<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   FORM 10-QSB

(Mark One)

[x]      QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
         ACT OF 1934

         For the quarterly period ended March 31, 2000

[ ]      TRANSITION REPORT UNDER SECTION 13 OR 15(d) OF THE EXCHANGE ACT

         For the transition period _________ to _________

                              ANTEX BIOLOGICS INC.
        -------------------------------------------------------------------
        (Exact name of small business issuer as specified in its charter)

<TABLE>
<S>                                                                   <C>
                        Delaware                                                52-1563899
         ---------------------------------------------                ---------------------------------
         (State or other jurisdiction of incorporation                (IRS Employer Identification No.)
                  or organization)
</TABLE>

                 300 Professional Drive, Gaithersburg, MD 20879
        -------------------------------------------------------------------
                   (Address of principal executive offices)

                                 (301) 590-0129
        -------------------------------------------------------------------
                           (Issuer's telephone number)

        -------------------------------------------------------------------
              (Former name, former address and former fiscal year,
                          if changed since last report)

Check whether the issuer (1) filed all reports required to be filed by Section
13 or 15(d) of the Exchange Act during the past 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. Yes [x] No [ ]

                       APPLICABLE ONLY TO CORPORATE USERS

State the number of shares outstanding of each of the issuer's classes of common
equity, as of the latest practicable date.

48,200,254 shares of Antex Biologics Inc. Common Stock, $.01 par value, were
--------------------------------------------------------------------------------
outstanding as of April 28, 2000
--------------------------------

Transitional Small Business Disclosure Format (check one):

Yes               No  X
    ----             ---

<PAGE>   2

                              ANTEX BIOLOGICS INC.

                                   FORM 10-QSB

                          QUARTER ENDED MARCH 31, 2000

                                      INDEX

<TABLE>
<S>                                                                                  <C>
Part I.    Financial Information                                                     Page No.
                                                                                     --------
     Item 1.     Financial Statements

                Consolidated Balance Sheets at December 31, 1999 and
                March 31, 2000 (Unaudited)                                                  3

                Consolidated Statements of Operations (Unaudited) for the three
                months ended March 31, 1999 and 2000 and the period
                August 3, 1991 (inception) to March 31, 2000                                4

                Consolidated Statements of Stockholders' Equity (Deficit) for
                the period August 3, 1991 (inception) to December 31, 1999
                and the three months ended March 31, 2000 (Unaudited)                     5-6

                Consolidated Statements of Cash Flows (Unaudited) for the three
                months ended March 31, 1999 and 2000 and the period
                August 3, 1991 (inception) to March 31, 2000                              7-8

                Notes to Consolidated Financial Statements                               9-13

     Item 2.    Management's Discussion and Analysis of Financial Condition
                And Results of Operations                                               13-16

Part II.   Other Information

     Item 2.    Changes in Securities and Use of Proceeds                                  16

     Item 6.    Exhibits and Reports on Form 8-K                                           16

Signatures                                                                                 17
</TABLE>

                                       2
<PAGE>   3

                              Antex Biologics Inc.
                        (a development stage enterprise)

                           CONSOLIDATED BALANCE SHEETS
<TABLE>
<CAPTION>
                                                                                    DECEMBER 31,            MARCH 31,
                                                                                        1999                  2000
                                                                                        ----                  ----
                                                                                                          (UNAUDITED)
<S>                                                                             <C>                       <C>
ASSETS
Current assets:
   Cash and cash equivalents                                                    $     1,706,275           $    15,589,582
   Accounts and other receivables                                                       104,766                   105,059
   Prepaid expenses                                                                      62,087                   120,247
                                                                                    -----------              ------------
Total current assets                                                                  1,873,128                15,814,888
Property and equipment, net                                                             734,051                   740,706
Restricted cash                                                                         146,600                   146,600
Other                                                                                    27,291                    27,291
                                                                                    -----------              ------------
                                                                                $     2,781,070           $    16,729,485
                                                                                    ===========              ============

LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
   Accounts payable and accrued expenses                                        $       297,171           $       368,895
   Deferred research and development revenue                                            558,156                   558,156
   Deferred gain on equipment                                                            49,590                    49,590
                                                                                    -----------              ------------
Total current liabilities                                                               904,917                   976,641
Deferred gain on equipment                                                              103,419                    91,021
Other                                                                                    44,701                    37,642
                                                                                    -----------              ------------
Total liabilities                                                                     1,053,037                 1,105,304
                                                                                    ===========              ============

Commitments and contingencies

Stockholders' equity:
   Preferred stock, $.01 par value; 5,000,000 shares
     authorized; Series A convertible preferred stock-
     none and 44,545 shares issued and outstanding                                            -                   122,945
   Common stock, $.01 par value; 95,000,000 shares
     authorized; 29,458,990 and 48,200,254 shares
     issued and outstanding                                                             294,590                   482,003
   Additional paid-in capital                                                        19,911,906                34,695,522
   Deficit accumulated during the development stage                                 (18,478,463)              (19,676,289)
                                                                                    -----------              ------------
Total stockholders' equity                                                            1,728,033                15,624,181
                                                                                    -----------              ------------
                                                                                $     2,781,070           $    16,729,485
                                                                                    ===========              ============
</TABLE>

The accompanying notes are an integral part of these financial statements.

