interferon alfa 2b (Intron A, Interferon alfa-2b)

Dosing and uses of Intron A, Interferon alfa-2b (interferon alfa 2b)

• Adult
• Pediatric

 

Adult dosage forms and strengths

injectable solution

• 6 million International Units/mL (3.8mL vial)
• 10 million International Units/mL (3.2mL vial)

multidose pen; 6 doses each

• 22.5 million International Units/1.5mL
• 37.5 million International Units/1.5mL
• 75 million International Units/1.5mL

powder for injection

• 10 million International Units/vial
• 18 million International Units/vial
• 50 million International Units/vial

 

Hairy Cell Leukemia

2 million Units/m² IM/SC 3 times/wk for up to 6 mo

If severe adverse reaction (ADR) develop: reduce dose by 50% or temporarily withhold, THEn

Resume at 50% after ADRs abate: 1 million Units/m² IM/SC 3 times/wk

If severe ADRs persist discontinue permanently

Discontinue Intron A for progressive disease or failure to respond after 6 mo of treatment

 

Malignant Melanoma

Induction 20 million Units/m² IV over 20 min, 5 days/wk for 4 wk

Maintenance dose: 10 million Units/m² SC 3 times/wk for 48 wk

Withhold treatment if ANC <500/mm³ or ALT/AST >5 times upper limit of normal (ULN); re-start at 50% previous dose

Permanently discontinue if the following is observed

• Toxicity does not abate after withholding
• Severe ADRs recur in patients receiving reduced doses
• ANC <250/mm³ or ALT/AST >10x ULN

 

Follicular Lymphoma

5 million units 3 times/week for up to 18 mo in conjunction with anthracycline-containing combination chemotherapy in patients >18 years old

See Mfr's prescribing packet for additional chemo dosing information

 

Condylomata Acuminata

1 million units injected into each lesion 3 times/week qODay for 3week

May repeat course if unsatisfactory results 12-16 wk after initial treatment

Max 5 lesions/single course of treatment

Do not use the 18 or 50 million Units powder for injection

Do not use the 18 million Units multidose Intron A solution for injection

Do not use multidose pens

 

AIDS-related Kaposi's Sarcoma

30 million Units/m² IM/SC 3 times/wk for 16 wk

Dose reduction frequently required: See Mfr's PI

 

Chronic Hepatitis C

3 million units IM/SC 3 times/wk for16 wk

If ALT normalized after 16 wk, continue treatment for 18-24 mo

If ALT not normalized or high levels of HCV RNA after 16 wk, consider discontinuing treatment

 

Acute Hepatitis C

5 million Units SC/IM qd for 4 wk, then 3 times/wk for 20 wk

If severe adverse reactions develop reduce dose by 50% or temporarily withhold until adverse reactions abate

If intolerance persists discontinue permanently

 

Chronic Hepatitis B

30-35 million Units SC/IM per wk, either as 5 million Units qDay or 10 millon Units 3 times/wk for 16 wk

Reduce 50%: WBC <1.5 x 10^9/L; Granulocyte <0.75 x 10^9/L; platelets <50 x 10^9/L

Discontinue permanently: WBC < 1.0 x 10^9/L; Granulocyte <0.5 x 10^9/L; platelet < 25 x 10^9/L

If severe adverse reactions develop reduce dose by 50% or temporarily withhold until adverse reaction abate

If intolerance persists discontinue permanently

 

Other Information

Monitor: LFTs, CBC, platelets, Hgb, Electrolytes, TSH

See also combo with ribavirin

 

Pediatric dosage forms and strengths

injectable solution

• 6 million International Units/mL (3.8mL vial)
• 10 million International Units/mL (3.2mL vial)

multidose pen; 6 doses each

• 22.5 million International Units/1.5mL
• 37.5 million International Units/1.5mL
• 75 million International Units/1.5mL

powder for injection

• 10 million International Units/vial
• 18 million International Units/vial
• 50 million International Units/vial

 

Chronic Hepatitis B

3 million Units/m² IM/SC 3 times/wk for 1 wk; increase to 6 million U/m² 3 times/wk SC for 16-24 wk; not to exceed 10 million Units/dose 3 times/wk

Dose adjustments: See manufacturer's package insert

 

Intron A, Interferon alfa-2b (interferon alfa 2b) adverse (side) effects

>10%

Fatigue (8-96%)

Fever (34-94%)

Neutropenia (92%)

