Interferon alfa-2b
Also known as: Betaseron, IFN-α2b, IFN‑α2b, IFNA2B, interferon alpha-2b, interferon alpha‑2b, Intron A, NSC-377523, PEG-Intron (pegylated form), rIFN-α2b
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Summary
Interferon alfa-2b is a recombinant type I interferon cytokine that is prescribed for its antiviral, antiproliferative, and immunomodulatory effects. It is approved in pegylated form for cytoreductive therapy in polycythaemia vera and has been investigated for chronic viral hepatitis and as the therapeutic payload in an intravesical adenoviral gene‑therapy (nadofaragene firadenovec) for BCG‑unresponsive non‑muscle‑invasive bladder cancer. The drug can be administered by injection (intramuscular, subcutaneous, intravenous, intralesional) or, in the bladder study, by direct bladder instillation of a viral vector delivering its cDNA.
Mechanism of Action
Interferon alfa‑2b binds the heterodimeric interferon‑α receptor (IFNAR1/2) on most nucleated cells, triggering JAK1 and TYK2 activation. Phosphorylated STAT1/STAT2 form complexes that translocate to the nucleus and drive expression of interferon‑stimulated genes. These genes inhibit viral replication, increase antigen presentation, promote apoptosis of proliferating hematopoietic cells, and enhance natural‑killer and Th1‑type immune responses. In the intravesical gene‑therapy, an adenoviral vector delivers IFN‑α2b cDNA to bladder epithelium, resulting in local production of the cytokine and the same downstream signaling.
What the Research Shows
A phase‑3 trial of nadofaragene firadenovec, an adenoviral vector delivering IFN‑α2b cDNA, reported a 53.4% complete response rate in patients with carcinoma in situ of the bladder, with 45.5% of responders maintaining response at 12 months; grade 3‑4 urgency occurred in 1% and no treatment‑related deaths were observed. An older family‑medicine review listed IFN‑α2b as an investigational agent for polycythaemia vera. A European LeukemiaNet guideline (2022) recommended recombinant interferon‑α (including ropeginterferon alfa‑2b, a pegylated form) as a first‑line cytoreductive drug for younger, low‑risk polycythaemia vera patients. In hepatitis B and C studies, IFN‑α2b monotherapy achieved HBV DNA clearance in 10/16 patients and, when combined with thymosin α1, improved ALT normalization and HCV RNA clearance compared with IFN‑α2b alone.
Reported Benefits
Clinical data support several potential benefits of interferon alfa‑2b. In bladder cancer, intravesical delivery of IFN‑α2b cDNA achieved durable complete responses in over half of carcinoma‑in‑situ patients. In polycythaemia vera, pegylated interferon formulations provide a cytoreductive option that can control hematocrit and reduce thrombotic risk, as endorsed by expert guidelines. Antiviral activity is demonstrated by HBV DNA clearance rates comparable to other interferons and by enhanced viral suppression when combined with thymosin α1 in hepatitis C trials.
Limitations of the Evidence
Evidence for interferon alfa‑2b varies by indication. The bladder cancer benefit derives from a gene‑therapy vector rather than direct protein administration, limiting extrapolation to standard interferon use. Hepatitis studies are small, heterogeneous, and show mixed outcomes, with some trials reporting no significant ALT improvement. Polycythaemia vera recommendations rely on newer pegylated formulations (ropeginterferon) rather than the non‑pegylated molecule, and long‑term safety data remain limited. Overall, large‑scale randomized trials are lacking for many applications.
Safety Considerations
Across studies, interferon alfa‑2b was generally well tolerated. In the bladder gene‑therapy trial, the only grade 3‑4 adverse event was micturition urgency in 2 of 157 patients (1%); no treatment‑related deaths occurred. Typical interferon‑related toxicities—flu‑like symptoms, fatigue, hematologic changes, and injection‑site reactions—are reported in other contexts, though not detailed in the cited abstracts. Monitoring of blood counts and liver function is advised, and patients should be counseled about potential mood changes and autoimmune phenomena.
