When he first stepped into the field of glycoproteomics, particularly the potential of truncated O-glycans as cancer targets, Constantine Theodoropulos, CEO of Go Therapeutics Inc., said the reaction from peers was less than encouraging. “They said, ‘You’re nuts, it’s too complicated.’” Now, however, the company he co-founded has landed a deal with Astellas Pharma Inc.’s immuno-oncology-focused subsidiary, Xyphos Biosciences Inc., that brings $20.5 million up front, with the potential for up to $763 million in milestone and contingency payments down the road.