Astellas will pay $1.4 billion for Ganymed and its oncology pipeline of monoclonal antibodies targeting the tight-junction protein Claudin-18.2. The Tokyo-based Astellas announced in October it will pay €422 ($461) million upfront and up to €860 ($940) million in milestones to acquire the biotech located in Mainz, Germany, and its new class of therapeutic drugs called Ideal Monoclonal Antibodies. Ganymed, founded in 2001 as a spin-off from the Universities of Mainz and Zurich, owns a portfolio focused on a unique cancer target, the tight-junction protein Claudin-18.2, which regulates cellular permeability by sealing the space between the epithelial and endothelial cellular sheet. Claudin18.2 is expressed on differentiated stomach cells only and is absent in healthy tissues. It is expressed, however, in up to 80% of gastrointestinal adenocarcinomas, 60% of pancreatic tumors and in other solid tumors. Some 24 Claudins have been described in humans. Ganymed's IMAB362 is a first-in-class anti-Claudin-18.2 mAb currently in phase 2 trials for gastroesophageal cancer. The IMAB027, in phase 1 trials, targets Claudin-6, an embryonic antigen present in a wide range of cancers but absent from healthy adult tissue.