                                       3
<PAGE>   4

                              Antex Biologics Inc.
                        (a development stage enterprise)

                      CONSOLIDATED STATEMENTS OF OPERATIONS
                                   (UNAUDITED)
<TABLE>
<CAPTION>
                                                                      THREE MONTHS                      AUGUST 3, 1991
                                                                     ENDED MARCH 31                       (INCEPTION)
                                                                                                               TO
                                                                  1999                  2000               MARCH 31, 2000
                                                                  ----                  ----               --------------
<S>                                                        <C>                  <C>                       <C>
Revenues                                                   $      921,068       $       129,763           $      16,712,027
                                                                  -------               -------                  ----------
Expenses:
   Research and development                                     1,040,267             1,006,958                  22,884,316
   General and administrative                                     464,578               433,198                  12,028,709
                                                               ----------             ---------                  ----------
Total expenses                                                  1,504,845             1,440,156                  34,913,025
                                                                ---------             ---------                  ----------

Loss from operations                                             (583,777)           (1,310,393)                (18,200,998)

Other income (expense):
   Interest income                                                 45,196               112,567                   1,447,420
   Expense recorded on issuance of warrant                              -                     -                    (502,540)
   Cost of treasury shares in excess
     of fair value                                                      -                     -                  (1,711,814)
   Interest expense                                                     -                     -                    (708,357)
                                                                ---------             ---------                  ----------

Net loss                                                         (538,581)           (1,197,826)          $     (19,676,289)
                                                                                                                 ==========
Non-cash dividend accretion                                             -              (122,500)
                                                                ---------             ---------
Net loss applicable to common
  stockholders                                             $     (538,581)      $    (1,320,326)
                                                                 ========            ==========
Loss per common share:
   Basic and diluted                                               $(0.02)               $(0.04)
                                                                   =======               =======
Weighted average common shares outstanding:
   Basic and diluted                                           25,863,726            32,762,776
                                                               ==========           ===========
</TABLE>

The accompanying notes are an integral part of these financial statements.

                                       4
<PAGE>   5

                              Antex Biologics Inc.
                        (a development stage enterprise)

            CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT)

         For the Period August 3, 1991 (Inception) to December 31, 1999
              and the Three Months Ended March 31, 2000 (Unaudited)

<TABLE>
<CAPTION>
                                                                                 PREFERRED STOCK
                                                                              ------------------------
                                                                              SHARES       PAR VALUE
                                                                              ------------------------
<S>                                                                           <C>          <C>
Initial capitalization ($.20 per share)                                                -   $         -
Net loss                                                                               -             -
                                                                              ------------------------
Balance at December 31, 1991                                                           -             -

Sale of common stock for cash, January 1992 ($4.61 per share)                          -             -
Sale of common stock for cash, February 1992 ($6.90 per share)                         -             -
Issuance of common stock for services, March 1992 to July 1992 ($2.00 per
     share)                                                                            -             -
Conversion of notes payable into preferred stock, September 1992 ($4.48
     per share)                                                                  113,700         1,137
Sale of preferred stock for cash, September 1992 ($4.48 per share)                89,328           893
Issuance of preferred stock upon exercise of warrants, September 1992
     ($1.92 per share)                                                            46,900           469
Issuance of common stock for cash ($1.00 per share) and services
     ($1.00 per share), October 1992                                                   -             -
Conversion of preferred stock into common stock, December 1992                  (249,928)       (2,499)
Sale of common stock and warrants for cash, December 1992 ($4.84 per unit,
     net of offering costs of $1,396,893 or $1.16 per unit)                            -             -
Net loss                                                                               -             -
                                                                              ------------------------

Balance at December 31, 1992                                                           -             -

Sale of common stock and warrants for cash, January 1993 ($5.27 per unit,
     net of offering costs of $131,723 or $.73 per unit)                               -             -
Compensation and consulting expense in connection with options granted                 -             -
Net loss                                                                               -             -
                                                                              ------------------------

Balance at December 31, 1993                                                           -             -
Net loss                                                                               -             -
                                                                              ------------------------

Balance at December 31, 1994                                                           -             -

Sale of common stock and warrants for cash, March and April 1995 ($39,972 per
     unit, net of offering costs of $706,971 or $10,028 per unit)                      -             -
Required registration of common stock and warrants, October 1995
     ($1,525 per unit)                                                                 -             -
Net loss                                                                               -             -
                                                                              ------------------------

Balance at December 31, 1995                                                           -             -
The accompanying notes are an integral part of these financial statements.
</TABLE>

                                       5
<PAGE>   6

<TABLE>
<CAPTION>

                                                   DEFICIT
                                                  ACCUMULATED
          COMMON STOCK                            DURING THE        TREASURY STOCK
------------------------------   ADDITIONAL       DEVELOPMENT   ----------------------
    SHARES       PAR VALUE    PAID-IN CAPITAL        STAGE        SHARES         COST       TOTAL
------------------------------------------------------------------------------------------------------
<S>                  <C>        <C>         <C>                    <C>         <C>    <C>
       390,830       $ 3,908    $   74,093   $         -             -          $  -   $    78,001
             -             -             -      (941,145)            -             -      (941,145)
------------------------------------------------------------------------------------------------------
       390,830         3,908        74,093      (941,145)            -             -      (863,144)

