Press Releases

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

Ligand Ranked as one of the Top Industry Innovators by Pharmaceuticals Patent Scorecard

SAN DIEGO--

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.

Caution Regarding Forward-Looking Statements

This news release contains forward-looking statements by Ligand that involve risks and uncertainties and reflect Ligand's judgment as of the date of this release. These statements also include those regarding timing and results of clinical data for LGD-4665 and other drug candidates, data analysis and evaluation of LGD-4665, utility or potential benefits to patients, the potential commercial market for LGD-4665, plans for continued development and further studies of LGD-4665 for the treatment of diseases associated with thrombocytopenia. Actual events or results may differ from our expectations. For example, there can be no assurance that other trials or evaluations of LGD-4665 or other TPO-related product candidates will be favorable or that they will confirm results of previous studies, that data evaluation will be completed or demonstrate any hypothesis or endpoint, that LGD-4665 or other TPO-related product candidates will provide utility or benefits to certain patients, that any presentations will be favorably received, that LGD-4665 or other TPO-related product candidates will be useful as a single agent or in combination with other drugs, that marketing applications will be filed or, if filed, approved, or that clinical or commercial development of these product candidates will be initiated, completed or successful or that our rights to LGD-4665 and other TPO-related product candidates will not be successfully challenged. Our stock price may suffer as a result of the failure of any trials to be completed or meet their endpoints or if any actual events differ from our expectations. Additional information concerning these and other risk factors affecting Ligand can be found in prior press releases as well as in public periodic filings with the Securities and Exchange Commission, available via www.ligand.com. Ligand disclaims any intent or obligation to update these forward-looking statements beyond the date of this press release. This caution is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

Source: Ligand Pharmaceuticals Incorporated