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                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
 
                             WASHINGTON, D.C. 20549
 
                            ------------------------
 
                                   FORM 10-Q
 
  /X/    QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
         SECURITIES EXCHANGE ACT OF 1934
 
                  FOR THE QUARTERLY PERIOD ENDED JUNE 30, 1998
                                       OR
 
  / /    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
         SECURITIES EXCHANGE ACT OF 1934
 
        FOR THE TRANSITION PERIOD FROM ______________ TO ______________
 
                         COMMISSION FILE NUMBER 0-27628
 
                            ------------------------
 
                                 SUPERGEN, INC.
 
             (Exact name of registrant as specified in its charter)
 
                  DELAWARE                             91-1841574
        (State or other jurisdiction          (IRS Employer Identification
     of incorporation or organization)                   Number)
 
  TWO ANNABEL LANE, SUITE 220, SAN RAMON,                 94583
                 CALIFORNIA                            (Zip Code)
  (Address of principal executive offices)
 
                                 (925) 327-0200
              (Registrant's telephone number, including area code)
 
                                 NOT APPLICABLE
   (Former name, former address and former fiscal year, if changed since last
                                    report)
 
                            ------------------------
 
    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 / /
 
                      APPLICABLE ONLY TO CORPORATE ISSUERS
 
    The number of shares of the registrant's Common Stock, $.001 par value,
outstanding as of July 20, 1998, was 20,376,439.
 
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<PAGE>
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                                                            PAGE NO.
                                                                                                          -------------
<S>                                                                                                       <C>
PART I  FINANCIAL INFORMATION
 
    Item 1--Financial Statements
 
            Consolidated Balance Sheets as of June 30, 1998 and December 31, 1997.......................            3
 
            Consolidated Statements of Operations for the three and six month periods ended June 30,
               1998 and 1997............................................................................            4
 
            Consolidated Statements of Cash Flows for the six month periods ended June 30, 1998 and
               1997.....................................................................................            5
 
            Notes to Consolidated Financial Statements..................................................            6
 
    Item 2-- Management's Discussion and Analysis of Financial Condition and Results of
             Operations.................................................................................            8
 
PART II  OTHER INFORMATION
 
    Item 2--Changes in Securities and Use of Proceeds...................................................           14
 
    Item 4--Submission of Matters to a Vote of Security Holders.........................................           15
 
    Item 6--Exhibits and Reports on Form 8-K............................................................           15
</TABLE>
 
                                       2
<PAGE>
                                 SUPERGEN, INC.
                          CONSOLIDATED BALANCE SHEETS
               (IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)
                                  (UNAUDITED)
 
                                     ASSETS
 
<TABLE>
<CAPTION>
                                                                                           JUNE 30,   DECEMBER 31,
                                                                                             1998         1997
                                                                                           ---------  ------------
<S>                                                                                        <C>        <C>
Current assets:
  Cash and cash equivalents..............................................................  $  11,630   $   23,326
  Marketable securities..................................................................      4,062           --
  Accounts receivable, net...............................................................        534          303
  Inventories............................................................................      1,411        1,428
  Due from related parties...............................................................        664          570
  Prepaid expenses and other current assets..............................................        945          493
                                                                                           ---------  ------------
    Total current assets.................................................................     19,246       26,120
 
Property, plant and equipment, net.......................................................      3,259        2,906
Developed technology at cost, net........................................................      1,289        1,289
Investment in preferred stock of related party...........................................        500          500
Due from related party...................................................................         20           80
Other assets.............................................................................         88          116
                                                                                           ---------  ------------
    Total assets.........................................................................  $  24,402   $   31,011
                                                                                           ---------  ------------
                                                                                           ---------  ------------
 
                                       LIABILITIES AND STOCKHOLDERS' EQUITY
 
Current liabilities:
  Accounts payable and accrued liabilities...............................................  $   1,418   $    1,243
  Allowance for product returns..........................................................         94          239
  Accrued compensation and related expenses..............................................        185          212
  Amount due under asset purchase agreement..............................................         --          750
                                                                                           ---------  ------------
    Total current liabilities............................................................      1,697        2,444
 
