Additional Data from Exploratory Phase II Studies of BOTOX-R- -Botulinum Toxin Type A- as a Preventive Migraine/Headache Treatment to Be Presented at the American Headache Society's Annual Meeting.

Allergan, Inc. has completed several exploratory Phase II clinical trials investigating the potential use of BOTOX(R) (botulinum toxin type A) to treat various forms of headache and levels of headache severity, in an effort to identify a responsive patient population, dose and efficacy endpoints to guide its Phase III program.

--  In studies of patients with chronic headache conditions (i.e.,
        chronic daily headache (CDH), a disabling headache disorder
        characterized by headaches and/or migraines that occur on 16
        or more days each month), no statistically significant
        between-group differences (BOTOX(R) vs. placebo) on
        predetermined primary outcome measures were observed. However,
        significant differences in favor of BOTOX(R) were demonstrated
        on other key, clinically meaningful efficacy measures such as
        decrease in the frequency of headache episodes; decrease of at
        least 50% in headache days; and decrease in acute medication
        use.

        --  Furthermore, a priori planned subgroup analyses of
            patients in the CDH trials revealed that the predetermined
            primary outcome measure (i.e., mean change from baseline
            in the number of headache-free days at day 180) was met in
            several subsets of patients receiving BOTOX(R).

    --  In studies of patients with episodic migraine, no significant
        between-group differences were observed on predetermined
        outcome measures. Additional studies are needed to further
        examine the possible role of BOTOX(R) in the treatment of
        patients with episodic migraine.

    --  While the primary endpoints in the chronic and episodic
        studies were not met, results may have been confounded by
        several factors including a high proportion of patients taking
        concomitant prophylactic and acute headache pain medications
        during the studies, increasing the difficulty of
        differentiating study treatment from placebo.

    --  Across all Phase II studies, BOTOX(R) was found to be
        generally well-tolerated with less than 5% of patients
        discontinuing the studies due to adverse events.

Based on the Phase II findings specific to patients with CDH, Allergan has reached an agreement with the U.S. Food and Drug Administration (FDA) to move forward with a large Phase III clinical trial program, currently scheduled to begin in late 2005, to investigate the safety and efficacy of BOTOX(R) as a prophylactic therapy in a subset of migraine patients with CDH. Patients with CDH are at the more severe end of the headache/migraine spectrum, and currently available therapies typically provide inadequate relief to these patients due to intolerable side effects or other limitations. BOTOX(R) is not currently approved by the FDA for the treatment of any headache disorder.

Investigators will present all new as well as previously reported data from Allergan's Phase II clinical trial program exploring the use of BOTOX(R) as a treatment for various forms of migraine and headache at the American Headache Society (AHS) 2005 Annual Meeting, as follows:

Where:   Philadelphia Marriott Downtown
         Philadelphia, Pennsylvania

When:    June 23 - 26, 2005

What:    Data from Allergan's Exploratory Phase II Clinical Trial
         Program Investigating BOTOX(R) as a Treatment for Various
         Forms of Migraine and Headache

Chronic Daily Headache (CDH)

"Botulinum Toxin Type A for the Prophylaxis of Chronic Daily Headache in Migraineurs: A Randomized, Double-Blind, Placebo-Controlled Trial," Benjamin M. Frishberg, MD, et al.

(PLATFORM SESSION III: SATURDAY JUNE 25TH, 3:00-4:30 PM)

(Please see summary below.)

"Botulinum Toxin Type A for the Prophylaxis of Chronic Daily Headache in Migraineurs: Subgroup Analysis of Patients Not Receiving Other Prophylactic Medications (A Randomized, Double-blind, Placebo-Controlled Study)," David W. Dodick, MD, et al.

(PLATFORM SESSION III: SATURDAY JUNE 25TH, 3:00-4:30 PM)

(Please see summary below.)

"Efficacy of Prophylactic Treatment with Botulinum Toxin Type A in Migraineurs with Chronic Daily Headache Overusing Acute Headache Pain Medications," Joel R. Saper, MD, FACP, FAAN, et al.

