<PAGE>   1
                UNITED STATES SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 10-Q

(Mark One)

[X] QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
    ACT OF 1934

    For the quarterly period ended March 31, 2000

                                       OR

[ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
    ACT OF 1934.

                       COMMISSION FILE NUMBER  0-23641
                                              ---------

                      ALLERGAN SPECIALTY THERAPEUTICS, INC.

 A DELAWARE CORPORATION                              IRS EMPLOYER IDENTIFICATION
                                                            33-0779207

                   2525 DUPONT DRIVE, IRVINE, CALIFORNIA 92612

                          TELEPHONE NUMBER 714/246-4500


Indicate by a check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

 (1)   X   yes          no
     ------       ------
 (2)   X   yes          no
     ------       ------

Indicate the number of shares outstanding of each of the issuer's classes of
common stock as of the latest practicable date.

As of May 5, 2000, there were 3,272,690 shares of callable Class A common stock
outstanding, and 1,000 shares of Class B common stock outstanding.

<PAGE>   2

                      ALLERGAN SPECIALTY THERAPEUTICS, INC.

                 FORM 10-Q FOR THE QUARTER ENDED MARCH 31, 2000

                                      INDEX



                                                                        Page
                                                                        ----
PART I - FINANCIAL INFORMATION

    ITEM 1 - FINANCIAL STATEMENTS

             Condensed Statements of Operations                           3

             Condensed Balance Sheets                                     4

             Condensed Statements of Cash Flows                           5

             Notes to Condensed Financial Statements                    6-7

    ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
             CONDITION AND RESULTS OF OPERATIONS                        8-9

    ITEM 3 - QUANTITATIVE AND QUALITATIVE DISCLOSURES
             ABOUT MARKET RISK                                           10

             CERTAIN FACTORS AND TRENDS AFFECTING ALLERGAN
             SPECIALTY THERAPEUTICS, INC. AND ITS BUSINESSES          10-12


PART II - OTHER INFORMATION

    ITEM 6 - EXHIBITS AND REPORTS ON FORM 8-K                            13

Signature                                                                14

Exhibits


                                       2

<PAGE>   3

PART I - FINANCIAL INFORMATION

                      ALLERGAN SPECIALTY THERAPEUTICS, INC.
                          (a development stage company)

                       Condensed Statements of Operations
                                   (unaudited)

                        (In thousands, except share data)

<TABLE>
<CAPTION>
                                                                                           Inception
                                                          Quarter Ended               (November 12, 1997)
                                                             March 31,                        to
                                                  -------------------------------          March 31,
                                                     2000                1999                2000
                                                  -----------         -----------         -----------
<S>                                               <C>                 <C>                 <C>
Revenues                                          $       980         $     2,150         $    17,133

Costs and expenses:
       Research and development                        15,940              10,689             101,026
       Technology fees                                  1,375               1,375              13,395
       General and administrative expenses                376                 284               2,507
                                                  -----------         -----------         -----------
           Total costs and expenses                    17,691              12,348             116,928
                                                  -----------         -----------         -----------
Loss before income taxes                              (16,711)            (10,198)            (99,795)
Provision for taxes                                       452                 601               6,982
                                                  -----------         -----------         -----------
Net loss                                          $   (17,163)        $   (10,799)        $  (106,777)
                                                  ===========         ===========         ===========
Basic and diluted loss per share                  $     (5.24)        $     (3.30)        $    (32.62)
                                                  ===========         ===========         ===========
Basic and diluted shares outstanding                3,273,690           3,273,690           3,273,690
</TABLE>

See accompanying notes to condensed financial statements.


