BRUSSELS (Reuters) - Europe's top court on Tuesday backed U.S. gene sequencing company Illumina's fight against EU antitrust regulators' investigation into its $7.1 billion bid for cancer diagnostic test maker Grail.

"The Court of Justice sets aside the judgment of the General Court and annuls the decisions by which the Commission accepted requests from national competition authorities seeking the examination of the proposed concentration," the Luxembourg-based Court of Justice of the European Union (CJEU) said.

The General Court had in 2022 ruled in favour of the European Commission.

Illumina, which founded Grail and spun it off in 2016 only to re-acquire it in 2021 for $7.1 billion, had fought against the European Commission's rarely used power called Article 22 to assess the deal even though it was below the EU merger revenue threshold.

The cases are Cases C-611/22 P Illumina v Commission and C-625/22 P Grail v Commission.