<PAGE>

================================================================================

                                  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 period ended June 30, 2000

                                       OR

     [ ]  Transition report pursuant to Section 13 or 15(d) of the Securities
          Exchange Act of 1934

                        Commission file number: 000-24207

                                  ABGENIX, INC.
             (Exact name of registrant as specified in its charter)

               DELAWARE                                 94-3248826
      (State or other jurisdiction of                (I.R.S. Employer
      incorporation or organization)               Identification Number)


                              7601 DUMBARTON CIRCLE
                            FREMONT, CALIFORNIA 94555
                    (Address of principal executive offices)

                         TELEPHONE NUMBER (510) 608-6500
              (Registrant's telephone number, including area code)

          Indicate by 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.

                               Yes X       No

As of July 31, 2000 there were 81,191,610 shares of the Registrant's Common
Stock outstanding.

================================================================================


                                       1
<PAGE>

                                  ABGENIX, INC.

                                    FORM 10-Q

                                      INDEX

<TABLE>
<CAPTION>

                                                                        Page No.
                                                                        --------
<S>  <C><C>                                                                  <C>

PART I - FINANCIAL INFORMATION

     ITEM 1 -- FINANCIAL STATEMENTS

        Condensed Consolidated Balance Sheets -- June 30, 2000 and
          December 31, 1999.................................................   3

        Condensed Consolidated Statements of Operations -- Three months
          and six months ended June 30, 2000 and June 30, 1999..............   4

        Condensed Consolidated Statements of Cash Flows -- Six months
          ended June 30, 2000 and June 30, 1999.............................   5

        Notes to Condensed Consolidated Financial Statements................   6

     ITEM 2 -- MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
        AND RESULTS OF OPERATIONS...........................................  11

     ITEM 3 -- QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK...  33

PART II - OTHER INFORMATION

     ITEM 1 -- LEGAL PROCEEDINGS............................................  33

     ITEM 2 -- CHANGES IN SECURITIES AND USE OF PROCEEDS....................  33

     ITEM 3 -- DEFAULTS UPON SENIOR SECURITIES..............................  34

     ITEM 4 -- SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS..........  34

     ITEM 5 -- OTHER INFORMATION............................................  35

     ITEM 6 -- EXHIBITS AND REPORTS ON FORM 8-K.............................  35

     SIGNATURES.............................................................  36


</TABLE>


                                       2
<PAGE>

                                  ABGENIX, INC.
                      CONDENSED CONSOLIDATED BALANCE SHEETS
                 (IN THOUSANDS, EXCEPT SHARE AND PER SHARE DATA)

<TABLE>
<CAPTION>

                                                                   JUNE 30,      DECEMBER 31,
                                                                     2000            1999
                                                                   ---------     ------------
                                                                   Unaudited
<S>                                                                <C>            <C>

                                     ASSETS
Current assets:
     Cash and cash equivalents ...............................     $ 124,546      $  13,366
     Marketable securities ...................................       430,991         43,543
     Interest receivable .....................................         5,907          1,103
     Accounts receivable .....................................           600          4,150
     Prepaid expenses and other current assets ...............         8,726          4,861
                                                                   ---------      ---------
               Total current assets ..........................       570,770         67,023

Property and equipment, net ..................................         6,254          5,300
Long-term investment .........................................        31,896         29,225
Intangible assets, net .......................................        45,038         46,591
Deposits and other assets ....................................           708            402
                                                                   ---------      ---------
                                                                   $ 654,666      $ 148,541
                                                                   =========      =========

                      LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
     Accounts payable ........................................     $   1,821      $   1,705
     Deferred revenue ........................................        12,539          3,767
     Accrued product development costs .......................         2,191          1,667
     Accrued employee benefits ...............................         1,018          1,287
     Other accrued liabilities ...............................         1,035            725
     Current portion of long-term debt .......................           541          1,759
                                                                   ---------      ---------
               Total current liabilities .....................        19,145         10,910

Deferred rent ................................................           207            150
Long-term debt ...............................................            33            421
Commitments
Stockholders' equity:
     Preferred stock, $.0001 par value; 5,000,000 shares
       authorized, none issued and outstanding
     Common stock, $0.0001 par value; 100,000,000 shares
       authorized, 81,126,168 and 68,669,092 shares issued
       and outstanding at June 30, 2000 and December 31, 1999,
       respectively, at amount paid in .......................       681,715        181,263
     Additional paid-in capital ..............................        32,849         32,254
     Deferred compensation ...................................          (419)          (670)
     Accumulated other comprehensive income ..................        16,739         14,013
     Accumulated deficit .....................................       (95,603)       (89,800)
                                                                   ---------      ---------
               Total stockholders' equity ....................       635,281        137,060
                                                                   ---------      ---------
                                                                   $ 654,666      $ 148,541
                                                                   =========      =========

</TABLE>

                             See accompanying notes.


                                       3
<PAGE>

                                  ABGENIX, INC.
                 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
                      (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                   (UNAUDITED)

<TABLE>
<CAPTION>

                                                      THREE MONTHS ENDED        SIX MONTHS ENDED
                                                           JUNE 30,                  JUNE 30,
                                                     --------------------     ---------------------
                                                       2000        1999         2000         1999
                                                     --------    --------     --------     --------
<S>                                                  <C>         <C>          <C>          <C>

Revenues:
     Contract revenue ..........................     $  3,478    $  1,720     $  5,443     $  1,720
     Interest income ...........................        8,781         797       13,122        1,192
                                                     --------    --------     --------     --------
             Total revenues ....................       12,259       2,517       18,565        2,912

Costs and expenses:
     Research and development ..................       11,912       5,312       19,126        9,878
     General and administrative ................        1,805       1,210        3,390        2,295
     Amortization of intangible assets .........          777          --        1,553           --
     Equity from  the Xenotech joint venture ...           --        (548)          --         (540)
     Interest expense ..........................          185         111          300          244
                                                     --------    --------     --------     --------
             Total costs and expenses ..........       14,679       6,085       24,369       11,877
                                                     --------    --------     --------     --------
Net loss .......................................     $ (2,420)   $ (3,568)    $ (5,804)    $ (8,965)
                                                     ========    ========     ========     ========
Basic and diluted net loss per share ...........     $  (0.03)   $  (0.06)    $  (0.07)    $  (0.17)
                                                     ========    ========     ========     ========
Shares used in computing basic and diluted
 net loss per share ............................       80,545      59,664       77,522       54,216
                                                     ========    ========     ========     ========

</TABLE>

                             See accompanying notes.

                                       4
<PAGE>

                                  ABGENIX, INC.
                 CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                                 (IN THOUSANDS)
                                   (UNAUDITED)

<TABLE>
<CAPTION>

                                                                    SIX MONTHS ENDED
                                                                        JUNE 30,
                                                                -----------------------
                                                                  2000          1999
                                                                ---------     ---------
<S>                                                             <C>           <C>

Operating activities:
Net loss ...................................................    $  (5,804)    $  (8,965)
Adjustments to reconcile net loss to net cash provided by
    (used in) operating activities:
    Equity in (income) losses of Xenotech ..................           --          (540)
    Depreciation and amortization ..........................        2,511           831
    Stock-based compensation related to stock options issued
      to consultants .......................................          595           390
    Changes for certain assets and liabilities:
      Interest receivable ..................................       (4,804)         (682)
      Accounts receivable ..................................        3,550            --
      Prepaid expenses and other current assets ............       (3,864)         (899)
      Deposits and other assets ............................         (315)           --
      Accounts payable .....................................          116         1,215
      Deferred revenue .....................................        8,772            --
      Accrued product development costs ....................          524           886
      Other accrued liabilities ............................           41           159
      Deferred rent ........................................           57            --
                                                                ---------     ---------
Net cash provided by (used in) operating activities ........        1,379        (7,605)
                                                                ---------     ---------
Investing activities:
    Purchases of marketable securities .....................     (514,607)      (47,780)
    Maturities of marketable securities ....................      127,214         5,183
    Capital expenditures ...................................       (1,652)         (245)
                                                                ---------     ---------
Net cash used in investing activities ......................     (389,045)      (42,842)
                                                                ---------     ---------
Financing activities:
    Net proceeds from issuances of common stock from
      the follow-on public offering in February 2000 .......      496,657            --
    Net proceeds from other issuances of common stock ......        3,795        52,884
    Payments on long-term debt .............................       (1,606)         (842)
                                                                ---------     ---------
Net cash provided by financing activities ..................      498,846        52,042
                                                                ---------     ---------
Net increase in cash and cash equivalents ..................      111,180         1,595
Cash and cash equivalents at the beginning of the period ...       13,366         1,415
                                                                ---------     ---------
Cash and cash equivalents at the end of the period .........    $ 124,546     $   3,010
                                                                =========     =========

</TABLE>

                             See accompanying notes.


                                       5
<PAGE>

                                  ABGENIX, INC.
              CONDENSED CONSOLIDATED NOTES TO FINANCIAL STATEMENTS
                                  JUNE 30, 2000

1.   BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

BASIS OF PRESENTATION - The unaudited condensed financial statements of Abgenix,
Inc. (the "Company" or "Abgenix") included herein have been prepared by the
Company pursuant to the rules and regulations of the Securities and Exchange
Commission. Certain information or footnote disclosure normally included in
financial statements prepared in accordance with generally accepted accounting
principles have been condensed or omitted pursuant to such rules and
regulations. In the opinion of the Company, the accompanying unaudited condensed
financial statements contain all adjustments, consisting only of normal
recurring adjustments, necessary to present fairly the financial information
included therein. These financial statements should be read in conjunction with
the audited financial statements for the year ended December 31, 1999 and
accompanying notes included in the Company's Annual Report as filed on Form 10-K
with the Securities and Exchange Commission on March 28, 2000. The results of
operations for the quarter and six months ended June 30, 2000 are not
necessarily indicative of the results to be expected for the full year or for
any other future period.

REVENUE RECOGNITION - In December 1999, the Securities and Exchange Commission
issued Staff Accounting Bulletin No. 101--Revenue Recognition in Financial
Statements ("SAB 101"), which provides guidance on the accounting for revenue
recognition. The Company is currently evaluating the applicability of SAB 101 to
its existing agreements. Should the Company conclude that its approach is
different from the approach described in SAB 101, it will change its method of
accounting. As amended, SAB 101 is required to be implemented no later than the
fourth fiscal quarter of 2000, for companies with fiscal years beginning between
December 16, 1999 and March 15, 2000.

The Company receives payments from customers for licenses, options and services.
These payments are generally non-refundable but are reported as deferred revenue
until they are recognizable as revenue. The Company has followed the following
principles in recognizing revenue:

     -    Research license fees: Fees to license the use of XenoMouse in
          research performed by the customer are generally recognized when both
          the inception of the license period and delivery of the technology has
          occurred. If Abgenix is obligated to provide significant assistance to
          enable the customer to practice the license, then the revenue is
          recognized over the period of such obligation.

     -    Product license fees: Fees to license the production, use and sale of
          an antibody generated by XenoMouse are generally recognized when both
          the inception of the license period and delivery of the technology has
          occurred. If Abgenix is obligated to provide significant assistance to
          enable the customer to practice the license, then the revenue is
          recognized over the period of such obligation.

