Sandoz Launches Tyruko (Natalizumab-Sztn), First Tysabri Biosimilar, in US After JCV Assay Delays

Sandoz has launched TYRUKO (natalizumab-sztn), the first and only FDA-approved biosimilar to Tysabri for relapsing forms of multiple sclerosis (MS), in the US on November 17, 20251 2 3 4 6 7.

TYRUKO is approved for all indications of the reference product Tysabri, including relapsing MS and Crohn’s disease in adults1 3 4 6.

The US launch was delayed due to the need for FDA approval of a test for anti-JCV antibodies, which are essential for managing the PML risk associated with natalizumab therapy2 5 8.

Sandoz partnered with Labcorp to provide a laboratory-developed test (LDT) for detecting anti-JCV antibodies; this JCV antibody testing program is offered at no cost to eligible patients with Sandoz covering the test fees1 4.

The launch follows delays specifically related to the assay required to evaluate John Cunningham virus (JCV) antibody status, a necessary safety measure to mitigate PML risk2 5 8.

Risk Evaluation and Mitigation Strategy (REMS) protocols are part of the TYRUKO rollout, informing prescribers and patients about the ongoing PML risk, which is heightened in JCV-positive individuals and those with prior immunosuppressant use1 4.

Differences exist between the JCV assays used for monitoring patients:
Sandoz uses the Immunowell assay, while Biogen’s Tysabri historically used the proprietary Stratify JCV assay, leading to discussions about consistency and standardization in biosimilar safety monitoring10.

Tyruko was developed by Polpharma Biologics under a global commercialization agreement with Sandoz, granting Sandoz exclusive global distribution rights1 6.

Tyruko is positioned as a cost-effective therapeutic alternative, aiming to improve access for US patients with MS1 4 7.