Presentation materials

(NASDAQ: AUXL)

May 2008

Exhibit 99.1

(NASDAQ: AUXL)

Safe Harbor Statement

will

make

various

remarks

during

this

presentation

that

constitute

“forward-looking

statements”

for

purposes

the

safe

harbor

provisions under The Private Securities Litigation Reform Act of

1995, including statements regarding the pricing, time to market, size of

market, growth potential and therapeutic benefits of the Company’s product candidates, including those for the treatment of Dupuytren’s

contracture, Peyronie’s disease, and Frozen Shoulder syndrome; interpretation of market research data; competition within certain

markets relevant to the Company’s product candidates; interpretation of clinical results, including the efficacy and tolerability of the

Company’s product candidates; the timing of the commencement and completion of clinical trials and the timing of reporting of results

therefrom; the timing of manufacturing scale up for the Company’s product candidates; the Company’s ability to manufacture XIAFLEX™

(clostridial collagenase for injection –

formerly referred to as AA4500)

at the Company’s Horsham facility; the timing of the completion of

phase

III

trials

for

XIAFLEX

for

the

treatment

Dupuytren’s

contracture

and

the

reporting

results

therefrom;

the

timing

the

filing

the Biologics License Application for approval of XIAFLEX for the treatment of Dupuytren’s contracture and the approval thereof; the

timing of the phase IIb trials for XIAFLEX for the treatment of Peyronie’s disease; competitive developments affecting the Company’s

products and product candidates, including generic competition; the success of the Company’s development activities; future Testim

market share, prescriptions and sales growth and factors that may drive such growth; size and growth potential of the testosterone

replacement therapy market and the gel segment thereof and factors that may drive such growth; the protection for Testim afforded by

U.S. Patent No. 7,320,968, and its listing in the Orange Book, the value of extending patent protection for Testim through January 2025,

the

value

and

likelihood

that

patents

will

granted

from

the

continuation

and

divisional

applications

filed

Bentley

Pharmaceuticals,

Inc.; the absence of an ANDA for the generic to Testim; the Company’s development and operational goals and strategic priorities for

fiscal 2008; the ability to fund future operations; and the Company’s expected financial performance during 2008 and financial milestones

that it may achieve for 2008, including 2008 net revenues, research and development spending, selling, general and administrative

expenses, stock-based compensation expenses, and net loss. All remarks other than statements of historical facts made during this

presentation,

including

but

not

limited

to,

statements

regarding

future

expectations,

plans

and

prospects

for

the

Company,

statements

regarding

forward-looking

financial

information

and

other

statements

containing

the

words

“believe,”

“may,”

“could,”

“will,”

“estimate,”

“continue,”

“anticipate,”

“intend,”

“should,”

“plan,”

“expect,”

and similar expressions, as they relate to the Company, constitute forward-

looking statements. Actual results may differ materially from those reflected in these forward-looking statements due to various factors,

including general financial, economic, regulatory and political conditions affecting the biotechnology and pharmaceutical industries and

those discussed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2007 under the heading “Risk Factors”,

which is on file with the Securities and Exchange Commission (the “SEC”) and may be accessed electronically by means of the SEC’s

home

page

the

Internet

http://www.sec.gov

means

the

Company’s

home

page

the

Internet

http://www.auxilium.com

under

the

heading

“Investor

Relations

SEC

Filings.”

There

may

additional

risks

that

the

Company

does

not

presently

know

that

the

Company

currently

believes

are

immaterial

which

could

also

cause

actual

results

differ

from

those

contained

the

forward-looking

statements. Given these risks and uncertainties, any or all of these forward-looking statements may prove to be incorrect. Therefore, you

should not rely on any such factors or forward-looking statements.

addition,

forward-looking

statements

provide

the

Company’s

expectations,

plans

forecasts

future

events

and

views

the

date

of this presentation. The Company anticipates that subsequent events and developments will cause the Company’s assessments to

change.

