Tysabri (Natalizumab)

1 natalizumab biosimilar from 1 maker is licensed. The 12-year reference exclusivity date of 11/2016 is an estimate from first approval; the Purple Book does not list patents, which can protect a biologic longer.

Tysabri was first approved by the FDA in 2004; the application holder is Biogen Inc.

Holder Biogen Inc.Approved 2004

Open full profile Start free trial

Data as of 10/30/2026

Reference exclusivityEndedEst. 11/2016; patents not in the Purple Book Biosimilars1 licensedNone interchangeable FDA shortageClearNot listedCurrent FDA list

01Exclusivity

When biosimilar competition can legally begin. The Purple Book lists reference exclusivity but not patents, which can protect a biologic longer.

Patents: Not listed in the Purple Book
Reference exclusivity: 11/201612-year estimate from first approval

02Competition

Biosimilars: 1 biosimilar from 1 maker

Every makerEach licensed product and biosimilar maker.

PrescribersWho prescribes it, from Medicare data.

Spend and safetyMedicare Part B spend and safety reports.

Available in the full Tysabri profile.See what is included

03Supply and price

FDA drug shortage: ClearNot on the current shortage list

04Product

Application holder: Biogen Inc.
First approved: 2004

Sources: FDA Orange Book, FDA Purple Book, FDA drug shortages, FDA enforcement reports and CMS NADAC, read through QOPE. Not medical or legal advice.