Affinivax, a clinical stage biotechnology company with its novel MAPS technology platform for vaccines and immunotherapies, today announced the completion of a $120 million Series B financing round, led by Viking Global Investors with participation from Bain Capital Life Sciences and Ziff Capital Partners. This represents the first financing round to be completed since the company's founding in June 2014, when Affinivax received an initial seed and Series A equity investment from the Bill & Melinda Gates Foundation. The company has leveraged the initial investment, non-dilutive grant funding, and a partnership with Astellas Pharma to advance its novel Multiple Antigen Presentation System ("MAPS") vaccine technology into clinical trials. Proceeds from the Series B financing will be used to continue advancing the company's MAPS pneumococcal vaccine program and to advance several additional vaccine candidates targeting hospital-associated infections (HAIs) into clinical studies.

"We are very pleased to welcome such a strong syndicate of new investors to Affinivax and look forward to benefiting from their deep experience," said Steven B. Brugger, CEO of Affinivax. "Having built the company to over 70 employees and advanced MAPS into clinical testing in less than 5 years, we are very excited to look ahead to our next phase of growth, taking our lead pneumococcal vaccine through Phase 3 testing and bringing several additional novel MAPS vaccines and immunotherapies into clinical trials."

Concurrent with the Series B financing, Andrew Hack, MD, PhD, and Steven Altschuler, MD, have joined Affinivax's Board of Directors. Prior to joining Bain Capital, Dr. Hack was the Chief Financial Officer of Editas Medicine, and a portfolio manager at Millennium Management. Prior to joining Ziff Capital, Dr. Altschuler was the founder and chairman of Spark Therapeutics, and the CEO of Children's Hospital of Philadelphia.

"The Affinivax team is addressing a critical public health need with a novel and creative approach," said Dr. Hack, a Managing Director of Bain Capital Life Sciences. "As our team seeks to invest in breakthrough technologies with the potential to improve patient health around the world, we were impressed by the approach and progress made by the Affinivax team and look forward to helping advance its pipeline of innovative vaccines into clinical trials."

"With the ongoing increase in the global health threat posed by a broad range of infectious diseases, new prevention strategies to combat disease are more important than ever," said Dr. Altschuler, Managing Director of Ziff Capital Partners. "We believe Affinivax's novel MAPS vaccine technology with its promise for broad protection can play a key role in the prevention of serious infectious diseases."

Affinivax's lead vaccine targeting Streptococcus pneumoniae (ASP3772, partnered with Astellas Pharma) includes 24 pneumococcal serotypes, more than any other vaccine on the market or in clinical testing today. ASP3772 is currently being studied in pneumococcal infection in elderly adults, its initial indication, in an ongoing Phase 2 study that is nearing completion. In a previously completed Phase 1 study, ASP3772 was demonstrated to be safe and highly immunogenic in healthy adults. These studies are listed on Clinicaltrials.gov. The clinical program for ASP3772 is expected to expand to include an infant indication. Affinivax recognizes the ongoing need to increase protection against new, emerging pneumococcal serotypes and will continue to focus on developing additional pneumococcal MAPS vaccines designed to prevent against an even greater number of serotypes.

With the significant increase in antimicrobial resistance now creating a global health challenge in medical care facilities today, Affinivax's pipeline includes MAPS vaccine candidates targeting the most prevalent HAIs. The effectiveness and availability of antibiotics against these serious bacterial infections remains very limited, and while prevention strategies would have the greatest impact, there are no effective vaccines against HAIs available today. Addressing antimicrobial resistance head-on, Affinivax is advancing several first-in-class MAPS vaccines targeting Klebsiella pneumoniae and Pseudomonas aeruginosa (through a research partnership with Astellas Pharma), Clostridium difficile, and Staphylococcus aureus.

About the Global Impact of Pneumococcal Disease

Streptococcus pneumoniae (pneumococcus) is a bacterium frequently found in the upper respiratory tract of healthy children and adults, and can cause serious infections ranging from pneumonia, meningitis, and sepsis, representing a major global health problem. The World Health Organization estimates that half a million deaths in children under 5 years old occur each year worldwide due to infection by this bacterium. In the United States, there are over 900,000 cases of pneumococcal pneumonia each year, leading to 400,000 hospitalizations with an associated 5-7% mortality rate in hospitalized patients. Streptococcus pneumoniae is the leading cause of lower respiratory infection morbidity and mortality globally, contributing to more deaths than all other etiologies combined in 2016.1 Prevnar 13® is currently the top selling vaccine worldwide and the top selling product in Pfizer's entire product portfolio, generating 2019 sales of $5.8 billion and more than $30 billion since 2015.

