Exhibit 99.1

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Auxilium Pharmaceuticals, Inc. Announces First Patient Enrolled in XIAFLEX^® Phase

IIIb Dupuytren’s Contracture Multicord Study

MALVERN, PA, (October 3, 2011) — Auxilium Pharmaceuticals, Inc. (NASDAQ: AUXL), a specialty biopharmaceutical company, today announced that the first patients have been dosed in the Company’s phase IIIb trial of XIAFLEX^® for the treatment of adult Dupuytren’s contracture patients with multiple palpable cords. The study is expected to enroll approximately 60 patients at eight sites throughout the U.S. and Australia and patients will be monitored for 60 days following their last injection. It is estimated by SDI Health, LLC that up to 40% of annual Dupuytren’s surgeries are performed to treat two or more cords concurrently.

“We are extremely pleased to initiate this important post-approval study as we believe the results could provide those physicians that treat Dupuytren’s additional important safety information about treating multiple joints in the same hand concurrently,” said Dr. James Tursi, Chief Medical Officer of Auxilium. “We anticipate having the results of this trial in the second half of 2012.”

The phase IIIb study is an open-label study that is designed to assess the safety and efficacy of concurrent administration of two injections of XIAFLEX into the same hand of subjects with at least two Dupuytren’s contractures caused by palpable cords. Safety assessments, including immunogenicity testing, will be made during all study visits. Efficacy assessments will include measuring finger goniometry and range of motion of the treated joints on days 1, 8, 30, and 60, following the first cycle of two injections. Upon completion of the day 60 follow-up visit following the first treatment cycle, subjects who require additional treatment in the treated hand may receive XIAFLEX in other individual cords, up to a total of five total injections.

About Dupuytren’s contracture

Dupuytren’s contracture is a chronic condition that affects the connective tissue that lies beneath the skin in the palm. The disease is progressive in nature. Typically, skin pits then nodules develop in the palm as collagen deposits accumulate. As the disease progresses, the collagen deposits form a cord that stretches from the palm of the hand to the base of the finger. Once this cord develops, the patient’s fingers contract and the function of the hand is impaired. The incidence of Dupuytren’s disease, inclusive of pits, nodules and cords, is highest in Caucasians, historically those of Northern European descent, with a global prevalence of three to six percent of the Caucasian population¹. Most cases of Dupuytren’s contracture occur in patients older than 50 years².

The most frequently affected parts of the hand associated with Dupuytren’s contracture are the joints called the Metacarpal Phalangeal Joint, or MP joint, which is the joint closest to the palm of the hand and the Proximal Intra-Phalangeal Joint, or the PIP joint, which is the middle joint in the finger. The little finger and ring finger are most frequently involved. XIAFLEX is the only drug approved by the U.S. Food and Drug Administration for treatment of Dupuytren’s contracture, which has historically been treated primarily by an open surgical procedure.

About Auxilium

Auxilium Pharmaceuticals, Inc. is a specialty biopharmaceutical company with a focus on developing and marketing products to predominantly specialist audiences, such as urologists, endocrinologists, certain targeted primary care physicians, hand surgeons, subsets of orthopedic, general, and plastic surgeons who focus on the hand, and rheumatologists. Auxilium markets XIAFLEX® (collagenase clostridium histolyticum) for the treatment of adult Dupuytren’s contracture patients with a palpable cord and Testim® 1%, a testosterone gel, for the topical treatment of hypogonadism in the U.S. Pfizer Inc. has marketing rights for XIAPEX® (the EU tradename for collagenase clostridium histolyticum) in 46 countries in Eurasia and Asahi Kasei Pharma Corporation has development and commercial rights for XIAFLEX in Japan. Ferring International Center S.A. markets Testim in the EU and Paladin Labs Inc. markets Testim in Canada. Auxilium has three projects in clinical development. XIAFLEX is in phase III of development for the treatment of Peyronie’s disease, in phase IIa of development for the treatment of Frozen Shoulder syndrome (Adhesive Capsulitis) and is in phase Ib 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 release contains “forward-looking-statements” within the meaning of The Private Securities Litigation Reform Act of 1995, including statements regarding the design, methodology, safety, efficacy, enrollment and timing of the Company’s phase IIIb trial for XIAFLEX for the treatment of adult Dupuytren’s contracture patients with multiple cords; the prevalence of Dupuytren’s contracture; products in development for Peyronie’s disease, Frozen Shoulder syndrome and cellulite; and the potential for XIAFLEX to be used in multiple indications.

Forward-looking statements often address Auxilium’s expected future financial position or business strategy and plans and objectives of management for future operations. Forward-looking statements provide Auxilium’s current expectations or forecasts of future events. Auxilium’s performance and financial results could differ materially from those reflected in these forward-looking statements due to various risks and uncertainties.

A more detailed list and description of the risks and uncertainties that Auxilium faces may be found under the heading “Risk Factors” in Auxilium’s Annual Report on Form 10-K for the year ended December 31, 2010 and Form 10-Q for the quarter ended June 30, 2011, which are on file with the Securities and Exchange Commission. Given these risks and uncertainties, any or all of the forward-looking statements contained in this release may prove to be incorrect. Therefore, you should not rely on any such factors or forward-looking statements. Auxilium undertakes no obligation to update publicly any forward-looking statement.

CONTACT:

James E. Fickenscher

Chief Financial Officer, Auxilium Pharmaceuticals, Inc.

+1-484-321-5900

jfickenscher@auxilium.com

or

William Q. Sargent Jr.

Vice-President, Investor Relations and Corporate Communications

+1-484-321-5900

wsargent@auxilium.com

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