(PLATFORM SESSION II, #ABH0163: SATURDAY JUNE 25TH, 12:00-2:00 PM)

Summary:

--Between-group differences (BOTOX(R) vs. placebo) on the primary efficacy measure (i.e., mean change from baseline in the number of headache-free days at day 180) did not reach statistical significance. However, significant differences compared to placebo were demonstrated on other key, clinically meaningful efficacy measures, including a decrease in the frequency of headache episodes, a decrease of at least 50% in headache days, and a decrease in acute medication use (Frishberg et al).

--Differences on key efficacy measures in favor of BOTOX(R) were even more evident in a subgroup analysis of patients who were not taking other prophylactic medication to treat their headache (Dodick et al), and were more robust still in a further subanalysis of these patients who were overusing acute pain medications (Saper et al). These latter results are especially meaningful since the overuse of pain medication for headache is associated with maintenance of chronic headache and considerable disability.

--Treatment with BOTOX(R) was well-tolerated.

"Botulinum Toxin Type A for the Prophylaxis of Chronic Daily Headache in Migraineurs: Effect on Acute Headache Pain Medication Use," Frederick G. Freitag, DO, et al.

(PLATFORM SESSION II, #ABH0161: SATURDAY JUNE 25TH, 12:00-2:00 PM)

--This was a subanalysis of Frishberg et al, in which between-group differences (BOTOX(R) vs. placebo) on the primary efficacy measure (i.e., mean change from baseline in the number of headache-free days at day 180) did not reach statistical significance.

--However, significant differences in favor of BOTOX(R) were demonstrated on other key, clinically meaningful efficacy measures such as decrease in the frequency of headache episodes; decrease of at least 50% in headache days; and decrease in acute medication use.

--Furthermore, decreases in acute headache pain medication use were consistently greater for BOTOX(R)-treated patients vs. placebo throughout the study period, with statistically significant between-group differences at four time points (p less than or equal to 0.05).

--Between-group differences in mean change from baseline were greater after repeated treatments.

--Treatment with BOTOX(R) was well-tolerated.

"Botulinum Toxin Type A for the Prophylaxis of Chronic Daily Headache in Migraineurs: Effect on the Frequency of Headaches of greater than or equal to 4 Hours Duration (A Randomized, Double-blind, Placebo-Controlled Study)," Sheena K. Aurora, MD, et al.

(PLATFORM SESSION II, #ABH0162: SATURDAY JUNE 25TH, 12:00-2:00 PM)

--This was a subanalysis of Frishberg et al, in which between-group differences (BOTOX(R) vs. placebo) on the primary efficacy measure (i.e., mean change from baseline in the number of headache-free days at day 180) did not reach statistical significance.

--However, significant differences in favor of BOTOX(R) were demonstrated on other key, clinically meaningful efficacy measures such as decrease in the frequency of headache episodes; decrease of at least 50% in headache days; and decrease in acute medication use.

--Furthermore, the decrease from baseline in the number of headaches of long duration (greater than or equal to 4 hours) was significantly greater for BOTOX(R)-treated patients vs. placebo at each assessment (p less than or equal to 0.05).

--Treatment with BOTOX(R) was well-tolerated.

"Botulinum Toxin Type A (BOTOX(R)) for the Prophylaxis of Chronic Daily Headache in Migraineurs Using a Fixed-Site, Fixed-Dose Treatment Paradigm: A Randomized, Double-Blind, Placebo-Controlled Trial," Stephen D. Silberstein, MD, et al.

(PLATFORM SESSION II, #ABH0166: SATURDAY JUNE 25TH, 12:00-2:00 PM)

--Between-group differences (BOTOX(R) vs. placebo) on the primary efficacy measure (i.e., mean change from baseline in the number of headache-free days at day 180) did not reach statistical significance.

--However, following three treatment sessions, the 225 U and 150 U BOTOX(R) treatment groups had a significantly greater reduction from baseline in the frequency of headache episodes vs. placebo at day 240.

--Statistically significant between-group differences were observed for the mean change from baseline in the number of migrainous headaches vs. placebo at days 30, 90, and 150.

--Treatment with BOTOX(R) was well-tolerated.

"Burden of Disease Among Patients with Transformed Migraine Participating in a Clinical Trial," Richard B. Lipton, MD, et al.