     -    Option fees: Fees for granting options to obtain product licenses are
          recognized as revenue when the option is exercised or when the option
          period expires, whichever occurs first.

     -    Payments for research services performed by Abgenix are recognized
          ratably over the period during which these services are performed.

     -    Milestone payments are recognized as revenue when the milestone is
          achieved.


                                       6
<PAGE>

TWO-FOR-ONE STOCK SPLITS - The accompanying financial statements have been
restated to reflect both a two-for-one common stock split effective on April 6,
2000 and a two-for-one common stock split effective on July 7, 2000.

BASIC AND DILUTED NET LOSS PER SHARE

Net loss per share is based on the weighted average number of shares of common
stock outstanding. Potentially dilutive securities have been excluded from the
computation, as their effect is antidilutive.

2.   MARKETABLE SECURITIES

The following is a summary of marketable securities at June 30, 2000 and
December 31, 1999:

<TABLE>
<CAPTION>

                                                   AS OF JUNE 30, 2000                   AS OF DECEMBER 31, 1999
                                          ------------------------------------    ------------------------------------
                                          Amortized   Unrealized    Estimated     Amortized   Unrealized    Estimated
                                             Cost     Gain/(Loss)   Fair Value      Cost      Gain/(Loss)   Fair Value
                                          ---------   -----------   ----------    ---------   -----------   ----------
                                                    (in thousands)                          (in thousands)
<S>                                       <C>          <C>           <C>          <C>          <C>           <C>
Commercial obligations ...............    $  19,650    $     (45)    $  19,605    $  22,829    $     (73)    $  22,756
Commercial paper .....................      515,670          (43)      515,627       15,358           10        15,368
Obligations of the U.S. government
  and its agencies ...................       16,000          (69)       15,931       17,822         (149)       17,673
Marketable equity securities .........       15,000       16,896        31,896       15,000       14,225        29,225
                                          ---------    ---------     ---------    ---------    ---------     ---------
Total ................................    $ 566,320    $  16,739     $ 583,059    $  71,009    $  14,013     $  85,022
                                          =========    =========     =========    =========    =========     =========

Classified as:
   Cash equivalents ..................                               $ 120,172                               $  11,151
   Marketable securities .............                                 430,991                                  44,646
   Long-term investment ..............                                  31,896                                  29,225
                                                                     ---------                               ---------
                                                                     $ 583,059                               $  85,022
                                                                     =========                               =========

</TABLE>

The Company's available-for-sale debt securities have the following
maturities at June 30, 2000:

<TABLE>
<CAPTION>

<S>                                                                  <C>
Due in one year or less........................                      $ 559,180
Due after one year but less that five years....                          1,983
                                                                     ---------
                                                                     $ 561,163
                                                                     =========

</TABLE>

3.   COMPREHENSIVE INCOME

Other comprehensive gains/(losses) consist of unrealized gains or losses on
available-for-sale securities. For the quarter and six month periods ended June
30, 2000 the company recorded an unrealized loss of $7.73 million and an
unrealized gain of $2.67 million, respectively, relating to its investment in
CuraGen Corporation. Additionally, for the quarter and six month periods ended
June 30, 2000 the company recorded unrealized losses of $50,000 and $156,000,
respectively, in other available for sale investments. There were no other
comprehensive gains or losses for the quarter or six months ended June 30, 1999.

4.   STOCKHOLDER'S EQUITY AND FOLLOW-ON PUBLIC OFFERING

All shares and per share amounts have been restated to reflect both the
two-for-one common stock split effective April 6, 2000 and the two-for-one
common stock split effective July 7, 2000.

On February 10, 2000 the Company completed a follow-on public offering in which
the Company sold 8,640,000 shares and Cell Genesys sold 3,360,000 shares of the
Company's common stock to the public at a


                                       7
<PAGE>

price of $52.50 per share. On February 29, 2000 the Company's underwriters
exercised their overallotment option to purchase 1,800,000 additional shares, of
which 1,296,000 shares were sold by the Company and 504,000 shares were sold by
Cell Genesys at a price of $52.50 per share. The Company received net proceeds
from the offerings of approximately $496.5 million after the underwriters'
discount and costs of offering.

In January 2000, Cell Genesys exercised its warrants to purchase 486,668 shares
of the Company's stock at an exercise price of $1.50 per share.

On May 3, 2000 the Company's stockholders approved an increase to the aggregate
number of shares of common stock authorized for issuance under the Company's
1996 Incentive Stock Plan by 1,200,000 shares.

On May 3, 2000 the Company's stockholders approved an amendment to the Company's
Certificate of Incorporation to increase the authorized number of shares of
common stock from 50,000,000 to 100,000,000.

5.   CUSTOMER AND LICENSE AGREEMENTS

Abbott: In May 2000, the Company entered into a collaboration agreement,
including an option and research license, with Abbott Laboratories to generate
fully human antibodies to disease targets. Under this agreement, Abbott is
required to pay the Company to perform the immunizations and certain research
activities.

Corixa: In March 2000, the Company entered into an agreement to discover and
develop fully human antibodies against selected targets from Corixa
Corporation's library of proprietary autoimmune disease, cancer and infectious
disease antigens.

Elan: In January 2000, the Company entered into a research license and option
agreement with Elan Pharmaceuticals Inc. to generate fully human antibodies to
an undisclosed antigen in the field of neurological diseases.

Gliatech: In January 2000, the Company entered into a research agreement, option
and license agreement with Gliatech Medical Inc. to generate fully human
antibodies for use in the fields of cardiovascular and inflammatory diseases.
Under this agreement, Gliatech is required to pay the Company to perform the
immunizations and certain research activities.

Millennium: In March 2000, the Company granted Millennium Pharmaceuticals, Inc.
a license to use XenoMouse in research performed by Millennium and several
licenses to make, use and sell antibodies generated with XenoMouse. Payments
totaling $10 million were made in the first quarter of 2000 representing a
research license fee, product license fees and service fees to establish the
technology at Millennium. The Company is recognizing these fees ratably each
month over the period ended December 31, 2000 during which Abgenix is obligated
to assist in establishing the technology at Millennium, which will enable
Millennium to practice the research license and product licenses. Accordingly,
$1.0 million was recognized as revenue in the quarter ended March 31, 2000, and
$3.0 million was recognized as revenue in the quarter ended June 30, 2000. At
June 30, 2000, $6.0 million remained in deferred revenue. The $10 million
payment was made in common stock of Millennium, which was subsequently sold in
May 2000 shortly after the shares were registered. Millennium was obligated to
make up the difference, if any, between the fair value of such stock upon sale
and $10 million, and the Company was obligated to pay, and did pay, the excess
of the fair value of such stock upon sale and $10 million.

SmithKline Beecham: In May 2000, the Company entered into a collaboration
agreement, including an option and research license with SmithKline Beecham
Pharmaceuticals Inc. to generate fully human antibodies to an undisclosed
antigen.


                                       8
<PAGE>

6.   OTHER CONTRACTUAL OBLIGATIONS

In May 2000, the Company entered into an agreement to produce commercial
quantities of its fully human antibody, ABX-IL8, using Genzyme Transgenics
Corporation's manufacturing system. Under the terms of the agreement, in
exchange for fees and milestone payments, Genzyme Transgenics agreed to develop
transgenic goats that express ABX-IL8 in their milk.

In May 2000, the Company entered into an agreement with a contract manufacturer
of its product candidates, to reserve manufacturing capacity by acquiring an
option to negotiate a supply agreement, the terms of which are generally
outlined in the option agreement. The total amount paid for this agreement was
approximately $3.8 million of which $2.3 million was recorded as an expense in
research and development and approximately $1.5 million was recorded as a
deposit because it is creditable to the supply agreement. If a supply agreement
is not entered into, all of the $3.8 million is non-refundable except under
limited circumstances.

7.   FACILITY LEASES AND LETTER OF CREDIT

In February 2000, the Company signed an operating lease for an additional
100,100 square foot facility to be used primarily for offices. In May 2000,
the Company also signed an operating lease for an additional 100,000 square
foot facility to be built and used for pilot scale manufacturing. Both leases
expire in the year 2015, with options to extend the lease terms. The Company
issued a stand-by letter of credit for $2.0 million to the lessor for the
lease term, as a condition to the lease. Future minimum payments under these
non-cancelable operating leases are as follows (in thousands): 2000--$1,121;
2001--$3,986; 2002--$4,802; 2003--$4,969; 2004--$5,138; and thereafter
$65,509.

8.   SUBSEQUENT EVENTS

Lexicon: On July 12, 2000 the Company entered into a collaborative agreement
with Lexicon Genetics Inc. Under the terms of the agreement, Lexicon agreed to
contribute antigen targets that derive from its proprietary portfolio of
full-length human genes whose functions are defined using Lexicon's knockout
mouse technology. The Company will use its XenoMouse technology to generate
fully human antibodies for each of the targets selected by a joint committee.
Each party will have the right to obtain exclusive commercialization rights,
including sublicensing rights, for an equal number of qualifying antibodies.
Each party will receive milestone payments and royalties on sales of antibody
drugs from the collaboration that are commercialized by the other party.

Immunex: On July 26, 2000 the Company entered into a joint development and
commercialization agreement with Immunex Corporation, for ABX-EGF, a fully human
antibody created by the Company and currently in a Phase I clinical trial
involving several tumor types. Under the agreement, Immunex has agreed to make
an initial license fee payment to the Company, and a second license fee payment
upon commencement of Phase II clinical trials of ABX-EGF. Development costs will
be shared equally, as would any potential profits from sales of a targeted
product. Immunex and the Company will share responsibility for product
development. The Company will complete the ongoing Phase I trial, while both
parties would share efforts in the execution of Phase II trials across a variety
of indications. Immunex would have primary responsibility for Phase III clinical
trials, and would market any potential product, while the Company would retain
co-promotion rights.

SangStat: On August 8, 2000, the Company entered into a joint development and
commercialization agreement with SangStat Medical Corporation for ABX-CBL, an
antibody developed by the Company and currently in a Phase II/III clinical
trial. Under the agreement, SangStat will make an initial license fee payment
and


                                       9
<PAGE>

additional milestone payments to Abgenix. Development costs will be shared
equally, as would any potential profits from sales of collaboration products.
SangStat and Abgenix will share responsibility for product development,
including the ongoing Phase II/III clinical trial. SangStat will market any
potential products and Abgenix will be responsible for manufacturing ABX-CBL.



                                       10
<PAGE>

                                  ABGENIX, INC.