Flu-like syndrome (79%)

Myalgia (28-75%)

Anorexia (1-69%)

Leukopenia (68%)

Nausea (17-66%)

Transaminases increased (13-63%)

Weakness (63%)

Headache (21-62%)

Chills (54%)

Diarrhea (2-45%)

Rigors (42%)

Depression (up to 40% of pts), suicidal ideation/ attempts, suicide

Alopecia (38%)

Dyspnea (34%)

Somnolence (33%)

Vomiting (2-32%)

Anemia (32%)

Cough (31%)

Pharyngitis (31%)

Chest pain (28%)

Xerostomia (28%)

Rash (25%)

Dizziness (24%)

Taste alteration (24%)

Abdominal pain (1-23%)

Irritability (22%)

Sinusitis (21%)

Skeletal pain (21%)

Diaphoresisi (1-21%)

Paresthesias (1-21%)

Arthralgia/back pain (19%)

Pain (18%)

Moniliasis (17%)

Thrombocytopenia (15%)

Amnesia (14%)

Constipation (14%)

Gingivitis (14%)

Impaired concentration (14%)

Malaise (14%)

Weight loss (1-13%)

Amenorrhea (12%)

BUN increased (12%)

Confusion (12%)

Insomnia (12%)

Iruritus (11%)

 

1-10%

Bronchitis (10%)

Dry skin (10%)

Edema (10%)

Hypoestheisa (10%)

Loose stools (10%)

Nasal congestion (10%)

Polyuria (10%)

Anxiety (9%)

Hypertension (9%)

Dermatitis (8%)

Dyspepsia (8%)

Vertigo (8%)

Agitation (7%)

Infection (7%)

SCr increased (6%)

Herpes virus infections (5%)

UTI (5%)

 

<1%

Acute hypersensitivity reactions; exacerbation of preexisting psoriasis & sarcoidosis

Myelosuppression, thyroid dysfunction, hepatotox., pulmonary infiltrates, retinal hemorrhage

Severe cytopenias incl aplastic anemia

Autoimmune dz, DM/hyperglycemia (rare)

 

Posmarketing reports

Pulmonary fibrosis

 

Warnings

Black box warnings

Alfa interferons cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders

The risk of serious depression, with suicidal ideation and completed suicides, and other serious neuropsychiatric disorders are increased with alpha interferons

Discontinue drug if persistently severe or worsening signs or symptoms of the above conditions are present; disorders typically resolve after stopping therapy

These disorders may not resolve after the drug is discontinued

Monitored closely with periodic clinical and laboratory evaluations

Combination therapy with ribavirin

• Ribavirin may cause birth defects and/or fetal death
• Extreme care must be taken to avoid pregnancy in women taking peginterferon alfa-2a and in female partners of men taking peginterferon alfa-2a
• Ribavirin causes hemolytic anemia; associated anemia may result in worsening of cardiac disease
• Because ribavirin is genotoxic and mutagenic, consider it a potential carcinogen

 

Contraindications

Hypersensitivity

Autoimmune hepatitis

Decompensated liver disease (Child-Pugh >6 [class B and C])

Contraindications for combination therapy with ribavirin:

• Pregnant women and men whose female partners are pregnant.
• Hemoglobinopathies (e.g., thalassemia major, sickle-cell anemia)
• Creatinine clearance less than 50 mL/min

 

Cautions

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 reported in patients with and without a previous psychiatric disorder during therapy and follow-up; psychoses, hallucinations, bipolar disorders, and mania have been observed in patients treated with interferon alpha should be used with caution in patients with a history of psychiatric disorders; discontinue if severe depression develops

If psychiatric symptoms persist or worsen, or suicidal or homicidal ideation or aggressive behavior towards others identified, discontinue therapy and follow patient closely, with psychiatric intervention as appropriate; narcotics, hypnotics, or sedatives may be used concurrently with caution and patients should be closely monitored until adverse effects resolved

Dyspnea, pulmonary infiltrates, pneumonia, bronchiolitis obliterans, interstitial pneumonitis, pulmonary hypertension, and sarcoidosis, some resulting in respiratory failure or patient deaths, may be induced or aggravated by therapy; recurrence of respiratory failure has been observed with interferon rechallenge; monitor

Development or exacerbation of autoimmune disorders (e.g., thyroiditis, thrombotic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, rheumatoid arthritis, interstitial nephritis, systemic lupus erythematosus, and psoriasis) observed; use with caution in patients with autoimmune disorders

