Prescription medicine
Interferon beta 1a Brand names: Rebif, Avonex
Interferon beta 1a (Avonex) is a prescription medicine with an FDA approval on record since 1996. No generic is listed; pharmacies paid $1,848.67 per mL (Rebif rebidose 44 mcg/0.5 mL) in the October 7, 2026 NADAC survey.
- No generic listed
Check it at the source: the interferon beta 1a FDA label on DailyMed (effective September 22, 2025, EMD Serono, Inc.); the BLA 103628 record on Drugs@FDA; every interferon beta 1a label on DailyMed.
Highlights of the record
FDA label of September 22, 2025; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026; NADAC October 7, 2026
Used for
From the label: indications and usageREBIF is indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults.
Forms and strengths
- 0.5ml
Injection (solution); kit.
On the market
- Earliest approval on file
- May 17, 1996 Avonex, Biogen; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- No generic approved
- Labelers listed (NDC)
- 2 of which 0 under generic applications, 2 under brand applications, repackagers included
Supply and safety
- Pharmacy cost (NADAC)
- $1,848.67 per mL Rebif rebidose 44 mcg/0.5 mL
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- No recall recorded
- FAERS reports
- 192,061 through July 30, 2026
What is interferon beta 1a used for?
From the label: indications and usageREBIF is indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults. Rebif is an interferon beta indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults.
Conditions named in the indications of interferon beta 1a's FDA labels, with every medicine labeled for each:
FDA pharmacologic class: Interferon beta.
Source: FDA drug label (REBIF), EMD Serono, Inc., effective September 22, 2025 (SPL set c6fcb5d2-8fcd-44fa-a838-b84ee5f44f0f), via openFDA; the full label on DailyMed
What does the patient leaflet for interferon beta 1a say first?
The FDA-approved Medication Guide or Patient Information that comes with the medicine, in its own words.
From the patient leaflet: What is the most important information I should know about REBIF?REBIF can cause serious side effects. Tell your healthcare provider right away if you have any of the symptoms listed below while taking REBIF. 1. Behavioral health problems including depression and suicidal thoughts. You may have mood problems including: depression (feeling hopeless or feeling bad about yourself) thoughts of hurting yourself or suicide 2. Liver problems or worsening of liver problems including liver failure. Symptoms may include: nausea loss of appetite tiredness dark colored urine and pale stools yellowing of your skin or the white part of your eye bleeding more easily than normal confusion sleepiness During your treatment with REBIF you will need to see your healthcare provider regularly and have regular blood tests to check for side effects. 3. Serious allergic and skin reactions. Symptoms may include: itching swelling of your face, eyes, lips, tongue or throat trouble breathing anxiousness feeling faint skin rash, hives, sores in your mouth, or skin blisters and peels 4. Injection site problems. REBIF may cause redness, pain, itching or swelling at the place where your injection was given. Call your healthcare provider right away if an injection site becomes swollen and painful or the area looks infected. You may have a skin infection or an area of severe skin damage (necrosis) requiring treatment by a healthcare provider.
From the patient leaflet: How should I store REBIF?Store REBIF in the refrigerator between 36°F to 46°F (2°C to 8°C). Do not freeze REBIF. If you cannot refrigerate your REBIF, you can store your REBIF at temperatures above 36°F and below 77°F (2°C to 25°C) for up to 30 days. Keep REBIF away from heat and light. Keep REBIF and all medicines out of the reach of children.
Source: FDA drug label (REBIF), EMD Serono, Inc., effective September 22, 2025 (SPL set c6fcb5d2-8fcd-44fa-a838-b84ee5f44f0f), via openFDA; the full label on DailyMed
Is there a generic for interferon beta 1a (Avonex)?
No generic interferon beta 1a is approved (Drugs@FDA, October 8, 2026).
- 1996 earliest approval on file
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
What do pharmacies pay for interferon beta 1a (Avonex)?
In CMS's NADAC survey of October 7, 2026, pharmacies paid $1,848.67 per mL (Rebif rebidose 44 mcg/0.5 mL), up 4% from $1,777.57 on October 8, 2025. The chart's scale runs from the lowest to the highest price shown, not from zero. NADAC is what retail pharmacies paid their wholesalers, per unit, in CMS's monthly survey; what a patient pays depends on insurance and the pharmacy.
- Rebif rebidose 44 mcg/0.5 mL (brand)
| Strength and form | Brand or generic | Pharmacy cost | 30 tablets, or one pen or vial | 12-month change |
|---|---|---|---|---|
| Avonex 30 mcg/0.5 mL syringe kit (4 pack) | Brand | $8,776.25 per syringe | n/a | +5% |
| Avonex pen 30 mcg/0.5 mL kit (4 pack) | Brand | $8,772.02 per pen | n/a | +4% |
| Rebif rebidose 44 mcg/0.5 mL | Brand | $1,848.67 per mL | n/a | +4% |
Source: CMS National Average Drug Acquisition Cost (NADAC) survey, October 7, 2026: what retail pharmacies paid per unit; not a counter price
What does the interferon beta 1a label say about other medicines?
The interferon beta 1a label names no other medicine on this site. The labels of 2 other medicines name interferon beta 1a. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
Source: FDA drug label (REBIF), EMD Serono, Inc., effective September 22, 2025 (SPL set c6fcb5d2-8fcd-44fa-a838-b84ee5f44f0f), via openFDA; the full label on DailyMed
What do FAERS reports show for interferon beta 1a?
The FDA Adverse Event Reporting System holds 192,061 reports that list interferon beta 1a among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 9,782 are coded as a death and 61,393 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What else is labeled for the same conditions as interferon beta 1a?
4 other medicines are given the same way (subcutaneous) and in the same FDA class as interferon beta 1a or labeled mainly for the same use (multiple sclerosis), the same class first. Multiple sclerosis lists all 23 medicines labeled for it, by any route. They are listed as records, not as substitutes: whether one can replace another is a prescriber's decision.
| Medicine | Shared indication | Generic labelers (subcutaneous) | Pharmacy cost | Shortage |
|---|---|---|---|---|
| Peginterferon beta 1a | Multiple sclerosis | none listed | n/a | No current entry |
| Glatiramer | Multiple sclerosis | 8 labelers | $86.10 per mL 40 mg/mL syringe | No current entry |
| Corticotropin | Multiple sclerosis | none listed | n/a | No current entry |
| Ofatumumab | Multiple sclerosis | none listed | $24,369.37 per mL 20 mg/0.4 mL pen | No current entry |
Every medicine labeled for the same conditions as interferon beta 1a
Source: FDA drug labels (indications), NDC Directory, NADAC of October 7, 2026, FDA shortages (October 8, 2026)
What next?
- Alternatives to interferon beta 1a
- 4 medicines for the same use
- Other interferon betas
- the pharmacologic class, with prices and generics
- Interferon beta 1a side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other