EXHIBIT 21.1 SUBSIDIARIES OF NEXSTAR PHARMACEUTICALS, INC. Name of Subsidiary Country/State in Which Incorporated ------------------ ----------------------------------- NeXstar Pharmaceuticals International, Inc. United States (Delaware) NeXstar Pharmaceuticals GmbH Germany NeXstar Farmaceutica, S.A. Spain NeXstar Pharmaceuticals Italia, Srl Italy NeXstar Pharmaceuticals Limited United Kingdom NeXstar Pharmaceuticals International Limited United Kingdom NeXstar Farmaceutica Porugal, LDA Portugal NeXstar Pharmaceuticals B.V. The Netherlands NeXstar Pharmaceutique Sarl France NeXstar Pharmaceuticals PTY Limited Australia NeXstar Pharmaceuticals Limited Ireland