Ligand Receives Equity Milestone Payment from Retrophin

  Ligand Receives Equity Milestone Payment from Retrophin

         Retrophin Advancing Clinical Program for Rare Kidney Disease

Business Wire

SAN DIEGO -- January 9, 2013

Ligand Pharmaceuticals Incorporated (NASDAQ: LGND) announced today that it has
received a milestone payment of 620,000 shares of common stock in newly public
partner Retrophin, Inc. (OTCQB: RTRX). The milestone arose under the
previously executed license agreement for the development and
commercialization of Retrophin’s lead clinical candidate RE-021, formerly
known as DARA (a Dual Acting Receptor Antagonist of Angiotensin and Endothelin
receptors) and was triggered by the completion of Retrophin’s merger with
Desert Gateway, Inc. and its transition to a publicly traded company. Ligand
will record milestone revenue equal to the estimated fair value of the shares
received, which will be determined by an independent valuation firm. The
shares issued to Ligand represent approximately 7% of Retrophin’s outstanding
capital stock and may be subject to certain trading restrictions.

RE-021 is in development for the treatment of focal segmental
glomerulosclerosis (FSGS), a rare disease that attacks the kidney’s filtering
system (glomeruli), causing serious scarring, progressive kidney function
degeneration and rapid loss of the kidneys. FSGS is one cause of a serious
condition known as Nephrotic Syndrome. An estimated 50,000 patients in the
United States suffer from FSGS, with most patients diagnosed as children or
young adults. Ligand believes that Retrophin expects to begin enrollment in a
Phase 2 clinical trial known as “FONT-3” during the first half of 2013.

“We are pleased to see our partner Retrophin meet this corporate milestone,”
commented John Higgins, President and Chief Executive Officer of Ligand
Pharmaceuticals. “The leadership at Retrophin has shown tremendous passion and
commitment to advance this important program, working with the FDA and raising
additional capital. RE-021 has the potential to be a very significant therapy
for serious diseases, and we are encouraged to see Retrophin position itself
to advance this potential medicine to patients in need.”

About RE-021 (DARA)

Ligand acquired DARA (currently known as RE-021) in its acquisition of
Pharmacopeia in December 2008. The compound possesses two clinically validated
mechanisms of action that selectively block two potent vasoconstrictor and
mitogenic agents, angiotensin II and endothelin 1, at their respective
receptors. In Phase 2b studies for hypertension completed in 2009, DARA was
found to be safe and well tolerated, and demonstrated statistically
significant greater reduction in blood pressure compared with placebo and with
irbesartan.

The 261-patient, randomized, double-blind, placebo- and active-controlled
study evaluated safety and efficacy at three different doses in subjects with
Stage 1 and Stage 2 hypertension over 12 weeks of treatment. The high dose of
DARA produced a statistically significantly greater reduction in blood
pressure than the active comparator, irbesartan, which was tested at its
highest approved dose.

About Retrophin

Retrophin is a biotechnology company focused on discovering and developing
treatments for rare and life-threatening diseases. Retrophin is currently
developing treatments for FSGS, Pantothenate Kinase-Associated
Neurodegeneration (PKAN), Duchenne Muscular Dystrophy and other catastrophic
diseases. The company’s lead compound, RE-021, formerly known as DARA, is
scheduled to begin enrollment in a potentially pivotal Phase 2 clinical trial
for FSGS in the first half of 2013.

About Ligand Pharmaceuticals

Ligand is a biopharmaceutical company that develops and acquires assets it
believes will generate royalty revenues and, under its lean corporate cost
structure, produce sustainable profitability. Ligand has a diverse asset
portfolio addressing the unmet medical needs of patients for a broad spectrum
of diseases including thrombocytopenia, multiple myeloma, diabetes, hepatitis,
muscle wasting, dyslipidemia, anemia and osteoporosis. Ligand’s Captisol
platform technology is a patent-protected, chemically modified cyclodextrin
with a structure designed to optimize the solubility and stability of drugs.
Ligand has established multiple alliances with the world's leading
pharmaceutical companies including GlaxoSmithKline, Merck, Pfizer, Eli Lilly &
Company, Baxter International, Bristol-Myers Squibb, Celgene, Onyx
Pharmaceuticals, Lundbeck Inc. and The Medicines Company, among others. Please
visit www.captisol.com for more information on Captisol or www.ligand.com for
more information on Ligand.

Follow Ligand on Twitter @Ligand_LGND.

Forward-Looking Statements

This news release contains certain forward-looking statements by Ligand that
involve risks and uncertainties and reflect Ligand's judgment as of the date
of this release. These statements include those related to continued
development of RE-021. Actual events or results may differ from our
expectations. There can be no assurance Retrophin will continue clinical
development of RE-021; that future clinical trial data will be favorable or
that such trials will confirm any improvements over other products or lack of
negative impacts; that RE-021 will receive required regulatory approvals or
that it will be a commercially successful therapy or be successfully marketed;
or that any future milestone or royalty payments will be received. The failure
to meet expectations with respect to any of the foregoing matters may have a
negative effect on Ligand's stock price. Additional information concerning
these and other risk factors affecting Ligand's business can be found in prior
press releases available via www.ligand.com as well as in Ligand's public
periodic filings with the Securities and Exchange Commission at www.sec.gov.
Ligand disclaims any intent or obligation to update these forward-looking
statements beyond the date of this release. This caution is made under the
safe harbor provisions of the Private Securities Litigation Reform Act of
1995.

Contact:

Ligand Pharmaceuticals Incorporated
John L. Higgins, President and CEO
Jennifer Capuzelo, Investor Relations
858-550-7584
jcapuzelo@ligand.com
or
LHA
Don Markley
310-691-7100
dmarkley@lhai.com
 
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