        43,430           435       199,565             -             -             -       200,000
       115,801         1,158       798,842             -             -             -       800,000
             -             -       383,014             -             -             -       383,014
             -             -       507,972             -             -             -       509,109
             -             -       399,296             -             -             -       400,189

             -             -        89,531             -             -             -        90,000

        75,000           750       149,250             -             -             -       150,000
       249,928         2,499             -             -             -             -             -

     1,200,000        12,000     5,791,227             -             -             -     5,803,227
             -             -             -    (2,415,723)            -             -    (2,415,723)
------------------------------------------------------------------------------------------------------
     2,074,989        20,750     8,392,790    (3,356,868)            -             -     5,056,672

       180,000         1,800       946,477             -             -             -       948,277
             -             -        64,011             -             -             -        64,011
             -             -             -    (2,725,902)            -             -    (2,725,902)
------------------------------------------------------------------------------------------------------
     2,254,989        22,550     9,403,278    (6,082,770)            -             -     3,343,058
             -             -             -    (3,040,032)            -             -    (3,040,032)
------------------------------------------------------------------------------------------------------
     2,254,989        22,550     9,403,278    (9,122,802)            -             -       303,026

    10,071,630       100,716     2,717,314             -             -             -     2,818,030

             -             -      (107,530)            -             -             -      (107,530)
             -             -             -    (3,131,059)            -             -    (3,131,059)
------------------------------------------------------------------------------------------------------
    12,326,619       123,266    12,013,062   (12,253,861)            -             -      (117,533)
                                                                                        (continued)
</TABLE>

                                       5
<PAGE>   7

                              Antex Biologics Inc.
                        (a development stage enterprise)

            CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT)

         For the Period August 3, 1991 (Inception) to December 31, 1999
              and the Three Months Ended March 31, 2000 (Unaudited)

<TABLE>
<CAPTION>
                                                                                                  PREFERRED STOCK
                                                                                           -----------------------------
                                                                                               SHARES       PAR VALUE
                                                                                           -----------------------------
<S>                                                                                        <C>              <C>
Issuance of exchange option, May 1996 ($.37 per share, net of  costs of $351,082)                       -   $         -
Issuance of common stock upon exercise of Class B Warrants and stock options,
     May to August 1996, ($.50 per share, net of related costs of $214,811)                             -             -
Net income                                                                                              -             -
                                                                                           -----------------------------
Balance at December 31, 1996                                                                            -             -

Issuance of common stock upon excise of stock options, October 1997                                     -             -
Net loss                                                                                                -             -
                                                                                           -----------------------------
Balance at December 31, 1997                                                                            -             -

Forfeiture of escrowed shares, May 1998                                                                 -             -
Cashless exercise of Placement Agent's unit purchase option, September 1998
     ($121,430 per unit)                                                                                -             -
Issuance of common stock for services, October 1998 ($.29 per share)                                    -             -
Net loss                                                                                                -             -
                                                                                           -----------------------------
Balance at December 31, 1998                                                                            -             -

Exercise of exchange option, September 1999                                                             -             -
Issuance of amended and restated warrant, September 1999                                                -             -
Cancellation of treasury stock, September 1999                                                          -             -
Net loss                                                                                                -             -
                                                                                           -----------------------------
Balance at December 31, 1999                                                                            -             -

Issuance of common stock upon exercise of stock options, February 2000                                  -             -
Sale of preferred stock, common stock, and warrants for cash, March 2000
     ($.66 per unit, net of offering costs of $206,602)                                            44,545           445
Dividend accretion on preferred Series A                                                                -       122,500
Net loss for the period                                                                                 -             -
                                                                                           -----------------------------
Balance at March 31, 2000                                                                          44,545   $   122,945
                                                                                           =============================
</TABLE>

The accompanying notes are an integral part of these financial statements.

                                       6
<PAGE>   8

<TABLE>
<CAPTION>
                                                   DEFICIT
                                                  ACCUMULATED
          COMMON STOCK                            DURING THE         TREASURY STOCK
------------------------------   ADDITIONAL       DEVELOPMENT   ------------------------
    SHARES       PAR VALUE    PAID-IN CAPITAL        STAGE        SHARES         COST      TOTAL
------------------------------------------------------------------------------------------------------
<S>                  <C>        <C>          <C>              <C>               <C>    <C>
             -       $     -    $  979,166   $          -             -         $  -   $   979,166

    10,153,060       101,531     4,760,188              -             -            -     4,861,719
             -             -             -        535,435             -            -       535,435
------------------------------------------------------------------------------------------------------

    22,479,679       224,797    17,752,416    (11,718,426)            -            -     6,258,787

           625             6           423              -             -            -           429
             -             -             -       (442,676)            -            -      (442,676)
------------------------------------------------------------------------------------------------------
    22,480,304       224,803    17,752,839    (12,161,102)            -            -     5,816,540
      (291,663)       (2,916)        2,916              -             -            -             -

