More than two years after securing FDA approval, Sandoz has launched Tyruko (natalizumab-sztn) in the US, making it the first biosimilar version of Biogen's multiple sclerosis (MS) treatment Tysabri (natalizumab) to hit the North American market. Approved in August 2023, Tyruko had been set to launch in the US the following year, subject to FDA approval of a test for anti-JCV antibodies. However, delays in authorisation of the assay led to delays in Tyruko — seen as a key growth driver for Sandoz — hitting the US market. The company said Monday that it has partnered with Labcorp to develop and validate a laboratory-developed test for detecting the presence of anti-JCV antibodies, a major risk factor for progressive multifocal leukoencephalopathy. This test will be offered by Labcorp free of charge to eligible patients, with Sandoz covering the cost of the test. "As the only biosimilar available to treat multiple sclerosis in the US, Tyruko has an important opportunity to help people with MS navigate this disease in a way that is more cost effective," remarked Keren Haruvi, president of Sandoz North America. Tyruko is approved in the US for the same indications as Tysabri, which is cleared as a monotherapy for relapsing forms of MS, including clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS) and active secondary progressive disease, as well as Crohn's disease in adults. Tysabri — an anti-α4 integrin monoclonal antibody disease modifying treatment — generated sales of $1.7 billion in 2024. Sandoz gained rights to Tyruko as part of an agreement with Polpharma in 2019, under which the latter is responsible for development, manufacturing and supply of the therapy's active substance, with the former commercialising and distributing it in all markets. Tyruko was approved in the EU in 2023 and has so far been launched in 14 countries.