What Is Interferon Used For? Approved Uses, Per the Label

The short answer

Interferon is the name of a family of signalling proteins and of the prescription medicines built from them. Recombinant interferon alfa, interferon beta and interferon gamma products are regulated prescription biologics in the United States, each with its own FDA-approved prescribing information that lists the conditions the product is approved to treat. A second group of prescription medicines works on the interferon system from the other direction, either blocking interferon signalling or neutralising an interferon, and those products carry their own separate indications.

Because the word "interferon" covers several distinct products, there is no single label to quote. The approved uses depend on which molecule is being discussed: interferon alfa-2b, peginterferon alfa, interferon beta-1a, interferon beta-1b, interferon gamma-1b, the gene therapy that delivers interferon alfa-2b locally, or the antibodies that target interferon signalling. The authoritative source for any one of them is that product's current prescribing information. A broader background overview sits on the interferon learn page.

This page is for educational purposes only and is not medical advice; consult a licensed physician or prescribing clinician about whether any medicine is appropriate, and about anything specific to a personal medical history. No dosing information appears here.

How the interferon medicines divide up

Approved uses: interferon products themselves

Interferon alfa in oncology

Recombinant interferon alfa-2b carried oncology indications long before modern checkpoint inhibitors. A 2018 review of immunotherapy in melanoma placed interferon alfa among the earlier systemic immunotherapy approaches used in that disease, and researchers described how the field later shifted toward checkpoint blockade and other agents (PMID 30149766). The review treated interferon alfa as part of the historical adjuvant landscape rather than as the current default, which is consistent with how prescribing patterns in melanoma changed over the last decade.

The precise wording of any oncology indication, including the tumour types and the treatment setting, appears in the current prescribing information for the specific interferon alfa product, together with the pivotal trial citations that supported it. Labels are revised periodically, so the revision date printed on the document matters when comparing wording.

Interferon alfa-2b delivered as a local gene therapy

A newer approval uses a non-replicating adenoviral vector to deliver the interferon alfa-2b gene directly into the bladder wall rather than giving interferon systemically. A 2023 first-approval review in Drugs described nadofaragene firadenovec and its approval in the United States for adults with high-risk, Bacillus Calmette-Guerin unresponsive non-muscle invasive bladder cancer with carcinoma in situ, and reported on the development programme that led to that decision (PMID 36856952). The study-level data behind that approval and the full indication wording are set out in the product's prescribing information.

Interferon beta and interferon gamma products

Interferon beta-1a and interferon beta-1b products are approved prescription medicines in the United States for relapsing forms of multiple sclerosis, and interferon gamma-1b is an approved prescription medicine for specified rare conditions. The exact indication statements, the patient populations they cover, and the clinical trials cited in support of them appear in each product's own current prescribing information. Those product labels, rather than any secondary summary, are the correct reference for the approved wording.

Interferon alfa in chronic viral hepatitis

Interferon alfa and pegylated interferon alfa products have carried chronic viral hepatitis indications in the United States, although treatment practice in hepatitis C moved decisively to direct-acting antivirals. Hepatitis D is a separate situation: a 2023 review of emerging drugs for hepatitis D examined the treatment landscape for that infection and reported that pegylated interferon alfa featured in clinical practice while newer agents were still moving through development (PMID 37096555). Whether a particular hepatitis indication is listed on a particular product's current label is a question for that label and for a prescribing clinician.

Approved uses: medicines that target the interferon pathway

Several approved medicines act on interferon biology without being interferons. They appear here because people searching for interferon uses frequently encounter them.

Anifrolumab in systemic lupus erythematosus

Anifrolumab is a monoclonal antibody directed at subunit 1 of the type I interferon receptor. A 2021 first-approval review in Drugs reported its approval in the United States for adults with moderate to severe systemic lupus erythematosus receiving standard therapy, and summarised the clinical development programme behind that approval (PMID 34554438). A 2023 drug profile reviewed the pharmacology and the trial evidence in lupus in more detail (PMID 36811405), and a 2024 review traced interferon inhibition in lupus from laboratory observation to clinical use (PMID 39193183).

Later reviews placed that approval in context. A 2024 overview of new and emerging therapies for systemic lupus erythematosus described anifrolumab alongside other approved and investigational agents for the disease (PMID 38582250), and a 2025 review of progress in type I interferon blockade in lupus examined how the strategy has developed since approval (PMID 40693799).