     7,048,712        70,487     2,925,187              -     3,423,627   (1,283,860)    1,711,814
        50,000           500        14,000              -             -            -        14,500
             -             -             -     (2,833,687)            -            -    (2,833,687)
------------------------------------------------------------------------------------------------------

    29,287,353       292,874    20,694,942    (14,994,789)    3,423,627   (1,283,860)    4,709,167

     3,595,264        35,953       (35,953)             -             -            -             -
             -             -       502,540              -             -            -       502,540
    (3,423,627)      (34,237)   (1,249,623)             -    (3,423,627)   1,283,860             -
             -             -             -     (3,483,674)            -            -    (3,483,674)
------------------------------------------------------------------------------------------------------

    29,458,990       294,590    19,911,906    (18,478,463)            -            -     1,728,033

        23,400           234         6,552              -             -            -         6,786

    18,717,864       187,179    14,899,564              -             -            -    15,087,188
             -             -      (122,500)             -             -            -             -
             -             -             -     (1,197,826)            -            -    (1,197,826)
------------------------------------------------------------------------------------------------------
    48,200,254      $482,003   $34,695,522   $(19,676,289)            -         $  -   $15,624,181
======================================================================================================
</TABLE>

                                       6
<PAGE>   9

                              Antex Biologics Inc.
                        (a development stage enterprise)

                      CONSOLIDATED STATEMENTS OF CASH FLOWS
                                   (UNAUDITED)
<TABLE>
<CAPTION>
                                                                      THREE MONTHS                      AUGUST 3, 1991
                                                                     ENDED MARCH 31                       (INCEPTION)
                                                                                                               TO
                                                                1999                  2000               MARCH 31, 2000
                                                                ----                  ----               --------------
<S>                                                        <C>                  <C>                       <C>
OPERATING ACTIVITIES
Net loss                                                   $     (538,581)      $    (1,197,826)          $     (19,676,289)
Adjustments to reconcile net loss to net
   cash used in development stage activities:

   Depreciation and amortization of
     property and equipment, net of
     amortization of deferred gain on
     sale/leaseback and equipment                                  26,270                43,198                     467,844
   Amortization of deferred credits                                (7,059)               (7,059)                   (450,710)
   Expense recorded on cashless exercise
     of common stock options and warrants                               -                     -                   1,711,814
   Writedown of construction in progress                                -                     -                     174,400
   Expense recorded on issuance of
     common stock and warrant
     and vesting of options                                             -                     -                   1,048,174

Changes in operating assets and liabilities:
   Accounts and other receivables                                 (50,590)                 (293)                   (105,059)
   Prepaid expenses                                               (38,241)              (58,160)                     (4,005)
   Other assets                                                         -                     -                     (27,291)
   Accounts payable and accrued expenses                          (99,854)               71,724                     (38,113)
   Deferred research and development                              (62,234)                    -                     558,156
   Due from affiliate                                                   -                     -                     420,448
                                                                 --------            ----------                   ---------

Net cash used in development stage activities                    (770,289)           (1,148,416)                (15,920,631)
                                                                 --------            -----------                ------------

INVESTING ACTIVITIES
Purchase of property and equipment                                (80,341)              (62,251)                 (1,242,340)
Increase in restricted cash                                             -                     -                    (146,600)
                                                                 --------            ----------                    --------

Net cash used in investing activities                             (80,341)              (62,251)                 (1,388,940)
                                                                  --------              --------                 -----------
</TABLE>

The accompanying notes are an integral part of these financial statements.
                                                                     (Continued)

                                       7
<PAGE>   10

                              Antex Biologics Inc.
                        (a development stage enterprise)

                CONSOLIDATED STATEMENTS OF CASH FLOWS (CONTINUED)
                                   (UNAUDITED)
<TABLE>
<CAPTION>
                                                                      THREE MONTHS                      AUGUST 3, 1991
                                                                     ENDED MARCH 31                       (INCEPTION)
                                                                                                               TO
                                                                1999                  2000               MARCH 31, 2000
                                                                ----                  ----               --------------
<S>                                                        <C>                  <C>                       <C>
FINANCING ACTIVITIES
Net proceeds from sales of common stock
   and warrants and the exchange option                    $            -       $    15,087,188           $      26,693,358
Net proceeds from exercise of warrants
   and stock options                                                    -                 6,786                   4,868,934
Proceeds from sale and leaseback agreement                              -                     -                   2,164,792
Principal repayments on sale and leaseback
   agreement                                                            -                     -                  (2,164,792)
Proceeds from issuance of notes payable                                 -                     -                     500,000
Proceeds from sale of preferred stock                                   -                     -                     400,189
                                                             -------------       --------------                ------------
Net cash provided by financing activities                               -            15,093,974                  32,462,481
                                                             -------------       --------------                ------------
Net increase (decrease) in cash and cash
   equivalents                                                   (850,630)           13,883,307                  15,152,910

Cash and cash equivalents at beginning
   of period                                                    4,856,479             1,706,275                     436,672
                                                             -------------       --------------                ------------
Cash and cash equivalents at end of period                 $    4,005,849       $    15,589,582            $     15,589,582
                                                             =============       ==============                ============
Supplemental cash flows disclosures:
   Cashless exercise of common stock
     options and warrants                                  $            -       $             -            $      2,995,674
   Notes payable and accrued interest
     converted to preferred stock                          $            -       $             -            $        509,109
   Sale and leaseback of property and
     equipment                                             $            -       $             -            $      2,099,175
   Capitalized equipment                                   $       50,015       $             -            $        247,957
   Deferred compensation                                   $     (264,920)      $             -            $              -
   Interest paid                                           $            -       $             -            $        699,248
</TABLE>

The accompanying notes are an integral part of these financial statements.

