Patients should bemonitored for the following serious conditions, some of which may become life threatening. Patients with persistently severe or worsening signs or symptoms should be withdrawn from therapy.
REBETOL may cause birth defects and death of the unborn child. REBETOL 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 2 forms of contraception and have monthly pregnancy tests [see BOXED WARNING, CONTRAINDICATIONS, Patient Counseling Information, and REBETOL package insert].
Ribavirin caused hemolytic anemia in 10% of PegIntron (peginterferon alfa-2b) /REBETOL-treated subjects within 1 to 4weeks of initiation of therapy. 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 REBETOL therapy may result in a worsening of cardiac disease. Decrease in dosage or discontinuation of REBETOL may be necessary [see DOSAGE AND ADMINISTRATION and REBETOL package insert].
Life-threatening or fatal neuropsychiatric events, including suicide, suicidal and homicidal ideation, depression, relapse of drug addiction/overdose, and aggressive behavior sometimes directed towards others have occurred in patients with and without a previous psychiatric disorder during PegIntron (peginterferon alfa-2b) treatment and follow-up. Psychoses, hallucinations, bipolar disorders, and mania have been observed in patients treated with interferon alpha. PegIntron (peginterferon alfa-2b) should be used with extreme caution in patients with a history of psychiatric disorders. Patients should be advised to report immediately any symptoms of depression or suicidal ideation to their prescribing physicians. Physicians should monitor all patients for evidence of depression and other psychiatric symptoms. 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 is identified, it is recommended that treatment with PegIntron (peginterferon alfa-2b) be discontinued, and the patient followed, with psychiatric intervention as appropriate. In severe cases, PegIntron (peginterferon alfa-2b) should be stopped immediately and psychiatric intervention instituted [see DOSAGE AND ADMINISTRATION]. Cases of encephalopathy have been observed in some patients, usually elderly, treated at higher doses of PegIntron (peginterferon alfa-2b) .
Cardiovascular events, which include hypotension, arrhythmia, tachycardia, cardiomyopathy, angina pectoris, and myocardial infarction, have been observed in patients treated with PegIntron (peginterferon alfa-2b) . PegIntron (peginterferon alfa-2b) should be used cautiously in patients with cardiovascular disease. Patients with a history of myocardial infarction and arrhythmic disorder who require PegIntron (peginterferon alfa-2b) therapy should be closely monitored [see WARNINGS AND PRECAUTIONS]. Patients with a history of significant or unstable cardiac disease should not be treated with PegIntron (peginterferon alfa-2b) /REBETOL combination therapy [see REBETOL package insert].
PegIntron (peginterferon alfa-2b) causes or aggravates hypothyroidism and hyperthyroidism. Hyperglycemia has been observed in patients treated with PegIntron (peginterferon alfa-2b) . Diabetes mellitus has been observed in patients treated with alpha interferons. Patients with these conditions who cannot be effectively treated by medication should not begin PegIntron (peginterferon alfa-2b) therapy. Patients who develop these conditions during treatment and cannot be controlled with medication should not continue PegIntron (peginterferon alfa-2b) therapy.
Decrease or loss of vision, retinopathy including macular edema, retinal artery or vein thrombosis, retinal hemorrhages and cotton wool spots, optic neuritis, and papilledema may be induced or aggravated by treatment with peginterferon alfa-2b or other alpha interferons. 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. Peginterferon alfa-2b treatment should be discontinued in patients who develop new or worsening ophthalmologic disorders.
Ischemic and hemorrhagic cerebrovascular events have been observed in patients treated with interferon alfa-based therapies, including PegIntron (peginterferon alfa-2b) . 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 alfa-based therapies and these events is difficult to establish.
Bone Marrow Toxicity
PegIntron (peginterferon alfa-2b) suppresses bone marrow function, sometimes resulting in severe cytopenias. PegIntron (peginterferon alfa-2b) should be discontinued in patients who develop severe decreases in neutrophil or platelet counts [see DOSAGE AND ADMINISTRATION]. Ribavirin may potentiate the neutropenia induced by interferon alpha. Very rarely alpha interferons may be associated with aplastic anemia.
Development or exacerbation of autoimmune disorders (e.g., thyroiditis, thrombotic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, rheumatoid arthritis, interstitial nephritis, systemic lupus erythematosus, and psoriasis) have been observed in patients receiving PegIntron (peginterferon alfa-2b) .
PegIntron (peginterferon alfa-2b) should be used with caution in patients with autoimmune disorders.
