Longevity
Dutch and Italian regulators probe Biogen over MS blood test access
By John Hyland, . Life and Health Today.
Antitrust regulators in the Netherlands and Italy are separately investigating whether Biogen has used its control of a safety blood test to disadvantage competitors in the multiple sclerosis drug market, according to a quarterly report Biogen filed with the US Securities and Exchange Commission.
What the test is and why it matters
Patients taking Tysabri, Biogen's biggest-selling MS drug, must be regularly screened for the risk of developing progressive multifocal leukoencephalopathy, a potentially fatal brain infection caused by a virus. Biogen developed a test for that virus, called the STRATIFY JCV assay, and provides it free of charge exclusively to patients receiving Tysabri, according to STAT News, which first reported the Dutch investigation.
The concern regulators appear to be examining is whether that exclusivity crosses into anticompetitive territory. Tyruko, a biosimilar version of Tysabri sold by Sandoz, requires the same safety monitoring, but patients switching to it cannot access the Biogen-controlled test, according to STAT News.
Two countries, two investigations
The Netherlands Authority for Consumers and Markets, known by its Dutch acronym ACM, informed Biogen in September 2026 that it was investigating the company's conduct around the assay, according to the SEC filing. Italy's competition authority announced a parallel investigation in May 2026, the same filing states.
Biogen's SEC filing names both probes but gives no further detail about their scope, timeline or potential penalties. Neither regulator has announced a finding or a charge.
What this means for patients and the market
A biosimilar is a drug that is biologically equivalent to an approved original but made by a different manufacturer, typically at lower cost. Biosimilars are designed to increase competition and bring prices down once a drug's exclusivity period ends. If a safety test required for a biosimilar is available only through the original drug's maker, that creates a practical barrier to switching, regardless of whether the barrier was intentional.
The investigations do not establish that Biogen broke any law, and the company has not been found liable. Regulatory probes of this kind can take years to resolve and may end without action. Whether either authority concludes that Biogen's test policy constitutes an abuse of market dominance remains an open question.
For patients currently on Tysabri or considering Tyruko, the practical question of test access is one to raise with a treating neurologist, who will know what monitoring options are available in their country.
Life & Health Today provides information for educational purposes only, not medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional.