial infection (1-3%) <1% Angina, Cardiac dysrhythmia, Aggressive behavior, Cerebral hemorrhage, Cerebral ischemia, Coma, Drug Abuse, Peripheral neuropathy, Psychotic disorder, Suicide, Diabetes mellitus, Colitis, Gastrointestinal hemorrhage, Pancreatitis, Peptic ulcer disease, Aplastic anemia, Thrombotic thrombocytopenic purpura, Abnormal liver function, Cholangitis, Liver failure, Steatosis of liver, Myositis, Corneal ulcer, Pulmonary embolism Frequency Not Defined Myocardial infarction, Erythroderma (rare), Stevens-Johnson syndrome (rare), Hypo/hyperthyroidism, Hypo/hyperglycemia, Anemia (severe), Cytopenia (severe), Autoimmune disease (rare), Hypersensitivity reaction (severe), Serous retinal detachment, Pulmonary infiltrates, Liver graft rejection and renal graft rejection

Mode of Action

Peginterferon alfa-2a are interferon proteins bound to polyethylene glycol (PEG) molecules resulting in higher and more prolonged serum interferon concentrations. It has antiviral, antiproliferative and immune-regulating activity. Interferons are activated when it interacts with cells through high affinity cell surface receptors. The effects of this activation include the induction of gene transcription, inhibition of cellular growth, alteration of cellular differentiation, interference with oncogene expression, alteration of cell surface antigen expression, increase in phagocytic activity of macrophages and augmentation of cytotoxicity of lymphocytes for target cells.