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

THE FOLLOWING MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
RESULTS OF OPERATIONS CONTAINS FORWARD-LOOKING STATEMENTS BASED UPON CURRENT
EXPECTATIONS THAT INVOLVE RISKS AND UNCERTAINTIES. WHEN USED IN THIS QUARTERLY
REPORT ON FORM 10-Q, THE WORDS "INTEND," "ANTICIPATE," "BELIEVE," "ESTIMATE,"
"PLAN" AND "EXPECT" AND SIMILAR EXPRESSIONS AS THEY RELATE TO ABGENIX ARE
INCLUDED TO IDENTIFY FORWARD-LOOKING STATEMENTS. OUR ACTUAL RESULTS AND THE
TIMING OF CERTAIN EVENTS COULD DIFFER MATERIALLY FROM THOSE ANTICIPATED IN THESE
FORWARD-LOOKING STATEMENTS AS A RESULT OF CERTAIN FACTORS, INCLUDING THOSE SET
FORTH BELOW AND UNDER "ADDITIONAL FACTORS THAT MIGHT AFFECT FUTURE RESULTS" SET
FORTH BELOW IN THIS QUARTERLY REPORT ON FORM 10-Q AND ELSEWHERE IN THIS
QUARTERLY REPORT ON FORM 10-Q.

OVERVIEW

We are a biopharmaceutical company that develops and intends to commercialize
antibody therapeutic products for the treatment of a variety of disease
conditions, including transplant-related diseases, inflammatory and autoimmune
disorders, cardiovascular disease, infectious diseases and cancer. We have
developed XenoMouse technology, a proprietary technology, which we believe
offers many advantages, including rapid generation of highly specific, fully
human antibody product candidates that bind to essentially any disease target
appropriate for antibody therapy. In addition, we believe our technology offers
advantages in product development and flexibility in manufacturing. We intend to
use XenoMouse technology to build a large and diversified product portfolio that
we plan to develop and commercialize through licensing to pharmaceutical
companies, joint development and commercialization licensing arrangements with
pharmaceutical companies and internal product development programs. We have
contractual arrangements with multiple pharmaceutical, biotechnology and
genomics companies involving our XenoMouse technology. In addition, we have
three proprietary antibody product candidates currently in clinical trials, one
of which we recently agreed to co-develop and commercialize with Immunex.

Contractual Arrangements

As of August 9, 2000 we have established contractual arrangements to use our
XenoMouse technology to produce fully human antibodies with twenty-three
customers covering numerous antigen targets. Pursuant to these arrangements, we
and our customers intend to generate antibody product candidates for the
treatment of cancer, inflammation, auto immune diseases, transplant rejection,
cardiovascular disease, growth factor modulation, neurological diseases and
infectious disease. Our customers as of August 9, 2000 include Abbott
Laboratories, Amgen, AVI BioPharma, BASF Bioresearch Corporation, Cell Genesys,
Centocor/Johnson and Johnson, Chiron, Corixa, CuraGen, Elan, Genentech,
Gliatech, Human Genome Sciences, Immunex, Japan Tobacco, Lexicon Genetics,
Millennium, Pfizer, Research Corporation Technologies, Sangstat,
Schering-Plough, SmithKline Beecham and the U.S. Army. Of these customers, six
have each entered into new or expanded agreements with us specifying additional
antigens for XenoMouse antibody development. Additionally, of the customers with
whom we have entered technology license deals, AVI BioPharma, Japan Tobacco,
Millennium, Pfizer, and Schering-Plough have entered into product licenses. The
terms of the arrangements vary, but can generally be categorized as follows:

-    Antigen Target Sourcing Arrangements-Four of our contractual arrangements
     are target sourcing arrangements with genomics and biopharmaceutical
     companies which will enable us to generate a continuous stream of
     proprietary fully human antibody product candidates. Typically, these
     arrangements


                                       11
<PAGE>

     provide that we make fully human antibodies to the partners' antigen
     targets. There are various mechanisms for each of the parties to evaluate
     and select antibodies from the pool of generated antibodies for further
     development and commercialization. The party selecting a product candidate
     will generally pay to the other, for rights to develop and commercialize
     such product, license fees, milestone payments and royalty payments on any
     eventual product sales.

-    Proprietary Product Licensing-In July and August 2000, we entered into two
     joint development and commercialization agreements. The first was with
     Immunex Corporation for ABX-EGF, a fully human antibody created by us.
     Under the agreement, Immunex agreed to make an initial license fee payment
     to us and a second license fee payment to us upon commencement of Phase II
     clinical trials of ABX-EGF. Development costs will be shared equally, as
     would any potential profits from sales of collaboration products. We both
     share responsibility for product development. We will complete the ongoing
     Phase I trial. If Phase I trials are successful, both companies will share
     efforts in the execution of Phase II trials across a variety of
     indications. Immunex will have primary responsibility for Phase III
     clinical trials, and will market any potential product, while we will
     retain co-promotion rights. The second agreement was with Sangstat Medical
     Corporation for ABX-CBL, an antibody developed by us. Under the agreement,
     SangStat agreed to make an initial license fee payment to us and additional
     milestone payments to us. Development costs will be shared equally, as
     would any potential profits from sales of collaboration products. SangStat
     and Abgenix will share responsibility for product development, including
     the ongoing Phase II/III clinical trial. SangStat will market any potential
     product and we will be responsible for manufacturing ABX-CBL.

     We intend to build our product portfolio by generating antibodies to
     antigen targets that we source, self-funding clinical activities to
     determine preliminary safety and efficacy, and entering into more
     development and commercialization agreements with pharmaceutical and
     biotechnology companies. These arrangements may or may not involve joint
     sharing of costs and profits.

-    Technology Licensing Deals-These agreements typically provide our customers
     with access to XenoMouse technology for the purpose of generating fully
     human antibody product candidates to one or more specific antigen targets
     provided by the customer. In most cases, we provide our mice to the
     customers who then carry out immunizations with their specific antigen
     targets. In other cases, we immunize the mice with the customers' antigen
     targets for additional compensation. The customer generally has a period of
     time to acquire product licenses for any antibody product they wish to
     develop and commercialize, generally referred to as an option. The
     financial terms of these agreements may include license fees, option fees,
     and milestone payments paid to us by our customers. Based on our
     agreements, these payments and fees would average $8.0 to $10.0 million per
     antigen target if our customer takes the antibody product candidate into
     development and ultimately to commercialization. Additionally we are
     entitled to receive royalties on any future product sales by the customer.

Proprietary Products

We also have three antibody product candidates that are currently in clinical
trials as follows:

-    ABX-IL8 - Generated using XenoMouse technology, ABX-IL8 is our fully human
     antibody candidate for the treatment of psoriasis. We completed Phase I and
     Phase I/II clinical trials and initiated Phase II clinical trials in April
     2000 in which enrollment is ongoing.

-    ABX-EGF - Generated using XenoMouse technology, ABX-EGF is our fully human
     antibody candidate for the treatment of a variety of cancers. We initiated
     a Phase I clinical trial for ABX-EGF in cancer in 1999 in which enrollment
     is ongoing. In July 2000 we entered the joint development and
     commercialization agreement with Immunex Corporation for ABX-EGF, described
     above.


                                       12
<PAGE>

-    ABX-CBL - An in-licensed mouse antibody, ABX-CBL is an antibody we
     developed for the treatment of a transplant-related disease known as graft
     versus host disease, or GVHD. We completed a multi-center Phase II clinical
     trial for ABX-CBL and initiated a Phase II/III clinical trial in December
     1999 in which enrollment is ongoing. In August 2000 we entered into the
     joint development and commercialization agreement with Sangstat Medical
     Corporation, for ABX-CBL, described above.

We will expend significant capital to conduct clinical trials for these product
candidates. We believe that more extensive clinical data will enable us to enter
into more favorable proprietary product licensing agreements. We expect that
this will increase our operating losses until our development expenses can be
covered by increased revenues from licensing of XenoMouse technology and
marketing of proprietary products. If clinical trials of one or more product
candidates at any stage are unsuccessful, we may abandon that product candidate
which would result in the substantial loss of our investment in such candidate.

Other

In December 1999, we paid $47.0 million to purchase Japan Tobacco's interest in
the Xenotech joint venture, and a non-recurring payment of $10.0 million to
terminate rights to the current XenoMouse technology. Additionally, Japan
Tobacco paid us $6.0 million to acquire a license to new technology, and $4.0
million to acquire a research license and commercialization rights under
existing and future XenoMouse technology on a more limited basis than it had
under our prior collaboration with Japan Tobacco.

RESULTS OF OPERATIONS

THREE MONTHS AND SIX MONTHS ENDED JUNE 30, 2000 AND 1999

Contract revenue totaled $3.5 million and $5.4 million in the three and
six-month periods ended June 30, 2000 compared to $1.7 million in both of the
comparable 1999 periods. Revenue recognized during the 2000 three and six month
periods included $1.0 million and $4.0 million, respectively, of the $10 million
payment received under the agreement with Millennium Pharmaceuticals. Although
the payment from Millennium is non-refundable and was received at the inception
of a research license and product licenses granted to Millennium upon signing of
the agreement, Abgenix is obligated up to December 31, 2000 to provide
assistance to enable Millennium to practice these licenses, so the payment from
Millennium is being recognized ratably over this period. Additionally, in the
2000 periods, contract revenue included fees for research funding and the
performance of certain research work, and in the six-month period included fees
for two product licenses. In the three and six month periods ended June 30,
1999, contract revenue consisted primarily of non-refundable signing fees, a
research milestone fee and a non-refundable reimbursement fee for clinical trial
costs.

Interest income consists primarily of interest from cash, cash equivalents and
short-term investments. Interest income totaled $8.8 million and $13.1 million
in the three and six-month periods ended June 30, 2000 compared to $0.8 million
and $1.2 million in the comparable 1999 periods. This is a result of our
follow-on offering in February of 2000 in which we received net proceeds of
approximately $496.5 million, after the costs of the offering.

Research and development expenses consist primarily of compensation and other
expenses related to research and development personnel, costs associated with
preclinical testing and clinical trials of our product candidates, including the
costs of manufacturing the product candidates, and facilities expenses. Research
and development expenses increased to $11.9 million in the three months ended
June 30, 2000 from $5.3 million in the comparable period in 1999 and to $19.1
million in the six months ended June 30, 2000 from


                                       13
<PAGE>

     $9.9 million in the comparable period in 1999. The increase reflects
     primarily costs associated with the following:

-    Increased personnel - Staffing at June 30, 2000 increased by approximately
     60% from June 30, 1999. The increase is to support the increased level of
     product development activities, including new target validation, process
     sciences, manufacturing and increased clinical activities. Additionally,
     the increase in personnel is related to increased licensing activity.
     Included in the increase are salary and related fringe benefits, recruiting
     and relocation costs. We expect personnel costs to increase further as we
     continue to build our organization.

-    Product Supply Agreement - Included in the quarter and six month period
     ended June 30, 2000, is a charge of approximately $2.3 million to reserve
     manufacturing capacity by acquiring an option to negotiate a supply
     agreement with a contract manufacturer. The total amount paid for this
     agreement was approximately $3.8 million, of which approximately $1.5
     million is creditable to the supply agreement. If a supply agreement is not
     executed, all of the $3.8 million is non-refundable to us, except under
     limited circumstances.

-    Research Fee-Included in the quarter and six month period ended June 30,
     2000, is a fee paid to Genzyme Transgenics Corporation related to research
     they are performing in which they agreed to produce our antibody product
     candidate, ABX-IL8 using Genzyme's manufacturing system. Under this
     agreement, for undisclosed fees and milestone payments, Genzyme will
     develop transgenic goats that express ABX-IL8 in their milk. Additionally,
     there are several future payments required as certain milestones are met.

