May 26, 2017
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Included as part of the PRECAUTIONS section.


Treatment with INFERGEN and combination treatment with INFERGEN/ribavirin should be administered under the guidance of a qualified physician, and may lead to moderate-to-severe adverse reactions requiring dose reduction, temporary dose cessation, or discontinuation of further therapy.

Use with Ribavirin


Ribavirin may cause birth defects and death of the unborn child. Ribavirin therapy should not be started until a report of a negative pregnancy test has been obtained immediately prior to planned initiation of therapy. Patients should use at least two forms of contraception and have monthly pregnancy tests. Pregnancy should be avoided for at least six months after discontinuation of ribavirin [see BOXED WARNING, CONTRAINDICATIONS, Use In Specific Populations, PATIENT INFORMATION and Ribavirin Labeling].


Ribavirin caused hemolytic anemia in 30% of INFERGEN/ribavirin-treated subjects. Complete blood counts should be obtained pretreatment and at Week 2 and Week 4 of therapy or more frequently if clinically indicated. Anemia associated with ribavirin therapy may result in a worsening of cardiac disease. Decrease in dosage or discontinuation of ribavirin may be necessary [see DOSAGE AND ADMINISTRATION and Ribavirin Labeling].

Neuropsychiatric Disorders

Severe psychiatric adverse reactions may manifest in patients receiving therapy with interferon alphas, including INFERGEN. Depression, suicidal ideation, suicide attempt, suicide, and homicidal ideation may occur. Other prominent psychiatric adverse reactions including psychosis, aggressive behavior, nervousness, anxiety, emotional lability, abnormal thinking, agitation, apathy and relapse of drug addiction may occur. INFERGEN should be used with extreme caution in patients who report a history of depression. Physicians should monitor all patients for evidence of depression and other psychiatric symptoms. Prior to initiation of INFERGEN therapy, physicians should inform patients of the possible development of depression and patients should be advised to report any sign or symptom of depression and/or suicidal ideation immediately. If patients develop psychiatric problems, including clinical depression, it is recommended that the patients be carefully monitored during treatment and in the 6-month follow-up period. If psychiatric symptoms persist or worsen, or suicidal ideation or aggressive behavior towards others are identified, it is recommended that treatment with INFERGEN be discontinued, and the patient followed, with psychiatric intervention as appropriate. In severe cases, INFERGEN should be stopped immediately and psychiatric intervention instituted [see DOSAGE AND ADMINISTRATION: Dose Modifications].

Cardiovascular Events

Cardiovascular events, which include hypotension, arrhythmia, tachycardia, cardiomyopathy, angina pectoris, and myocardial infarction, have been observed in patients treated with INFERGEN. INFERGEN should be used cautiously in patients with cardiovascular disease. Patients with a history of myocardial infarction and arrhythmic disorder who require INFERGEN therapy should be closely monitored. Patients with a history of significant or unstable cardiac disease should not be treated with INFERGEN/ribavirin combination therapy [see Ribavirin Labeling].

Pulmonary Disorders

Dyspnea, pulmonary infiltrates, pneumonia, bronchiolitis obliterans, interstitial pneumonitis, pulmonary hypertension and sarcoidosis, some resulting in respiratory failure and/or patient deaths, may be induced or aggravated by interferon alpha therapy, including INFERGEN. Patients who develop persistent or unexplained pulmonary infiltrates or pulmonary function impairment should discontinue treatment with INFERGEN. Recurrence of respiratory failure has been observed with interferon rechallenge. INFERGEN treatment should be suspended in patients who develop pulmonary infiltrates or pulmonary function impairment. Patients who resume interferon treatment should be closely monitored.

Hepatic Failure

Chronic hepatitis C patients with cirrhosis may be at risk of hepatic decompensation when treated with interferon alphas, including INFERGEN. During treatment, patients' clinical status and hepatic function should be closely monitored, and INFERGEN treatment should be immediately discontinued if symptoms of hepatic decompensation, such as jaundice, ascites, coagulopathy, or decreased serum albumin are observed [see CONTRAINDICATIONS].