Emapalumab in primary haemophagocytic lymphohistiocytosis

Emapalumab is a monoclonal antibody that binds and neutralises interferon gamma. A 2019 first-global-approval review reported its approval in the United States for paediatric and adult patients with primary haemophagocytic lymphohistiocytosis, and summarised the development programme that supported it (PMID 30623346). Interferon gamma neutralisation has also been examined in related hyperinflammatory states: a 2024 systematic review informing the EULAR and PReS guidelines for Still's disease assessed therapies for Still's disease and macrophage activation syndrome, including agents acting on interferon gamma (PMID 39317415). Which of those settings appears as an approved indication is determined by the current prescribing information.

A short note on uses that are not approved indications

Published literature also describes interferon biology in settings that are not approved label indications, and those should not be read as uses. A 2002 review of antiangiogenesis agents in ophthalmology discussed interferon alfa among agents examined for ocular neovascular disease, which is not a United States label indication (PMID 12515077). Separately, a 2020 trial watch reported on STING agonists in cancer therapy, a class that works by driving type I interferon responses and which remained investigational in clinical trials rather than approved (PMID 32934881).

Regulatory history of the indications

The regulatory arc of interferon medicines runs in two phases. The first phase involved giving interferon itself. Recombinant interferon alfa reached the market in oncology and chronic viral hepatitis, interferon beta products followed in multiple sclerosis, and interferon gamma-1b was approved for rare conditions. Over time, newer classes displaced interferon alfa in several of those settings, a shift the 2018 melanoma review described for the adjuvant treatment of that disease (PMID 30149766) and the 2023 hepatitis D review described for that infection (PMID 37096555).

The second phase targets interferon signalling rather than supplying it. The 2019 first-approval review documented the arrival of interferon gamma neutralisation in primary haemophagocytic lymphohistiocytosis (PMID 30623346), the 2021 first-approval review documented type I interferon receptor blockade in lupus (PMID 34554438), and the 2023 first-approval review documented local gene delivery of interferon alfa-2b in bladder cancer (PMID 36856952). Reviews published since then have continued to map where interferon-directed therapy fits in lupus care (PMID 40693799).

Interferon and Interferon-Pathway Medicines: What Studies Report

Tolerability has shaped how interferon products are used. The 2018 melanoma review reported that the toxicity profile of interferon-based immunotherapy influenced its place in treatment as newer agents emerged (PMID 30149766). For the interferon-pathway antibodies, the first-approval reviews summarised both efficacy and safety findings from the clinical development programmes: the 2021 review covered the anifrolumab programme in lupus (PMID 34554438), a 2023 profile revisited those safety and efficacy data (PMID 36811405), and the 2019 review covered the emapalumab programme in primary haemophagocytic lymphohistiocytosis (PMID 30623346). The 2024 systematic review for the Still's disease guidelines assessed efficacy and safety across therapies used in Still's disease and macrophage activation syndrome (PMID 39317415). Full warnings, precautions and adverse reaction tables appear in each product's prescribing information, and interpretation of them for any individual belongs with a prescribing clinician.

How to read a label indication

• Match the product, not the class. Interferon alfa-2b, interferon beta-1a and interferon gamma-1b carry different indications.
• Check the revision date. Indication wording and safety sections change between revisions.
• Read the population wording. Labels often specify age ranges, disease severity, prior therapy or biomarker status.
• Separate published research from approved use. A review describing a setting, such as the ophthalmic work reported in 2002 (PMID 12515077), does not make that setting an indication.
• Take personal questions to a clinician. Suitability, monitoring and alternatives are clinical decisions.

References

• Anifrolumab: First Approval (Drugs, 2021)
• Immunotherapy in melanoma (Immunotherapy, 2018)
• Emapalumab: First Global Approval (Drugs, 2019)
• Antiangiogenesis agents (Ophthalmology Clinics of North America, 2002)
• Anifrolumab in systemic lupus erythematosus (Drugs of Today, 2023)
• Emerging drugs for hepatitis D (Expert Opinion on Emerging Drugs, 2023)
• Progress in the use of type I interferon blockade in systemic lupus erythematosus (Expert Opinion on Biological Therapy, 2025)
• Trial watch: STING agonists in cancer therapy (Oncoimmunology, 2020)
• New and emerging therapies for systemic lupus erythematosus (Clinical Immunology, 2024)
• Interferon Inhibition in SLE: From Bench to Bedside (Mediterranean Journal of Rheumatology, 2024)
• Nadofaragene Firadenovec: First Approval (Drugs, 2023)
• Efficacy and safety of therapies for Still's disease and macrophage activation syndrome: a systematic review informing the EULAR/PReS guidelines (Annals of the Rheumatic Diseases, 2024)