Stockholders' equity:
  Preferred stock, $.001 par value; 2,000,000 shares authorized; none outstanding........         --           --
  Common stock, $.001 par value; 40,000,000 shares authorized; 20,376,439 and 20,177,696
    shares issued and outstanding at June 30, 1998 and December 31, 1997, respectively...     70,075       68,976
  Accumulated other comprehensive loss...................................................       (132)         (93)
  Accumulated deficit....................................................................    (47,238)     (40,316)
                                                                                           ---------  ------------
    Total stockholders' equity...........................................................     22,705       28,567
                                                                                           ---------  ------------
    Total liabilities and stockholders' equity...........................................  $  24,402   $   31,011
                                                                                           ---------  ------------
                                                                                           ---------  ------------
</TABLE>
 
          See accompanying notes to consolidated financial statements
 
                                       3
<PAGE>
                                 SUPERGEN, INC.
                     CONSOLIDATED STATEMENTS OF OPERATIONS
                    (IN THOUSANDS, EXCEPT PER SHARE AMOUNTS)
                                  (UNAUDITED)
 
<TABLE>
<CAPTION>
                                                                         THREE MONTHS ENDED     SIX MONTHS ENDED
                                                                              JUNE 30,              JUNE 30,
                                                                        --------------------  --------------------
                                                                          1998       1997       1998       1997
                                                                        ---------  ---------  ---------  ---------
<S>                                                                     <C>        <C>        <C>        <C>
Net sales.............................................................  $     794  $     556  $   1,552  $     981
 
Operating expenses:
  Cost of sales.......................................................        263        450        588        776
  Research and development............................................      2,263      2,092      5,038      3,628
  Sales and marketing.................................................        804        497      1,447        791
  General and administrative..........................................        802        663      1,938      1,262
  Acquisition of in-process research and development..................     --         --         --            831
                                                                        ---------  ---------  ---------  ---------
    Total operating expenses..........................................      4,132      3,702      9,011      7,288
                                                                        ---------  ---------  ---------  ---------
Loss from operations..................................................     (3,338)    (3,146)    (7,459)    (6,307)
 
Interest income.......................................................        245        128        537        267
                                                                        ---------  ---------  ---------  ---------
Net loss..............................................................  $  (3,093) $  (3,018) $  (6,922) $  (6,040)
                                                                        ---------  ---------  ---------  ---------
                                                                        ---------  ---------  ---------  ---------
 
Basic loss per share..................................................  $   (0.15) $   (0.18) $   (0.34) $   (0.36)
                                                                        ---------  ---------  ---------  ---------
                                                                        ---------  ---------  ---------  ---------
Weighted average shares used in basic loss per share calculation......     20,364     16,986     20,300     16,979
                                                                        ---------  ---------  ---------  ---------
                                                                        ---------  ---------  ---------  ---------
</TABLE>
 
          See accompanying notes to consolidated financial statements
 
                                       4
<PAGE>
                                 SUPERGEN, INC.
 
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
 
                                 (IN THOUSANDS)
 
                                  (UNAUDITED)
 
<TABLE>
<CAPTION>
                                                                                               SIX MONTHS ENDED
                                                                                                   JUNE 30,
                                                                                             ---------------------
                                                                                                1998       1997
                                                                                             ----------  ---------
<S>                                                                                          <C>         <C>
Operating activities:
  Net loss.................................................................................  $   (6,922) $  (6,040)
  Adjustments to reconcile net loss to net cash used in operating activities:
    Depreciation and amortization..........................................................         214        144
    Stock options granted to consultants...................................................         170         --
    Changes in operating assets and liabilities:
      Accounts receivable..................................................................        (231)       (62)
      Inventories..........................................................................          17        441
      Prepaid expenses and other assets....................................................        (463)      (138)
      Accounts payable, accrued compensation and other liabilities.........................           3       (117)
      Due from related parties.............................................................         (34)      (334)
                                                                                             ----------  ---------
Net cash used in operating activities......................................................      (7,246)    (6,106)
Investing activities:
  Purchases of marketable securities.......................................................      (5,138)        --
  Sale of marketable security..............................................................       1,076         --
  Purchase of property and equipment.......................................................        (567)    (1,910)
  Acquisition of developed technology......................................................          --       (150)
  Purchase of preferred stock of related party.............................................          --       (500)
                                                                                             ----------  ---------
Net cash used in investing activities......................................................      (4,629)    (2,560)
Financing activities:
  Issuance of common stock.................................................................         179        311
  Common stock subscription................................................................          --     15,300
                                                                                             ----------  ---------
Net cash provided by financing activities..................................................         179     15,611
                                                                                             ----------  ---------
Net increase (decrease) in cash and cash equivalents.......................................     (11,696)     6,945
Cash and cash equivalents at beginning of period...........................................      23,326     13,915
                                                                                             ----------  ---------
Cash and cash equivalents at end of period.................................................  $   11,630  $  20,860
                                                                                             ----------  ---------
                                                                                             ----------  ---------
</TABLE>
 
