Moderna Therapeutics has caused a stir by raising a whopping $450 million, reportedly the largest-ever private financing round for any biotech.

Participating in the round were new backers Viking Global Investors, Invus, RA Capital Management and Wellington Management Company, as well as existing investors AstraZeneca and Alexion Pharmaceuticals. Since its founding in 2011, Moderna has secured more than $950 million in funding and now has $800 million in cash.

The company develops messenger RNA (mRNA) therapeutics and has 45 preclinical programmes running in oncology, cardiovascular and infectious diseases, plus rare disorders. A year ago, it set up an exclusive cancer venture, Onkaido Therapeutics, and also got $100 million from Alexion upfront; in 2013, it banked a $240 million upfront fee from AstraZeneca.

Moderna now plans to add more than 100 employees to its current staff of 145. Chief executive Stéphane Bancel said the financing “is a testament to the incredible work done by our team over the past three years in unlocking the potential of mRNA therapeutics to drive transformational advances for patients”.

He added that the Cambridge, Massachusetts-based firm is “committed to recruiting the best industry talent to support this growth at all levels, including bench scientists, seasoned drug hunters and leaders for our new ventures”.