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# FDA Approves 1st Tysabri Biosimilar
- URL: https://www.fdaweb.com/fda-approves-1st-tysabri-biosimilar/
- Published: 2023-08-24T12:00:00.000Z
- Updated: 2026-09-14T18:52:28.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5155178

FDA has [approved](https://c212.net/c/link/?t=0&l=en&o=3952528-1&h=779361800&u=https%3A%2F%2Fwww.accessdata.fda.gov%2Fdrugsatfda%5Fdocs%2Flabel%2F2023%2F761322s000lbl.pdf&a=approved&ref=fdaweb.com) a Sandoz BLA for Tyruko (natalizumab-sztn), the first biosimilar to Biogen’s Tysabri (natalizumab) injection for treating adults with relapsing forms of multiple sclerosis. “Tyruko, like Tysabri, is also indicated for inducing and maintaining clinical response and remission in adult patients with moderately to severely active Crohn's Disease (CD) with evidence of inflammation who have had an inadequate response to, or are unable to tolerate, conventional CD therapies and inhibitors of TNF-α (tumor necrosis factor, a substance in your body that causes inflammation),” an [agency release ](https://www.fda.gov/news-events/press-announcements/fda-approves-first-biosimilar-treat-multiple-sclerosis?ref=fdaweb.com)says. Approval was based on data showing that there are “no clinically meaningful differences between the two products in terms of safety, purity and potency (i.e., safety and effectiveness),” it says.

On the safety side, FDA is requiring that Tyruko carry Tysabri’s boxed warning about the increased risk of progressive multifocal leukoencephalopathy (PML), a viral infection of the brain that usually leads to death or severe disability. “Because of the risks of PML, natalizumab products are available only through a restricted drug distribution program, under a risk evaluation and mitigation strategy (REMS),” the agency says. The REMS requires prescribers and pharmacies to be specially certified in the REMS, and that patients be enrolled in the program. Prescribers under the REMS must also evaluate patients three and six months after the first infusion, every six months thereafter, as well as immediately and six months after discontinuing treatment, it says.