Ligand Collaborations

At Ligand, we believe collaboration is an important part of successful drug discovery and development. We have forged several joint programs aimed at developing compounds generated by our proprietary intracellular (IR) technology for large market indications. The following outlines the royalty rates we have disclosed for our leading partnerships.

Royalty

Royalties

As of December 31, 2007, several of our collaborative product candidates were in varying stages of human development. The table below summarizes our partnered research and development programs. It is not intended to be a comprehensive summary of these programs.

Leading Partnered Development Programs

LGD-4665 (TPO Mimetic)

SARM

EPO Mimetic

AiPC

SGRM

AVINZA^®

King Pharmaceuticals

Elrombopag(PROMACTA^TM)
GlaxoSmithKline

ITP
Hep C
CIT

Bazedoxifene(VIVIANT^TM)
Bazedoxifene(APRELA^TM)
Wyeth

Lasofoxifene (FABLYN^®)
Pfizer

LGD-2941 (SARM)
TAP Pharmaceutical Products

King Pharmaceuticals Collaboration

In February 2007, we completed the sale of our AVINZA^® product line to King
Pharmaceuticals, Inc (“King”). Ligand and King Pharmaceuticals currently have a royalty agreement for AVINZA^®.

GlaxoSmithKline Collaboration

In 1995, we entered into a research and development collaboration with SmithKline Beecham (now GlaxoSmithKline) to use our proprietary expertise to discover and characterize small-molecule, orally bioavailable drugs to control hematopoiesis (the formation and development of blood cells) for the treatment of a variety of blood cell deficiencies. PROMACTA^TM (eltrombopag) and a back up compound, SB-559448, resulted from this collaboration. These compounds are orally active, non-peptide, small molecule thrombopoietin (TPO) mimetics for the treatment of thrombocytopenia (low platelet counts). GlaxoSmithKline submitted an NDA for PROMACTA^TM in 4Q07 and in March 2008 received FDA review acceptance and was granted priority review for the treatment of short-term ITP. In addition, two Phase III trials were initiated by GSK in the fourth quarter of 2007 for hepatitis C, and GSK is currently studying the drug for chemotherapy-induced thrombopcytopenia (CIT). The backup compound, SB-559448, is in Phase I clinical trials.

Wyeth Collaboration

In 1994, we entered into a research and development collaboration with Wyeth-Ayerst Laboratories (now Wyeth) to discover and develop drugs that interact with estrogen and progesterone receptors for use in hormone therapy, anti-cancer therapy, gynecological diseases and central nervous system disorders associated with menopause and fertility control. Bazedoxifene, a selective estrogen receptor modulator (SERM), is the product of this collaboration.

VIVIANT^TM (bazedoxifene) is a synthetic drug that was designed to increase bone density while protecting breast and uterine tissue. Wyeth is developing VIVIANT^TM for the treatment and prevention of post-menopausal osteoporosis. In April 2007 Wyeth received an FDA approvable letter for osteoporosis prevention. An NDA for osteoporosis treatment as well as an MAA for osteoporosis prevention & treatment was submitted in 3Q:07 for VIVIANT^TM.

Wyeth is developing APRELA^TM (bazedoxifene in combination with Premarin^®) as a progesterone-free treatment for menopausal symptoms. Wyeth plans to file an NDA for APRELA^TM in 4Q08.

Pfizer Collaboration

We collaborated with Pfizer to develop therapies for osteoporosis. The collaboration produced FABLYN^®, formerly Oporia (lasofoxifene) that Pfizer has advanced through late-stage clinical development. FABYLN^® is a SERM that is being developed for the treatment and prevention of post-menopausal osteoporosis and vaginal atrophy. Pfizer submitted an NDA for the treatment of osteoporosis in postmenopausal women in 4Q07.

FABLYN^® is an estrogen partial agonist being developed for osteoporosis prevention and other diseases. Pfizer has retained marketing rights to the drug. We have milestone and royalty rights to FABLYN^®. Portions of these royalty rights have been sold to Royalty Pharma AG. See “Royalty Pharma Agreement.”

TAP Collaboration

In June 2001, we entered into a joint research and development alliance with TAP Pharmaceutical Products discovery and develop selective androgen receptor modulators (SARMs) for the treatment of osteoporosis, frailty, wasting disorders (such as cancer cachexia), and male hypogonadism. LGD-2941 is a product of that collaboration. LGD-2941 completed Phase I clinical trials in 4Q07.

	King Pharmaceuticals Collaboration In February 2007, we completed the sale of our AVINZA^® product line to King Pharmaceuticals, Inc (“King”). Ligand and King Pharmaceuticals currently have a royalty agreement for AVINZA^®.
	GlaxoSmithKline Collaboration In 1995, we entered into a research and development collaboration with SmithKline Beecham (now GlaxoSmithKline) to use our proprietary expertise to discover and characterize small-molecule, orally bioavailable drugs to control hematopoiesis (the formation and development of blood cells) for the treatment of a variety of blood cell deficiencies. PROMACTA^TM (eltrombopag) and a back up compound, SB-559448, resulted from this collaboration. These compounds are orally active, non-peptide, small molecule thrombopoietin (TPO) mimetics for the treatment of thrombocytopenia (low platelet counts). GlaxoSmithKline submitted an NDA for PROMACTA^TM in 4Q07 and in March 2008 received FDA review acceptance and was granted priority review for the treatment of short-term ITP. In addition, two Phase III trials were initiated by GSK in the fourth quarter of 2007 for hepatitis C, and GSK is currently studying the drug for chemotherapy-induced thrombopcytopenia (CIT). The backup compound, SB-559448, is in Phase I clinical trials.
	Wyeth Collaboration In 1994, we entered into a research and development collaboration with Wyeth-Ayerst Laboratories (now Wyeth) to discover and develop drugs that interact with estrogen and progesterone receptors for use in hormone therapy, anti-cancer therapy, gynecological diseases and central nervous system disorders associated with menopause and fertility control. Bazedoxifene, a selective estrogen receptor modulator (SERM), is the product of this collaboration. VIVIANT^TM (bazedoxifene) is a synthetic drug that was designed to increase bone density while protecting breast and uterine tissue. Wyeth is developing VIVIANT^TM for the treatment and prevention of post-menopausal osteoporosis. In April 2007 Wyeth received an FDA approvable letter for osteoporosis prevention. An NDA for osteoporosis treatment as well as an MAA for osteoporosis prevention & treatment was submitted in 3Q:07 for VIVIANT^TM. Wyeth is developing APRELA^TM (bazedoxifene in combination with Premarin^®) as a progesterone-free treatment for menopausal symptoms. Wyeth plans to file an NDA for APRELA^TM in 4Q08.
	Pfizer Collaboration We collaborated with Pfizer to develop therapies for osteoporosis. The collaboration produced FABLYN^®, formerly Oporia (lasofoxifene) that Pfizer has advanced through late-stage clinical development. FABYLN^® is a SERM that is being developed for the treatment and prevention of post-menopausal osteoporosis and vaginal atrophy. Pfizer submitted an NDA for the treatment of osteoporosis in postmenopausal women in 4Q07. FABLYN^® is an estrogen partial agonist being developed for osteoporosis prevention and other diseases. Pfizer has retained marketing rights to the drug. We have milestone and royalty rights to FABLYN^®. Portions of these royalty rights have been sold to Royalty Pharma AG. See “Royalty Pharma Agreement.”
	TAP Collaboration In June 2001, we entered into a joint research and development alliance with TAP Pharmaceutical Products discovery and develop selective androgen receptor modulators (SARMs) for the treatment of osteoporosis, frailty, wasting disorders (such as cancer cachexia), and male hypogonadism. LGD-2941 is a product of that collaboration. LGD-2941 completed Phase I clinical trials in 4Q07.