GSK to acquire clinical-stage biopharmaceutical company Affinivax


GSK plc is set to acquire Affinivax, Inc., a clinical-stage biopharmaceutical company based in Cambridge, Boston, Massachusetts, for a $2.1B upfront payment and up to $1.2B in potential development milestones. 

Affinivax is developing a novel class of vaccines, the most advanced of which are next-generation pneumococcal vaccines.

Pneumococcal disease includes pneumonia, meningitis, bloodstream infections, and milder diseases such as sinusitis and otitis media (middle ear infection). 

Pneumococcal pneumonia alone causes an estimated 150,000 hospitalizations each year in the U.S.

Affinivax has developed the multiple antigen presenting system (MAPS), which enables broader coverage against prevalent pneumococcal variants and potentially creates higher immune responses than current vaccines

Affinivax’s most advanced vaccine candidate (AFX3772) includes 24 pneumococcal polysaccharides plus two conserved pneumococcal proteins (compared to up to 20 serotypes in currently approved vaccines). A 30-plus valent pneumococcal candidate vaccine is also in preclinical development.

Dr Hal Barron, chief scientific officer and president R&D, GSK, said: “The proposed acquisition further strengthens our vaccines R&D pipeline, provides access to a new, potentially disruptive technology, and broadens GSK’s existing scientific footprint in the Boston area. We look forward to working with the many talented people at Affinivax to combine our industry-leading development, manufacturing, and commercialization capabilities to make this exciting new technology available to those in need.”

Affinivax vaccine trials

In the adult Phase I/II clinical trials, Affinivax said the AFX3772 was well tolerated in participants and demonstrated good immune responses compared to the current standard of care. In July 2021, the US Food and Drug Administration granted Breakthrough Therapy designation for AFX3772 to prevent Streptococcus pneumoniae invasive disease and pneumonia in adults 50 years and above. Phase III is expected to start soon. 

Phase I/II clinical trials to assess the use of the vaccine in pediatrics are planned to begin later this year.

Steven Brugger, CEO of Affinivax, Inc., said over the past eight years the company has gone from developing the MAPS vaccine platform at Boston Children’s Hospital to a pipeline of novel vaccines with its lead vaccine candidate in late-stage clinical studies. 

“We are proud that GSK has recognized our team’s accomplishments and are confident that GSK is an ideal new home for our MAPS platform and the team behind its success,” Brugger said. “GSK’s significant capabilities will enable continued advances with MAPS to improve existing vaccines – as is the case with our lead Streptococcus pneumoniae MAPS vaccine program – and develop vaccines that combat novel and resistant infectious diseases for which there are no effective immunization strategies available today.”

Deal details

Under the terms of the agreement, GSK will acquire 100% of the outstanding shares of Affinivax. This entails an upfront payment of $2.1B to be paid upon closing and two potential milestone payments of $600M to be paid upon the achievement of certain pediatric clinical development milestones. 

The transaction, subject to customary closing conditions, is expected to be completed in the third quarter of 2022.

MAPS technology platform

The MAPS vaccine technology platform enables the precise, high-affinity binding of disease-relevant polysaccharides to disease-relevant protein antigens in a single vaccine. Immunization with the resulting polysaccharide-protein complexes induces a broad and potentially protective B-cell (antibody) response to the polysaccharides and a separate B-cell and T-cell immune response to the proteins. 

The initial use of the technology has been directed primarily toward preventing pneumococcal disease. Applicability of the technology has also been demonstrated for additional infectious disease pathogens, including those that cause hospital-acquired infections.

Cover image: GSK

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