-    Clinical Costs- In the first six months of 2000, we had clinical trials in
     progress for three of our product candidates, ABX-CBL, ABX-IL8 and ABX-EGF,
     which are continuing. In 1999, during the comparable period, we had
     clinical trials in progress for two of our product candidates, ABX-CBL and
     ABX-IL8. The costs of such trials include the clinical investigator site
     fees, monitoring costs and data management costs. Additionally such costs
     include the costs of manufacturing the antibody used in clinical trials. In
     July and August 2000 we entered into separate agreements with Immunex and
     SangStat to share equally in the costs of developing and commercializing
     ABX-EGF and ABX-CBL, respectively. However, we expect clinical costs will
     increase in the future as we enter additional clinical trials for both new
     and existing product candidates.

General and administrative expenses include compensation and other expenses
related to finance and administrative personnel, professional services and
facilities. General and administrative expenses increased to $1.8 million in the
three months ended June 30, 2000 from $1.2 million in the comparable period in
1999 and to $3.4 million in the six months ended June 30, 2000 from $2.3 million
in the comparable period in 1999. The increase reflects increased personnel
costs including an accrual for incentive compensation, and additional investor
relations costs. We expect personnel costs to increase further as we continue to
build our organization.

Amortization of intangible assets relates primarily to patents and certain
royalty rights which were acquired through the acquisition of the Xenotech joint
venture in December of 1999.

Equity from the Xenotech joint venture in 1999 reflects our percentage ownership
of the net income from the joint venture, which was prior to our acquisition of
100% of the joint venture in December 1999.

Interest expense consists of interest incurred in connection with equipment
lease line financing and loan facilities. Interest expense increased due to
costs associated with obtaining a letter of credit.


                                       14
<PAGE>

LIQUIDITY AND CAPITAL RESOURCES

In February 2000, we completed a follow-on public offering in which we raised
net proceeds of $496.5 million by selling 9,936,000 shares of our common
stock. In addition to this funding, in 2000 we received $0.73 million from
Cell Genesys for the exercise of warrants and $3.2 million from the exercise
of stock options and our employee stock purchase plan. At June 30, 2000, we
had cash, cash equivalents and marketable securities of $555.5 million. We
have invested our cash equivalents and marketable securities in highly
liquid, interest bearing, investment grade and government securities in order
to preserve principal. In the first six months of 1999 net cash provided by
financing activities was $52.0 million, received primarily from a secondary
offering and the sale of stock to Genentech.

Net cash provided by operating activities was $1.4 million for the six months
ended June 30, 2000 and net cash used in operating activities was $7.6 million
for the six months ended June 30, 1999. In the six months ended June 30, 2000
cash was provided by interest income of $8.3 million net of interest receivable
of $4.8 million, and payments from customers of $14.2 million including $8.8
million recorded as deferred revenue. Additionally, we received $3.6 million
from customers, as payment on accounts receivable at December 31,1999. Cash was
used for operations in both periods primarily to fund research and development
expenses and manufacturing costs related to the development of new products.
Additionally, cash was used in the six month period ended June 30, 2000 for a
deposit related to a supply agreement.

Net cash used in investing activities was $389.0 million for the six months
ended June 30, 2000 and $42.8 million for the six months ended June 30, 1999.
The activity in both years reflects the purchasing of investments with the funds
we received from follow-on public offerings earlier in both years.

In March 2000, we issued a stand by letter of credit for $2.0 million from a
commercial bank as a deposit on our new leased facility. The stand-by letter
of credit is secured by an investment account which must maintain a $2.0
million balance. Additionally, we have an agreement with a financing company
under which we have financed purchases of about $2.0 million of our
laboratory and office equipment. The lease term is 48 months and bears
interest at rates ranging from 12.5% to 13.0%, which are based on the change
in the five year U.S. Treasury rate. We also had a construction financing
line with a bank in the amount of $4.3 million that was used to finance
construction of leasehold improvements at our current facility. The line was
paid off in May 2000. The line had an interest rate of prime plus one percent
(9.5 % at December 31, 1999).

We plan to make significant expenditures to establish our own manufacturing
facility and expand our research and development activities, including
preclinical product development and clinical trials. We may be required to make
substantial expenditures if unforeseen difficulties arise in the course of
development of product candidates, manufacturing of product candidates,
performing preclinical development and clinical trials of such product
candidates, obtaining necessary regulatory approvals or other aspects of our
business. Our future liquidity and capital requirements will depend on many
factors, including:

-    scope and results of preclinical testing and clinical trials;

-    the retention of existing and establishment of further licensing and
     contractual agreements, if any;

-    continued scientific progress in our research and development programs;

-    size and complexity of these programs;


                                       15
<PAGE>

-    cost of establishing our manufacturing capabilities, conducting
     commercialization activities and arrangements;

-    time and expense involved in obtaining regulatory approvals;

-    competing technological and market developments;

-    time and expense of filing and prosecuting patent applications and
     enforcing patent claims;

-    investment in, or acquisition of, other companies;

-    product in-licensing; and

-    other factors not within our control.

We believe that our current cash balances, cash equivalents, marketable
securities and the cash generated from our licensing and contractual agreements
will be sufficient to meet our operating and capital requirements for at least
two years. However, we may need additional financing within this timeframe. We
may need to raise additional funds through public or private financing,
licensing and contractual agreements or other arrangements. We cannot assure you
that such additional funding, if needed, will be available on terms favorable to
us. Furthermore, any additional equity financing may be dilutive to
stockholders, and debt financing, if available, may involve restrictive
covenants. Licensing and other contractual agreements may require us to
relinquish our rights to certain of our technologies, products or marketing
territories. Our failure to raise capital when needed may have a material
adverse effect on our business, financial condition and results of operations.

We have incurred operating losses in each of the last three years of operation,
including net losses of approximately $35.9 million in 1997, $16.8 million in
1998 $20.5 million in 1999 and $5.8 million in the six months ended June 30,
2000. As of June 30, 2000, we had an accumulated deficit of approximately $95.6
million. Our losses have resulted principally from costs incurred in performing
research and development for our XenoMouse technology and antibody product
candidates, costs associated with certain agreements with Japan Tobacco, costs
related to the non-recurring cross-license and settlement charge in 1997 and
from general and administrative costs associated with our operations. We expect
to incur additional operating losses for the foreseeable future as a result of
our expenditures for research and product development, including preclinical
testing and clinical trials, and charges related to purchases of technology or
other assets. We intend to invest significantly in our products prior to
entering into licensing arrangements. This may increase our need for capital and
will result in losses for several years. We expect the amount of such losses
will fluctuate significantly from quarter to quarter as a result of increases or
decreases in our research and development efforts, the execution or termination
of licensing arrangements, or the initiation, success or failure of clinical
trials.

As of December 31, 1999, we had federal net operating loss carryforwards of
approximately $61.0 million. Our net operating loss carryforwards exclude losses
incurred prior to the organization of Abgenix in July 1996. Further, the amounts
associated with the cross-license and settlement that have been expensed for
financial statement accounting purposes have been capitalized and are being
amortized over a period of approximately fifteen years for tax purposes. The net
operating loss and credit carryforwards will expire in the years 2011 through
2019, if not utilized. Utilization of the net operating losses and credits may
be subject to a


                                       16
<PAGE>

substantial annual limitation due to the "change in ownership" provisions of the
Internal Revenue Code of 1986 and similar state provisions. The annual
limitation may result in the expiration of net operating losses and credits
before utilization.

ADDITIONAL FACTORS THAT MIGHT AFFECT FUTURE RESULTS

The following factors represent current challenges that we face which create
risk and uncertainty. Failure to adequately overcome any of the following
challenges, either singly or in combination, could materially adversely effect
our results of operations, business, or financial position.

OUR XENOMOUSE TECHNOLOGY MAY NOT PRODUCE SAFE, EFFICACIOUS OR COMMERCIALLY
VIABLE PRODUCTS.

Our XenoMouse technology is a new approach to the generation of antibody
therapeutic products. We have not commercialized any antibody products based on
XenoMouse technology. We are not aware of any commercialized, fully human
antibody therapeutic products that have been generated from any technologies
similar to ours. Our antibody product candidates are still at an early stage of
development. We have begun clinical trials with respect to only two fully human
antibody product candidates, ABX-IL8 and ABX-EGF. We cannot be certain that
XenoMouse technology will generate antibodies against all the antigens to which
it is exposed in an efficient and timely manner, if at all. Furthermore,
XenoMouse technology may not result in any meaningful benefits to our current or
potential customers or be safe and efficacious for patients. If XenoMouse
technology fails to generate antibody product candidates that lead to the
successful development and commercialization of products, our business,
financial condition and results of operations will be materially and adversely
affected.

CLINICAL TRIALS FOR OUR PRODUCT CANDIDATES WILL BE EXPENSIVE AND THEIR OUTCOME
IS UNCERTAIN.

Conducting clinical trials is a lengthy, time-consuming and expensive process.
Before obtaining regulatory approvals for the commercial sale of any products,
we must demonstrate through preclinical testing and clinical trials that our
product candidates are safe and effective for use in humans. We will incur
substantial expense for, and devote a significant amount of time to, preclinical
testing and clinical trials.

Historically, the results from preclinical testing and early clinical trials
have often not been predictive of results obtained in later clinical trials. A
number of new drugs and biologics have shown promising results in clinical
trials, but subsequently failed to establish sufficient safety and efficacy data
to obtain necessary regulatory approvals. Data obtained from preclinical and
clinical activities are susceptible to varying interpretations, which may delay,
limit or prevent regulatory approval. In addition, regulatory delays or
rejections may be encountered as a result of many factors, including changes in
regulatory policy during the period of product development.

As of June 30, 2000, three of our product candidates, ABX-CBL, ABX-IL8 and
ABX-EGF, were in clinical trials. Patient follow-up for these clinical trials
has been limited. To date, data obtained from these clinical trials has been
insufficient to demonstrate safety and efficacy under applicable FDA guidelines.
As a result, this data will not support an application for regulatory approval
without further clinical trials. Clinical trials conducted by us or by third
parties on our behalf may not demonstrate sufficient safety and efficacy to
obtain the requisite regulatory approvals for ABX-CBL, ABX-IL8, ABX-EGF and or
any other potential product candidates. Regulatory authorities may not permit us
to undertake any additional clinical trials for our product candidates.


                                       17
<PAGE>

In addition, our other product candidates are in preclinical development, but we
have not submitted investigational new drug applications nor begun clinical
trials for these product candidates. Our preclinical or clinical development
efforts may not be successfully completed. We may not file further
investigational new drug applications. Our clinical trials may not commence as
planned. Completion of clinical trials may take several years or more. The
length of time generally varies substantially according to the type, complexity,
novelty and intended use of the product candidate. Our commencement and rate of
completion of clinical trials may be delayed by many factors, including:

     -    inability to manufacture sufficient quantities of materials for use in
          clinical trials;

     -    slower than expected rate of patient recruitment;

     -    inability to adequately follow patients after treatment;

     -    unforeseen safety issues;

     -    lack of efficacy during the clinical trials; or

     -    government or regulatory delays.

