Illumina’s deal to buy cancer test developer blocked by EU

BRUSSELS—The blocked European Union Illuminated acquisition of cancer test developer Grail Inc., jeopardizing a $7.1 billion merger just days after a U.S. administrative judge cleared it to go ahead.

The bloc’s antitrust regulator said on Tuesday the purchase would stifle innovation and reduce choice in an emerging market for early cancer detection blood tests. The ruling could force Illumina, a maker of gene sequencing machines, to dump Grail just over a year after picking him up.