The EU’s top court ruled Tuesday that an expanded merger control approach pursued by Brussels officials to go after killer acquisitions since 2021 violates EU rules—a decision that marks a major victory for U.S. biotech giant Illumina.

The Luxembourg-based Court of Justice of the European Union ruled that Brussels officials had no authority to scrutinize Illumina’s $8 billion acquisition of U.S. startup Grail and annulled the €432 million fine the Commission gave the U.S. genetic testing company for completing the deal while the agency’s investigation was still pending. The decision cannot be appealed.