However,

while

the

Company

may

elect

update

these

forward-looking

statements

some

point

the

future,

the

Company

specifically

disclaims

any

obligation

so.

These

forward-looking

statements

should

not

relied

upon

representing

the

Company’s

assessments

any

date

subsequent

the

date

this

presentation.

Late Stage

Company

Transforming

Product

Fastest Growing

TRT product in

the U.S.

Poised for Growth

(NASDAQ: AUXL)

Auxilium Pharmaceuticals, Inc. (NASDAQ: AUXL)

•

Specialty biopharmaceutical company focused on Urologists,

Endocrinologists, Orthopedists and certain PCPs

•

Founded in 1999

•

Headquarters in Malvern, Pa.

–

Manufacturing in Horsham, Pa.

–

Approximately 320 employees (~190 commercial)

•

I.P.O in July 2004

–

Currently approximately 41.2 million shares issued & outstanding

–

Additional 6.6 million shares subject to issuance from stock

options & warrants

•

A component of the NASDAQ BIOTECH INDEX

(NASDAQ: AUXL)

Broad Maturing Pipeline

Note: Worldwide rights for all products available, except Testim where ex -U.S. rights have been licensed.

XIAFLEX™

(clostridial collagenase for injection) was formally referred to as AA4500

Product

Late Research

Testim®

gel

Approved in U.S.

Europe & Canada

XIAFLEX™

Transmucosal Film

AA4010

Transmucosal Film

Market

Phase III

Phase II

Phase I

Pre-clinical

Hypogonadism

Dupuytren’s Contracture

Peyronie’s Disease

Frozen Shoulder Syndrome

Overactive Bladder

Hormones and Urology

Pain

Late Research

(NASDAQ: AUXL)

Anticipated News Flow Events

Q208:

•

XIAFLEX-

Top-line

Phase

III

(Double

Blind)

Data in June

•

XIAFLEX-

Initiate

Peyronie's

Phase

IIb

Study

•

Testim-

First

patient

enrolled

TRiUS

registry

H109:

•

XIAFLEX-

Open

Label

Safety

Data

Early 2009:

•

XIAFLEX-

File

BLA

for

Dupuytren's

Contracture

Q409

Q309

Q209

Q109

Q408

Q308

Q208

Early 2010

•

XIAFLEX –

FDA Approval In

Dupuytren’s Contracture

2010

XIAFLEX™

(clostridial collagenase for injection)

Unique, Late-Stage Opportunity with Blockbuster

Potential

(NASDAQ: AUXL)

XIAFLEX-

Unique, Late-Stage, Blockbuster

Opportunity

•

Potential to be first effective non-surgical treatment for two

high unmet needs

–

Late-Stage Phase III data for the treatment of Dupuytren’s

contracture -expect to file U.S. BLA in early 2009

–

We believe promising Phase II data in Peyronie’s disease

•

Well-characterized mode of action

•

Great fit for Specialty Biopharmaceutical Company

•

Worldwide rights offer options to build company or

generate cash –

exploring partnering opportunities now

•

We believe there are approximately 450,000 potential

patients annually in U.S. and EU for Dupuytren’s &

Peyronie’s indications -

> $1 Billion opportunity, based on

market research and analysis

(NASDAQ: AUXL)

Dupuytren’s Contracture—a Debilitating Condition

•

Excessive collagen deposition

•

Nodules represent early, active

form

•

Cords develop over time, are

palpable, and result in

contractures

•

Debilitating effect on quality of life

•

Surgery is reserved for advanced

disease due to unpredictable

results, complications, long

recovery and

recurrence/additional surgeries

(NASDAQ: AUXL)

Dupuytren’s Contracture—Unmet Medical Need

•

Disease prevalence is estimated at 3%-6% among

Caucasians,¹

but occurs in all populations

•

Higher prevalence in patients of northern-European descent

•

Hereditary component in approximately 40% of patients

•

On average, patients have 2.2 affected joints at the time of

diagnosis, and about half of patients have bilateral disease³

•

Recurrence rate in surgical patients

–

30% in 2 years

–

55% in 10 years

•

We believe Dupuytren’s contracture is under-diagnosed and

under-treated

Early, 1962; Murrell and Hueston, 1990; Yost et al, 1955.

