San Diego-based biopharmaceuticals firm Ligand Pharmaceuticals said today that it has purchased certain intellectual property and royalties from AstraZeneca's subsidiary, MedImmune. According to Ligand, it paid $2.75M for the IP and interest in future milestones and royalties for MEDI-528, an IL-9 antibody program being developed by MedImmune. The compound has possible applications in treating asthma.