Fatal and nonfatal pancreatitis have been observed in patients treated with alpha interferon. PegIntron (peginterferon alfa-2b) therapy should be suspended in patients with signs and symptoms suggestive of pancreatitis and discontinued in patients diagnosed with pancreatitis.
Fatal and nonfatal ulcerative or hemorrhagic/ischemic colitis have been observed within 12 weeks of the start of alpha interferon treatment. Abdominal pain, bloody diarrhea, and fever are the typical manifestations. PegIntron (peginterferon alfa-2b) treatment should be discontinued immediately in patients who develop these signs and symptoms. The colitis usually resolves within 1 to 3 weeks of discontinuation of alpha interferons.
Dyspnea, pulmonary infiltrates, pneumonia, bronchiolitis obliterans, interstitial pneumonitis, and sarcoidosis, some resulting in respiratory failure or patient deaths, may be induced or aggravated by PegIntron (peginterferon alfa-2b) or alpha interferon therapy. Recurrence of respiratory failure has been observed with interferon re-challenge. PegIntron (peginterferon alfa-2b) combination treatment should be suspended in patients who develop pulmonary infiltrates or pulmonary function impairment. Patients who resume interferon treatment should be closely monitored.
Chronic hepatitis C (CHC) patients with cirrhosismay be at risk of hepatic decompensation and death when treated with alpha interferons, including PegIntron (peginterferon alfa-2b) . Cirrhotic CHC patients coinfected with HIV receiving highly active antiretroviral therapy (HAART) and alpha interferons with or without ribavirin appear to be at increased risk for the development of hepatic decompensation compared to patients not receiving HAART. During treatment, patients' clinical status and hepatic function should be closely monitored, and PegIntron (peginterferon alfa-2b) treatment should be immediately discontinued if decompensation (Child-Pugh score > 6) is observed [see CONTRAINDICATIONS].
Patients with Renal Insufficiency
Increases in serum creatinine levels have been observed in patients with renal insufficiency receiving interferon alpha products, including PegIntron (peginterferon alfa-2b) . Patients with impaired renal function should be closely monitored for signs and symptoms of interferon toxicity, including increases in serum creatinine, and PegIntron (peginterferon alfa-2b) dosing should be adjusted accordingly or discontinued [see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION]. PegIntron (peginterferon alfa-2b) monotherapy should be used with caution in patients with creatinine clearance < 50 mL/min; the potential risks should be weighed against the potential benefits in these patients. Combination therapy with REBETOL must not be used in patients with creatinine clearance < 50 mL/min [see REBETOL Package Insert].
Serious, acute hypersensitivity reactions (e.g., urticaria, angioedema, bronchoconstriction, anaphylaxis) and cutaneous eruptions (Stevens-Johnson syndrome, toxic epidermal necrolysis) have been rarely observed during alpha interferon therapy. If such a reaction develops during treatment with PegIntron (peginterferon alfa-2b) , discontinue treatment and institute appropriate medical therapy immediately. Transient rashes do not necessitate interruption of treatment.
PegIntron (peginterferon alfa-2b) alone or in combination with ribavirin may cause severe decreases in neutrophil and platelet counts, and hematologic, endocrine (e.g.,TSH), and hepatic abnormalities. Transient elevations in ALT (2- to 5-fold above baseline)were observed in 10%of subjects treated with PegIntron (peginterferon alfa-2b) , and were not associated with deterioration of other liver functions. Triglyceride levels are frequently elevated in patients receiving alpha interferon therapy including PegIntron (peginterferon alfa-2b) and should be periodically monitored.
Patients on PegIntron (peginterferon alfa-2b) or PegIntron (peginterferon alfa-2b) /REBETOL combination therapy should have hematology and blood chemistry testing before the start of treatment and then periodically thereafter. In the adult clinical trial CBC (including hemoglobin, neutrophil, and platelet counts) and chemistries (including AST, ALT, bilirubin, and uric acid) were measured during the treatment period at Weeks 2, 4, 8, and 12, and then at 6-week intervals or more frequently if abnormalities developed. In pediatric subjects, the same laboratory parameters were evaluated with additional assessment of hemoglobin at treatment Week 6. TSH levels were measured every 12 weeks during the treatment period. HCV RNA should be measured periodically during treatment [see DOSAGE AND ADMINISTRATION].
Patients who have pre-existing cardiac abnormalities should have electrocardiograms done before treatment with PegIntron (peginterferon alfa-2b) /REBETOL.
