AstraZeneca and Alexion both contributed to the $450m round, the biggest ever raised by a privately held drug developer.

US-based Moderna Therapeutics yesterday closed the largest financing round ever raised by a private biopharmaceutical company, raising $450m from investors including pharmaceutical firms AstraZeneca and Alexion Pharmaceuticals.

Viking Global Investors, Invus, RA Capital Management and Wellington Management Company all participated in the round as new investors, while undisclosed existing backers also took part.

Moderna is developing an in vivo drug technology called messenger RNA therapeutics that produces human proteins, antibodies and protein constructs in cells in order to combat diseases…