Renal Insufficiency

Increases in serum creatinine levels, including renal failure, have been observed in patients receiving INFERGEN. INFERGEN has not been studied in patients with renal insufficiency. It is recommended that renal function be evaluated in all patients starting INFERGEN alone or with ribavirin therapy. Patients with impaired renal function should be closely monitored for signs and symptoms of interferon toxicity, including increases in serum creatinine. Combination treatment with INFERGEN/ribavirin should not be used in patients with creatinine clearance < 50 mL/min. [see CONTRAINDICATIONS and Ribavirin Labeling].

Cerebrovascular Disorders

Ischemic and hemorrhagic cerebrovascular events have been observed in patients treated with interferon alpha-based therapies, including INFERGEN. Events occurred in patients with few or no reported risk factors for stroke, including patients less than 45 years of age. Because these are spontaneous reports, estimates of frequency cannot be made and a causal relationship between interferon alpha-based therapies and these events is difficult to establish.

Bone Marrow Toxicity

Interferon alphas suppress bone marrow function and may result in severe cytopenias including aplastic anemia. It is advised that complete blood counts be obtained pretreatment and monitored routinely during therapy. INFERGEN therapy should be discontinued in patients who develop severe decreases in neutrophil ( < 0.5 x 109/L) or platelet counts ( < 25 x 109/L). INFERGEN should be used cautiously in patients with abnormally low peripheral blood cell counts or who are receiving agents that are known to cause myelosuppression. Transplantation patients or other chronically immunosuppressed patients should be treated with interferon alpha therapy with caution.

The use of ribavirin may result in a worsening of INFERGEN-induced neutropenia. Therefore combination treatment with INFERGEN/ribavirin should be used with caution in patients with low baseline neutrophil counts ( < 1500 cells/mm³) and may require that therapy be discontinued in the event of a severe decrease in neutrophil count [see DOSAGE AND ADMINISTRATION: Dose Modifications and Laboratory Tests].


Hemorrhagic/ischemic colitis, sometimes fatal, has been observed within 12 weeks of interferon alpha therapies and has been reported in patients treated with INFERGEN. INFERGEN treatment should be discontinued immediately in patients who develop signs and symptoms of colitis.


Pancreatitis, sometimes fatal, has been observed in patients treated with interferon alphas, including INFERGEN. INFERGEN should be suspended in patients with signs and symptoms suggestive of pancreatitis and discontinued in patients diagnosed with pancreatitis.


Serious acute hypersensitivity reactions have been reported following treatment with interferon alphas. If hypersensitivity reactions occur (e.g., urticaria, angioedema, bronchoconstriction, anaphylaxis), INFERGEN should be discontinued immediately and appropriate medical treatment instituted.

Autoimmune Disorders

Development or exacerbation of autoimmune disorders (e.g., autoimmune thrombocytopenia, idiopathic thrombocytopenic purpura, psoriasis, rheumatoid arthritis, thyroiditis, interstitial nephritis, systemic lupus erythematosus (SLE)) have been reported in patients receiving interferon alpha therapies, including INFERGEN. INFERGEN should not be used in patients with autoimmune hepatitis [see CONTRAINDICATIONS and should be used with caution in patients with other autoimmune disorders.

Ophthalmologic Disorders

Decrease or 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 are induced or aggravated by treatment with INFERGEN or other interferons alpha. All patients should receive an eye examination at baseline. Patients with preexisting ophthalmologic disorders (e.g., diabetic or hypertensive retinopathy) should receive periodic ophthalmologic exams during interferon alpha treatment. Any patient who develops ocular symptoms should receive a prompt and complete eye examination. INFERGEN therapy should be discontinued in patients who develop new or worsening ophthalmologic disorders.

Peripheral Neuropathy

Peripheral neuropathy has been reported when interferon alphas were given in combination with telbivudine. In one clinical trial, an increased risk and severity of peripheral neuropathy was observed with the combination use of telbivudine and pegylated interferon alfa-2a as compared to telbivudine alone. The safety and efficacy of telbivudine in combination with interferons for the treatment of chronic hepatitis B has not been demonstrated.

