Shares of Principia Biopharma were up more than 9% in premarket trading after Sanofi announced it was acquiring the company and its BTK inhibitors in a deal valued at about $3.68 billion as the French company continues to transform its R&D division to more heavily emphasize oncology and other lucrative programs. Principia Biopharma's medical technology is based on UCSF researcher Jack Taunton's work in protein kinase inhibitors.