          See accompanying notes to consolidated financial statements
 
                                       5
<PAGE>
                                 SUPERGEN, INC.
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                 JUNE 30, 1998
                                  (UNAUDITED)
 
NOTE 1. BASIS OF PRESENTATION
 
    The accompanying unaudited consolidated financial statements of SuperGen,
Inc. ("SuperGen" or "the Company") have been prepared in accordance with
generally accepted accounting principles for interim financial information on a
basis consistent with the audited financial statements for the year ended
December 31, 1997, and in accordance with the instructions to Form 10-Q. The
consolidated financial statements include the accounts of two wholly owned
subsidiaries, which are immaterial. The statements include all adjustments
(consisting of normal recurring accruals) which in the opinion of the Company's
management are necessary for a fair presentation of the results for the periods
presented. Certain prior year amounts have been reclassified to conform to the
current year's presentations. The interim results are not necessarily indicative
of results that may be expected for the full year. The accompanying financial
statements should be read in conjunction with the Company's audited financial
statements for the year ended December 31, 1997, which are included in the
Company's Annual Report on Form 10-K.
 
NOTE 2. CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES
 
    Cash and cash equivalents include bank demand deposits, certificates of
deposit, marketable securities with maturities of three months or less and an
interest in money market funds which invest primarily in U.S. government
obligations and commercial paper. These instruments are highly liquid and are
subject to insignificant risk.
 
    Marketable securities consist of corporate or government debt securities and
an equity security that have readily ascertainable market values and are readily
marketable. These investments are reported at fair value. All marketable
securities are designated as available-for-sale, with unrealized gains and
losses included in equity.
 
    The following is a summary of available-for-sale securities as of June 30,
1998 (in thousands):
 
<TABLE>
<CAPTION>
                                                                                    GROSS
                                                                   AMORTIZED     UNREALIZED      ESTIMATED
                                                                     COST      GAINS (LOSSES)   FAIR VALUE
                                                                  -----------  ---------------  -----------
<S>                                                               <C>          <C>              <C>
U.S. corporate debt securities..................................   $   9,151      $      (3)     $   9,148
U.S. government debt securities.................................         999              1          1,000
Marketable equity security......................................         167           (130)            37
                                                                  -----------         -----     -----------
    Total.......................................................   $  10,317      $    (132)     $  10,185
                                                                  -----------         -----     -----------
                                                                  -----------         -----     -----------
</TABLE>
 
<TABLE>
<CAPTION>
                                                                                    GROSS
                                                                   AMORTIZED     UNREALIZED      ESTIMATED
                                                                     COST      GAINS (LOSSES)   FAIR VALUE
                                                                  -----------  ---------------  -----------
<S>                                                               <C>          <C>              <C>
Amounts included in cash and cash equivalents...................   $   6,086      $      --      $   6,086
Marketable securities, current..................................       4,064             (2)         4,062
Amounts included in other assets................................         167           (130)            37
                                                                  -----------         -----     -----------
    Total.......................................................   $  10,317      $    (132)     $  10,185
                                                                  -----------         -----     -----------
                                                                  -----------         -----     -----------
</TABLE>
 
                                       6
<PAGE>
    Available-for-sale securities at June 30, 1998, by contractual maturity, are
shown below (in thousands):
 
<TABLE>
<CAPTION>
                                                                                      ESTIMATED
                                                                                     FAIR VALUE
                                                                                     -----------
<S>                                                                                  <C>
Debt securities:
  Due in one year or less..........................................................   $   7,096
  Due after one year through three years...........................................       3,052
                                                                                     -----------
                                                                                         10,148
Marketable equity security.........................................................          37
                                                                                     -----------
                                                                                      $  10,185
                                                                                     -----------
                                                                                     -----------
</TABLE>
 
    Realized gains and losses for the six months ended June 30, 1998 were not
material. The Company held no marketable securities at any time in the six
months ended June 30, 1997.
 