Endocrine Disorders

INFERGEN should be administered with caution to patients with a history of endocrine disorders. Occurrence or aggravation of hyperthyroidism or hypothyroidism have been reported with INFERGEN. Hyperglycemia and diabetes mellitus have also been observed in patients treated with INFERGEN. Patients who develop these conditions during treatment that cannot be controlled with medication should not continue INFERGEN therapy.

Laboratory Tests

Laboratory tests are recommended for all patients on INFERGEN therapy, as follows: prior to beginning treatment (baseline), 2 weeks after initiation of therapy, and periodically thereafter during the 24 or 48 weeks of therapy at the discretion of the physician. Following completion of INFERGEN therapy, any abnormal test values should be monitored periodically. The entrance criteria that were used for the clinical study of INFERGEN may be considered as a guideline to acceptable baseline values for initiation of treatment:

  • Platelet count ≥ 75 109/L
  • Hemoglobin concentration ≥ 10 g/dL
  • ANC ≥ 1500 106/L
  • Serum creatinine concentration < 180 μmol/L ( < 2.0 mg/dL) or creatinine clearance > 0.83 mL/second ( > 50 mL/minute)
  • Serum albumin concentration ≥ 25 g/L
  • Bilirubin ≤ 1.4 mg/dL (with the exception of patients with Gilbert's syndrome)
  • TSH and T4 within normal limits

Neutropenia, thrombocytopenia, hypertriglyceridemia and thyroid disorders have been reported with administration of INFERGEN [see ADVERSE REACTIONS]. Therefore, these laboratory parameters should be monitored closely.

Patients who have pre-existing cardiac abnormalities should have electrocardiograms administered before treatment with INFERGEN/ribavirin.

Patient Counseling Information

Information for Patients

Patients should be instructed on appropriate use by a health care professional. Patients receiving INFERGEN alone or in combination treatment with INFERGEN/ribavirin must be instructed as to the proper dosage and administration, and informed of the benefits and risks associated with treatment [see Medication Guide and Ribavirin Labeling]. Information included in the Medication Guide should be reviewed fully with the patient; it is not a disclosure of all or possible adverse reactions.

Patients must be informed that ribavirin may cause birth defects and/or death of the unborn child. Extreme care must be taken to avoid pregnancy in female patients and in female partners of male patients during combination treatment with INFERGEN/ribavirin therapy and for 6 months post-therapy. Combination treatment with INFERGEN/ribavirin should not be initiated until a report of a negative pregnancy test has been obtained immediately prior to initiation of therapy. It is recommended that patients undergo monthly pregnancy tests during therapy and for 6 months post-therapy [see CONTRAINDICATIONS and Ribavirin Labeling].

Patients should be informed that there are no data regarding whether INFERGEN therapy will prevent transmission of HCV infection to others. Also, it is not known if treatment with INFERGEN will cure hepatitis C or prevent cirrhosis, liver failure, or liver cancer that may be the result of infection with the hepatitis C virus.

The most common adverse reactions occurring with INFERGEN and combination treatment with INFERGEN/ribavirin are flu-like symptoms including fatigue, fever, nausea, headache, arthralgia, myalgia, rigors, and increased sweating. Non-narcotic analgesics and bedtime administration of INFERGEN may be used to prevent or lessen some of these symptoms. Other common adverse reactions are neutropenia, insomnia, leukopenia, and depression.

While fever may be related to the flu-like symptoms reported in patients treated with INFERGEN, when fever occurs, other possible causes of persistent fever should be ruled out.

Patients must be thoroughly instructed in the importance of proper disposal procedures and cautioned against the reuse of needles, syringes, or re-entry of the vial. A puncture-resistant container for the disposal of used syringes and needles should be used by the patient and should be disposed of according to the directions provided by the health care provider [see Medication Guide for instructions].

Patients should be advised that laboratory evaluations are required before starting therapy and periodically thereafter [see WARNINGS AND PRECAUTIONS: Laboratory Tests]. It is advised that patients be well hydrated, especially during the initial stages of treatment.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility


No carcinogenicity data for INFERGEN are available in animals or humans.


INFERGEN was not mutagenic when tested in several in vitro assays, including the Ames bacterial mutagenicity assay and an in vitro cytogenetic assay in human lymphocytes, either in the presence or absence of metabolic activation.

