Product Information

Registration Status: Active

PEGASYS PRE-FILLED SYRINGE FOR INJECTION 135mcg/0.5ml is approved to be sold in Singapore with effective from 2003-05-06. It is marketed by ROCHE SINGAPORE PTE LTD, with the registration number of SIN12314P.

This product contains Peginterferon Alfa-2A 135mcg/0.5ml in the form of INJECTION. It is approved for SUBCUTANEOUS use.

This product is manufactured by F HOFFMANN-LA ROCHE LTD in SWITZERLAND.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.

Peginterferon Alfa-2A


Peginterferon alfa-2a is a form of recombinant interferon used as part of combination therapy to treat chronic Hepatitis C, an infectious liver disease caused by infection with Hepatitis C Virus (HCV). HCV is a single-stranded RNA virus that is categorized into nine distinct genotypes, with genotype 1 being the most common in the United States, and affecting 72% of all chronic HCV patients [L852]. Treatment options for chronic Hepatitis C have advanced significantly since 2011, with the development of Direct Acting Antivirals (DAAs) resulting in less use of Peginterferon alfa-2a. Peginterferon alfa-2a is derived from the alfa-2a moeity of recombinant human interferon and acts by binding to human type 1 interferon receptors. Activation and dimerization of this receptor induces the body's innate antiviral response by activating the janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Use of Peginterferon alfa-2a is associated with a wide range of severe adverse effects including the aggravation and development of endocrine and autoimmune disorders, retinopathies, cardiovascular and neuropsychiatric complications, and increased risk of hepatic decompensation in patients with cirrhosis. The use of Peginterferon alfa-2a has largely declined since newer interferon-free antiviral therapies have been developed. In a joint recommendation published in 2016, the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) no longer recommend Peginterferon alfa-2a for the treatment of Hepatitis C [A19593]. Peginterferon alfa-2a was used alongside [DB00811] with the intent to cure, or achieve a sustained virologic response (SVR), after 48 weeks of therapy. SVR and eradication of HCV infection is associated with significant long-term health benefits including reduced liver-related damage, improved quality of life, reduced incidence of Hepatocellular Carcinoma, and reduced all-cause mortality [A19626]. Peginterferon alfa-2a is available as a fixed dose injector (tradename Pegasys) used for the treatment of chronic Hepatitis C. Approved in 2002 by the FDA, Pegasys is indicated for the treatment of HCV with [DB00811] or other antiviral drugs [FDA Label]. When combined together, Peginterferon alfa-2a and [DB00811] have been shown to achieve a SVR between 36% for genotype 1 and 59% for genotypes 2-6 after 48 weeks of treatment.


Peginterferon alfa-2a is indicated for the treatment of HCV in combination with other antiviral drugs in patients over 5 years of age with compensated liver disease [FDA Label]. May be used as a monotherapy in patients with contraindications to or significant intolerance to other anti-viral therapies. Peginterferon alfa-2a is also indicated as a monotherapy for adult patients with HBeAg positive and HBeAg negative chronic hepatitis B infection who have compensated liver disease and evidence of viral replication and liver inflammation [FDA Label].

Mechanism of Action

Peginterferon alfa-2a is derived from recombinant human interferon's alfa-2a moeity [FDA Label]. It binds to and activates human type 1 interferon receptors causing them to dimerize. This activates the JAK/STAT pathway. Activation of the JAK/STAT pathway increases expression of multiple genes in multiple tissues involved in the innate antiviral response.


Peginterferon alfa-2a reaches peak plasma concentration 72-96 hours after subcutaneous administration [FDA Label]. Trough concentrations at week 48 are approximately 2 fold higher than week 1. The peak to trough ratio at week 48 is 2.


The mean systemic clearance of peginterferon alfa-2a is 94 milliliters per hour [FDA Label].


Peginterferon alfa-2a may manifest neuropsychiatric complications include suicide, suicidal ideation, homicidal ideation, depression, relapse of drug addiction, and drug overdose [FDA Label]. Hypertension, supraventricular arrhythmias, chest pain, and myocardial infarction have been observed in patients using Peginterferon alfa-2a. Peginterferon alfa-2a may produce myelosuppression as well as the development or aggravation of autoimmune disorders including myositis, hepatitis, thrombotic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, psoriasis, rheumatoid arthritis, interstitial nephritis, thyroiditis, and systemic lupus erythematosus. Peginterferon alfa-2a causes or aggravates hypothyroidism and hyperthyroidism. Hyperglycemia, hypoglycemia, and diabetes mellitus have been observed to develop in patients treated with Peginterferon alfa-2a. Peginterferon alfa-2a may decrease or produce loss of vision, retinopathy including macular edema, retinal artery or vein thrombosis, retinal hemorrhages and cotton wool spots, optic neuritis, papilledema and serous retinal detachment. Peginterferon mayy be related to increased ischemic and hemorrhagic cerebrovascular events. Patients with cirrhosis on Peginterferon alfa-2a are at risk of hepatic decompensation. Dyspnea, pulmonary infiltrates, pneumonia, bronchiolitis obliterans, interstitial pneumonitis, pulmonary hypertension and sarcoidosis may be induced or aggravated by Peginterferon alfa-2a. Serious and severe infections (bacterial, viral, or fungal) have been reported during treatment with Peginterferon alfa-2a. Ulcerative and hemorrhagic/ischemic colitis have been observed within 12 weeks of starting Peginterferon alfa-2a treatment. Pancreatitis and peripheral nephropathy have also been reported. Peginterferon alfa-2a is associated with growth inhibition in pediatric patients. Use of Peginterferon alfa-2a while pregant may result in delopmental abnormalities or death of the fetus.

Active Ingredient/Synonyms

Pegylated interferon alfa-2a | Pegylated interferon alpha2a | Peginterferon alfa-2a |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank