Joint venture partners Ligand Pharmaceuticals Inc. andAllergan Inc. announced last week that they have filed suitagainst the La Jolla Cancer Research Foundation, SRIInternational and SelectRA Pharmaceuticals for infringingpatents licensed to the Ligand-Allergan joint venture.

Those patents, both issued and pending, cover retinoids, whichare naturally occurring hormones chemically related to vitaminA. Retinoids are known to have marked biological effects on awide variety of cell types, mediated by their selective bindingto intracellular receptors.

The four patents that are the subject of the infringement suitare licensed exclusively by the Salk Institute for BiologicalStudies to Ligand and are used by the Ligand-Allergan jointventure in its drug discovery program. In particular, U.S.patent numbers 4,981,784 and 5,071773 are for the co-transfection assay used for identifying compounds. And U.S.Patent No. 5,171671, covering the RAR gene, and No. 5,091518,for the RAR beta response element, are both composition-of-matter patents for elements of the co-transfection assay.

The suite filed by Ligand (NASDAQ:LGNDA) and Allergan(NYSE:AGN) seeks to prevent the La Jolla Cancer ResearchFoundation and SRI from commercializing through the specialpurpose corporation SelectRA the technology exclusivelylicensed to Ligand of San Diego and the Ligand-Allergan jointventure.

The joint venture filed the suit in response to a publicstatement made by Erkki Ruoslahti, president and chiefexecutive officer of the La Jolla Cancer Research Foundation,that SelectRA will develop retinoid compounds that are highlyspecific for individual retinoid receptors.

"The subject of this suit is for issued patents to Ligand," saidDavid Robinson, Ligand's president and chief executive officer."We intend to vigorously enforce our patent rights in the fieldto the fullest extent possible."

As part of the suit, Ligand is also suing SRI for breach of acontract that gives Ligand the first right to evaluate forpharmaceutical application and to commercialize retinoidcompounds synthesized at SRI.

The joint venture between Ligand and Allergan of Irvine, Calif.,filed its first investigational new drug (IND) application on aretinoid compound in late November for the use of the 9-cis-retinoic acid compound LGD1057 as an oral therapy for cancer.

-- Jennifer Van Brunt Senior Editor

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