Chimeric ErbB ligand binding molecules having detectable binding activity for more ErbB ligands than any one of native ErbB 1, ErbB3 or ErbB4 are disclosed. Preferably, the binding molecules bind a broad spectrum and, more preferably, the full spectrum of ErbB ligands. The chimeric ErbB ligand binding molecules generally have a subunit LI derived from one of ErbB1, 3, or 4 and a subunit LII derived from another distinct ErbB receptor type. The sub-domain, SI, which joins LI and LII can be from either one of the receptor types or can have portions from both. Pharmaceutical compositions that contain the molecules and methods for the treatment of ErbB sensitive diseases are also disclosed.