How It Is Administered
Interferon alfa‑2b is supplied for injection and can be given intramuscularly, subcutaneously, intravenously, or intralesionally. In the bladder cancer study, the drug was delivered intravesically as a 75 mL dose of an adenoviral vector (nadofaragene firadenovec) repeated at 3‑month intervals. Dosing schedules for other indications vary and are defined by prescribing information or clinical protocols.
Routes of Administration
Goals & Uses
- AIDS-Related Kaposi's SarcomaOncology / Infectious DiseaseModerate
- Chronic Hepatitis C treatmentAntiviralHigh
- Chronic Hepatitis B treatmentAntiviralHigh
- Melanoma (adjuvant)OncologyHigh
- Chronic hepatitis CAntiviralHigh
- Genital warts (condyloma acuminata)DermatologyModerate
- Kaposi sarcomaOncologyModerate
- Hairy cell leukemia treatmentOncologyHigh
- Chronic hepatitis BAntiviral / HepatologyHigh
- Follicular non-Hodgkin lymphomaOncology / HematologyModerate
- Malignant melanoma adjuvant therapyOncologyHigh
Contraindications
- Severe autoimmune disease (e.g., lupus, multiple sclerosis)AutoimmuneModerate
- PregnancyPopulationHighPotential fetal risk or insufficient safety data
- Neonates and Infants (benzyl alcohol-containing formulations)PediatricHigh
- Severe depression or psychiatric illnessPsychiatricModerate
- Concurrent use of telbivudineDrug InteractionHigh
- Autoimmune hepatitisHepatic / AutoimmuneHigh
- Hypersensitivity to interferon alfa‑2b or any formulation componentAllergyHigh
- Decompensated liver diseaseHepatic ImpairmentHigh
- Hypersensitivity to interferon alfa or any componentImmunologicHigh
- Severe psychiatric disorders (untreated)PsychiatricHigh
Adverse Effects
- Depression / suicidal ideationPsychiatricUncommon
- Neutropenia and thrombocytopeniaHematologicCommon
- Depression and neuropsychiatric effectsNeuropsychiatricCommon
- Injection site reactionsLocalCommon
- Thyroid dysfunctionEndocrineUncommon
- Elevated liver enzymes / hepatotoxicityHepaticUncommon
- Flu-like syndrome (fever, chills, myalgia, fatigue)SystemicCommon
- Elevated liver enzymesHepaticUncommonIncrease in AST/ALT or other hepatic markers
- Flu‑like syndrome (fever, chills, myalgia)SystemicCommon
- Leukopenia / neutropeniaHematologicUncommon
Drug Interactions
- Live vaccinesHigh
- Zidovudine (AZT)Moderate
- Immunosuppressants (e.g., cyclosporine)Moderate
- WarfarinModerate
- Theophylline / AminophyllineModerate
- TelbivudineHigh
- RibavirinModerate
- ClozapineHigh
- MethadoneModerate
Population Constraints
- PregnancyReproductive SafetyRelative
- Renal impairmentOrgan ImpairmentRelative
- Severe renal impairment (CrCl <50 mL/min)Renal ImpairmentRelative
- Pediatric patientsAgeRelative
- Pediatric patients (<1 year)AgeAbsolute
- Pre-existing autoimmune diseaseAutoimmuneRelative
- Elderly patients (>65 years)AgeRelative
- Severe cardiovascular diseaseCardiovascularRelative
- Elderly (>65 y)AgeRelative
Regulatory Status
- European UnionApprovedApproved: chronic hepatitis C, melanoma, Kaposi sarcoma, genital wartsEMA marketing authorisation aligns with US indications.
- United StatesApprovedApproved: chronic hepatitis C, chronic hepatitis B, melanoma (adjuvant), Kaposi sarcoma, genital wartsApproved as Intron A; dosing varies by indication.
- United KingdomApprovedApproved: chronic hepatitis C, melanoma, Kaposi sarcoma, genital wartsAvailable via NHS under specialist prescription.
FDA‑approved (e.g., Intron A) for hepatitis C, melanoma, Kaposi sarcoma, and genital warts; EMA approvals align with these indications.