Use with Ribavirin

See ribavirin labeling for additional warnings relevant to INFERGEN therapy in combination with ribavirin.

Impairment of Fertility

INFERGEN at doses as high as 100 mcg/kg did not selectively affect reproductive performance or the development of the offspring when administered subcutaneous injection to male and female golden Syrian hamsters for 70 and 14 days before mating, respectively, and then through mating and to day 7 of pregnancy.

Use In Specific Populations


INFERGEN Monotherapy - Pregnancy Category C

INFERGEN has been shown to have embryo lethal or abortifacient effects in golden Syrian hamsters when given at doses > 150 mcg/kg/day (135 times the human dose) and in cynomolgus and rhesus monkeys when given at doses of 3 mcg/kg/day and 10 mcg/kg/day (9 to 81 times the human dose), respectively, based on body surface area, the human dose. There are no adequate and well-controlled studies in pregnant women. INFERGEN should not be used during pregnancy. If a woman becomes pregnant or plans to become pregnant while taking INFERGEN, she should be informed of the potential hazards to the fetus. Males and females treated with INFERGEN should be advised to use effective contraception.

Combination Treatment with INFERGEN/Ribavirin - Pregnancy Category X

Significant teratogenic and/or embryocidal effects have been demonstrated in all animal species exposed to ribavirin. Ribavirin therapy is contraindicated in women who are pregnant and in the male partners of women who are pregnant [see CONTRAINDICATIONS and Ribavirin Labeling].

Ribavirin Pregnancy Registry: A Ribavirin Pregnancy Registry has been established to monitor maternal-fetal outcomes of pregnancies in female patients and female partners of male patients exposed to ribavirin during treatment and for 6 months following cessation of treatment. Physicians and patients are encouraged to report such cases by calling 1-800-593-2214.

Nursing Mothers

It is not known whether INFERGEN or ribavirin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised if INFERGEN is administered to a nursing woman. The effect on the nursing neonate of orally ingested INFERGEN in breast milk has not been evaluated. Because of the potential for serious adverse reactions from the drug in nursing infants, a decision should be made whether to discontinue nursing or to delay or discontinue ribavirin.

Pediatric Use

The safety and effectiveness of INFERGEN have not been established in patients below the age of 18 years. INFERGEN therapy is not recommended in pediatric patients.

Geriatric Use

Clinical studies of INFERGEN alone or in combination with ribavirin did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently than younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. However, treatment with interferons, including INFERGEN, is associated with psychiatric, cardiac, and systemic (flu-like) adverse reactions. Since decreased hepatic, renal or cardiac function, concomitant disease, and the use of other drug therapies in elderly patients may produce adverse reactions of greater severity, caution should be exercised in the use of INFERGEN and INFERGEN/ribavirin in this population. Ribavirin should not be used in patients with creatinine clearance < 50 mL/min.

Hepatic Impairment

The safety and efficacy of INFERGEN, alone or in combination with ribavirin, for the treatment of chronic HCV infection in patients with hepatic impairment has not been studied. The use of INFERGEN in patients with hepatic decompensation (Child-Pugh score > 6 [class B and C]) is contraindicated [see CONTRAINDICATIONS].

Renal Impairment

The safety and efficacy of INFERGEN, alone or in combination with ribavirin, for the treatment of chronic HCV infection in patients with renal impairment has not been studied. In patients with impaired renal function, signs and symptoms of interferon toxicity should be closely monitored and INFERGEN dose should be adjusted as recommended in Tables 1-3. INFERGEN/ribavirin should not be administered to patients with creatinine clearance < 50 mL/min [see DOSAGE AND ADMINISTRATION: Dose Modifications, CONTRAINDICATIONS] and Ribavirin Labeling].

Organ Transplant Recipients

The safety and efficacy of INFERGEN, alone or in combination with ribavirin, for the treatment of chronic HCV infection in liver or other organ transplant recipients have not been evaluated.

HIV or HBV Coinfection

The safety and efficacy of INFERGEN, alone or in combination with ribavirin, for the treatment of chronic HCV infection in patients coinfected with HIV or HBV have not been determined.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 3/20/2017


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