GSK plc entered into a definitive agreement to acquire Affinivax, Inc., a clinical-stage biopharmaceutical company based in Cambridge, MA, for $2.1 billion upfront and as much as $1.2 billion in potential development milestones. Affinivax is pioneering the development of 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 m...