The Dutch competition authority is investigating Biogen over the way it makes Stratify, an anti-JCV blood test, available in the Netherlands. The test is offered only to patients who are being treated with Biogen’s multiple sclerosis drug Tysabri or are considering that treatment; it is not currently available to patients taking other MS drugs.

Stratify helps estimate the risk of a potentially life-threatening brain infection associated with natalizumab, the active ingredient in Tysabri. The authority is examining whether restricting access to the test could impede effective competition from existing or potential providers of natalizumab-based MS drugs. It says the conduct could affect prices, supply, and freedom of choice for healthcare providers and patients.

The investigation will assess whether Biogen has violated competition rules prohibiting the abuse of a dominant position, including through unfair conditions for buyers. The authority has not reached a conclusion and may find that no infringement occurred. It is inviting anyone with relevant information about Tysabri, Stratify, or how they are made available to submit it.

The Italian competition authority launched a similar investigation earlier in the year, and the two authorities are cooperating where their investigations overlap. The Dutch authority identifies prescription medicines as a priority sector and says the investigation forms part of its work to support accessible and affordable healthcare.