CSL chief executive Paul Perreault has made good on his threat and taken legal action against the US Customs and Border Protection agency, seeking a preliminary injunction to its sudden policy to ban Mexican citizens from crossing to donate blood plasma.

In a highly unusual move, the biotech giant has partnered with rival Spanish pharma firm Grifols SA in the lawsuit, which was filed in the District of Columbia in September. In June, the agency shut the border crossing to anyone who was not “essential”.