Dental and Periodontal Disorders
Dental and periodontal disorders have been reported in patients receiving PegIntron (peginterferon alfa-2b) /REBETOL combination therapy. In addition, dry mouth could have a damaging effect on teeth and mucous membranes of the mouth during long-term treatment with the combination of REBETOL and PegIntron (peginterferon alfa-2b) . Patients should brush their teeth thoroughly twice daily and have regular dental examinations. If vomiting occurs, patients should be advised to rinse out their mouth thoroughly afterwards.
Elevated triglyceride levels have been observed in patients treated with interferon alpha, including PegIntron (peginterferon alfa-2b) therapy. Hypertriglyceridemia may result in pancreatitis [see WARNINGS AND PRECAUTIONS]. Elevated triglyceride levels should be managed as clinically appropriate. Discontinuation of PegIntron (peginterferon alfa-2b) therapy should be considered for patients with symptoms of potential pancreatitis, such as abdominal pain, nausea, or vomiting, and persistently elevated triglycerides (e.g., triglycerides > 1000 mg/dL).
Impact on Growth – Pediatric Use
Data on the effects of PegIntron (peginterferon alfa-2b) plus REBETOL on growth come from an open-label study in subjects 3 through 17 years of age, and weight and height changes are compared to US normative population data. In general, the weight and height gain of pediatric subjects treated with PegIntron (peginterferon alfa-2b) plus REBETOL lags behind that predicted by normative population data for the entire length of treatment. After about 6 months posttreatment (follow-up Week 24), subjects had weight gain rebounds and regained their weight to 53rd percentile, above the average of the normative population and similar to that predicted by their average baseline weight (57th percentile). After about 6 months posttreatment, height gain stabilized, and subjects treated with PegIntron (peginterferon alfa-2b) plus REBETOL had an average height percentile of 44th percentile, which was less than the average of the normative population and less than their average baseline height (51st percentile). Severely inhibited growth velocity ( < 3rd percentile) was observed in 70% of the subjects while on treatment. Of the subjects experiencing severely inhibited growth, 20%had continued inhibited growth velocity ( < 3rd percentile) after 6 months of follow-up.
Among the boys studied, the age groups of 3 to 11 years old and 12 to 17 years old had similar height percentile decreases of approximately 5 percentiles after 6 months posttreatment; weight gain continued to be similar to their average baseline percentile. Girlswhowere 3 to 11 years old and treated for 48 weeks had the largest average drop in height and weight percentiles (13 percentiles and 7 percentiles, respectively), whereas girls 12 to 17 years old continued along their average baseline height and weight percentiles after 6 months posttreatment.
Patient Counseling Information
A patient should self-inject PegIntron (peginterferon alfa-2b) only if it has been determined that it is appropriate, the patient agrees to medical follow-up as necessary, and training in proper injection technique has been given to him/her.
Patients receiving PegIntron (peginterferon alfa-2b) alone or in combination with REBETOL should be directed in its appropriate use, informed of the benefits and risks associated with treatment, and referred to the MEDICATION GUIDES for PegIntron (peginterferon alfa-2b) and, if applicable, REBETOL (ribavirin).
Patients must be informed that REBETOL may cause birth defects and death of the unborn child. Extreme care must be taken to avoid pregnancy in female patients and in female partners of male patients during treatment with combination PegIntron (peginterferon alfa-2b) /REBETOL therapy and for 6 months post therapy. Combination PegIntron (peginterferon alfa-2b) /REBETOL therapy 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 6months posttherapy [see CONTRAINDICATIONS, Use in Specific Populations, and REBETOL package insert].
Inform patients that there are no data regarding whether PegIntron (peginterferon alfa-2b) therapy will prevent transmission of HCV infection to others. Also, it is not known if treatment with PegIntron (peginterferon alfa-2b) will cure hepatitis C or prevent cirrhosis, liver failure, or liver cancer that may be the result of infection with the hepatitis C virus.
Laboratory Evaluations, Hydration, “Flu-like” Symptoms
Patients should be advised that laboratory evaluations are required before starting therapy and periodically thereafter [see WARNINGS AND PRECAUTIONS]. It is advised that patients be well-hydrated, especially during the initial stages of treatment. “Flu-like” symptoms associated with administration of PegIntron (peginterferon alfa-2b) may be minimized by bedtime administration of PegIntron (peginterferon alfa-2b) or by use of antipyretics.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenesis and Mutagenesis
PegIntron (peginterferon alfa-2b) has not been tested for its carcinogenic potential. Neither PegIntron (peginterferon alfa-2b) nor its components, interferon or methoxypolyethylene glycol, caused damage to DNA when tested in the standard battery of mutagenesis assays, in the presence and absence of metabolic activation.