                                       8
<PAGE>   11

                              Antex Biologics Inc.
                        (a development stage enterprise)

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
            FOR THE THREE-MONTH PERIODS ENDED MARCH 31, 1999 AND 2000
                                   (UNAUDITED)

1.       BUSINESS

         Antex Biologics Inc. (the "Company") is a biopharmaceutical company
committed to improving human health by developing new products to prevent and
treat infections and related diseases. With respect to its human bacterial
vaccine research and development, the Company currently has strategic alliances
with SmithKline Beecham, Aventis Pasteur and the United States Navy.

         The Consolidated Balance Sheet as of March 31, 2000, the Consolidated
Statements of Operations for the three-month periods ended March 31, 1999 and
2000 and for the period August 3, 1991 (inception) to March 31, 2000, the
Consolidated Statement of Stockholders' Equity (Deficit) for the period January
1, 2000 to March 31, 2000, and the Consolidated Statements of Cash Flows for the
three-month periods ended March 31, 1999 and 2000 and for the period August 3,
1991 (inception) to March 31, 2000 have been prepared without audit. However,
such financial statements reflect all adjustments (consisting solely of normal
recurring adjustments) that are, in the opinion of management, necessary for a
fair presentation of the consolidated financial position of Antex Biologics Inc.
and its subsidiary at March 31, 2000, and the consolidated results of their
operations and their cash flows for the periods referred to above.

         Certain information and footnote disclosures normally included in
financial statements prepared in accordance with generally accepted accounting
principles have been condensed or omitted. These financial statements should be
read in conjunction with the financial statements and notes thereto for the
fiscal year ended December 31, 1999 included in the Company's Annual Report on
Form 10-KSB.

         The results of operations for the period ended March 31, 2000 are not
necessarily indicative of the operating results anticipated for the fiscal year
ending December 31, 2000.

         Since inception, the Company's revenues have been generated solely in
support of its research and development activities and as of March 31, 2000, the
Company's research and products are not sufficiently developed to enable the
Company to generate sufficient revenues on an ongoing basis. As a result, the
Company is considered to be in the development stage.

                                       9
<PAGE>   12

2.       STRATEGIC ALLIANCE

         Effective March 1996, the Company entered into definitive agreements
with SmithKline Beecham Corporation and SmithKline Beecham Biologicals
Manufacturing s.a. ("SmithKline") which established a corporate joint venture,
MicroCarb Human Vaccines Inc. ("MCHV"), to develop and commercialize human
bacterial vaccines utilizing the Company's proprietary technologies. At August
31, 1999, the agreements provided for the following: the option by SmithKline to
provide annual funding of research and development activities for future years;
an exchange option granted by the Company to SmithKline enabling SmithKline to
convert its 26.25% equity interest in MCHV for 3,595,264 shares of the Company's
common stock, under specified conditions; and a warrant granted by the Company
to SmithKline enabling SmithKline to acquire up to 5,730,802 shares of the
Company's common stock, under specified conditions. The agreements also provided
for SmithKline to make milestone payments and pay royalties to MCHV; and for
SmithKline to reimburse the Company for expenses the Company incurred for agreed
upon production lots of vaccines for clinical trials, the conduct of agreed upon
clinical trials, and agreed upon prosecution and maintenance of the Company's
patents and patent applications. As further stipulated in the agreements,
SmithKline was responsible for conducting additional clinical trials,
manufacturing, and sales and distribution.

         Effective September 1, 1999, the agreements were terminated and/or
amended and the Company entered into an Omnibus Agreement with SmithKline
Beecham plc and SmithKline Beecham Biologicals Manufacturing s.a. ("SB") and
MCHV. Under the provisions of the Omnibus Agreement and several related
documents, the following occurred: SmithKline's equity interest in MCHV was
converted into 3,595,264 shares of the Company's common stock and MCHV was
merged into the Company; a new license agreement was executed; and the Company
granted an amended and restated warrant to SB to purchase 3,865,769 shares of
common stock at an exercise price of $.37 per share exercisable on or before
September 1, 2003. The issuance of the warrant resulted in the recognition of a
noncash expense of $502,540 in 1999, as determined by using the Black-Scholes
valuation model.