                                       3

<PAGE>   4

                      ALLERGAN SPECIALTY THERAPEUTICS, INC.
                          (a development stage company)

                            Condensed Balance Sheets
                                   (unaudited)
                        (In thousands, except share data)

<TABLE>
<CAPTION>
                                                                  March 31,        December 31,
                                                                    2000              1999
                                                                  ---------        ------------
<S>                                                               <C>              <C>
                                     ASSETS

Cash                                                              $      --         $      47
Investments                                                          89,957           105,252
Prepaid technology fees                                               4,742             5,292
Other assets                                                            979             1,431
                                                                  ---------         ---------
                                                                  $  95,678         $ 112,022
                                                                  =========         =========

                      LIABILITIES AND STOCKHOLDERS' EQUITY

 Liabilities:
        Payable to Allergan, Inc.                                 $   6,633         $   6,047
        Accounts payable and accrued liabilities                        126                --
                                                                  ---------         ---------
                 Total liabilities                                    6,759             6,047

 Stockholders' equity:
        Callable Class A Common stock, $.01 par value;
          6,000,000 shares authorized,
          3,272,690 issued and outstanding                               33                33
        Class B Common stock, $1.00 par value;
          1,000 shares authorized, issued and outstanding                 1                 1
        Additional paid-in capital                                  196,753           196,753
        Accumulated other comprehensive loss                         (1,091)           (1,198)
        Deficit accumulated during development stage               (106,777)          (89,614)
                                                                  ---------         ---------
                 Total stockholders' equity                          88,919           105,975
                                                                  ---------         ---------
                                                                  $  95,678         $ 112,022
                                                                  =========         =========
</TABLE>

           See accompanying notes to condensed financial statements.

                                       4


<PAGE>   5

                      ALLERGAN SPECIALTY THERAPEUTICS, INC.
                          (a development stage company)

                       Condensed Statements of Cash Flows
                                   (unaudited)

                                 (In thousands)

<TABLE>
<CAPTION>
                                                                                                   Inception
                                                                       Quarter Ended          (November 12, 1997)
                                                                         March 31,                     to
                                                                 -------------------------         March 31,
                                                                   2000             1999             2000
                                                                 --------         --------         ---------
<S>                                                              <C>              <C>              <C>
 OPERATING ACTIVITIES:
        Net loss                                                 $(17,163)        $(10,799)        $(106,777)
        Noncash item included in net loss:
           Deferred income tax                                         25               41              (195)
        Changes in operating assets and liabilities:
           Other assets                                               355              270               (35)
           Prepaid technology fees                                    550             (300)           (4,742)
           Payable to Allergan, Inc.                                  586               62             6,633
           Accounts payable and accrued liabilities                   126              283               126
                                                                 --------         --------         ---------

                 Net cash used in operating activities            (15,521)         (10,443)         (104,990)

INVESTING ACTIVITIES:
        Purchases of investments                                   (1,112)          (2,333)         (193,637)
        Sales and maturities of investments                        16,586           13,191           101,840
                                                                 --------         --------         ---------
                 Net cash provided by (used in)
                   investing activities                            15,474           10,858           (91,797)

FINANCING ACTIVITIES:
        Issuance of common stock                                       --               --           200,001
        Offering costs                                                 --               --            (3,214)
                                                                 --------         --------         ---------
                 Net cash provided by financing activities             --               --           196,787
                                                                 --------         --------         ---------
Net (decrease) increase in cash                                       (47)             415                --

Cash - beginning of period                                             47               --                --
                                                                 --------         --------         ---------
Cash - end of period                                             $     --         $    415         $      --
                                                                 ========         ========         =========
Supplemental disclosure of cash paid for taxes                   $     --         $    255         $   7,080
                                                                 ========         ========         =========
</TABLE>

See accompanying notes to condensed financial statements.


                                       5

<PAGE>   6

ALLERGAN SPECIALTY THERAPEUTICS, INC.

Notes to Condensed Financial Statements

1.  Basis of Presentation and Significant Accounting Policies

    Allergan Specialty Therapeutics, Inc. ("ASTI" or "the Company") was
    incorporated in Delaware on November 12, 1997 and commenced operations on
    March 10, 1998. ASTI was formed for the purpose of conducting research and
    development of potential human pharmaceutical products, and to commercialize
    such products, most likely through licensing to Allergan, Inc. (Allergan).