Use with Ribavirin
Ribavirin is genotoxic and mutagenic and should be considered a potential carcinogen. See REBETOL package insert for additional warnings relevant to PegIntron (peginterferon alfa-2b) therapy in combination with ribavirin.
Impairment of Fertility
PegIntron (peginterferon alfa-2b) may impair human fertility. Irregular menstrual cycles were observed in female cynomolgus monkeys given subcutaneous injections of 4239 mcg/m² PegIntron (peginterferon alfa-2b) alone every other day for 1 month (approximately 345 times the recommended weekly human dose based upon body surface area). These effects included transiently decreased serum levels of estradiol and progesterone, suggestive of anovulation. Normal menstrual cycles and serum hormone levels resumed in these animals 2 to 3 months following cessation of PegIntron (peginterferon alfa-2b) treatment. Every other day dosing with 262mcg/m² (approximately 21 times the weekly human dose) had no effects on cycle duration or reproductive hormone status. The effects of PegIntron (peginterferon alfa-2b) on male fertility have not been studied.
Use In Specific Populations
PegIntron (peginterferon alfa-2b) Monotherapy
Pregnancy Category C: Nonpegylated interferon alfa-2b has been shown to have abortifacient effects in Macaca mulatta (rhesus monkeys) at 15 and 30 million IU/kg (estimated human equivalent of 5 and 10 million IU/kg, based on body surface area adjustment for a 60-kg adult). PegIntron (peginterferon alfa-2b) should be assumed to also have abortifacient potential. There are no adequate and well-controlled studies in pregnant women. PegIntron (peginterferon alfa-2b) therapy is to be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Therefore, PegIntron (peginterferon alfa-2b) is recommended for use in fertile women only when they are using effective contraception during the treatment period.
Use with Ribavirin
Pregnancy Category X: Significant teratogenic and/or embryocidal effects have been demonstrated in all animal species exposed to ribavirin. REBETOL therapy is contraindicated in women who are pregnant and in the male partners of women who are pregnant [see CONTRAINDICATIONS and the REBETOL Package Insert].
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.
It is not known whether the components of PegIntron (peginterferon alfa-2b) and/or REBETOL are excreted in human milk. Studies in mice have shown that mouse interferons are excreted in breast milk. Because of the potential for adverse reactions from the drug in nursing infants, a decision must be made whether to discontinue nursing or discontinue the PegIntron (peginterferon alfa-2b) and REBETOL treatment, taking into account the importance of the therapy to the mother.
Safety and effectiveness in pediatric patients below the age of 3 years have not been established. Clinical trials in pediatric patients < 3 years of age are not considered feasible due to the small proportion of patients in this age group requiring treatment for CHC.
In general, younger patients tend to respond better than older patients to interferon-based therapies. Clinical studies of PegIntron (peginterferon alfa-2b) alone or in combination with REBETOL did not include sufficient numbers of subjects aged 65 and over, however, to determine whether they respond differently than younger subjects. Treatment with alpha interferons, including PegIntron (peginterferon alfa-2b) , is associated with neuropsychiatric, cardiac, pulmonary, GI, and systemic (flu-like) adverse effects. Because these adverse reactions may be more severe in the elderly, caution should be exercised in the use of PegIntron (peginterferon alfa-2b) in this population. This drug is known to be substantially excreted by the kidney. Because elderly patients aremore likely to have decreased renal function, the risk of toxic reactions to this drug may be greater in patientswith impaired renal function [see CLINICAL PHARMACOLOGY].When using PegIntron (peginterferon alfa-2b) / REBETOL therapy, refer also to the REBETOL Package Insert.
Organ Transplant Recipients
The safety and efficacy of PegIntron (peginterferon alfa-2b) alone or in combination with REBETOL for the treatment of hepatitis C in liver or other organ transplant recipients have not been studied. In a small (n=16) single-center, uncontrolled case experience, renal failure in renal allograft recipients receiving interferon alpha and ribavirin combination therapy was more frequent than expected from the center's previous experience with renal allograft recipients not receiving combination therapy. The relationship of the renal failure to renal allograft rejection is not clear.
HIV or HBV Coinfection
The safety and efficacy of PegIntron (peginterferon alfa-2b) /REBETOL for the treatment of patients with HCV coinfected with HIV or HBV have not been established.
Last reviewed on RxList: 7/10/2009
This monograph has been modified to include the generic and brand name in many instances.
Additional Peg-Intron Information
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