We have limited experience in conducting and managing clinical trials. We rely
on third parties, including our customers, to assist us in managing and
monitoring clinical trials. Our reliance on these third parties may result in
delays in completing, or failing to complete, these trials if they fail to
perform under our agreements with them.

Our product candidates may fail to demonstrate safety and efficacy in clinical
trials. This failure may delay development of other product candidates, and
hinder our ability to conduct related preclinical testing and clinical trials.
As a result of these failures, we may also be unable to obtain additional
financing. Any delays in, or termination of, our clinical trials will materially
and adversely affect our business, financial condition and results of
operations.

THE CLINICAL SUCCESS OF ABX-CBL IS UNCERTAIN.

We recently completed a multi-center Phase II trial for the treatment of graft
versus host disease, or GVHD, with our mouse antibody, ABX-CBL.

As of June 30, 2000, ABX-CBL had been administered to a total of only 167
patients for GVHD and organ transplant rejection indications. ABX-CBL was
administered to a total of 85 of these 167 patients by third parties prior to
Abgenix obtaining an exclusive license to ABX-CBL. We cannot rely on data
obtained from patients studied prior to our obtaining an exclusive license to
ABX-CBL to support the efficacy of ABX-CBL in an application for regulatory
approval.

Data from 27 patients included in the Phase II study was submitted to the FDA.
As an extension to the original Phase II trial protocol, we have enrolled an
additional 32 patients. In December 1999, we initiated a multicenter randomized,
and controlled Phase II/III study comparing ABX-CBL to ATG(R). The study is
designed to demonstrate statistically significant efficacy of a single dose
level of ABX-CBL in comparison to a control group of patients receiving ATG(R).
The results of the Phase II/III trial may not be favorable or may not extend the
findings of the original Phase II study. The FDA may view the result of our
Phase III trial as insufficient and may require additional clinical trials.
There are several issues that could adversely affect the


                                       18
<PAGE>

clinical trial results, including the lack of a standard therapy for GVHD
patients in the control group, unforeseen side effects, variability in the
number and types of patients in the study, and response rates required to
achieve statistical significance in the study. In addition, our clinical trials
are being conducted with patients who have failed conventional treatments and
who are in the most advanced stages of GVHD. During the course of treatment,
these patients can die or suffer adverse medical effects for reasons that may
not be related to ABX-CBL. These adverse effects may affect the interpretation
of clinical trial results. There is a risk that the FDA will not accept the
results of the Phase II/III study or other elements of the product license
application as being sufficient for approval to market. Additional clinical
trials will be extensive, expensive and time-consuming. If ABX-CBL fails to
receive regulatory approval, our business, financial condition and results of
operations may be materially and adversely affected.

SUCCESSFUL DEVELOPMENT OF OUR PRODUCTS IS UNCERTAIN.

Our development of current and future product candidates is subject to the risks
of failure inherent in the development of new pharmaceutical products and
products based on new technologies. These risks include:

     -    delays in product development, clinical testing or manufacturing;

     -    unplanned expenditures in product development, clinical testing or
          manufacturing;

     -    failure in clinical trials or failure to receive regulatory approvals;

     -    emergence of superior or equivalent products;

     -    inability to manufacture on our own, or through others, product
          candidates on a commercial scale;

     -    inability to market products due to third-party proprietary rights;

     -    election by our customers not to pursue product development;

     -    failure by our customers to successfully develop products; and

     -    failure to achieve market acceptance.

Because of these risks, our research and development efforts or those of our
customers may not result in any commercially viable products. To date, only four
of our customers have exercised their right to obtain a product license. If a
significant portion of these development efforts is not successfully completed,
required regulatory approvals are not obtained, or any approved products are not
commercially successful, our business, financial condition and results of
operations will be materially and adversely affected.

OUR OWN ABILITY TO MANUFACTURE IS UNCERTAIN.

We are in the planning stages of establishing our own pilot scale manufacturing
facility for the manufacture of products for Phase I and Phase II clinical
trials, in compliance with FDA good manufacturing practices. In May 2000 we
signed a long-term lease for a facility to be built for this pilot scale
facility. Construction schedules for this facility may take longer than
expected, and the planned and actual construction costs of building and
qualifying the facility for regulatory compliance may be higher than expected.
The process of manufacturing antibody products is complex. We have no experience
in clinical or commercial scale


                                       19
<PAGE>

manufacture of ABX-CBL, ABX-IL8 and ABX-EGF, or any other antibody products.
Such antibody products will also need to be manufactured in a facility and by a
process which complies with FDA and other regulations. It may take a substantial
period of time to begin producing antibodies in compliance with such
regulations. Our manufacturing operations will be subject to ongoing, periodic
unannounced inspection by the FDA and state agencies to ensure strict compliance
with good manufacturing practices. If we are unable to establish and maintain a
manufacturing facility within our planned time and costs parameters, the
development and sales of our products and our financial performance may be
adversely affected.

We also may encounter problems with the following:

     -    production yields;

     -    quality control and assurance;

     -    shortages of qualified personnel;

     -    compliance with FDA regulations;

     -    production costs; and

     -    development of advanced manufacturing techniques and process controls.

For Phase III clinical trial supplies and commercial production of our antibody
products we are currently evaluating our options, which include use of third
party contract manufacturers, establishing our own commercial scale
manufacturing facility, or entering into a manufacturing joint venture
relationship with a third party. We are aware of only a limited number of
companies on a worldwide basis who operate manufacturing facilities in which our
product candidates can be manufactured under good manufacturing practice
regulations, a requirement for all pharmaceutical products. It would take a
substantial period of time for a contract facility which has not been producing
antibodies to begin producing antibodies under good manufacturing practice
regulations. We cannot assure you that we will be able to contract with any of
these companies on acceptable terms, if at all.

In addition, we and any third-party manufacturer will be required to register
manufacturing facilities with the FDA and other regulatory authorities. The
facilities will then be subject to inspections confirming compliance with FDA
good manufacturing practice or other regulations. If we or our third-party
manufacturer fail to maintain regulatory compliance, our business, financial
condition and results of operations will be materially and adversely affected.

WE CURRENTLY RELY ON A SOLE SOURCE THIRD-PARTY MANUFACTURER.

We currently rely, and will continue to rely for at least the next two years, on
a sole source contract manufacturer to produce ABX-CBL, ABX-IL8 and ABX-EGF
under good manufacturing practice regulations, for use in our clinical trials.
Our contract manufacturer has a limited number of facilities in which our
product candidates can be produced. Our contract manufacturer has limited
experience in manufacturing ABX-CBL, ABX-IL8 and ABX-EGF in quantities
sufficient for conducting clinical trials or for commercialization. We currently
rely on our contract manufacturer to produce our product candidates under good
manufacturing practice regulations, which meet acceptable standards for our
clinical trials.


                                       20
<PAGE>

Contract manufacturers often encounter difficulties in scaling up production,
including problems involving production yields, quality control and assurance,
shortage of qualified personnel, compliance with FDA regulations, production
costs, and development of advanced manufacturing techniques and process
controls. Our contract manufacturer may not perform as agreed or may not remain
in the contract manufacturing business for the time required by us to
successfully produce and market our product candidates. If our contract
manufacturer fails to deliver the required quantities of our product candidates
for clinical use on a timely basis and at commercially reasonable prices, and we
fail to find a replacement manufacturer or develop our own manufacturing
capabilities, our business, financial condition and results of operations will
be materially and adversely affected.

WE DEPEND ON KEY PERSONNEL AND MUST CONTINUE TO ATTRACT AND RETAIN KEY EMPLOYEES
AND CONSULTANTS.

We are highly dependent on the principal members of our scientific and
management staff. For us to pursue product development, marketing and
commercialization plans, we will need to hire additional qualified scientific
personnel to perform research and development. We will also need to hire
personnel with expertise in clinical testing, government regulation,
manufacturing, marketing and finance. Attracting and retaining qualified
personnel will be critical to our success. We may not be able to attract and
retain personnel on acceptable terms given the competition for such personnel
among biotechnology, pharmaceutical and healthcare companies, universities and
non-profit research institutions. If we lose any of these persons, or are unable
to attract and retain qualified personnel, our business, financial condition and
results of operations may be materially and adversely affected.

In addition, we rely on members of our Scientific Advisory Board and other
consultants to assist us in formulating our research and development strategy.
All of our consultants and the members of our Scientific Advisory Board are
employed by other entities. They may have commitments to, or advisory or
consulting agreements with, other entities that may limit their availability to
us. If we lose the services of these advisors, the achievement of our
development objectives may be impeded. Such impediments may materially and
adversely affect our business, financial condition and results of operations.

WE ARE AN EARLY STAGE COMPANY.

You must evaluate us in light of the uncertainties and complexities present in
an early stage biopharmaceutical company. Our product candidates are in early
stages of development. We will require significant additional investment in
research and development, preclinical testing and clinical trials, regulatory
and sales and marketing activities to commercialize current and future product
candidates. Our product candidates, if successfully developed, may not generate
sufficient or sustainable revenues to enable us to be profitable.

WE HAVE A HISTORY OF LOSSES.

We have incurred net losses in each of the last five years of operation,
including net losses of approximately $8.3 million in 1995, $7.1 million in
1996, $35.9 million in 1997, $16.8 million in 1998, $20.5 million in 1999 and
$5.8 million in the six months ended June 30, 2000. As of June 30, 2000, our
accumulated deficit was $95.6 million. Our losses to date have resulted
principally from:

     -    research and development costs relating to the development of our
          XenoMouse technology and antibody product candidates;

     -    costs associated with certain agreements with Japan Tobacco.


                                       21
<PAGE>

     -    costs related to a cross-license and settlement agreement relating to
          our intellectual property portfolio; and

     -    general and administrative costs relating to our operations.

We expect to incur additional losses for the foreseeable future as a result of
increases in our research and development costs, including costs associated with
conducting preclinical development and clinical trials, and charges related to
purchases of technology or other assets. We intend to invest significantly in
our products prior to entering into licensing agreements. This may increase our
need for capital and will result in losses for several years. We expect that the
amount of operating losses will fluctuate significantly from quarter to quarter
as a result of increases or decreases in our research and development efforts,
the execution or termination of licensing and contractual agreements, or the
initiation, success or failure of clinical trials.

OUR FUTURE PROFITABILITY IS UNCERTAIN

Prior to June 1996 our business was owned by Cell Genesys and operated as a
business unit. Since that time, we have funded our research and development
activities primarily from:

     -    the follow-on public offering of our common stock in February 2000

     -    initial contributions from Cell Genesys;

     -    private placements of our capital stock;

     -    the initial public offering of our common stock;

     -    the follow-on public offering of our common stock in 1999;

     -    revenues generated from our licensing and contractual agreements;

     -    equipment leaseline financings; and

     -    loan facilities.