    The Company is subject to risks associated with development stage companies.
    All of the Company's efforts to date have been limited to obtaining capital
    and conducting research and development. The Company does not yet generate
    any revenues from product sales or royalties. Research and development is
    performed by Allergan and the costs incurred are reimbursed by ASTI.

    In the opinion of management, the accompanying condensed financial
    statements contain all adjustments (consisting only of normal recurring
    accruals) necessary to present fairly the financial information contained
    therein. These statements do not include all disclosures required by
    generally accepted accounting principles. The results of operations for the
    three month period ended March 31, 2000 and for the period from inception to
    March 31, 2000 are not necessarily indicative of the results to be expected
    for the year ending December 31, 2000.

    Use of estimates

    The preparation of financial statements in accordance with generally
    accepted accounting principles requires management to make estimates and
    assumptions that affect the amounts reported in the financial statements and
    accompanying notes. Actual results could differ from those estimates.


                                       6

<PAGE>   7

ALLERGAN SPECIALTY THERAPEUTICS, INC.

Notes to Condensed Financial Statements

1.  Basis of Presentation and Significant Accounting Policies (Continued)

    Per share information

    Statement of Financial Accounting Standards (SFAS) No. 128, "Earnings per
    Share," (EPS) requires calculations for "basic earnings per share" including
    only actual weighted shares outstanding and "diluted earnings per share"
    including the effect of any common equivalent shares or other items that are
    dilutive. The Company has no common equivalent shares or other items that
    are dilutive. The reconciliations of the numerators and denominators of the
    basic and diluted loss per share computations for the quarters ended March
    31, 2000 and 1999 and for the period from inception (November 12, 1997) to
    March 31, 2000 are as follows:

<TABLE>
<CAPTION>
                                                     Quarter Ended March 31,                Inception
                                                ---------------------------------      (November 12, 1997)
                                                    2000                 1999           to March 31, 2000
                                                ------------         ------------      -------------------
<S>                                             <C>                  <C>               <C>
    Loss during period                          $(17,163,000)        $(10,799,000)        $(106,777,000)

    Basic and diluted shares outstanding
                                                   3,273,690            3,273,690             3,273,690

    Per share loss during period
                                                      $(5.24)              $(3.30)              $(32.62)
</TABLE>

2.  Comprehensive Income (Loss)

    SFAS No. 130, "Reporting Comprehensive Income," established standards for
    reporting comprehensive income and its components. Other comprehensive loss
    for the quarters ended March 31, 2000 and 1999 were comprised of unrealized
    loss on investments. Other comprehensive loss for the three months ended
    March 31, 2000 and 1999 and for the period from inception to March 31, 2000
    are as follows:

<TABLE>
<CAPTION>
                                                                 Quarter Ended March 31,
                               --------------------------------------------------------------------------------------
                                                 2000                                           1999
                               ----------------------------------------         -------------------------------------
                                                 Tax                                            Tax
                               Before-tax     (expense)      Net-of-tax         Before-tax   (expense)     Net-of-tax
                                 amount       or benefit        amount             amount    or benefit      amount
                               ----------     ----------     ----------         ----------   ----------    ----------
                                                                  (in thousands)
<S>                            <C>            <C>            <C>                <C>          <C>           <C>
Unrealized holdings (loss)
  gain arising during period      $179          $(72)         $    107            $(958)        $416        $   (542)
                                  ====          ====                              =====
Net loss                                                       (17,163)                                      (10,799)
                                                              --------                                      --------
Total comprehensive loss                                      $(17,056)                                     $(11,341)
                                                              ========                                      ========
</TABLE>

<TABLE>
<CAPTION>
                                                        Inception to March 31, 2000
                                               -------------------------------------------
                                                                  Tax
                                               Before-tax      (expense)        Net-of-tax
                                                 amount        or benefit         amount
                                               ----------      ----------       ----------
                                                             (in thousands)
<S>                                            <C>             <C>              <C>
Unrealized holdings (loss) gain arising
  during period                                 $(1,840)           $749         $  (1,091)
                                                =======            ====
Net loss                                                                         (106,777)
                                                                                ---------
Total comprehensive loss                                                        $(107,868)
                                                                                =========
</TABLE>


                                       7

<PAGE>   8

ALLERGAN SPECIALTY THERAPEUTICS, INC.

MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF
OPERATIONS FOR THE QUARTER ENDED MARCH 31, 2000

This Quarterly Report on Form 10-Q may contain certain projections, estimates
and other forward-looking statements that involve a number of risks and
uncertainties. While this outlook represents management's current judgment on
the future direction of the business, such risks and uncertainties could cause
actual results to differ materially from any future performance suggested below.
The Company undertakes no obligation to release publicly the results of any
revisions to these forward-looking statements to reflect events or circumstances
arising after the date hereof.

The following should be read in conjunction with the section entitled "--Risks
and Uncertainties" included in the Company's annual report on Form 10-K for the
year ended December 31, 1999 and the Company's Financial Statements and notes
thereto in Item 1 above.

RESULTS OF OPERATIONS

Net interest and investment income earned on investments were $980,000 and
$2,150,000 for the quarters ended March 31, 2000 and 1999, respectively, and
$17,133,000 for the period from ASTI's inception, November 12, 1997, through
March 31, 2000. Interest and investment income was earned subsequent to March
10, 1998, the date Allergan contributed $200 million to ASTI. In the future, as
ASTI's funds are used pursuant to the R&D Agreement and to pay the Technology
Fee pursuant to the Technology Agreement, lower cash balances will be available
for investment and therefore interest and investment income is expected to
decrease.

Research and development expenses were $15,940,000 and $10,689,000 for the
quarters ended March 31, 2000 and 1999, respectively. Research and development
expenses were $101,026,000 for the period from inception through March 31, 2000.
ASTI paid technology fees of $825,000 and $1,675,000 to Allergan during the
quarters ended March 31, 2000 and 1999, respectively. ASTI paid technology fees
of $18,137,000 to Allergan for the period from inception to March 31, 2000.

Provision for taxes were $452,000 and $601,000 for the quarters ended March 31,
2000 and 1999, respectively. Provision for taxes for the period from inception
through March 31, 2000 was $6,982,000. ASTI expects to have taxable income as a
result of the requirement to capitalize technology fees and its election to
capitalize research and development expenses for tax purposes.

The results of operations of ASTI are expected to reflect primarily interest and
investment income on the funds contributed by Allergan, and research and
development expenses related to development of ASTI Products and the Technology
Fee. ASTI's net loss for the quarters ended March 31, 2000 and 1999 were
$17,163,000 or $(5.24) per share and $10,799,000 or $(3.30) per share
respectively. ASTI's net loss for the period from inception through March 31,
2000 was $106,777,000 or $(32.62) per share. ASTI is expected to continue to
record significant net losses in future periods, as expenses under its
agreements with Allergan are expected to continue to exceed investment income.


                                       8

<PAGE>   9

ALLERGAN SPECIALTY THERAPEUTICS, INC.

MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF
OPERATIONS FOR THE QUARTER ENDED MARCH 31, 2000 (Continued)

LIQUIDITY AND CAPITAL RESOURCES

On March 9, 1998, Allergan contributed $200 million in cash to ASTI in exchange
for all of the issued and outstanding shares of callable Class A Common Stock of
ASTI. On March 10, 1998, Allergan distributed the Class A shares to holders of
Allergan common stock and ASTI commenced operations. The funds contributed by
Allergan, plus investment income earned thereon, will be used primarily to fund
the development of ASTI Products and to conduct related activities. Funds not
immediately required for development activities will be invested in investment
grade securities.

At March 31, 2000, ASTI had $89,957,000 in investments. The Company invests its
excess cash in money market funds, equity securities and debt instruments of
financial institutions and corporations with strong credit ratings. The Company
has established guidelines with respect to diversification and maturities in
order to maintain safety and liquidity of its investment portfolio.

Additionally, ASTI classifies all investments as available-for-sale securities
with net unrealized holding gains or losses as a component of other
comprehensive income. ASTI liquidates investments to pay for operating expenses
as needed.

