Exhibit 99.1

AUXILIUM PHARMACEUTICALS, INC.

RAISES $50 MILLION IN ADDITIONAL FINANCING

CHESTERBROOK, PA (September 20, 2013) - Auxilium Pharmaceuticals, Inc. (Nasdaq: AUXL), a specialty biopharmaceutical company, today announced it entered into an Incremental Assumption Agreement (“Incremental Agreement”) with Morgan Stanley Senior Funding, Inc. (“MSSF”) under its existing Credit Agreement with MSSF.  Under the Incremental Agreement, the Company raised an additional $50,000,000 from a syndicate of lenders, and this additional amount is on terms consistent with its existing $225,000,000 senior secured credit facility.  The Company expects to use these proceeds for general corporate purposes, including potential corporate development and licensing activities.

“This Incremental Agreement allows Auxilium to access additional capital at attractive financing rates and we believe this successful financing helps demonstrate investors’ continued confidence in our Company, our strategy and our future,” said Adrian Adams, Chief Executive Officer and President of Auxilium Pharmaceuticals.  “We remain focused on maximizing our existing portfolio of products, while maintaining flexibility to bring in additional products with a preference for late stage or marketed products that leverage our anchor positions in men’s healthcare or orthopedics.”

About Auxilium

Auxilium Pharmaceuticals, Inc. is a specialty biopharmaceutical company with a focus on developing and marketing products to predominantly specialist audiences.  Auxilium markets Testim® 1% (testosterone gel) for the topical treatment of hypogonadism in the U.S. and XIAFLEX® (collagenase clostridium histolyticum (CCH)) for the treatment of adult Dupuytren’s contracture patients with a palpable cord in the U.S. Ferring International Center S.A. markets Testim in certain countries of the EU and Paladin Labs Inc. markets Testim in Canada.  Swedish Orphan Biovitrium AB has marketing rights for XIAPEX® (the EU tradename for collagenase clostridium histolyticum) in 71 Eurasian and African countries.  Asahi Kasei Pharma Corporation has development and commercial rights for XIAFLEX in Japan and Actelion Pharmaceuticals Ltd has development and commercial rights for XIAFLEX in Canada, Australia, Brazil and Mexico.  Auxilium also markets TESTOPEL®, a long-acting implantable testosterone replacement therapy, Edex®, the leading branded non-oral drug for erectile dysfunction, Striant®, a buccal system for testosterone delivery, Osbon ErecAid®, the leading device for aiding erectile dysfunction, and also has a non-promoted respiratory franchise, including Theo-24® and Semprex®-D, along with three other non-promoted products, in the U.S.  Auxilium has three projects in clinical development.  XIAFLEX is in phase III of development for the treatment of Peyronie’s disease.  CCH is in phase II of development for the treatment of Frozen Shoulder syndrome (adhesive capsulitis) and phase II of development for the treatment of cellulite (edematous fibrosclerotic panniculopathy).  Auxilium also has rights to pursue additional indications for XIAFLEX. For additional information, visit http://www.auxilium.com.

SAFE HARBOR STATEMENT UNDER THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995

This news release contains forward-looking statements as defined by the Private Securities Litigation Reform Act of 1995, which discuss matters that are not facts, and may include words to indicate their uncertain nature such as “believe,” “expect,” anticipate,” “intend,” “plan,” “could,” “estimate,” “project,” “will,” and “target.”  Our forward-looking statements convey management’s expectations, beliefs, plans and objectives regarding future performance of the Company and are based upon preliminary information

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and management assumptions.  No specific assurances can be given regarding the potential use of the proceeds from the additional financing, the Company’s ability to maximize its existing portfolio or the Company’s ability to bring in additional products. While the Company may elect to update the forward-looking statements made in this news release in the future, the Company specifically disclaims any obligation to do so.  Such forward-looking statements are subject to a wide range of risks and uncertainties that could cause results to differ in material respects, including those relating to product development, revenue, expense and earnings expectations, intellectual property rights, results and timing of clinical trials, success of marketing efforts, the need for additional research and testing, and the timing and content of decisions made by regulatory authorities, including the U.S. Food and Drug Administration, and those risks discussed in our reports on file with the Securities and Exchange Commission (the “SEC”).  Our SEC filings may be accessed electronically by means of the SEC’s home page on the Internet at http://www.sec.gov or by means of the Company’s home page on the Internet at http://www.auxilium.com under the heading “For Investors - SEC Filings.”  There may be additional risks that the Company does not presently know or that the Company currently believes are immaterial which could also cause actual results to differ from those contained in the forward-looking statements.

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