We expect that substantially all of our revenues for the foreseeable future will
result from payments under licensing and contractual agreements and interest
income. To date, payments under licensing and contractual agreements have been
in the form of option fees, reimbursement for research and development expenses,
license fees and milestone payments. Payments under our existing and any future
customer agreements will be subject to significant fluctuation in both timing
and amount. Our revenues may not be indicative of our future performance or of
our ability to continue to achieve such milestones. Our revenues and results of
operations for any period may also not be comparable to the revenues or results
of operations for any other period. We may not be able to:

     -    enter into further licensing and contractual agreements;

     -    successfully complete preclinical development or clinical trials;

     -    obtain required regulatory approvals;


                                       22
<PAGE>

     -    successfully develop, manufacture and market product candidates; or

     -    generate additional revenues or profitability.

If we fail to achieve any of the above goals, our business, financial condition
and results of operations will be materially and adversely affected.

WE WILL NEED TO FIND THIRD PARTIES TO LICENSE AND DEVELOP MANY OF OUR PRODUCT
CANDIDATES.

Our strategy for the development and commercialization of antibody therapeutic
products depends, in large part, upon the formation of licensing agreements with
third parties. Potential third parties include pharmaceutical and biotechnology
companies, academic institutions and other entities. We must enter into these
agreements to successfully develop and commercialize product candidates. These
agreements are necessary in order for us to:

     -    access proprietary antigens for which we can generate fully human
          antibody products;

     -    fund our research and development activities;

     -    fund preclinical development, clinical trials and manufacturing;

     -    seek and obtain regulatory approvals; and

     -    successfully commercialize existing and future product candidates.

Only a limited number of fully human antibody product candidates have been
generated pursuant to our collaboration agreements. Only ABX-IL8 and ABX-EGF
have entered clinical testing. We cannot assure you that any of them will
result in commercially successful products. Current or future collaboration
agreements may not be successful. If we fail to maintain our existing
collaboration agreements or to enter into additional agreements our business,
financial condition and results of operations will be materially and
adversely affected.

Our dependence on licensing and contractual agreements with third parties
subjects us to a number of risks. These agreements may not be on terms
favorable to us. Agreements with collaborators typically allow them
significant discretion in electing whether to pursue any of the planned
activities. We cannot control the amount and timing of resources our
collaborators may devote to the product candidates. Our collaborators may
not perform their obligations as expected. Business combinations or
significant changes in a collaborator's business strategy may adversely
affect a collaborator's willingness or ability to complete its obligations
under the arrangement. Even if we fulfill our obligations under an agreement,
our collaborators can terminate the agreement at any time following proper
written notice. If any collaborators were to terminate or breach our
agreement with it, or otherwise fail to complete its obligations in a timely
manner, our business, financial condition and results of operations may be
materially and adversely affected. If we are not able to establish further
collaboration agreements or any or all of our existing agreements are
terminated, we may be required to seek new collaborators or to undertake
product development and commercialization at our own expense. Such an
undertaking may:

     -    limit the number of product candidates that we will be able to develop
          and commercialize;


                                       23
<PAGE>

     -    reduce the likelihood of successful product introduction;

     -    significantly increase our capital requirements; and

     -    place additional strain on management's time.

Existing or future collaborators may pursue alternative technologies,
including those of our competitors. Disputes may arise with respect to the
ownership of rights to any technology or products developed with any current
or future collaborator. Lengthy negotiations with potential new collaborators
or disagreements between us and our collaborators may lead to delays or
termination in the research, development or commercialization of product
candidates or result in time consuming and expensive litigation or
arbitration. If our collaborators pursue alternative technologies or fail to
develop or commercialize successfully any product candidate to which they
have obtained rights from us, our business, financial condition and results
of operations may be materially and adversely affected.

WE FACE INTENSE COMPETITION AND RAPID TECHNOLOGICAL CHANGE.

The biotechnology and pharmaceutical industries are highly competitive and
subject to significant and rapid technological change. We are aware of several
pharmaceutical and biotechnology companies that are actively engaged in research
and development in areas related to antibody therapy. These companies have
commenced clinical trials of antibody products or have successfully
commercialized antibody products. Many of these companies are addressing the
same diseases and disease indications as Abgenix or our customers. Also, we
compete with companies that offer antibody generation services to companies that
have antigens. These competitors have specific expertise or technology related
to antibody development. These companies include GenPharm International, Inc., a
wholly-owned subsidiary of Medarex, Inc., Medarex's joint venture partner, Kirin
Brewing Co., Ltd., Cambridge Antibody Technology Group plc, Protein Design Labs,
Inc. and MorphoSys AG.

Some of our competitors have received regulatory approval or are developing or
testing product candidates that may compete directly with our product
candidates. For example, SangStat Medical Corp. and Protein Design Labs market
organ transplant rejection products that may compete with ABX-CBL, which is in
clinical trials. In addition, MedImmune, Inc. has a potential antibody product
candidate in clinical trials for graft versus host disease that may compete with
ABX-CBL. We are also aware that several companies, including Genentech, Inc.,
have potential product candidates that may compete with ABX-IL8, which is in
clinical trials. Furthermore, we are aware that ImClone Systems, Inc., Medarex,
AstraZeneca and Pfizer, in collaboration with OSI Pharmaceuticals, Inc., have
potential antibody and small molecule product candidates in clinical development
that may compete with ABX-EGF, which is also in clinical trials.

Many of these companies and institutions, either alone or together with their
customers, have substantially greater financial resources and larger research
and development staffs than we do. In addition, many of these competitors,
either alone or together with their customers, have significantly greater
experience than we do in:

     -    developing products;

     -    undertaking preclinical testing and human clinical trials;

     -    obtaining FDA and other regulatory approvals of products; and

     -    manufacturing and marketing products.


                                       24
<PAGE>

Accordingly, our competitors may succeed in obtaining patent protection,
receiving FDA approval or commercializing products before us. If we commence
commercial product sales, we will be competing against companies with greater
marketing and manufacturing capabilities, areas in which we have limited or no
experience.

We also face, and will continue to face, competition from academic institutions,
government agencies and research institutions. There are numerous competitors
working on products to treat each of the diseases for which we are seeking to
develop therapeutic products. In addition, any product candidate that we
successfully develop may compete with existing therapies that have long
histories of safe and effective use. Competition may also arise from:

     -    other drug development technologies and methods of preventing or
          reducing the incidence of disease;

     -    new small molecules; or

     -    other classes of therapeutic agents.

Developments by competitors may render our product candidates or technologies
obsolete or noncompetitive. We face and will continue to face intense
competition from other companies for agreements with pharmaceutical and
biotechnology companies for establishing relationships with academic and
research institutions, and for licenses to proprietary technology. These
competitors, either alone or with their customers, may succeed in developing
technologies or products that are more effective than ours.

MARKET ACCEPTANCE OF OUR PRODUCTS IS UNCERTAIN.

Our product candidates may not gain market acceptance among physicians,
patients, healthcare payors and the medical community. We may not achieve market
acceptance even if clinical trials demonstrate safety and efficacy, and the
necessary regulatory and reimbursement approvals are obtained. The degree of
market acceptance of any product candidates that we develop will depend on a
number of factors, including:

     -    establishment and demonstration of clinical efficacy and safety;

     -    cost-effectiveness of our product candidates;

     -    their potential advantage over alternative treatment methods;

     -    reimbursement policies of government and third-party payors; and

     -    marketing and distribution support for our product candidates.

Physicians will not recommend therapies using our products until such time as
clinical data or other factors demonstrate the safety and efficacy of such
procedures as compared to conventional drug and other treatments. Even if the
clinical safety and efficacy of therapies using our antibody products is
established, physicians may elect not to recommend the therapies for any number
of other reasons, including whether the mode of administration of our antibody
products is effective for certain indications. For example, antibody products
are typically administered by infusion or injection, which requires substantial
cost and inconvenience to patients. Our product candidates, if successfully
developed, will compete with a number of


                                       25
<PAGE>

drugs and therapies manufactured and marketed by major pharmaceutical and other
biotechnology companies. Our products may also compete with new products
currently under development by others. Physicians, patients, third-party payors
and the medical community may not accept and utilize any product candidates that
we or our customers develop. If our products do not achieve significant market
acceptance, our business, financial condition and results of operations will be
materially and adversely affected.

OUR PATENT POSITION IS UNCERTAIN AND OUR SUCCESS DEPENDS ON OUR PROPRIETARY
RIGHTS.

Our success depends in part on our ability to:

     -    obtain patents;

     -    protect trade secrets;

     -    operate without infringing upon the proprietary rights of others; and

     -    prevent others from infringing on our proprietary rights.

We will be able to protect our proprietary rights from unauthorized use by
third parties only to the extent that our proprietary rights are covered by
valid and enforceable patents or are effectively maintained as trade secrets.
We solely own two issued patents in the U.S., one granted patent in Europe,
three granted patents in Japan, and have several pending patent applications
in the U.S. and abroad relating to XenoMouse technology. Our wholly owned
subsidiary Xenotech owns two issued U.S. patents, one Australian patent and
several pending U.S. and foreign pending patent applications related to
methods of treatment of bone disease in cancer patients. In addition, we have
four issued U.S. patents and several pending patent applications in the U.S.
and abroad that are jointly owned with Japan Tobacco relating to antibody
technology or genetic manipulation. We try to protect our proprietary
position by filing United States and foreign patent applications related to
our proprietary technology, inventions and improvements that are important to
the development of our business. The patent position of biopharmaceutical
companies involves complex legal and factual questions and, therefore,
enforceability cannot be predicted with certainty. Patents, if issued, may be
challenged, invalidated or circumvented. Thus, any patents that we own or
license from third parties may not provide any protection against
competitors. Our pending patent applications, those we may file in the
future, or those we may license from third parties, may not result in patents
being issued. Also, patent rights may not provide us with adequate
proprietary protection or competitive advantages against competitors with
similar technologies. The laws of certain foreign countries do not protect
our intellectual property rights to the same extent as do the laws of the
United States.

In addition to patents, we rely on trade secrets and proprietary know-how. We
seek protection, in part, through confidentiality and proprietary information
agreements. These agreements may not provide meaningful protection or adequate
remedies for our technology in the event of unauthorized use or disclosure of
confidential and proprietary information. The parties may breach such
agreements. Also, our trade secrets may otherwise become known to, or be
independently developed by, our competitors. Furthermore, others may
independently develop similar technologies or duplicate any technology that we
have developed.

WE MAY FACE CHALLENGES FROM THIRD PARTIES REGARDING THE VALIDITY OF OUR PATENTS
AND PROPRIETARY RIGHTS.

Research has been conducted for many years in the antibody field. This has
resulted in a substantial number of issued patents and an even larger number of
still-pending patent applications. Patent applications in the United States are,
in most cases, maintained in secrecy until patents issue. The publication of
discoveries in


                                       26
<PAGE>

the scientific or patent literature frequently occurs substantially later than
the date on which the underlying discoveries were made. Our commercial success
depends significantly on our ability to operate without infringing the patents
and other proprietary rights of third parties. Our technologies may
unintentionally infringe the patents or violate other proprietary rights of
third parties. In the event of such infringement or violation, we and our
customers may be prevented from pursuing product development or
commercialization. Such a result will materially and adversely affect our
business, financial condition and results of operations. In March 1997, we
entered into a cross-license and settlement agreement with GenPharm
International Inc. to avoid protracted litigation. Under the cross-license, we
licensed on a non-exclusive basis certain patents, patent applications,
third-party licenses, and inventions pertaining to the development and use of
certain transgenic rodents, including mice, that produce fully human antibodies
that are integral to our products and business. Our business, financial
condition and results of operations will be materially and adversely affected if
any of the parties breaches the cross-license agreement. We have one granted
European patent relating to XenoMouse technology that is currently undergoing
opposition proceedings within the European Patent Office and the outcome of this
opposition is uncertain.