NOTE 3. INVENTORIES
 
    Inventories consisted of (in thousands):
 
<TABLE>
<CAPTION>
                                                              JUNE 30, 1998  DECEMBER 31, 1997
                                                              -------------  -----------------
<S>                                                           <C>            <C>
Raw material................................................    $     265        $     235
Work in process.............................................          726              720
Finished goods..............................................          420              473
                                                                   ------           ------
                                                                $   1,411        $   1,428
                                                                   ------           ------
                                                                   ------           ------
</TABLE>
 
NOTE 4. COMPREHENSIVE LOSS
 
    During the second quarters of 1998 and 1997, total comprehensive losses
amounted to $3,097,000 and $3,018,000 respectively. During the first six months
of 1998 and 1997, total comprehensive losses amounted to $6,961,000 and
$6,040,000 respectively. There was no other comprehensive loss in the first six
months of 1997.
 
NOTE 5. BASIC LOSS PER SHARE
 
    Basic loss per share information is computed using the weighted average
number of shares of common stock outstanding during each period. The exercise of
options and warrants is not assumed since the result would be antidilutive.
 
                                       7
<PAGE>
ITEM 2.
 
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
 
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS
 
PRELIMINARY NOTE REGARDING FORWARD-LOOKING STATEMENTS
 
    THIS QUARTERLY REPORT ON FORM 10-Q CONTAINS FORWARD-LOOKING STATEMENTS
WITHIN THE MEANING OF SECTION 27A OF THE SECURITIES ACT OF 1933, AS AMENDED, AND
SECTION 21E OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED. THESE
FORWARD-LOOKING STATEMENTS REPRESENT THE COMPANY'S EXPECTATIONS OR BELIEFS
CONCERNING FUTURE EVENTS AND INCLUDE STATEMENTS, AMONG OTHERS, REGARDING:
 
    - THE TIMING AND PROGRESS OF THE DEVELOPMENT OF THE COMPANY'S PROPOSED
      PRODUCTS,
 
    - FILING FOR AND RECEIVING REGULATORY APPROVALS,
 
    - ACQUIRING ADDITIONAL PRODUCTS AND TECHNOLOGIES,
 
    - ANTICIPATING THE MARKET OPPORTUNITIES FOR ITS EXTRA AND OTHER PROPRIETARY
      PRODUCTS,
 
    - MARKETING CURRENT AND PROPOSED PRODUCTS,
 
    - DEVELOPING PARTNERSHIP RELATIONSHIPS,
 
    - INCURRING OPERATING EXPENSES AND LOSSES AND REQUIRING ADDITIONAL CAPITAL,
      AND
 
    - INCURRING CAPITAL EXPENDITURES.
 
    ACTUAL RESULTS COULD DIFFER MATERIALLY FROM THOSE PROJECTED IN THE
FORWARD-LOOKING STATEMENTS AS A RESULT OF A VARIETY OF FACTORS, INCLUDING THOSE
SET FORTH UNDER "MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
RESULTS OF OPERATIONS--FACTORS AFFECTING FUTURE OPERATING RESULTS" AND ELSEWHERE
IN THIS REPORT.
 
OVERVIEW
 
    SuperGen, Inc. (the "Company" or "SuperGen") is an emerging pharmaceutical
company dedicated to the acquisition, rapid development and commercialization of
products for the treatment of life-threatening diseases, particularly cancer.
The Company's primary oncology programs target leukemias and lymphomas, solid
tumors and the development of the Company's proprietary Extra technology (its
enhanced line of already established anticancer drugs). SuperGen also seeks to
expand its portfolio of anticancer drugs through the acquisition of products and
product candidates that complement its portfolio and provide the Company with
promising market opportunities. The Company also has non-oncology programs in
the large market areas of anemias and other blood cell disorders,
obesity/diabetes and certain autoimmune diseases. The Company intends to seek
partnership opportunities in these areas. A key element of the Company's
strategy is to identify, acquire and develop pharmaceutical products in the
later stages of development. The Company believes this strategy will shorten the
research and development cycle and thereby minimize the time, expense and
technical risk associated with drug development.
 