Evidence & Sources
- Journal ArticleModerateBoorjian SA, et al.2021-01-01T00:00:00.000000Z
- Journal ArticleModerateStuart BJ, Viera AJ2004-01-01T00:00:00.000000Z
- Journal ArticleModerateAncell CD, Phipps J, Young L2001-01-01T00:00:00.000000Z
- Journal ArticleModerateMarchetti M, et al.2022-01-01T00:00:00.000000Z
Frequently Asked Questions
What medical conditions have been studied with interferon alfa‑2b?
Interferon alfa‑2b has been investigated for viral hepatitis (HBV and HCV), as a cytoreductive agent in polycythaemia vera (especially in pegylated forms), and as the therapeutic gene in an intravesical adenoviral vector for BCG‑unresponsive non‑muscle‑invasive bladder cancer.
How is interferon alfa‑2b administered?
The drug is available for injection and may be given intramuscularly, subcutaneously, intravenously, or intralesionally. In the bladder cancer trial, it was delivered directly into the bladder as part of an adenoviral vector (intravesical instillation).
What are the most common side effects?
Reported adverse events include flu‑like symptoms, fatigue, hematologic changes, and injection‑site irritation. In the bladder gene‑therapy study, the only serious adverse effect was urinary urgency in 1% of patients; no deaths were reported.
Is interferon alfa‑2b approved for any indication?
Pegylated formulations of interferon alfa‑2b (e.g., ropeginterferon alfa‑2b) are approved in Europe for cytoreductive therapy in polycythaemia vera. The non‑pegylated molecule is prescription‑only and is used off‑label or in clinical trials for other conditions.
Can interferon alfa‑2b cure viral hepatitis?
Clinical trials show interferon alfa‑2b can suppress HBV DNA and improve HCV outcomes, but cure rates are modest and vary between studies. It is one of several antiviral options, and treatment decisions depend on disease stage and patient factors.
What is Interferon alfa-2b?
Interferon alfa-2b is a recombinant type I interferon cytokine that is prescribed for its antiviral, antiproliferative, and immunomodulatory effects. It is approved in pegylated form for cytoreductive therapy in polycythaemia vera and has been investigated for chronic viral hepatitis and as the therapeutic payload in an intravesical adenoviral gene‑therapy (nadofaragene firadenovec) for BCG‑unresponsive non‑muscle‑invasive bladder cancer. The drug can be administered by injection (intramuscular, subcutaneous, intravenous, intralesional) or, in the bladder study, by direct bladder instillation of a viral vector delivering its cDNA.
What is Interferon alfa-2b used for?
Interferon alfa-2b is educationally associated with: AIDS-Related Kaposi's Sarcoma, Chronic Hepatitis C treatment, Chronic Hepatitis B treatment, Melanoma (adjuvant), Chronic hepatitis C, Genital warts (condyloma acuminata), Kaposi sarcoma, Hairy cell leukemia treatment, Chronic hepatitis B, Follicular non-Hodgkin lymphoma, Malignant melanoma adjuvant therapy. Educational only — not medical advice.
How is Interferon alfa-2b administered?
Recorded routes of administration: Intralesional, Intramuscular, Intravenous, Subcutaneous.
What are the potential side effects of Interferon alfa-2b?
Reported adverse effects include: Depression / suicidal ideation, Neutropenia and thrombocytopenia, Depression and neuropsychiatric effects, Injection site reactions, Thyroid dysfunction, Elevated liver enzymes / hepatotoxicity, Flu-like syndrome (fever, chills, myalgia, fatigue), Elevated liver enzymes, Flu‑like syndrome (fever, chills, myalgia), Leukopenia / neutropenia. This list is not exhaustive — consult a qualified clinician.
Who should avoid Interferon alfa-2b?
Recorded contraindications: Severe autoimmune disease (e.g., lupus, multiple sclerosis), Pregnancy, Neonates and Infants (benzyl alcohol-containing formulations), Severe depression or psychiatric illness, Concurrent use of telbivudine, Autoimmune hepatitis, Hypersensitivity to interferon alfa‑2b or any formulation component, Decompensated liver disease, Hypersensitivity to interferon alfa or any component, Severe psychiatric disorders (untreated). Consult a qualified clinician before use.