Dosing and uses of Infergen (interferon alfacon 1)
Adult dosage forms and strengths
injectable solution
- 9mcg/0.3mL
- 15mcg/0.5mL
Chronic Hepatitis C
This product was discontinued in September 2013
9 mcg SC 3 times/week for 24 wk
Retreatment: Allow 48 hr between doses
If severe toxicity occurs: Reduce to 7.5 mcg SC 3 times/week or discontinue
Monitor: Hgb, WBC, Plt, LFTs, creatinine, thyroid
Combination use with ribavirin
- Retreatment: 15 mcg SC with ribavirin qDay for up to 48 weeks
- <75 kg: ribavirin 1 g PO divided q12hr
- ≥75 kg: ribavirin 1.2 g PO divided q12hr
- Monitor: Hgb, WBC, Plt, LFTs, creatinine, thyroid
Renal Impairment
CrCl <50 mL/min: Avoid combination therapy with ribavirin in hepatitis C treatment
Hepatic Impairment
Moderate-to-severe (Child-Pugh Class B and C): Contraindicated
Other Indications & Uses
Off-label: Hairy-cell leukemia (in combination with G-CSF)
Pediatric dosage forms and strengths
Safety and efficacy not established
Infergen (interferon alfacon 1) adverse (side) effects
>10%
Headache (~80%)
Fatigue (~70%)
Fever (~60%)
Rigors (~60%)
Myalgia (~55%)
Body pain (~50%)
Arthralgia (~45%)
Back pain (29-42%)
Granulocytopenia (23-42%)
Abd pain (24-41%)
Nausea (30-40%)
Insomnia (24-39%)
Pharyngitis (17-34%)
Nervousness (16-31%)
URI (16-31%)
Leukopenia (15-28%)
Limb pain (13-26%)
Diarrhea (~25%)
Cough (12-22%)
Dyspepsia (12-21%)
Anorexia (~20%)
Depression (~20%)
Inj site erythema (~20%)
Anxiety (19%)
Thrombocytopenia (19%)
Alopecia (14%)
Pruritus (14%)
Skeletal pain (14%)
Rash (13%)
Rhinitis (13%)
Chest pain (5-13%)
Hot flushes (4-13%)
Vomiting (12%)
Inj site pain (8-11%)
Asthenia (~10%)
1-10% (selected)
Abnormal LFTs
Amnesia
Constipation
Dysmenorrhea
Libido decrease
Bronchitis
Epistaxis
Hypertension
Palpitations
Vaginitis
Frequency not defined
Vision loss or retinopathy
Warnings
Black box warnings
Alfa interferons cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders
Monitor closely with periodic clinical and laboratory evaluations
Avoid use in history of autoimmune disorders
May cause or worsen fatal of life-threatening ischemic or infectious disorders
Discontinue drug if persistently severe or worsening signs or symptoms of the above conditions are present; disorders typically resolve after stopping therapy
Use with ribavirin
- Ribavirin may cause birth defects and fetal death; avoid pregnancy in female patients and in partners of male patients
- Ribavirin causes hemolytic anemia which may exacerbate cardiac disease
- Ribavirin is a potential carcinogen
- Combination therapy may be carcinogenic
Contraindications
Hypersensitivity to drug or any other component
Decompensated hepatic disease
Autoimmune hepatitis
Additional contraindications when used with ribavirin
- Pregnant women
- Men whose female partners are pregnant
- Hemoglobinopathies (eg, thalassemia major, sickle-cell anemia)
- CrCl <50 mL/min
Cautions
History of endocrine disorder, pre-existing cardiac disease
May worsen depression and cause suicidal ideation
Discontinue if new or worsening visual disorder
Advise patients to use contraception
Suspend if signs suggestive of pancreatitis
Discontinue if pancreatitis or colitis develops
Discontinue if severe myelosuppression develops
Pregnancy and lactation
Pregnancy category: C (interferon monotherapy); X (combination with ribavirin)
Lactation: not known if excreted in breast milk, use caution
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 Infergen (interferon alfacon 1)
Mechanism of action
Immunomodulating cytokine; may interfere with oncogene expression, induce gene transcription, may alter cellular differentiation and cell surface antigen expression , may increase phagocytic activity of macrophages, may inhibit cell growth; may increase phagocytic activity of macrophages and increase cytotoxicity effects of lymphocytes for target
Pharmacokinetics
Peak Plasma Time: 24-36 hr (healthy volunteers)