    Beginning in late 1996, the Company has actively marketed several
pharmaceutical products. Sales of Nipent-Registered Trademark- (pentostatin for
injection) were responsible for virtually all product revenues in the first six
months of 1998 and for approximately 80% of product revenues in the same period
in 1997. The Company acquired this proprietary drug, along with associated North
American marketing rights, in 1996. In December 1997, the Company received
governmental approval to sell Nipent-Registered Trademark- manufactured under
its own Supplemental New Drug Application. Nipent-Registered Trademark- is
indicated for the treatment of Hairy Cell Leukemia and has Orphan Drug
Designation for both chronic lymphocytic leukemia and cutaneous T-cell lymphoma.
In April of 1998, the Company received FDA approval to market the generic drug
mitomycin for injection. Mitomycin, originally developed and marketed by
Bristol-Myers Squibb Company under the tradename
 
                                       8
<PAGE>
Mutamycin-Registered Trademark-, is approved in the U.S. for the treatment of
adenocarcinoma of the stomach and pancreas in combination with other approved
chemotherapeutics. The Company commenced commercial sales of mitomycin in June
of 1998. Remaining product sales in 1997 consisted of sales of several generic
products purchased in 1997 and 1996. Sales of those generic products are not
expected to be significant in 1998 and beyond.
 
    In September 1997, the Company acquired exclusive worldwide rights to a
patented anticancer compound (RFS2000), which is currently in Phase II human
trials for pancreatic cancer, the fifth leading cause of cancer death. It has
also shown activity against an array of solid tumors in animal and initial human
studies with a favorable side effect profile. At the end of 1997, SuperGen filed
for governmental approval for its first Extra product, Mito Extra. The Food and
Drug Administration accepted that filing for review in February 1998. The
Company intends to file for approval for several additional Extra and generic
anticancer products over the next several years. Also, the Company has continued
development of a proprietary blood cell disorder product for the treatment of
aplastic anemia (and other anemias associated with chemotherapy, radiotherapy,
and renal failure). SuperGen's proprietary obesity/diabetes pill, which has
shown promise in early preclinical and human studies, is currently in Phase II
clinical trials for a genetic disorder leading to chronic obesity and is
expanding into multi-center Phase I/II trials for Type II diabetes. To date, the
Company has received Orphan Drug Designations for its aplastic anemia agent and
obesity pill for the treatment of a genetic disorder leading to chronic obesity.
The Company has also received a grant from the U.S. government for aplastic
anemia clinical trials.
 
    The Company has incurred losses in each year since its inception and has
accumulated approximately $47.2 million in net losses through June 30, 1998.
While the Company's products are being sold in the United States and certain
international markets, there can be no assurance that revenue from future
product sales or other sources will increase or be sufficient to fund operations
or that the Company will achieve profitability or positive cash flow.
 
    The Company expects its research and development expenses to increase as a
result of expanded clinical trials of Nipent-Registered Trademark-, RFS 2000,
the Extra product line and other drugs. The Company expects its marketing and
sales expenses to increase as it expands its United States direct sales and
marketing organization. As of June 30, 1998, the Company's United States sales
team consisted of ten individuals experienced in the sale of pharmaceutical
products, with particular emphasis on oncology.
 
    The Company's future quarterly operating results will depend on a variety of
factors, including
 
    - the price, volume and timing of sales of the Company's products,
 
    - the mix between Nipent-Registered Trademark- sales in the United States
      and those under a supply agreement for sale outside North America,
 
    - variations in gross margins of the Company's products, which may be
      affected by the sales mix referred to above and by competitive pricing
      pressures,
 
    - regulatory approvals of new products or expanded labeling of existing
      products,
 
    - changes in the Company's level of research and development, including the
      timing of any expansion of clinical trials, and
 
    - acquisitions of products or technology.
 