(PLATFORM SESSION I, #ABH0168: FRIDAY JUNE 24TH, 12:30-2:30 PM)

--This was a clinical trial designed to assess the burden of disease among migraine patients with CDH (also known as transformed migraine). During the 90-day period prior to their enrollment in Allergan's primary Phase II clinical trial (Frishberg et al), migraine patients with CDH experienced an average of 62.9 days of headache (+/- 22.6) and an average of 57.6 days (+/- 55) of activity limitation (e.g., missed days or reduced productivity at work, school or home, or missed social activities).

--Based on the overall mean Migraine Disability Assessment Questionnaire (MIDAS) score (57.6), most subjects were severely disabled (score greater than 21).

--All outcome measures showed these patients experience a substantial burden of disease (e.g., economic, quality of life, satisfaction and health-related costs).

Chronic Tension-Type Headache (CTTH)

"The Safety and Efficacy of a Single Treatment of Botulinum Toxin Type A in the Prophylactic Treatment of Chronic Tension-Type Headache (CTTH): A Multicenter, Double-Blind, Randomized, Placebo-Controlled, Parallel-Group Study," Stephen D. Silberstein, MD, et al.

(PLATFORM SESSION II, #ABH0165: SATURDAY JUNE 25TH, 12:00-2:00 PM)

--Between-group differences (BOTOX(R) vs. placebo) on the primary efficacy measure (i.e., mean change from baseline in the number of tension headache-free days at day 60 post-injection) did not reach statistical significance. Nor were there any significant between-group differences on other key efficacy measures (e.g., headache severity, concurrent headache medication usage, Beck Depression Inventory score, etc.).

--However, at day 90, significantly more patients in three BOTOX(R) treatment groups had a greater than or equal to 50% decrease in tension headache days vs. placebo (p less than or equal to 0.024).

--Treatment with BOTOX(R) was well-tolerated.

--The results of the study may have been confounded by several factors including a high proportion of patients taking concomitant prophylactic and acute headache pain medications.

Episodic Migraine

"Botulinum Toxin Type A Prophylactic Treatment for Episodic Migraine Using a Modified Follow-the-Pain Treatment Paradigm: A Randomized, Double-Blind, Placebo-Controlled, Phase II Study," Sheena K. Aurora, MD, et al.

(PLATFORM SESSION II, #ABH0164: SATURDAY JUNE 25TH, 12:00-2:00 PM)

--Between-group differences (BOTOX(R) vs. placebo) on the primary efficacy measure (i.e., mean change from baseline in the number of migraines for 30 days prior to day 180) did not reach statistical significance.

--Treatment with BOTOX(R) was well-tolerated.

--The results of the study may have been confounded by several factors including a high proportion of patients taking concomitant prophylactic and acute headache pain medications.

--Additional studies are needed to further examine the possible role of BOTOX(R) in the treatment of patients with episodic migraine.

About BOTOX(R)

BOTOX(R) is a medical product that contains tiny amounts of highly purified botulinum toxin protein refined from a bacterium. The product is administered in small therapeutic doses by injection directly into the affected area, and works by blocking the overactive nerve.

BOTOX(R) therapy was granted approval by the FDA in 1989 for the treatment of strabismus (crossed eyes) and blepharospasm (uncontrollable eye blinking) associated with dystonia, including benign essential blepharospasm or VII nerve disorders in patients 12 years of age and above. BOTOX(R) has since received approval in December 2000 for the treatment of cervical dystonia in adults to decrease the severity of abnormal head position and neck pain associated with cervical dystonia. In 2002, with dosing specific to treat frown lines between the eyebrows, the product was approved by the FDA for the temporary improvement in the appearance of moderate to severe glabellar lines (the vertical "frown lines" between the eyebrows) in adult men and women aged 65 and younger, under the name BOTOX(R) Cosmetic. More recently, in July 2004, BOTOX(R) was granted FDA approval for the treatment of severe primary axillary hyperhidrosis (excessive underarm sweating) that is inadequately managed with topical agents. In the U.S., BOTOX(R) is currently being investigated for the treatment of additional medical conditions, including migraine and headache, post-stroke spasticity, and overactive bladder.

