Pharmaceutical giant Pfizer (NYSE:PFE) is helping to pump money into a promising early-stage biotech company. Amplyx Pharmaceuticals, which is still privately held, announced Tuesday it received a $53 million extension to its Series C financing round. Other than Pfizer, the financing syndicate was mostly comprised of venture capital companies. It was not specified how much Pfizer contributed.

Amplyx is a clinical-stage company that concentrates on serious illnesses that attack patients with compromised immune systems -- a particularly pressing area of research given the spread of the SARS-CoV-2 coronavirus, which causes COVID-19.

A coronavirus colony.

Image source: Getty Images.

At the moment the company has two drug candidates undergoing clinical trials -- the anti-fungal medication fosmanogepix, and MAU868, which is aimed at treating transplant patients afflicted with BK, a common virus.

"The current pandemic highlights the continued need for the development of safe and effective antimicrobial agents able to address emerging threats," Amplyx said in the press release announcing the new funding. 

With the additional investment provided by Pfizer and its partners, Amplyx's Series C round now stands at $90 million. The company says it will utilize the funds to continue clinical trials of its two leading candidates.

Large pharmaceutical companies frequently invest in early-stage biotechs at various points in their development and for various reasons. Many of those promising biotechs wind up being purchased outright; in 2019, for example, pharmaceutical companies spent a whopping $195 billion on acquisitions.

Pfizer hasn't yet made any public statement about its recent involvement in Amplyx's funding. On Tuesday, Pfizer stock moved largely in sync with the equities market as a whole, dropping by slightly more than 1%.