    In addition, sales of any product in any given period may include a
significant amount of orders for inventory by distributors and wholesalers and
may not be indicative of actual demand for products by physicians and patients.
There can be no assurance that distributors or wholesalers will be able to
forecast demand for product accurately. The Company expects quarterly operating
results to continue to fluctuate in the future.
 
                                       9
<PAGE>
RESULTS OF OPERATIONS
 
THREE MONTHS ENDED JUNE 30, 1998 COMPARED TO THREE MONTHS ENDED JUNE 30, 1997.
 
    Total revenues were $794,000 in the second quarter of 1998 compared to
$556,000 in the same period in 1997. The increase in revenue was due primarily
to higher sales volumes of Nipent-Registered Trademark-, which resulted from the
initial sales of Nipent-Registered Trademark- under a supply agreement for sale
outside North America. Product revenues in the second quarter of 1998 consisted
almost entirely of sales of Nipent-Registered Trademark-. Gross margin was 67%
in the second quarter of 1998 compared to 19% in the same period in 1997. This
increase was due primarily to the lower unit cost of
Nipent-Registered Trademark- sold in the second quarter of 1998 compared to the
same period in 1997 partially offset by lower selling prices for
Nipent-Registered Trademark- sold under the supply agreement.
Nipent-Registered Trademark- sold in the second quarter of 1998 consisted
entirely of inventory manufactured by the Company while
Nipent-Registered Trademark- sales in the second quarter of 1997 consisted
entirely of inventory acquired from Warner-Lambert Company. The unit cost of
manufactured Nipent-Registered Trademark- is, and is expected to continue to be,
significantly lower than the unit cost assigned to the
Nipent-Registered Trademark- inventory acquired from Warner-Lambert Company.
However, manufactured Nipent-Registered Trademark- unit costs may vary
significantly in the future. The Company is in the early stages of
Nipent-Registered Trademark- sales and manufacturing, and current margins may
not be indicative of future margins due to possible future variations in selling
prices and manufacturing costs.
 
    Research and development expenses were $2,263,000 in the second quarter of
1998 compared to $2,092,000 in 1997. Since the second quarter of 1997, the
research and development group has grown by 11 employees, primarily in the areas
of product development and clinical trials administration. The increase in
research and development expenses in 1998 was due primarily to the resultant
increase in personnel and related costs. Variations in other costs were largely
offsetting. In the second quarter of 1998, the Company incurred charges of
approximately $300,000 relating to ongoing development and clinical trials for
RFS2000. In the second quarter of 1997, the Company incurred a charge of
$400,000 related to a supply agreement for a source of bulk paclitaxel. While
the Company continues to develop its own version of paclitaxel, there have been
no further charges relating to this supply agreement.
 
    Sales and marketing expenses were $804,000 in the second quarter of 1998
compared to $497,000 in the same period in 1997. This increase was primarily due
to the expansion of the sales and marketing group to 15 at June 30, 1998,
resulting in higher personnel and related costs. Expanded participation at
selected trade shows and Nipent-Registered Trademark- media advertising costs
also contributed to the higher level of expense in 1998.
 
    General and administrative expenses were $802,000 in the second quarter of
1998, compared to $663,000 in 1997. The increase was due principally to costs
relating to investor relations, higher facilities and legal expenses and higher
personnel expenses reflecting a slight increase in administrative staff.
 
SIX MONTHS ENDED JUNE 30, 1998 COMPARED TO SIX MONTHS ENDED JUNE 30, 1997.
 
    Total revenues were $1,552,000 in the first six months of 1998 compared to
$981,000 in the same period in 1997. The increase in revenue was due primarily
to higher sales volumes of Nipent-Registered Trademark- in 1998, which resulted
principally from the initial sales of Nipent-Registered Trademark- under a
supply agreement for sale outside North America. Product revenues in the first
six months of 1998 consisted almost entirely of sales of
Nipent-Registered Trademark-. Gross margins were 62% in the first six months of
1998 compared to 21% in the same period in 1997. This increase was due primarily
to the lower unit cost of Nipent-Registered Trademark- sold in the first six
months of 1998 partially offset by lower selling prices for
Nipent-Registered Trademark- sold under the supply agreement. The Company is in
the early stages of Nipent-Registered Trademark- sales and manufacturing, and
current margins may not be indicative of future margins due to possible future
variations in selling prices and manufacturing costs.
 
