TARRYTOWN, N.Y.--(BUSINESS WIRE)--Dec. 23, 2005--Progenics Pharmaceuticals, Inc. (Nasdaq: PGNX) today announced that it has acquired a substantial portion of the royalty and milestone rights for its lead investigational drug, methylnaltrexone (MNTX). In October 2001, Progenics in-licensed the MNTX patent portfolio in exchange for rights to future MNTX royalties. In the transaction announced today, the MNTX licensors received a total of 686,000 shares of Progenics’ common stock and $2.6 million in cash in exchange for a substantial portion of the MNTX royalty rights, thereby extinguishing Progenics’ obligations with respect to the rights that were acquired.