Pfizer shelled out $850 million upfront to Merck KGA for rights to an anti-PD-L1 antibody currently in phase 2 to treat skin cancer. Milestone payments to the Darmstadt, Germany–based pharma for MSB0010718C could reach $2 billion based on the drug's successful development. Merck KGA originally licensed the antibody from the 20-year old antibody pioneers Morphosys, of Martinsreid, Germany. Merck's MSB0010718C, rivals Astra Zeneca's MEDI4736, an anti-PD-L1 antibody in phase 3 for treating lung cancer. Pfizer's move is fuelling speculation that the New York-based pharma has cooled on the idea of making another bid for London-based AstraZeneca.