Ligand Pharmaceuticals Awarded U.S. Patent for LGD-4665

Ligand Pharmaceuticals Incorporated (NASDAQ:LGND) (the Company or Ligand) today announced that the United States Patent and Trademark Office issued U.S. Patent No. 7,314,887, titled “Thrombopoietin Activity Modulating Compounds and Methods,” to Ligand for LGD-4665, the Company’s lead thrombopoietin (TPO) receptor agonist and a family of related compounds. The patent describes LGD-4665 and other small-molecule TPO mimetic compounds discovered at Ligand, formulations involving these compounds, as well as methods of making and using the compounds and formulations.

The Patent Scorecard—Quarterly Leader Board report, issued on 11/30/2007, listed Ligand Pharmaceuticals Incorporated as one of the top innovators in the industry with the highest score for the Industry Impact metric (www.patentboard.com/scorecard). The quarterly leader board data is calculated on 13 week rolling averages and reflects standard blended quality and quantity patent metrics.

“Receipt of this patent reflects our continued focus on innovation while strengthening our intellectual property portfolio, and covers a platform molecule that we believe has significant market potential,” said John L. Higgins, President and Chief Executive Officer of Ligand Pharmaceuticals. “Our commitment to creating high-quality drug compounds and shareholder value is further validated by Ligand’s recent rating as one of the industry’s top innovators in the Patent Board’s Pharmaceuticals Patent Scorecard.”

About LGD-4665

LGD-4665 was selected from a group of novel oral TPO mimetics synthesized at Ligand, for which Ligand has retained exclusive worldwide rights. LGD-4665 has shown a promising profile of thrombopoietin receptor agonist activity in Phase I studies, and in terms of efficacy, potency and selectivity has the potential to become a competitive molecule for the treatment of different forms of thrombocytopenia. Thrombocytopenia or low platelet count is a common clinical finding associated with a diverse group of clinical disorders or conditions affecting platelet production and/or survival. Prevalent clinical disorders where platelet loss or dysfunction leads to significant morbidity include hepatitis C, chemotherapy-induced thrombocytopenia (CIT), myelodysplastic syndromes (MDS), idiopathic thrombocytopenic purpura (ITP) and several other cancers and liver diseases.

About Ligand Pharmaceuticals

Ligand discovers and develops new drugs that address critical unmet medical needs of patients in the areas of thrombocytopenia, hepatitis C, cancer, hormone-related diseases, osteoporosis and inflammatory diseases. Ligand's proprietary drug discovery and development programs are based on its leadership position in gene transcription technology, primarily related to intracellular receptors.