         The new license agreement covers prophylactic and/or therapeutic
vaccines for certain designated infectious diseases and provides for the
reversion to the Company of all other technology rights previously licensed to
SmithKline. The terms of the license agreement provide for the following:
funding for research and development of $1,333,334 for the period July 1, 1999
to December 31, 1999 with SB having the option to provide annual funding of
research and development activities in the future; milestone payments and
royalties; and, subject to mutual agreement in the future, the reimbursement by
SB of expenses incurred by the Company for production lots of vaccines, the
conduct of clinical trials, and the prosecution and maintenance of the Company's
patents and patent applications pertaining to the licensed technology. As
further stipulated in the agreement, SB will be responsible for conducting
clinical trials, manufacturing, and sales and distribution for the licensed
vaccines.

         Provision was made in the new agreements for the number of shares of
common stock purchasable by SB under the amended and restated warrant agreement
to be increased by an additional 866,189 shares, provided that SB made the
scheduled research and development funding payment of $666,667 on or before
October 1, 1999. The payment was received

                                       10
<PAGE>   13

subsequent to October 1, 1999, and accordingly, no increase occurred. SB has
subsequently notified the Company it disagrees that the delay in receipt of the
payment should have negated SB's right to the increase. The Company and SB are
in discussions on this matter and the ultimate outcome is unknown.

         In 2000, SB notified the Company that it was executing a cashless
exercise of the entire amended and restated warrant that was not in dispute,
and subsequently in May 2000, the Company issued 3,495,204 shares of its common
stock to SB.

         The Company recognized revenue related to human bacterial vaccine
research and development and qualifying reimbursable expenses pursuant to these
agreements of $921,068, $79,765, and $12,441,869 for the three-month periods
ended March 31, 1999 and 2000, and for the period August 3, 1991 (inception) to
March 31, 2000, respectively.

3.       FINANCING

         On March 15, 2000, the Company completed a private placement resulting
in gross proceeds to the Company of $15,293,790. Pursuant to the terms of the
private placement, the Company offered and sold 18,717,864 A Units and 4,454,545
B Units, in each case at a price of $0.66 per Unit.

         Each A Unit consisted of one share of common stock and one Class A
Warrant. Each Class A Warrant has a five-year term and is exercisable
immediately upon issuance to purchase one share of common stock at an exercise
price of $1.50 per share. At the election of the Company, the Class A Warrants
may be redeemed, upon 30 days prior written notice to the holders, at a
redemption price of $0.10 per warrant, if (i) after September 15, 2001, the
average market price of the common stock exceeds $7.50 per share for 20
consecutive trading days or (ii) after March 15, 2002, the average market price
of the common stock exceeds $4.50 per share for 20 consecutive trading days.

         Each B Unit consisted of (i) one-one hundredth (1/100) of a share of
Series A Convertible Preferred Stock and (ii) one Class B Warrant. Effective
March 15, 2001, each one-one hundredth (1/100) of a share of preferred stock is
convertible, at the option of the holder, into one share of common stock. The
preferred stock has no dividend rights, has no voting rights (except as required
by law), and is entitled to participate in a dissolution and liquidation of the
Company with the holders of common stock on an "as converted" basis. The Class B
Warrants are identical to the Class A Warrants, except that the Class B Warrants
do not become exercisable until March 15, 2001.  Since the B Unit was sold at a
price of $0.66, the Series A Convertible Preferred Stock is being accounted for
giving effect to its beneficial conversion features.  Under such accounting,
the Company will record a charge of $2,940,000 to additional paid-in capital on
a pro-rata basis over the one-year non-conversion period.

         The redemption of the Class A Warrants and the Class B Warrants is
contingent upon the effectiveness of a registration statement registering for
resale the shares of common stock issuable upon the exercise of the warrants.
The Company has agreed to file such a registration statement with the Securities
and Exchange Commission, and to use its best efforts to have it declared
effective.

                                       11
<PAGE>   14

         In connection with the financing, the Company paid compensation of
1,666,666 B Units; 3,409,091 Class C Warrants, each having a five-year term and
exercisable March 15, 2001 to purchase one share of common stock at an exercise
price of $.66 per share; 3,409,091 Class D Warrants, each having a five-year
term and exercisable March 15, 2001 to purchase one share of common stock at an
exercise price of $1.50 per share; and $100,000. Neither the Class C Warrants
nor the Class D Warrants are redeemable by the Company.

         The issuance of the shares of preferred stock and the exercise of the
warrants related to compensation is subject to sufficient shares of common stock
being made available.

         In addition, the Company was to enter into a two-year consulting
agreement with one of the entities receiving compensation pursuant to which the
entity was to provide strategic consulting advice to the Company for a fee of
$3,000 per month. Subsequently, both parties mutually agreed to forego the
agreement.

4.       REVERSE STOCK SPLIT

         On June 10, 1999, the stockholders approved resolutions authorizing the
Board of Directors, at its discretion, to effect by amendment of the Certificate
of Incorporation, prior to the next Shareholders Meeting, a reverse stock split
in the range of one-for-four to one-for-ten. To date, no reverse stock split has
been effected.

5.       OPERATING SEGMENTS

         Prior to 1998, the Company devoted substantially all its efforts to a
single product segment, bacterial vaccines. In 1998, the Company established a
second reportable product segment, therapeutics. The therapeutics segment
focuses on research and development of drugs for infections and related
diseases. For 1999 and 2000, only direct costs and fixed asset acquisitions were
attributed to the therapeutics segment.