Hueston 1963

Skoog 1948

Mikkelsen 1976

(NASDAQ: AUXL)

XIAFLEX I.P. position

for Dupuytren’s

Contracture

•Method of Use Patent in U.S. through 2014

•Use Patent in France, UK, Sweden through 2018

–Pending in Germany and Denmark

•10 years of market exclusivity in EU

–Can be extended to 11 years on approval of additional indication

–Data protection granted for 8 years

–Biosimilars

would need to generate extensive regulatory, safety, and efficacy

data

•U.S. Orphan Drug Exclusivity granted on May 23, 1996 for 7

years post approval

•Highly Purified Collagenase API and manufacturing patent

filed (expected expiry 2027)

(NASDAQ: AUXL)

Current Treatment Options Are Invasive or

Ineffective

•

Surgery

•

Non-surgical options

–

Splinting

–

Physical therapy

–

Corticosteroids

•

Needle

fasciotomy/

aponeurotomy

•

Amputation

(NASDAQ: AUXL)

XIAFLEX—Potential to Revolutionize Treatment

for Dupuytren’s Contracture

(NASDAQ: AUXL)

91%

86%

100%

85%

20%

40%

60%

80%

100%

Pivotal Phase III Study (DUPY-303): Results*

•

54/62 (87%) joints achieved 0°-5°

contracture in the study

and its open-label extension

•

Recurrence rates

–

3 of 54 joints followed for 12 months

–

5 of 27 joints followed for 24 months

•

Mean number of injections for success was 1.4

•

Injections well tolerated with only local AEs

*The Journal of Hand Surgery.

2007;32(6).

* After up to three injections. Success rate was 70% after a single injection.

21/23

12/14

9/9

33/39

Primary joint

P<.001

MP joint

P<.001

PIP joint

P<.001

Non-Primary joints

0/12

0/7

0/5

XIAFLEX

Placebo

(NASDAQ: AUXL)

Most Patients Achieved Full Extension,

Regardless of Joint Affected or Severity

92%

78%

86%

61%

47%

53%

79%

60%

70%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

PIP

Combined

10,000 units, approximately 0.58 mg.

Joint Type

Response rate by joint type and baseline joint severity

Studies 202-303-404 combined

Low severity

High severity

Total

(NASDAQ: AUXL)

Dupuytren’s Clinical Plan

•

CORD I Study:

–

216 patients in at least 15 sites in the U.S.

–

Double blind placebo controlled, randomized in 2:1 ratio of active to placebo

–

Primary endpoint is reduction in contracture to within 0 -

5º

of normal

–

Secondary endpoints to measure clinical improvement and time to success

–

Top-line data expected to be

made available publicly in June 2008

•

CORD II Study:

–

60 patients, following protocol similar to U.S. trial

–

Top-line data expected to be

made available publicly in June 2008

–

Five Australian sites

•

JOINT I (open label in U.S.) completed enrollment

•

JOINT II (open label ex-U.S.) completed enrollment

•

As of Apr. 30, 2008, over approx. 1,000 patients have received XIAFLEX

and over 2,000 injections have been administered

(NASDAQ: AUXL)

We believe:

•

There is a pent-up demand for non-surgical therapy

•

Surgeons and patients prefer non-invasive treatment

•

Each patient on average has 2.2 joints which will require

treatment; about half have contractures in both hands

•

Early data indicates on average 1.4 vials of XIAFLEX required

per joint

2.2 joints per patient x 1.4 vials per joint = 3.1 vials per patient on

average

•

We believe XIAFLEX treatment can be priced competitively to

cost of surgery (~$5,000 in the U.S.)