At the time of its formation, ASTI was projected to spend its funds over a
five-year period. The Board of Directors of ASTI recently approved a research
and development plan for the year ending December 31, 2000 which, if executed in
its entirety, would represent an acceleration in spending on ASTI's research and
development programs. This potential accelerated spending is the result of the
acceptance by ASTI of more research and development projects as well as more
rapid research and development of compounds than anticipated at the time of
ASTI's formation. ASTI anticipates the acceleration of spending could result in
the use of substantially all of the funds available for research and development
remaining in ASTI in the first half of 2001. Pursuant to ASTI's Restated
Certificate of Incorporation and Allergan's rights as the sole holder of all of
the ASTI Class B Common Stock, Allergan has certain rights (but no obligation)
to purchase all of the ASTI Class A Common Stock, which purchase rights could be
triggered by the use of substantially all of ASTI's funds. Allergan's purchase
rights, which expire if not exercised by the 90th day after the date on which
Allergan receives notice that the amount of cash and marketable securities held
by ASTI is less than $15 million, are summarized in ASTI's Prospectus dated
March 6, 1998.


                                        9

<PAGE>   10

ALLERGAN SPECIALTY THERAPEUTICS, INC.

QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

ASTI does not use derivative financial instruments in its non-trading investment
portfolio. The Company's primary investment objective is preservation of capital
in order to fund research and development of potential pharmaceutical products
incurred pursuant to the Company's agreement with Allergan, Inc. As such, the
Company invests its excess cash in investment grade securities consisting of
money market funds, equity securities and debt instruments. Interest and
investment income earned on the Company's investment portfolio is most sensitive
to fluctuations in the general level of U.S. interest rates. The Company
mitigates interest rate risk by a program of diversification so that exposure to
risks relating to a single security or investment manager is minimal. Further,
the Company invests in money market funds and debt instruments with varying
maturity dates to correspond to anticipated research and development expenses.
These securities typically bear minimal credit risk and ASTI has not experienced
any losses on its investments to date due to credit risk.

The Company's investments in equity securities, which are subject to price risk,
are generally invested in companies that have a history of paying dividends. The
Company addresses price risk by a program of diversification so that exposure to
risks relating to a single security is minimal.

CERTAIN FACTORS AND TRENDS AFFECTING ASTI AND ITS BUSINESSES

The Company believes that certain statements made by the Company in this report
and in other reports and statements released by the Company constitute
"forward-looking statements" within the meaning of the Private Securities
Litigation Reform Act of 1995, such as comments which express the Company's
opinions about trends and factors which may impact future operating results.
Disclosures which use words such as the Company "believes," "anticipates,"
"expects" and similar expressions are intended to identify forward-looking
statements. Such statements are subject to certain risks and uncertainties that
could cause actual results to differ materially from expectations. Any such
forward-looking statements, whether made in this report or elsewhere, should be
considered in context with the various disclosures made by the Company in its
press releases and publicly filed reports such as the Company's Annual Report on
Form 10-K for the year ended December 31, 1999, which disclosures are
incorporated herein by this reference. In addition to those risks identified
elsewhere in this report on Form 10-Q and those risks described in the Company's
press releases and publicly filed reports, the Company's business and results of
operations are subject to other risks, including the following risk factors:

o   ASTI is a recently formed company and is subject to the risks inherent in
    the establishment of a new business enterprise in the biotechnology
    industry. ASTI will incur substantial losses for several years due to the
    long-term nature of the research and development of pharmaceutical products
    through clinical testing and the regulatory process, which losses may never
    be recovered.


                                       10

<PAGE>   11

ALLERGAN SPECIALTY THERAPEUTICS, INC.