         The following tables present information regarding the two segments for
for the three-month periods ended March 31, 1999 and 2000:

<TABLE>
<CAPTION>
                                                             Three Months Ended March 31, 1999
                                                             ---------------------------------
                                           Bacterial                             Reconciling
     Category                              Vaccines         Therapeutics            Items               Total
     --------                              --------         ------------            -----               -----
<S>                                     <C>                 <C>                 <C>                <C>
Revenues                                $     763,400       $           -       $      157,668     $       921,068

Research and development
expenses                                $     833,189       $     207,078       $            -     $     1,040,267

Loss from operations                    $     (69,789)      $    (207,078)      $     (306,910)    $      (583,777)

Fixed asset acquisitions                $      54,567       $       4,905       $       20,869     $        80,341
</TABLE>

                                       12
<PAGE>   15

Reconciling items include reimbursable patent costs of $157,668; general and
administrative expenses, net of reimbursable patent costs, of $306,910; and
corporate fixed asset acquisitions and construction in progress expenditures of
$20,869.

<TABLE>
<CAPTION>
                                                             Three Months Ended March 31, 2000
                                                             ---------------------------------
                                           Bacterial                             Reconciling
     Category                              Vaccines         Therapeutics            Items               Total
     --------                              --------         ------------            -----               -----
<S>                                    <C>                  <C>                 <C>                <C>
Revenues                               $       49,998       $           -       $       79,765     $       129,763

Research and development
expenses                               $      790,355       $     216,603       $            -     $     1,006,958

Loss from operations                   $     (740,357)      $    (216,603)      $     (353,433)    $    (1,310,393)

Fixed asset acquisitions               $      103,608       $           -       $      (41,357)    $        62,251
</TABLE>

Reconciling items include reimbursable patent costs of $79,765; general and
administrative expenses, net of reimbursable patent costs, of $353,433; and net
corporate fixed asset acquisitions and construction in progress transfers of
$41,357.

6.       EARNINGS PER SHARE

         Basic earnings per share is computed by dividing net income (loss)
available to common shareholders by the weighted average number of common shares
outstanding during the period. Diluted earnings per share is computed by
dividing net income (loss) available to common shareholders by the weighted
average number of common shares outstanding after giving effect to all dilutive
potential common shares that were outstanding during the period. The Company did
not have any dilutive potential common shares during the three-month periods
ended March 31, 1999 and 2000; and excluded 15,006,594 and 29,130,927 shares,
respectively, represented by stock options, an exchange option and warrants from
the earnings per share calculation as they are anti-dilutive. Net loss as
reported was adjusted for a non-cash dividend accretion to determine the net
loss applicable to common shareholders for the computation of basic or diluted
earnings per share.

ITEM 2.           MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
                  AND RESULTS OF OPERATION

         The Company commenced operations in August 1991.

                                       13
<PAGE>   16

         Effective March 1996, the Company executed definitive agreements with
SmithKline Beecham which established a corporate joint venture, MicroCarb Human
Vaccines Inc., to develop and commercialize human bacterial vaccines utilizing
the Company's proprietary technologies. Effective September 1, 1999, these
agreements were terminated and/or amended and new definitive agreements were
entered into to develop and commercialize related human bacterial vaccines (see
Note 2 to the financial statements).

         The strategic alliances with SmithKline Beecham and Aventis Pasteur are
consistent with one aspect of the Company's overall strategy which, since its
inception, has been to establish strategic partnerships and to focus on
researching technologies with the goal of developing new products to prevent and
treat infectious diseases and their related disorders. The Company is operating
as a development stage enterprise.

RESULTS OF OPERATIONS

         Revenues for the first quarter of 2000 consisted of $79,765 of
reimbursable patent expenses pursuant to the strategic alliance with SmithKline
Beecham and $49,998 from a Small Business Technology Transfer contract. Revenues
for the comparable period in 1999 consisted of human bacterial vaccine research
and development support of $728,900 and reimbursable expenses incurred of
$192,168 pursuant to the SmithKline Beecham alliance.

         The decreases in human bacterial vaccine research and development
support and reimbursable expenses were due to a reduction in the services
requested by SmithKline Beecham and a reduction in reimbursable patent expenses.

         Research and development expenses in the first quarter of 2000
decreased $33,309 to $1,006,958. Decreases occurred in research material costs
and personnel expenditures and were related to the reduction in the services
requested by SmithKline Beecham. These decreases were offset, in part, by
increased facility costs resulting from the recently completed renovation and
expansion of the laboratories.

         General and administrative expenses in the first quarter of 2000
decreased $31,380 to $433,198. Decreases in patent and general legal fees were
offset, in part, by increased facility costs.

         The increase in interest income in the first quarter of 2000 reflects
the increase in cash available for investing resulting from the recently
completed equity financing.

LIQUIDITY AND CAPITAL RESOURCES

         As a development stage company, the Company's operating activities have
been limited primarily to research and development involving its proprietary
technologies, and accordingly, have generated limited revenues.

