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Interferon alfa-2b is a recombinant human cytokine given by injection for chronic hepatitis B and C and for several cancers; direct acting antivirals have made it obsolete for hepatitis C across most of the world.
- A recombinant human cytokine, made rather than extracted
- Given by injection for chronic hepatitis B and C
- Also used against several cancers
- Switches on hundreds of interferon stimulated genes at once
- Broad antiviral and antiproliferative reach in one molecule
- One of the first recombinant biotech medicines ever approved
- Quesada's 1984 NEJM report that alpha interferon induced remission in hairy cell leukaemia was the first demonstration that a recombinant cytokine could treat a human cancer [1]; purine analogues have since displaced it as first-line.
- Perrillo's 1990 NEJM trial established interferon alfa-2b as the first effective therapy for chronic hepatitis B, with HBeAg loss and HBV DNA clearance in about a third of treated patients [2].
- ECOG EST 1684 made high-dose interferon alfa-2b the first FDA-approved adjuvant therapy for resected high-risk melanoma, improving relapse-free and overall survival [3]; pooled reanalysis of four ECOG trials confirms a durable relapse-free survival benefit with a smaller and less certain survival effect [6].
- Manns's 2001 Lancet trial showed pegylated interferon alfa-2b plus ribavirin achieved a 54% sustained virological response versus 47% with standard interferon plus ribavirin, defining the hepatitis C standard of care for a decade [4].
- Cochrane's assessment of peginterferon plus ribavirin [5] has been rendered largely historical by direct-acting antivirals, which cure over 95% of hepatitis C without interferon; interferon alfa-2b is no longer standard therapy for hepatitis C anywhere.
- Interferon alfa-2b (Intron A) was discontinued by its manufacturer in the United States in 2019, so most remaining indications are served by peginterferon alfa-2a or by newer agents.
Mechanism
Binding the type I interferon receptor triggers JAK/STAT signalling and transcription of hundreds of interferon stimulated genes, which block viral replication, raise MHC class I antigen presentation and suppress cell proliferation. The same broad immune activation produces the flu like syndrome, the cytopenias and the mood effects that limit how long anyone can tolerate it.
receptor fingerprint
IFNAR1/IFNAR2 (type I interferon receptor heterodimer)Agonist
Tumour and virally infected cell cycle (p21, cyclin-dependent kinase inhibition) and angiogenesisSuppressed
JAK1 and TYK2, then STAT1/STAT2/IRF9 (ISGF3 complex)Activated downstream of IFNAR
2'-5'-oligoadenylate synthetase / RNase L and PKR (EIF2AK2)Induced antiviral effectors
MHC class I expression and NK-cell / macrophage cytotoxicityUpregulated
Safetyrisks and cautions, not medical advice
an injectable recombinant cytokine with severe systemic toxicity including depression and suicidality, bone marrow suppression, thyroid and autoimmune disease; it requires blood count, thyroid and psychiatric monitoring and is not something to inject unsupervised
Subjective profileweighing the evidence above
Direct acting antivirals retired this drug for hepatitis C across most of the world, which is the kindest available summary of a treatment defined by how badly people tolerated it. Depression and suicidality, marrow suppression and autoimmune thyroid disease are not rare accidents; they are the predictable price of switching on hundreds of interferon stimulated genes in every tissue at once. Blood counts, thyroid checks and psychiatric oversight are part of the treatment, which is why this page documents the drug and refuses to help anyone inject it unsupervised.
Resources
No suppliers are provided for compounds like this. This entry is here for reference.
Research
- 1984first citedAlpha interferon for induction of remission in hairy-cell leukemia
- 2014meta-analysisPeginterferon plus ribavirin versus interferon plus ribavirin for chronic hepatitis C
- 2019most recentAn updated analysis of 4 randomized ECOG trials of high-dose interferon in the adjuvant treatme…
- 1.Alpha interferon for induction of remission in hairy-cell leukemia
- 2.A randomized, controlled trial of interferon alfa-2b alone and after prednisone withdrawal for the treatment of chronic hepatitis B. The Hepatitis Interventional Therapy Group.
- 3.Interferon alfa-2b adjuvant therapy of high-risk resected cutaneous melanoma: the Eastern Cooperative Oncology Group Trial EST 1684
- 4.Peginterferon alfa-2b plus ribavirin compared with interferon alfa-2b plus ribavirin for initial treatment of chronic hepatitis C: a randomised trial
- 5.Peginterferon plus ribavirin versus interferon plus ribavirin for chronic hepatitis C
- 6.An updated analysis of 4 randomized ECOG trials of high-dose interferon in the adjuvant treatment of melanoma
6 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
Notes and cautions
- Interferon alfa-2b carries a BOXED WARNING that alpha interferons, including interferon alfa-2b, cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischaemic and infectious disorders, and that patients must be monitored closely with periodic clinical and laboratory evaluations and withdrawn from therapy for persistently severe or worsening signs of these conditions.
- When combined with ribavirin the warning extends to ribavirin's haemolytic anaemia, which can worsen cardiac disease and precipitate myocardial infarction, and to its significant teratogenic and embryocidal effects, which require two forms of contraception in patients and partners during treatment and for six months afterwards.
- Depression and completed suicide are the best-known neuropsychiatric hazards and warrant baseline and ongoing psychiatric screening.
- Retinopathy, thyroid dysfunction, pancreatitis, colitis, pulmonary infiltrates and severe cytopenias also occur, and it is contraindicated in autoimmune hepatitis and decompensated cirrhosis.