CERTAIN FACTORS AND TRENDS AFFECTING ASTI AND ITS BUSINESSES (Continued)

o   There can be no assurance that the ASTI Board of Directors will continue the
    funding of the research and development of all of the current ASTI Products
    or Pre-Selection Work, or that any ASTI Products can be successfully
    researched, developed and/or commercialized within the anticipated cost
    estimates or time frames, if at all. Certain of the ASTI Products are at
    critical stages of research and development, and technical and clinical
    outcomes are impossible to predict. Because of the long-range nature of any
    pharmaceutical product research and development plan, research and
    development of a particular product or project could accelerate, slow down
    or be discontinued, and other unforeseen events could occur, all of which
    would significantly affect the timing and amount of ASTI's expenditures on a
    particular product, or in total. As a result, estimates of costs and timing
    of research and development programs and for the use of Available Funds may
    not be accurate.

o   All ASTI Products, Developed Technology Products and Pre-Selection Products
    will require FDA clearance before such products may be lawfully marketed in
    the United States. Applications for FDA clearance must be based on costly
    and extensive clinical trials designed to demonstrate safety and efficacy.
    Clearance to market such products will also be required from corresponding
    regulatory authorities in foreign countries before such products may be
    marketed in those countries. There can be no assurance that the necessary
    regulatory clearances and approvals will be obtained in a timely fashion or,
    if obtained, that such clearances and approvals will not be revoked or
    withdrawn.

o   Allergan has contributed $200 million in cash to ASTI. Allergan has no
    obligation to contribute additional funds to ASTI, and, to the best of
    ASTI's knowledge, has no present intention to do so. For the foreseeable
    future, ASTI's only ongoing source of revenue will be investment income and
    certain milestone payments. There can be no assurance that ASTI will have
    sufficient funds to complete the research and development of any or all of
    the ASTI Products.

o   Allergan is not obligated to exercise the License Option for any ASTI
    Product or to exercise the Purchase Option, and Allergan will exercise any
    such option only if it is in Allergan's best interest to do so. The timing
    of the exercise of the Purchase Option is within Allergan's sole discretion.
    The timing of the exercise of the License Option with respect to any
    Licensed Product is also within Allergan's sole discretion and thereafter
    research, development and funding of any such product will be controlled by
    Allergan.

o   ASTI Products, Developed Technology Products and Pre-Selection Products are
    likely to face competition from other therapies for the same indications.
    Competitors potentially include any of the world's pharmaceutical and
    biotechnology companies. A number of companies have developed and are
    developing competing technologies and products.


                                       11

<PAGE>   12

ALLERGAN SPECIALTY THERAPEUTICS, INC.

CERTAIN FACTORS AND TRENDS AFFECTING ASTI AND ITS BUSINESSES (Continued)

o   In February 1999, the Financial Accounting Standards Board released a
    revised Exposure Draft of a Proposed Statement of Financial Accounting
    Standards - Consolidated Financial Statements: Purpose and Policy. If
    adopted as a SFAS, the terms of this Exposure Draft could require Allergan
    to include the financial position and results of operation of ASTI in its
    consolidated results on a retrospective basis. In addition, in 1999 the
    Emerging Issues Task Force ("EITF") of the FASB began deliberating Issue No.
    99-16 relating to the appropriate methods of accounting for entities similar
    to ASTI. Certain alternatives under consideration by the EITF could require
    Allergan to account for the activities of ASTI in Allergan's Consolidated
    Financial Statements.


                                       12

<PAGE>   13

ALLERGAN SPECIALTY THERAPEUTICS, INC.

PART II - OTHER INFORMATION

Item 6. Exhibits and Reports on Form 8-K

        -  Exhibits
           (numbered in accordance with Item 601 of Regulation S-K)

           27.1 -- Financial Data Schedule

        -  Reports on Form 8-K.

           None.


                                       13

<PAGE>   14

                                    SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


Date: May 12, 2000                         ALLERGAN SPECIALTY THERAPEUTICS, INC.



                                           /s/ JAMES M. HINDMAN
                                           -------------------------------------
                                           James M. Hindman
                                           Chief Financial Officer
                                           and Duly Authorized Officer


                                       14
<PAGE>   15
                                 EXHIBIT INDEX

                  EXHIBIT
                  NUMBER                     DESCRIPTION
                  -------                    -----------
                    27.1                     Financial Data Schedule