Caution in pre-existing cardiac abnormalities &/or advanced cancer Ischemic and hemorrhagic cerebrovascular events reported

Pancreatitis and ulcerative or hemorrhagic/iscemic colitis may occur

Severe decreases in neutrophil or platelet counts reported

Hepatitis C (CHC) patients with cirrhosis may be at risk of hepatic decompensation and death when treated with alpha interferons, including peginterferon alpha 2b; cirrhotic CHC patients co-infected with HIV receiving highly active antiretroviral therapy (HAART) and alpha interferons with or without ribavirin appear to be at increased risk for development of hepatic decompensation compared to patients not receiving HAART; monitor clinical status and hepatic function during treatment and discontinue immediately if decompensation (Child-Pugh score greater than 6) observed

Monitor patients with impaired renal function, for signs and symptoms of interferon toxicity, including increases in serum creatinine; adjust dose or discontinue therapy accordingly

Serious, acute hypersensitivity reactions and cutaneous eruptions reported

Dental/periodontal disorders reported with combination therapy Hypertriglyceridemia may result in pancreatitis (e.g., triglycerides greater than 1000 mg/dL)

Weight loss and growth inhibition reported during combination therapy in pediatric patients

Long-term growth inhibition (height) reported in some patients

Peripheral neuropathy observed when used in combination with telbivudine

Risk of visual impairment and retinal disorders; discontinue if ophthalmologic problems develop

Use with caution in patients with endocrine disorder: thyroid disease; DM prone to ketoacidosis

Pre-existing cardiac abnormalities &/or advanced cancer

AIDS-related Kaposi's Sarcoma: do not use in patients w/ rapidly progressive disease

Discontinue if acute hypersensitivity occurs

Risk of exacerbation of preexisting psoriasis & sarcoidosis; risk of developing new sarcoidosis

Patients should be well hydrated during initial treatment

If platelets <50,000/mm³, do not administer IM (may admin SC)

Do not use the 18 million IU or 50 million IU powder for injection or the18 million IU multidose vial for condylomata acuminata

Increases risk of hepatic decompensation and death in patients with cirrhosis; any patient developing liver function abnormalities during treatment should be monitored closely and if appropriate, treatment should be discontinued

Numerous cardiotoxicities, including arrhythmias, ischemia, infarction, and cardiomyopathy occur during and immediately after infusion

 

Pregnancy and lactation

Pregnancy category: C

Lactation: unknown

 

Pregnancy categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

 

Pharmacology of Intron A, Interferon alfa-2b (interferon alfa 2b)

Mechanism of action

Inhibits HBV replication; immunomodulatory actions; may induce gene transcription; interferes with oncogene expression, may change cell surface antigen expressoin; cytotoxic activity of macrophages increases

Suppresses cell proliferation

 

Pharmacokinetics

Half-Life: 2-3 hr (IM/SC); 2 hr (IV)

Peak Plasma Time: 3-12 hr (IM/SC); 30 min (IV)

 

Pharmacogenomics

Polymorphic cytokine genes (encoding IL-10, a Th2 cytokine); Th2 responses are associated with production of large amounts of antibodies

Patients with chronic hepatitis C are 5 times more likely to have a favorable response to interferon alfa if they carried the IL-10 genetic polymorphism that results in low expression of IL-10 than if they did not

 

Administration

IV Preparation

GeneraL

• Reconstitute vials with provided diluent
• Preparation should be clear & colorless to light yellow

IM, SC, or Intralesional Preparation

• Inject 1 mL diluent (SWI, supplied) into drug vial
• Swirl gently to dissolve powder
• Withdraw appropriate dose to be injected
• Refer to Medication Guide for detailed instructions

IV Administration

• Prepare immediately prior to use
• Reconstitute w/ diluent provided
• Inject 1 mL diluent (SWI, supplied) into drug vial
• Swirl gently to dissolve powder
• Withdraw appropriate dose & inject into a 100 mL bag of NS
• Make sure final conc of Intron A is NOT <10 MIU/100 mL
• Refer to Medication Guide for detailed instructions

Intron A Solution for Injection not recommended for IV

 

SC Administration

SC administration is suggested for those who are at risk for bleeding or thrombocytopenic

Rotate SC injection site

 

Storage

Refrigerate intact vials

Powder & premixed solutions are stable at room temp for 7 d & for 30 d if refrigerated