         For 2000, the Company will rely primarily upon the net proceeds of
approximately $15,000,000 from the private placement completed in March 2000 to
fund its operations (see

                                       14
<PAGE>   17

Note 3 to the financial statements). During 2000, the Company will continue to
assess to which human bacterial vaccine projects and antibacterials projects
resources will be allocated. The Company anticipates that its research and
development expenses related to these projects will be substantial for the
foreseeable future. It is anticipated that in 2000 SmithKline Beecham will limit
its funding to the reimbursement of certain agreed upon patent-related expenses.
The Company intends to pursue additional strategic alliances, technology
licenses, and grants and contracts to help fund its research and development
expenses.

         The Company currently anticipates that it will increase its total
employees and contract personnel from its 1999 year-end total of 28 to
approximately 35 in 2000. The annual rent and pro-rata share of building
operating expenses and administrative charges for the Company's facility are
estimated at approximately $882,000 for 2000.

         In order to sustain its research and development programs beyond 2001,
as well as to fund its future operations, the Company will continue to seek
additional financing. The Company has no lines of credit. In seeking additional
funding, the Company continues to examine a range of possible transactions,
including: additional strategic alliances; additional equity or debt public
offerings and private placements; the exercise of currently outstanding
warrants; additional grants and contracts; the sale and leaseback of existing
assets; and research and development funding from third parties. However, there
is no assurance that additional funds will be available from these or any other
sources or, if available, that, with the exception of the warrants, the terms on
which such funds can be obtained will be acceptable to the Company.

NEW ACCOUNTING STANDARDS

         The Financial Accounting Standards Board has issued a new standard.
Statement of Financial Accounting Standards No. 133 ("SFAS 133"), Accounting for
Derivative Instruments and Hedging Activities, which becomes effective for years
beginning after June 15, 2000, requires that every derivative instrument be
recorded in the balance sheet as either an asset or liability measured at its
fair value. The statement requires that changes in the derivative's fair value
be recognized in earnings unless specific hedge accounting criteria are met. The
Company believes that the effect of adoption of SFAS 133 will not be material to
the Company's financial statements.

         In December 1999, the Securities and Exchange Commission issued Staff
Accounting Bulletin No. 101 ("SAB No. 101"), Revenue Recognition in Financial
Statements, which summarizes certain of the staff's views on revenue
recognition. The Company's revenue recognition policies have been and continue
to be in accordance with SAB No. 101.

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

         Statements contained herein that are not historical facts may be
forward-looking statements that are subject to a variety of risks and
uncertainties. There are a number of important factors that could cause actual
results to differ materially from those expressed in any forward-looking
statements made by the Company. These factors include, but are not limited to:
(i) the Company's ability to fund its future operations; (ii) the Company's
ability to successfully

                                       15
<PAGE>   18

complete product research and development, including preclinical and clinical
studies and commercialization; (iii) the Company's ability to obtain required
governmental approvals; (iv) the Company's ability to attract and/or maintain
manufacturing sales, distribution and marketing partners; and (v) the Company's
ability to develop and commercialize its products before its competitors.

                           PART II OTHER INFORMATION

ITEM 2.  CHANGES IN SECURITIES AND USE OF PROCEEDS

         On March 15, 2000, the Company completed the sale of 18,717,864 A Units
and 4,454,545 B Units to a number of individual investors as the result of which
the Company received aggregate proceeds approximately of $15.3 million (see
Note 3 to the financial statements). The sale was effected in reliance on the
exemption from registration afforded by Rule 506 under the Securities Act of
1933, as amended.

ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

EXHIBITS

        Exhibit
          No.            Description
        -------          -----------
         27.1            Financial Data Schedule

REPORTS ON FORM 8-K

         The Company filed a Form 8-K on March 22, 2000 which contained a
description of the equity financing that the Company completed on March 15,
2000, and included the definitive agreements as exhibits.

         The Company filed a Form 8-K on May 5, 2000 indicating that effective
April 28, 2000, the Company's independent accountants, PricewaterhouseCoopers
LLP, resigned. The Form 8-K cited that during the last two calendar years, and
to the date of resignation, there were no disagreements with
PricewaterhouseCoopers LLP on any matter of accounting principle or practice,
financial statement disclosure, or auditing scope or procedure that, if not
resolved to the satisfaction of PricewaterhouseCoopers LLP, would have caused
PricewaterhouseCoopers LLP to refer to the matter in its report. The Audit
Committee of the Company is conducting a search for new independent accountants.

                                       16
<PAGE>   19

                                   SIGNATURES

         In accordance with Section 13 or 15(d) of the Exchange Act, the
registrant has caused this report to be signed on its behalf by the undersigned,
thereunto duly authorized.

                                                         ANTEX BIOLOGICS INC.

     Date:    May 22, 2000                  By:      /s/V. M. Esposito
                                                  --------------------
                                                  V. M. Esposito, President and
                                                  Chief Executive Officer

     Date:    May 22, 2000                  By:      /s/Gregory C. Zakarian
                                                  -------------------------
                                                  Gregory C. Zakarian, Treasurer
                                                  and Chief Financial Officer