About the Global Impact of HAIs (Healthcare-Associated Infections)

HAIs have now emerged as a major global health concern today due to the significant increase in antimicrobial resistance. The Centers for Disease Control and Prevention estimates that 4% of patients in the U.S. alone will contract a HAI each year in medical facilities including ambulatory surgical centers, hospice centers, nursing homes and rehabilitation centers. HAIs can significantly delay patient recovery and increase healthcare costs, with the direct costs to medical facilities estimated at between $28 billion and $45 billion2. Of the approximately two million patients who acquire a HAI annually in the U.S. alone, an estimated 90,000 will die2. The most common bacterial pathogens causing HAIs in U.S. medical facilities include Clostridium difficile, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli3 many of which are highly resistant to available antibiotic therapies. In addition to the significant limitations of current therapeutic treatments against HAIs, there are no vaccines available today to address this expanding global health crisis.

About Multiple Antigen Presenting System (MAPS)

The MAPS technology platform uses proprietary chemistry that capitalizes on the highly specific and durable non-covalent, affinity binding between biotin and rhizavidin, a biotin-binding protein. The highly stable MAPS complex created by this affinity binding contributes to a simple, modular, and efficient approach to the development of novel vaccines and immunotherapies. Conventional vaccine conjugation technology seeks to optimize the generation of protective antibody responses mainly to polysaccharide antigens, using the protein antigen as a carrier. In stark contrast, a MAPS vaccine can present both the polysaccharide and the protein antigens to the host immune system to induce both a B- and T-cell immune response. This unique capability of the MAPS technology allows for the tailored development of each MAPS vaccine or immunotherapy based on the specific type of immune response that is most desired for each pathogen and disease.

About Affinivax, Inc.

Affinivax is advancing a next generation technology platform to enable the development of vaccines and immunotherapies. Backed by investments from Viking Global Investors, Bain Capital Life Sciences, Ziff Capital Partners, and the Bill & Melinda Gates Foundation, Affinivax is focused on the most challenging bacterial infections, both improving upon existing vaccines and providing vaccines for which there are no prevention strategies available today. The company's proprietary technology platform, called MAPS, enables the high affinity binding of protective polysaccharides and proteins in a single vaccine or immunotherapy to uniquely induce a broad and protective B and T cell immune response. The company's lead pneumococcal vaccine, in a partnership with Astellas Pharma, includes 24 pneumococcal serotypes, more than any other vaccine on the market or in clinical testing today. This vaccine has been demonstrated to be safe and highly immunogenic in healthy adults and is currently in Phase 2 clinical trials. In addition to targeting Streptococcus pneumoniae, the company is advancing a pipeline of MAPS vaccines targeting the most common hospital-associated infections (HAIs), and is also extending the utility of MAPS to a range of other potential applications, including vaccines and immunotherapies targeting viral diseases and cancer. For more information, visit www.affinivax.com.

1 GBD 2016 Lower Respiratory Infections Collaborators. Estimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries, 1990-2016: A systematic analysis for the Global Burden of Disease Study 2016. Lancet Infect Dis. 2018 Sep 19. pii: S1473-3099(18)30310-4. doi: 10.1016/S1473-3099(18)30310-4.

2 Patricia W Stone (2014) "Economic burden of healthcare-associated infections: an American perspective," Expert Review of Pharmacoeconomics & Outcomes Research, 9:5, 417-422, DOI: 10.1586/erp.09.53. https://www.ncbi.nlm.nih.gov/pmc/articles/ PMC2827870/.

3 Multistate Point-Prevalence Survey of Health Care-Associated Infections. Shelley S. Magill, M.D., Ph.D., Jonathan R. Edwards, M.Stat., Wendy Bamberg, M.D., Zintars G. Beldavs, M.S., Ghinwa Dumyati, M.D., Marion A. Kainer, M.B., B.S., M.P.H., Ruth Lynfield, M.D., Meghan Maloney, M.P.H., Laura McAllister-Hollod, M.P.H., Joelle Nadle, M.P.H., Susan M. Ray, M.D., Deborah L. Thompson, M.D., M.S.P.H., Lucy E. Wilson, M.D., and Scott K. Fridkin, M.D. for the Emerging Infections Program Healthcare-Associated Infections and Antimicrobial Use Prevalence Survey Team. N Engl J Med 2014; 370:1198-1208, March 27, 2014.