The Federal Circuit last week issued two opinions that substantially impact the tactics used in Texas-based patent litigation. In Hewlett-Packard v. Acceleron,* the court revisited declaratory judgment jurisdiction, finding that carefully crafted pre-suit correspondence from nonpracticing entity Acceleron could not prevent a declaratory judgment action in Delaware. In another case earlier in the week, the Federal Circuit issued a rare writ of mandamus, ordering transfer of a case out of the Eastern District of Texas.