Affinivax has a lead program with early clinical data showing the potential to best a pharmaceutical giant’s blockbuster vaccine. The startup now has $120 million in financing to see just how much further its technology can go.
The Series B round of funding announced Thursday was led by Viking Global Investors.
Cambridge, MA-based Affinivax develops bacterial vaccines. But to understand how the company’s technology works, it’s best to start with the vaccine technology it’s trying to beat. Vaccines typically use an antigen, a substance that the body sees as foreign, to prompt an immune response. In a conjugate vaccine, the antigen is a polysaccharide, a chain of sugar molecules from the outer coat of bacteria. The polysaccharide is bonded to a “carrier” protein to help it along.
Affinivax aims to improve upon bacterial vaccines with technology that offers a new way to bind polysaccharides and proteins together. The result, says CEO Steven Brugger, is a vaccine that offers up both the polysaccharide and the protein to elicit an immune response. Affinivax calls its technology “MAPS,” which is short for Multiple Antigen Presenting System.
“It’s a one-two punch: a polysaccharide and a protein,” Brugger says. “It just depends on what you want to present—both, one, or the other.”
Pneumococcal bacteria are the targets for Affinivax’s lead program. These bacteria can cause a wide range of infections, including pneumonia and meningitis. Prevnar 13, a conjugate vaccine from Pfizer (NYSE: PFE), protects against 13 common strains of pneumococcus. The pharmaceutical giant recently reported Phase 3 data for an experimental pneumococcal conjugate vaccine that addresses 20 strains. There are more than 90.
Affinivax hasn’t gotten to all 90 yet, but it’s already topped Pfizer’s research efforts. Brugger says early clinical data for his company’s pneumococcal vaccine show it produces a strong immune response and addresses four more strains than the Pfizer candidate currently in late-stage testing. The startup can do so because its vaccines can carry more polysaccharides, Brugger says. In its ongoing research, the startup is vying to go beyond 24 strains.
Other companies have tried to beat Pfizer’s pneumococcal vaccine. A candidate from Cambridge-based Genocea Biosciences (NASDAQ: GNCA) failed a Phase 2 test in 2015. South San Francisco-based SutroVax, spinout of Sutro Biopharma, is developing conjugate vaccines that it says can address more strains. Last month, SutroVax closed a $110 million Series D round of financing to advance its lead candidate to clinical testing.
Affinivax started in 2013 when Brugger, a veteran of infectious disease startup Visterra, Momenta Pharmaceuticals (NASDAQ: MNTA), and Millenium Pharmaceuticals, met for coffee in Cambridge with Rick Malley, an infectious disease specialist at Boston Children’s Hospital and a professor of pediatrics at Harvard Medical School. The technology underpinning Affinivax’s way of binding polysaccharides and proteins is based on the research of Malley and the company’s other scientific co-founders, Fan Zhang and Yingjie Lu—both fellow professors of pediatrics at Harvard.
Six years ago, Brugger’s attempts to raise financing produced no interest from venture capitalists. He found a more receptive ear in the Bill & Melinda Gates Foundation, which seeded the startup with $4 million.
What’s different today is Affinivax’s promising early clinical data and attention from a set of financiers with a different aim. Viking, the lead investor in the Series B round, along with the other firms that participated, Bain Capital Life Sciences and Ziff Capital Partners, aren’t early-stage investors, Brugger says. They’ve seen Prevnar—a more than $1 billion a year seller for Pfizer—and want to get a piece of the vaccines market with a long-term bet on a (potentially) disruptive technology.
The Affinivax pneumococcal vaccine candidate, ASP3772, is currently in Phase 2 testing but not a dime of the company’s new capital will fund that clinical trial. That program’s clinical development is fully financed by Astellas Pharma. Brugger describes the partnership signed in 2017 as a way for Astellas to make a splash in vaccines, a space dominated by Pfizer, Merck (NYSE: MRK), Sanofi (NYSE: SNY), and GlaxoSmithKline (NYSE: GSK). “The only way in is to do something fundamentally different,” Brugger says. “That’s where we aligned.”
With its lead program funded, Affinivax is now preparing to accelerate its research into more applications of its technology. Next up: healthcare-associated infections (HAIs), the kinds of infections that elderly and immune-compromised patients are prone to contract while being treated for other conditions in medical facilities, such as hospitals and nursing homes. Brugger says the company is developing MAPS vaccines for Clostridium difficile and Staphylococcus aureus. Under its partnership with Astellas, the startup is also researching vaccines for Klebsiella pneumoniae and Pseudomonas aeruginosa.
Affinivax also plans to take MAPS beyond bacterial vaccines. Last year, the company started a cancer vaccines program. It’s an area of growing interest for drug developers, startups, and big pharmaceutical companies alike. Affinivax has some early, encouraging data from animal tests for its cancer vaccines.
COVID-19 presents yet another opportunity. Affinivax is testing to see if MAPS can present proteins in a way that generates an immune response to the novel coronavirus. Though Brugger says it’s premature to say when this research might yield data, he adds that the work could also help the company assess the applicability of MAPS to viruses.