GSK has agreed to acquire Affinivax in a deal announced Tuesday, betting more than $3 billion that the eight-year-old startup’s technology can lead to a more effective pneumococcal vaccine than other currently available shots.
GSK will pay $2.1 billion in cash upfront and potentially as much as $1.2 billion in milestone payments for Affinivax, a privately held biotechnology company based in Cambridge, Massachusetts. The deal, which the companies expect to close in the third quarter, is only the third biotech acquisition GSK has made since 2018 but follows six weeks after the pharma’s $3 billion buyout of Sierra Oncology.
Through the deal, GSK gets rights to an experimental vaccine known as AFX3722 that’s currently in clinical testing for pneumococcal disease, a bacterial infection that’s also been targeted by rival drugmakers Pfizer and Merck & Co.
Despite the wide availability of vaccines that prevent pneumococcal infection, pneumonia caused by the bacteria still leads to roughly 150,000 hospitalizations in the U.S. each year. Pneumococcal meningitis and bacteremia related to these infections resulted in about 3,250 deaths in 2019, according to data from the Centers for Disease Control and Prevention.
Pfizer’s Prevnar 13 has long been the primary vaccine used as well as one of the industry’s most lucrative products, generating nearly $6 billion in sales in 2020 and more than $5 billion last year. But the shot only covers 13 strains of the bacteria, leaving gaps in coverage as emerging strains have created new challenges. Pfizer and Merck each recently won approvals of new vaccines — Prevnar 20 and Vaxenuvance, respectively — that are meant to cover more strains.
GSK is betting Affinivax’s technology can surpass those products. The company, formed in 2014 and seeded by the Bill & Melinda Gates Foundation, is built around an approach invented at Boston Children’s Hospital for a new way to make “conjugate” vaccines.
Conjugate vaccines typically tie a target antigen — a substance that provokes an immune response — to a protein that boosts that response. The strategy is useful when the antigen alone isn’t strong enough to spur an immune reaction against a pathogen, and has led to approved vaccines for infections like Typhoid and streptococcus.