We are aware of at least two companies that each have a patent claiming the use
of antibodies to the EGF receptor in combination with chemotherapy. We believe
that our antibody product candidate targeting the EGF receptor, ABX-EGF, may be
effective alone, and may be used without chemotherapy. We believe use of ABX-EGF
alone is not covered by claims in these other companies' patents. If clinical
trials demonstrate that combination therapy is preferable or necessary in the
treatment of patients, we may desire to, or be required to, obtain a license
under the other companies' patents in order to commercialize ABX-EGF. Any
license under these other patents may not be available on commercially
reasonable terms, if at all.

The biotechnology and pharmaceutical industries have been characterized by
extensive litigation regarding patents and other intellectual property rights.
The defense and prosecution of intellectual property suits, United States Patent
and Trademark Office interference proceedings and related legal and
administrative proceedings in the United States and internationally involve
complex legal and factual questions. As a result, such proceedings are costly
and time-consuming to pursue and their outcome is uncertain. Litigation may be
necessary to:

     -    enforce patents that we own or license;

     -    protect trade secrets or know-how that we own or license; or

     -    determine the enforceability, scope and validity of the proprietary
          rights of others.

If we become involved in any litigation, interference or other administrative
proceedings, we will incur substantial expense and the efforts of our technical
and management personnel will be significantly diverted. An adverse
determination may subject us to loss of our proprietary position or to
significant liabilities, or require us to seek licenses that may not be
available from third parties. We may be restricted or prevented from
manufacturing and selling our products, if any, in the event of an adverse
determination in a judicial or administrative proceeding or if we fail to obtain
necessary licenses. Costs associated with these arrangements may be substantial
and may include ongoing royalties. Furthermore, we may not be able to obtain the
necessary licenses on satisfactory terms, if at all. These outcomes will
materially and adversely affect our business, financial condition and results of
operations.


                                       27
<PAGE>

WE ARE SUBJECT TO EXTENSIVE GOVERNMENT REGULATIONS AND WE MAY NOT BE ABLE TO
OBTAIN REGULATORY APPROVALS.

Our product candidates under development are subject to extensive and rigorous
domestic government regulation. The FDA regulates, among other things, the
development, testing, manufacture, safety, efficacy, record-keeping, labeling,
storage, approval, advertising, promotion, sale and distribution of
biopharmaceutical products. If our products are marketed abroad, they also are
subject to extensive regulation by foreign governments. None of our product
candidates has been approved for sale in the United States or any foreign
market. The regulatory review and approval process, which includes preclinical
studies and clinical trials of each product candidate, is lengthy, expensive and
uncertain. Securing FDA approval requires the submission of extensive
preclinical and clinical data and supporting information to the FDA for each
indication to establish the product candidates' safety and efficacy. The
approval process takes many years, requires the expenditure of substantial
resources, involves post-marketing surveillance, and may involve ongoing
requirements for post-marketing studies. Delays in obtaining regulatory
approvals may:

     -    adversely affect the successful commercialization of any drugs that we
          or our customer develop;

     -    impose costly procedures on us or our customers;

     -    diminish any competitive advantages that we or our customers may
          attain; and

     -    adversely affect our receipt of revenues or royalties.

Certain material changes to an approved product such as manufacturing changes or
additional labeling claims are subject to further FDA review and approval. Any
required approvals, once obtained, may be withdrawn. Compliance with other
regulatory requirements may not be maintained. Further, if we fail to comply
with applicable FDA and other regulatory requirements at any stage during the
regulatory process, we or our contract manufacturers may be subject to
sanctions, including:

     -    delays;

     -    warning letters;

     -    fines;

     -    product recalls or seizures;

     -    injunctions;

     -    refusal of the FDA to review pending market approval applications or
          supplements to approval applications;

     -    total or partial suspension of production;

     -    civil penalties;

     -    withdrawals of previously approved marketing applications; and


                                       28
<PAGE>

     -    criminal prosecutions.

We expect to rely on our customers to file investigational new drug applications
and generally direct the regulatory approval process for many of our products.
Our customers may not be able to conduct clinical testing or obtain necessary
approvals from the FDA or other regulatory authorities for any product
candidates. If we fail to obtain required governmental approvals, our customers
will experience delays in or be precluded from marketing products developed
through our research. In addition, the commercial use of our products will be
limited. Delays and limitations may materially and adversely affect our
business, financial condition and results of operations.

We and our contract manufacturers also are required to comply with the
applicable FDA current good manufacturing practice regulations. Good
manufacturing practice regulations include requirements relating to quality
control and quality assurance as well as the corresponding maintenance of
records and documentation. Manufacturing facilities are subject to inspection by
the FDA. These facilities must be approved before we can use them in commercial
manufacturing of our products. We or our contract manufacturers may not be able
to comply with the applicable good manufacturing practice requirements and other
FDA regulatory requirements. If we or our contract manufacturers fail to comply,
our business, financial condition and results of operations will be materially
and adversely affected.

WE DO NOT HAVE MARKETING AND SALES EXPERIENCE.

We do not have a marketing, sales or distribution capability. For certain
products, we may establish an internal marketing and sales force. We intend to
enter into arrangements with third parties to market and sell most of our
products. We may not be able to enter into marketing and sales arrangements with
others on acceptable terms, if at all. To the extent that we enter into
marketing and sales arrangements with other companies, our revenues, if any,
will depend on the efforts of others. These efforts may not be successful. If we
are unable to enter into third-party arrangements, then we must develop a
marketing and sales force, which may need to be substantial in size, in order to
achieve commercial success for any product candidate approved by the FDA. We may
not successfully develop marketing and sales experience or have sufficient
resources to do so. If we do develop such capabilities, we will compete with
other companies that have experienced and well-funded marketing and sales
operations. If we fail to establish successful marketing and sales capabilities
or fail to enter into successful marketing arrangements with third parties, our
business, financial condition and results of operations will be materially and
adversely affected.

WE MAY REQUIRE ADDITIONAL FINANCING.

We will continue to expend substantial resources for the expansion of research
and development, including costs associated with conducting preclinical
development and clinical trials. We will be required to expend substantial funds
in the course of completing required additional development, preclinical testing
and clinical trials of and regulatory approval for product candidates. Our
future liquidity and capital requirements will depend on many factors,
including:

     -    the scope and results of preclinical development and clinical trials;

     -    the retention of existing and establishment of further licensing and
          contractual agreements, if any;

     -    continued scientific progress in our research and development
          programs;



                                       29
<PAGE>

     -    the size and complexity of these programs;

     -    the cost of establishing manufacturing capabilities and conducting
          commercialization activities and arrangements;

     -    the time and expense involved in obtaining regulatory approvals, if
          any;

     -    competing technological and market developments;

     -    the time and expense of filing and prosecuting patent applications and
          enforcing patent claims;

     -    investment in, or acquisition of, other companies;

     -    product in-licensing; and

     -    other factors not within our control.

We believe that the net proceeds from our February 2000 offering, our cash
balances, cash equivalents, short-term investments and cash generated from our
customer agreements will be sufficient to meet our operating and capital
requirements for at least two years. However, we may need additional financing
within this timeframe. We may need to raise additional funds through public or
private financings, licensing and contractual agreements or other arrangements.
Additional funding may not be available to us on favorable terms, if at all.
Furthermore, any additional equity financing would be dilutive to stockholders,
and debt financing, if available, may involve restrictive covenants. Contractual
arrangements may require us to relinquish our rights to certain of our
technologies, product candidates or marketing territories. If we fail to raise
additional funds when needed, our business, financial condition and results of
operations will be materially and adversely affected.

CELL GENESYS EXERCISES INFLUENCE OVER US.

As of June 30, 2000 Cell Genesys beneficially owned approximately 12.0% of our
outstanding common stock. We may be adversely impacted by the influence that
Cell Genesys will have with respect to matters affecting us.

WE FACE UNCERTAINTY OVER REIMBURSEMENT AND HEALTHCARE REFORM.

In both domestic and foreign markets, sales of our product candidates will
depend in part upon the availability of reimbursement from third-party payors.
Such third-party payors include government health administration authorities,
managed care providers, private health insurers and other organizations. These
third-party payors are increasingly challenging the price and examining the cost
effectiveness of medical products and services. In addition, significant
uncertainty exists as to the reimbursement status of newly approved healthcare
products. We may need to conduct post-marketing studies in order to demonstrate
the cost-effectiveness of our products. Such studies may require us to provide a
significant amount of resources. Our product candidates may not be considered
cost-effective. Adequate third-party reimbursement may not be available to
enable us to maintain price levels sufficient to realize an appropriate return
on our investment in product development. Domestic and foreign governments
continue to propose and pass legislation designed to reduce the cost of
healthcare. Accordingly, legislation and regulations affecting the pricing of
pharmaceuticals may change before our proposed products are approved for
marketing. Adoption of such legislation could further


                                       30
<PAGE>

limit reimbursement for pharmaceuticals. If the government and third-party
payors fail to provide adequate coverage and reimbursement rates for our product
candidates, the market acceptance of our products may be adversely affected. If
our products do not receive market acceptance, our business, financial condition
and results of operations will be materially and adversely affected.

WE FACE PRODUCT LIABILITY RISKS AND MAY NOT BE ABLE TO OBTAIN ADEQUATE
INSURANCE.

The use of any of our product candidates in clinical trials, and the sale of any
approved products, may expose us to liability claims resulting from such use or
sale of our products. These claims might be made directly by consumers,
healthcare providers or by pharmaceutical companies or others selling such
products. We may experience financial losses in the future due to product
liability claims. We have obtained limited product liability insurance coverage
for our clinical trials. Our insurance coverage limits are $5.0 million per
occurrence and $5.0 million in the aggregate. We intend to expand our insurance
coverage to include the sale of commercial products if marketing approval is
obtained for product candidates in development. We may not be able to maintain
insurance coverage at a reasonable cost or in sufficient amounts to protect us
against losses. If a successful product liability claim or series of claims is
brought against us for uninsured liabilities or in excess of insured
liabilities, our business, financial condition and results of operations may be
materially and adversely affected.

OUR OPERATIONS INVOLVE HAZARDOUS MATERIALS.

Our research and manufacturing activities involve the controlled use of
hazardous materials. We cannot eliminate the risk of accidental contamination or
injury from these materials. In the event of an accident or environmental
discharge, we may be held liable for any resulting damages, which may exceed our
financial resources and may materially and adversely affect our business,
financial condition and results of operations.

OUR STOCK PRICE IS HIGHLY VOLATILE.

