FTC prepares to block Amgen’s $28.3bn deal for Horizon Therapeutics

The US Federal Trade Commission will sue to block Amgen’s $28.3 billion deal to acquire Horizon Therapeutics, according to a person familiar with the matter.

The lawsuit, which is set to be filed Tuesday, will mark the first time in more than a decade that the FTC has sought to block a deal in the pharmaceutical sector.

FTC chair Leena Khan is among a new group of progressive antitrust officials appointed by US President Joe Biden who have vowed to take a tougher stance and crack down on anti-competitive conduct in the US.

Shares in Horizon, which is based in Ireland, were down over 17 per cent in pre-market trade. The news also appeared to affect Siegen, which was down 5.6 percent in pre-market trading as investors weighed the possibility of the FTC targeting other deals in the sector. The oncology-focused biotech struck a $43 billion deal in March to be acquired by Pfizer.

The move was first reported by Bloomberg.

Additional reporting by Peter Wells in New York