Vertex Pharmaceuticals Inc. has entered into a definitive agreement to acquire ViaCyte, Inc., a privately held biotechnology company focused on novel stem cell-derived cell replacement therapies as a functional cure for type 1 diabetes (T1D), for $320 million in cash.   Vertex’s VX-880, an investigational allogeneic stem cell-derived, fully differentiated, insulin-producing islet cell therapy for T1D, has achieved proof-of-concept with highly promising safety and efficacy results from an ongoi...