Affinivax, Inc. announces initiation of Phase 1/2 clinical study of ASP3772, its novel pneumococcal MAPS vaccine, in collaboration with Astellas

Clinical study will evaluate safety, tolerability, and immunogenicity in adults

Initiation of clinical study triggers milestone payment to Affinivax

CAMBRIDGE, Mass., February 13, 2019Affinivax, Inc. (“Affinivax”) today announced that the first subject has been dosed with ASP3772, its novel MAPS vaccine targeting Streptococcus pneumoniae (pneumococcus).  The clinical study protocol – “A Phase 1/2, Randomized, Single Ascending Dose Study in Adults (Stage 1) and Randomized, Single Ascending Dose-Finding Study in Elderly Subjects (Stage 2) with ASP3772, a Pneumococcal Vaccine” – was initiated by Affinivax’s development partner, Astellas Pharma, Inc. (“Astellas”) following the successful submission of an Investigational New Drug (IND) application to the U.S. Food and Drug Administration in December 2018.   The study is posted on

Affinivax and Astellas entered into an exclusive worldwide license agreement in February 2017.  The strategic partnership leverages Affinivax’s proprietary MAPS vaccine technology platform utilizing Affinivax’s process development and analytical expertise to advance a novel pneumococcal MAPS vaccine, with Astellas playing a leadership role in development and commercialization.  This has resulted in the development of ASP3772, a novel vaccine which offers the potential to provide broader protection against pneumococcal disease.  The initiation of clinical testing for ASP3772 triggered a milestone payment of $10 million to Affinivax from Astellas.

“Advancing this program from the labs at Boston Children’s Hospital to clinical testing in less than 5 years realizes our vision to utilize the MAPS technology platform to offer a range of safe and effective  vaccines targeting multiple bacterial pathogens,“ said Richard Malley, MD, Affinivax’s Scientific Founder, Professor of Pediatrics at Harvard Medical School, and the Kenneth McIntosh Chair in Pediatric Infectious Diseases at Boston Children’s Hospital.  “We believe that MAPS, in contrast to traditional vaccines, offers a unique way to present the key epitopes of the desired antigens (polysaccharides and/or proteins) to induce a robust and broad immune response.  We now look forward to confirming this in clinical trials.”

“The initiation of clinical testing of ASP3772 is a major milestone for the development of our MAPS technology platform and for our company” said Steven B. Brugger, CEO of Affinivax, Inc.  “I want to recognize the tremendous effort on the part of the entire Affinivax team, in collaboration with our Astellas colleagues, to achieve this important milestone.  We now look forward to advancing this important vaccine towards clinical proof of concept and continuing to work to bring an improved pneumococcal vaccine to patients.”

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 (WHO) 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, generating more than $5.6 billion in sales in 2017.2

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 complex created by this affinity binding contributes to a simple, modular, and efficient approach to the development of MAPS vaccines.  In stark contrast to the highly complex chemistry of conventional vaccine conjugation (which is optimized to induce protective antibody responses to only the polysaccharide antigen with the protein antigen serving primarily as a carrier), a MAPS vaccine can present both the polysaccharide antigen and the protein antigen to induce a broad and potent immune response.  

About Affinivax, Inc.
Affinivax is advancing a next generation vaccine technology platform to enable the development of vaccines that provide the highest level of protection against challenging infectious diseases.  Backed by an initial investment from the Bill & Melinda Gates Foundation, and working with world experts in vaccine discovery and development, Affinivax is focused on creating a pipeline of vaccines for children and adults in both the developed and developing worlds. The company’s proprietary vaccine platform, called Multiple Antigen Presentation System (MAPS), enables the high affinity binding of protective polysaccharides and proteins in a single vaccine and uniquely induces a broad and protective immune response.  The MAPS technology provides a highly stable, modular, and efficient approach to develop vaccines against a wide range of diseases. The company has achieved preliminary preclinical proof-of-concept for several MAPS vaccines and is currently advancing its lead vaccine candidate against Streptococcus pneumoniae in clinical trials.  For more information, visit

About Affinivax – Astellas Strategic Partnership
Affinivax and Astellas entered into an exclusive worldwide license agreement in February 2017 to develop and commercialize a vaccine targeting Streptococcus pneumoniae (pneumococcus).  The partnership will utilize Affinivax’s proprietary MAPS vaccine technology platform to advance a novel MAPS vaccine targeted to prevent and reduce the spread of pneumococcal disease.  Astellas will lead and fully fund the development program and obtain worldwide rights to commercialize the MAPS vaccine for pneumococcal disease.  Affinivax is eligible to receive a range of development milestones and commercial milestones, as well as tiered royalties on any future product sales.

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   Top Vaccine Products Worldwide, Statista.

Brand names
Brand names appearing in italics throughout this document are trademarks of GSK or associated companies or used under licence by the Group.

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