Dupuytren’s Commercial Opportunity

(NASDAQ: AUXL)

Market Research Performed –

Dupuytren’s

•

Multiple prevalence data sets proved to be highly variable in

numbers of patients

•

Two rounds of quantitative primary research have been

commissioned by Auxilium on XIAFLEX for Dupuytren’s

contracture

•

A combined 571 Orthopedic Surgeons have been interviewed to

estimate market size (401 in U.S.; 170 in Europe) and 391 have

given feedback on potential usage of XIAFLEX (221 U.S.; 170

Europe)

•

Second study (n=444 total & 340 in depth) was designed to

provide 95% confidence level and 7.5% margin of error

(NASDAQ: AUXL)

Patients

Seeking

Treatment

~1,030,000

No Prior

Surgery

~540,000

Had Surgery

Previously

~490,000

Watchful

Waiting

~270,000

Medical/

Surgical

Treatment

~270,000

Medical/

Surgical

Treatment

~125,000

Watchful Wait/

In Follow Up

~365,000

XIAFLEX

Potential

Candidates

~240,000

240,000 Dupuytren’s Candidates In U.S. & Europe

Annually

Source: Auxilium research and analysis

~150,000 in U.S.

~ 90,000 in Europe

Prevalence

3 –

6% of

Population

~13,500,000 to

27,000,000

(NASDAQ: AUXL)

1. Smith BH. Am J Clin Pathol. 1966;45:670-678.

2. Somers KD, Dawson DM. J Urol. 1997;157:311-315.

Peyronie’s Disease—a Devastating Disorder

•

Scarring phenomenon affecting the

tunica albuginea

•

Plaques show excessive collagen

deposition

•

Potential Symptoms

–

Pain with erection, penile

curvature/deviation, penile

shortening, indentations, and/or

erectile dysfunction

–

May experience difficulty with sexual

intercourse, loss of self-esteem, and

depression

•

There are no approved therapies

for the treatment of Peyronie’s

disease

(NASDAQ: AUXL)

Epidemiology—Peyronie’s Disease

•

Prevalence of Peyronie’s disease is estimated at 1 in 20

adult men

–

Actual prevalence higher based on autopsies

•

Prevalence rate increases with age

–

The average age of disease onset is 53 years

•

High association with other diseases such as:

–

Diabetes, erectile dysfunction (ED), Dupuytren’s

contracture, plantar fascial contracture,

tympanosclerosis, gout, and Paget’s disease

•

We believe Peyronie’s disease is under-diagnosed and

under-treated

1. Schwarzer

U, The prevalence of Peyronie’s disease: Results of a large survey.

BJU Int

2001;88:727–30;

Mulhall

et al: J Urology

2004:171: 2350 –

2353;Rhoden

et al: Int J. Impot

Res

2001 :13 : 291 –

293; La Pera

et al : EUR Urology

2001: 40

:525 –

530.

2. Smith BH. Am J Clin Pathol. 1966;45:670-678.

3. Lindsay MB, J Urol.

1991;146:1007–1009.

4. Nyberg L, J Urol.128: 48, 1982

(NASDAQ: AUXL)

Current Treatment—Surgical

•

The goal of surgery is simply to make the two

sides of the penis equal in size

•

Graft or prosthetic may be required

(NASDAQ: AUXL)

Peyronie’s Disease—Unapproved Treatments

Have Been Used With Little Reported Success

•

Verapamil

•

Vitamin E

•

Colchicine

•

Potassium aminobenzoate (Potaba)

•

Tamoxifen

•

Interferon alpha-2a

•

Corticosteroids

•

Energy transfer treatment including extracorporeal

shock wave therapy (ESWT), laser and ultrasound

therapy, and orthovoltage radiation

(NASDAQ: AUXL)