Important Risk Information

BOTOX(R) and BOTOX(R) Cosmetic treatment is contraindicated in the presence of infection at the proposed injection site(s) and in individuals with known hypersensitivity to any ingredient in the formulation. Serious and/or immediate hypersensitivity reactions have been rarely reported. These reactions include anaphylaxis, urticaria, soft tissue edema, and dyspnea. If such a reaction occurs further injection of BOTOX(R) should be discontinued and appropriate medical therapy immediately instituted. BOTOX(R) and BOTOX(R) Cosmetic should only be diluted with 0.9 percent non-preserved sodium chloride. Individuals with peripheral motor neuropathic diseases (e.g., amyotrophic lateral sclerosis, or motor neuropathy) or neuromuscular junctional disorders (e.g., myasthenia gravis or Lambert-Eaton syndrome) should only receive BOTOX(R) or BOTOX(R) Cosmetic with caution. Patients with neuromuscular disorders may be at increased risk of clinically significant systemic effects including severe dysphagia and respiratory compromise from typical doses of BOTOX(R) or BOTOX(R) Cosmetic. There have been rare reports of adverse events involving the cardiovascular system, including arrhythmia and myocardial infarction, some with fatal outcomes. Some of these patients had risk factors including cardiovascular disease. The exact relationship of these events to the botulinum toxin injection has not been established.

BOTOX(R) for Blepharospasm in Patients greater than or equal to 12 Years of Age: Reduced blinking from BOTOX(R) injection of the orbicularis muscle can lead to corneal exposure, persistent epithelial defect and corneal perforation. The most frequently reported treatment-related adverse reactions in these patients are ptosis (20.8%), superficial punctate keratitis (6.3%) and eye dryness (6.3%).

BOTOX(R) for Strabismus in Patients greater than or equal to 12 Years of Age: Inducing paralysis in one or more extraocular muscles may produce spatial disorientation, double vision or past pointing. The most commonly reported adverse effects are ptosis (16%) and vertical deviation (17%).

BOTOX(R) for Cervical Dystonia in Adults: There have been rare cases of dysphagia severe enough to warrant the insertion of a gastric feeding tube. The most frequently reported adverse reactions in patients with cervical dystonia are dysphagia (19%), upper respiratory infection (12%), neck pain (11%), and headache (11%).

BOTOX(R) for Severe Primary Axillary Hyperhidrosis Inadequately Managed with Topical Agents: Patients should be evaluated for potential causes of secondary hyperhidrosis (e.g., hyperthyroidism) to avoid symptomatic treatment of hyperhidrosis without the diagnosis and/or treatment of the underlying disease. The most frequently reported adverse events (3 - 10%) are injection site pain and hemorrhage, non-axillary sweating, infection, pharyngitis, flu syndrome, headache, fever, neck or back pain, pruritus, and anxiety.

BOTOX(R) Cosmetic for Temporary Improvement in the Appearance of Frown Lines between the Brows: The most frequently reported adverse events are headache (13.3%), respiratory infection (3.5%), flu syndrome (2%), blepharoptosis (3.2%) and nausea (3%).

Full prescribing information for BOTOX(R) and BOTOX(R) Cosmetic is available at www.botox.com and www.botoxcosmetic.com.

Forward-Looking Statements

This media advisory contains "forward-looking statements," including, among other statements, statements regarding research and development outcomes, efficacy, and market and product potential. These statements are based on current expectations of future events. If underlying assumptions prove inaccurate or unknown risks or uncertainties materialize, actual results could vary materially from Allergan's expectations and projections. Risks and uncertainties include general industry and pharmaceutical market conditions; general domestic and international economic conditions, such as interest rate and currency exchange rate fluctuations; technological advances and patents obtained by competitors; challenges inherent in product marketing such as the unpredictability of market acceptance for new pharmaceutical and biologic products and/or the acceptance of new indications for such products; domestic and foreign health care reforms; the timing and uncertainty of the research and development and regulatory processes; trends toward managed care and health care cost containment; and governmental laws and regulations affecting domestic and foreign operations. Allergan expressly disclaims any intent or obligation to update these forward-looking statements except as required to do so by law. Additional information concerning these and other risk factors can be found in press releases issued by Allergan, as well as Allergan's public periodic filings with the Securities and Exchange Commission, including the discussion under the heading "Certain Factors and Trends Affecting Allergan and its Businesses" in Allergan's 2004 Form 10-K and Allergan's Form 10-Q for the quarter ended March 25, 2005. Copies of Allergan's press releases and additional information about Allergan is available on the World Wide Web at www.allergan.com or you can contact the Allergan Investor Relations Department by calling 1-714-246-4636.