The market price and trading volume of shares of our common stock are volatile,
and we expect them to continue to be volatile for the foreseeable future. For
example, during the period between June 30, 1999 and June 30, 2000, our common
stock closed as high as $99.75 per share and as low as $4.72 per share. This may
impact your decision to buy or sell your common stock. Factors affecting our
stock price include:

     -    fluctuations in our operating results;

     -    announcements of technological innovations or new commercial
          therapeutic products by us or our competitors;

     -    published reports by securities analysts;

     -    progress with clinical trials;

     -    government regulation;

     -    changes in reimbursement policies;

     -    developments in patent or other proprietary rights;


                                       31
<PAGE>

     -    developments in our relationship with customers;

     -    public concern as to the safety and efficacy of our products; and

     -    general market conditions.

WE HAVE IMPLEMENTED A STOCKHOLDER RIGHTS PLAN AND ARE SUBJECT TO OTHER
ANTI-TAKEOVER PROVISIONS.

In June 1999, our board of directors adopted a stockholder rights plan, which
was amended in November 1999. The stockholder rights plan provides for a
dividend distribution of one preferred share purchase right on each outstanding
share of our common stock. Each right entitles stockholders to buy 1/1000th of a
share of our Series A participating preferred stock at an exercise price of
$120.00. Each right will become exercisable following the tenth day after a
person or group, other than Cell Genesys or its affiliates, successors or
assigns, announces an acquisition of 15% or more of our common stock, or
announces commencement of a tender offer, the consummation of which would result
in ownership by the person or group of 15% or more of our common stock. In the
case of Cell Genesys, or its affiliates, successors or assigns, which
beneficially owned approximately 12.0% of our outstanding common stock as of
June 30, 2000, each right will become exercisable following the tenth day after
it announces the acquisition of more than 25% of our common stock, or announces
commencement of a tender offer, the consummation of which would result in
ownership by Cell Genesys, or its affiliates, successors or assigns, of more
than 25% of our common stock. We will be entitled to redeem the rights at $0.01
per right at any time on or before the close of business on the tenth day
following acquisition by a person or group of 15% or more, or in the case of
Cell Genesys, or its affiliates, successors or assigns, more than 25%, of our
common stock.

The stockholder rights plan and certain provisions of our amended and restated
certificate of incorporation and amended and restated bylaws may have the effect
of making it more difficult for a third party to acquire, or of discouraging a
third party from attempting to acquire control of Abgenix. This could limit the
price that certain investors might be willing to pay in the future for our
shares of common stock. Certain provisions of our amended and restated
certificate of incorporation and amended and restated bylaws allow us to:

     -    issue preferred stock without any vote or further action by the
          stockholders;

     -    eliminate the right of stockholders to act by written consent without
          a meeting;

     -    specify procedures for director nominations by stockholders and
          submission of other proposals for consideration at stockholder
          meetings; and

     -    eliminate cumulative voting in the election of directors.

We are subject to certain provisions of Delaware law which could also delay or
make more difficult a merger, tender offer or proxy contest involving us. In
particular, Section 203 of the Delaware General Corporation Law prohibits a
Delaware corporation from engaging in any business combination with any
interested stockholder for a period of three years unless certain conditions are
met. The stockholder rights plan, the possible issuance of preferred stock, the
procedures required for director nominations and stockholder proposals and
Delaware law could have the effect of delaying, deferring or preventing a change
in control of us, including without limitation, discouraging a proxy contest or
making more difficult the acquisition of a substantial block of our common
stock. The provisions could also limit the price that investors might be willing
to pay in the future for shares of our common stock.


                                       32
<PAGE>

WE DO NOT INTEND TO PAY CASH DIVIDENDS ON OUR COMMON STOCK.

We intend to retain any future earnings to finance the growth and development of
our business and we do not plan to pay cash dividends on our common stock in the
foreseeable future.

ITEM 3 -- QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

The objective of our investment activities is to preserve principal, while at
the same time maximizing yields without significantly increasing risk. To
achieve this objective, we invest in highly liquid and high quality debt
securities. Our investments in debt securities are subject to interest rate
risk. To minimize the exposure due to an adverse shift in interest rates, we
invest in short term securities and maintain an average maturity on one year or
less. A hypothetical 67 basis point increase in interest rates would result in
an approximate $650,000 decrease (0.12%) in the fair value of our debt
securities, classified as available-for-sale securities, at June 30, 2000. As
part of a strategic alliance effort, we invested in common stock of CuraGen
Corporation. This investment is subject to fluctuations from market value
changes in stock prices. As of June 30, 2000, our investment in CuraGen was
approximately $31,896,000. Assuming a 10% adverse change in the price of the
CuraGen stock, the Company's investment in CuraGen would decrease in value by
approximately $3,189,600, based upon the value of the stock as of June 30, 2000.

PART II

ITEM 1 -- LEGAL PROCEEDINGS

Not applicable.

ITEM 2 -- CHANGES IN SECURITIES AND USE OF PROCEEDS

CHANGES IN SECURITIES

On March 1, 2000, our Board of Directors declared a two-for-one common stock
split to be effected in the form of a stock dividend. The record date for the
stock split was March 16, 2000 and the payment date was April 6, 2000. Following
this stock split, our number of outstanding common shares was slightly under
40,000,000.

On May 3, 2000, our stockholders approved an amendment to our certificate of
incorporation to increase our number of authorized shares from 50,000,000 to
100,000,000 shares. The amendment became effective on June 6, 2000, the date
that we filed a Certificate of Amendment to our Amended and Restated Certificate
of Incorporation with the Secretary of State of the State of Delaware.

On June 8, 2000, our Board of Directors declared another two-for-one common
stock split to be effected in the form of a stock dividend. The record date for
this stock split was June 19, 2000 and the payment date was July 7, 2000.
Following this stock split, our number of outstanding common shares was slightly
over 80,000,000.

On July 6, 2000, our Board of Directors approved an amendment to our certificate
of incorporation to increase our number of authorized common shares from
100,000,000 to 220,000,000, subject to approval by our


                                       33
<PAGE>

stockholders at a special meeting to be held on August 23, 2000. Adoption of the
proposed amendment and any potential issuance of the additional common shares
would not affect the rights of the holders of our currently outstanding common
shares, except for effects incidental to increasing the number of shares
outstanding, such as dilution of the earnings per share and the voting rights of
current stockholders. If the amendment is adopted, it will become effective upon
filing of a Certificate of Amendment to our Amended and Restated Certificate of
Incorporation with the Secretary of State of the State of Delaware. The proposal
is further described in our definitive proxy statement filed with the Securities
and Exchange Commission on July 27, 2000.

USE OF PROCEEDS

Not applicable.

RECENT SALES OF UNREGISTERED SECURITIES

Not applicable.

ITEM 3 -- DEFAULTS UPON SENIOR SECURITIES

Not applicable.

ITEM 4 -- SUBMISSION OF MATTERS TO VOTE OF SECURITY HOLDERS

At our Annual Meeting of Stockholders, held on May 3, 2000 three matters were
voted upon. A description of each matter and tabulation of votes follows:

          1.   Election of Directors:

<TABLE>
<CAPTION>

                                                        Votes
                                            -----------------------------
                          Nominee                For           Withheld
                    --------------------    -------------    ------------
<S>                                           <C>              <C>
                    R. Scott Greer            56,555,172       10,214,932
                    M. Kathleen Behrens       49,058,448       17,711,656
                    Raju S. Kucherlapti       56,555,172       10,214,932
                    Mark B. Logan             56,553,512       10,216,592
                    Joseph E. Maroun          56,553,352       10,216,752
                    Stephen A. Sherwin        56,547,172       10,222,932

</TABLE>

               There were no abstentions or broker nonvotes.

          2.   To increase the aggregate number of shares of Common Stock
               authorized for issuance under the Company 1996 Incentive Stock
               Plan by 1,200,000 shares:

<TABLE>
<CAPTION>

                                     Votes
                    ----------------------------------------
                        For           Against       Abstain
                    ------------    -----------    ---------
<S>                  <C>             <C>              <C>
                     53,413,764      13,325,972       29,288

</TABLE>

               There were 1,080 broker nonvotes.


                                       34
<PAGE>

          3.   To amend the Company's Certificate of Incorporation to increase
               the authorized number of shares of Common Stock from 50,000,000
               to 100,000,000 shares:

<TABLE>
<CAPTION>

                                     Votes
                    ----------------------------------------
                        For           Against       Abstain
                    ------------    -----------    ---------
<S>                  <C>             <C>             <C>
                     64,702,384      2,051,776       15,744

</TABLE>

               There were no broker nonvotes.

ITEM 5 -- OTHER INFORMATION

Not applicable.

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

     (a)  Exhibits

<TABLE>
<CAPTION>

          Exhibit No.                    Caption
          -----------                    -------

<S>                    <C>
               10.54   Lease agreement dated February 24, 2000 between
                       Ardenwood Corporate Park Associates, a California
                       Limited Partnership and Abgenix, Inc.

               10.55   Lease agreement dated May 19, 2000 between Ardenwood
                       Corporate Park Associates, a California Limited
                       Partnership and Abgenix, Inc.

               10.56   Amendments to stock option plans dated April 27, 2000 to
                       eliminate the Company's ability to reprice issued and
                       outstanding options.

               27.1    Financial Data Schedule

</TABLE>

----------

        (b)     Reports on Form 8-K

                -       On January 7, 2000 a Form 8-K was filed relating to the
                        announcement that we had acquired JT America Inc.'s
                        interest in the Xenotech joint venture.

                -       On January 28, 2000 a Form 8-K was filed relating to our
                        signing several agreements with JT America Inc.,
                        including the acquisition of JT America Inc.'s interest
                        in the Xenotech joint venture that became effective on
                        December 31, 1999.

                -       On January 28, 2000 a Form 8-K was filed relating to our
                        Registration Statement on Form S-1 with the Securities
                        and Exchange Commission, covering the underwritten
                        public offering of our common stock.

                -       On March 2, 2000 a Form 8-K was filed relating to the
                        announcement that we had declared a two-for-one stock
                        split to be effected in the form of a stock dividend.

                -       On July 6, 2000 a Form 8-K was filed relating to the
                        announcement that we had declared a two-for-one stock
                        split to be effected in the form of a stock dividend.


                                       35
<PAGE>

SIGNATURES

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.

Dated:  August 14, 2000

                                  ABGENIX, INC.
                                  (Registrant)

                                  /s/   R. Scott Greer
                                  ---------------------------------------------
                                  R. Scott Greer
                                  President and Chief Executive Officer
                                  (Principal Executive Officer)

                                  /s/   Kurt Leutzinger
                                  ---------------------------------------------
                                  Kurt Leutzinger
                                  Vice President and Chief Financial Officer
                                  (Principal Financial and Accounting Officer)


                                       36
<PAGE>

                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>
EXHIBITS
--------

<S>      <C>
10.54    Lease agreement dated February 24, 2000 between Ardenwood Corporate
         Park Associates, a California Limited Partnership and Abgenix, Inc.

10.55    Lease agreement dated May 19, 2000 between Ardenwood Corporate Park
         Associates, a California Limited Partnership and Abgenix, Inc

10.56    Amendments to stock option plans dated April 27, 2000 to eliminate the
         Company's ability to reprice issued and outstanding options.

27.1     Financial Data Schedule

</TABLE>


                                       37