Promising Phase II Results: Patients With

25%

Reduction in the Angle of Deviation

Study 1030

58%

53%

35%

20%

40%

60%

80%

100%

Month 3

Month 6

Month 9

Study 1035

50%

100%

89%

20%

40%

60%

80%

100%

Week 6

Month 3

Month 6

Month 9

(NASDAQ: AUXL)

XIAFLEX I.P. Position for Peyronie’s Disease

•Method of Use Patent in U.S. through 2019

•Use Patent Granted in France, UK, and Ireland

(expiry 2020)

–Pending in Germany, Denmark, and Norway

•U.S. Orphan Drug Exclusivity granted on March

12, 1996 for 7 years post approval

•Highly Purified Collagenase API and

manufacturing patent filed (expected expiry 2027)

(NASDAQ: AUXL)

Market Research Performed –

Peyronie’s

•

Two rounds of quantitative primary research have

been commissioned by Auxilium on XIAFLEX for

Peyronie’s disease

•

A combined 575 Urologists have been interviewed to

estimate market size (415 in U.S.; 160 in Europe) and

383 have given feedback on potential usage of

XIAFLEX (223 U.S.; 160 Europe)

•

Second study (n=472 total & 333 in depth) was

designed to provide 95% confidence level and 7.5%

margin of error

(NASDAQ: AUXL)

Peyronie’s Clinical Plan

•

Final report of pre-clinical local effects/tolerability (ex-

plaque) study under review at FDA

•

Phase IIb dose ranging study expected to begin in Q2

2008

•

A proprietary Patient Reported Outcome (PRO)

questionnaire has been developed

–

To be validated in Phase IIb and likely to be used as a primary

efficacy endpoint in Phase III clinical trials

•

File as a Supplemental BLA for Peyronie’s indication.

–

Will not be filed before Dupuytren’s BLA approved.

(NASDAQ: AUXL)

Patients

Seeking

Treatment

~475,000

Surgery Not

Recommended

~365,000

Watchful

Waiting

~160,000

Medical or

Intralesional

Therapy

~205,000

Surgery

Recommended

~110,000

XIAFLEX

Potential

Candidates

~210,000

210,000 Peyronie’s Candidates In U.S. and Europe

Annually

Source: Auxilium research

~135,000 in U.S.

~ 75,000 in Europe

Prevalence

1 in 20 Adult

Males

(NASDAQ: AUXL)

XIAFLEX for Frozen Shoulder Syndrome

•

Arthroscopic procedure or surgery

Current treatment*

•

Early studies showed trend to efficacy and

tolerability at highest dose (10,000 units)

•

Additional phase II studies needed to assess

optimal dose, primary endpoints and dosing

regimen

Clinical status

•

Estimated 3% of people develop frozen shoulder

syndrome over their lifetime

–

Higher incidence among patients with diabetes (10-

20%) vs general population (2-5%)

–

Higher incidence among patients with insulin-

dependent diabetes (36%), with increased frequency

of bilateral shoulder involvement

–

Market research indicates ~700,000 patients visit

doctors in the U.S. every year

•

Most common in patients between 45 –

70 yrs

Target population*

•

Diminished shoulder motion, characterized by

restriction in active and passive range of motion

Disease

description*

* Pearsall, A. Adhesive capsulitis. eMedicine. 2005 http://www.emedicine.com/pmr/topics372.htm

Testim

1% Testosterone Gel:

Near-Term Growth Driver

Executing on Opportunities

(NASDAQ: AUXL)

Testim®

is the Fastest Growing Testosterone

Replacement Therapy Gel

•

Proprietary, topical

1% testosterone gel

–

Once-a-day application

–

Favorable clinical and commercial profile

•

Recent study indicates 39% of U.S. males over 45 yrs

are hypogonadal*

–

We estimate that less than 10% of affected population

receives treatment

•

We believe diagnosis is increasing through education

and awareness

*Mulligan T. et al. Int J. Clin Pract

2006

(NASDAQ: AUXL)

Patient Benefits are Clinically Proven

Note:

Adjusted geometric means (CV

%) of a single-dose (50 mg testosterone), randomized,

complete crossover study of 29 hypogonadal men.

Total Testosterone

2,000

3,000

4,000

5,000

6,000

Mean AUC

0-24

(ng*h/dL)

Testim

AndroGel

Free Testosterone

100

150

200

250

Mean AUC

0-24

(ng*h/dL)

Testim

AndroGel

•

16 clinical studies involving approx. 1,800 patients

–

largest placebo-controlled study ever conducted

•

Clinical trial of Testim

vs. AndroGel

–

Testim provides 30% higher testosterone absorption (p<0.001)

(NASDAQ: AUXL)

Gels Fastest Growing TRT Segment

Source: IMS data

($ in millions)

Gel

Patch

Oral

Injectables

$35

$117

$200

$287

$340

$383

$449

100

200

300

400

500

600

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

$459

$399

$302

$210

$77

$59

$49

$499

$118

$568

Gel Segment Growth ($)

Mar 2008 L12M:

+23.6%

Gel Segment Growth ($)

Mar 2008 L12M:

+23.6%

2007

700

$685

$563

(NASDAQ: AUXL)

$10

$15

$20

$25

$30

100

120

Net Revs

TRX

Testim

quarterly net revenues and scripts

($ in millions)

Established Track Record of Consistent Growth

Q1 2008 Net

Revenues

Y/Y Growth:

+47.2%

Q1 2008 Net

Revenues

Y/Y Growth:

+47.2%

Q1 2008 TRX

YY Growth:

+31.2%

Q1 2008 TRX

YY Growth:

+31.2%

Source: Auxilium and IMS data

(NASDAQ: AUXL)

Testim

Driving Growth in Market

Source: IMS data

Testim

Share of TRx of Gel Market

Strong market share with high-prescribing urologists & PCP’s;

41.3% gel market share of decile 8-10 Urologists and 29.2% share with

decile 8 –

10 PCP’s in March 2008

21.9%

10%

15%

20%

25%

Mar-03

Mar-08

(NASDAQ: AUXL)

•

U.S.

Testim

patent

(covering

Hsieh

Enhancers)

expires

June

2008

•

U.S. Patent # 7,320,968 covering method of use claims for Testim

issued January 22, 2008; expires 2025

•

We believe no Paragraph III ANDA was filed prior to issuance of

‘968 patent, since three months have passed since listing in the

Orange Book

•

Divisional application and continuations filed with USPTO in late

2007 with a plan to protect additional inventions and seek

additional claims

•

New patent issued in Canada; expires 2023

•

New patent issued in Europe; expires 2023

Note: The referenced Testim patents are owned by Bentley Pharmaceuticals, Inc.

Testim Patent Coverage

Financials / Strategic Priorities

(NASDAQ: AUXL)

2008

Q1 ’07

Q1 ’08

Guidance

Revenues

$18.4

$27.1

$120-125

R&D Expense

$8.7

$13.2

$52-56

SG&A Expense

$17.2

$21.0

$88-92

Net Loss

($11.9)

($12.3) ($44-48)

Stock –

Based

Comp Expense

$1.2

$2.1

$9-11

Cash & cash equivalents

$56.9

1Q08 Financial Results and 2008 Guidance

($ Millions)

(NASDAQ: AUXL)

Strategic Priorities

•

Continue Development of XIAFLEX with a plan to:

–

Release top line CORD I and CORD II results in June 2008 &

be prepared to file BLA in early 2009

–

Initiate Phase IIb in Peyronie’s Disease in Q2 2008

–

Continue market research activities; prepare commercial

team

–

Continue development of XIAFLEX in Peyronie’s Disease

and Frozen Shoulder Syndrome indications

•

Continue Driving Testim Growth

(NASDAQ: AUXL)

Late Stage

Company

Transforming

Product

Fastest Growing

TRT product in

the U.S.

Poised for Growth