    Research and development expenses were $5,038,000 in the first six months of
1998 compared to $3,628,000 in the same period in 1997. Product formulation and
development costs associated with RFS 2000 contributed to the overall increase
in expense. The Company added staff, primarily in the areas of
 
                                       10
<PAGE>
product development and clinical trials administration, which also contributed
to the increase in expense as did the investment in a related party in the first
quarter of 1998.
 
    Sales and marketing expenses were $1,447,000 in the first six months of 1998
compared to $791,000 in the same period in 1997. This increase was primarily due
to higher costs reflecting the expansion of the sales and marketing group to 15
at June 30, 1998. Also, in 1998 the Company initiated media advertising and
increased its presence at selected trade shows.
 
    General and administrative expenses were $1,938,000 in the first six months
of 1998, compared to $1,262,000 in the same period in 1997. The increase was due
principally to costs relating to investor relations, patent related legal fees
and enhancements in information technology. Higher facilities and personnel
costs also contributed to the overall increase in expense. The Company moved
into larger administrative offices in March of 1997 and the administrative staff
has grown slightly to accommodate the overall increase in headcount and business
activities.
 
    The Company incurred a charge for the acquisition of in-process research and
development of $831,000 in the first quarter of 1997 related to the acquisition
of the generic anticancer drug etoposide.
 
LIQUIDITY AND CAPITAL RESOURCES
 
    The Company's cash, cash equivalents and marketable securities totaled $15.7
million at June 30, 1998 compared to $23.3 million at December 31, 1997. The net
cash used in operating activities of $7.2 million in the first six months of
1998 reflected the net loss for the period of $6.9 million and prepayments for
insurance and other purposes. Cash used for purchases of property and equipment
was $569,000, principally for equipment, fixtures and other costs associated
with the Company's recently established research facility in Pleasanton,
California.
 
    The Company believes that its current cash, cash equivalents and marketable
debt securities will satisfy its budgeted cash requirements for at least the
next twelve months, based on the Company's current operating plan. The primary
planned uses of cash during that period are:
 
    - funding operations,
 
    - conducting clinical testing of potential proprietary and Extra products,
 
    - commercialization and marketing of any new products or expanded
      indications for Nipent-Registered Trademark- that may be developed,
 
    - continuing research and development programs, and
 
    - acquisition and licensing of additional products or technologies.
 
    The Company is actively considering future contractual arrangements that
would require significant financial commitments, particularly with respect to
acquiring rights to additional drug candidates and for clinical trials for
existing and new drug candidates. The Company does not anticipate significant
capital expenditures for the remainder of 1998. If the Company experiences
currently unanticipated cash requirements, it could require additional capital
prior to the second quarter of 1999. The Company may seek such additional
funding through public or private financings or collaborative or other
arrangements with third parties. The Company has no credit facility or other
committed sources of capital. There can be no assurance that additional funds
will be available on acceptable terms, if at all. See "Factors Affecting Future
Operating Results."
 
FACTORS AFFECTING FUTURE OPERATING RESULTS
 
    The future operating results of the Company cannot be predicted with any
degree of certainty. In assessing potential future outcomes, the following
factors should be carefully reviewed together with the other information
contained in this quarterly report on Form 10-Q.
 
                                       11
<PAGE>
    - HISTORY OF OPERATING LOSSES. The Company has incurred losses in every
      fiscal period to date and expects to continue to incur significant
      operating losses. The likelihood of the long-term success of the Company
      must be considered in light of the expenses, difficulties and delays
      frequently encountered in the development, commercialization and
      manufacturing of new pharmaceutical products, as well as competition and
      the burdensome regulatory environment in which the Company operates. The
      Company has limited experience in each of these areas. There can be no
      assurance that the Company will ever achieve significant revenues,
      profitable operations or positive cash flow.
 
    - EARLY STAGE OF PRODUCT DEVELOPMENT; UNCERTAINTY OF FINAL PRODUCT
      DEVELOPMENT. While the Company's proposed proprietary products are in the
      development rather than the research stage, significant development
      remains prior to the time any of these proposed products may be brought to
      market. The Company has obtained clearance from the FDA related to its
      Nipent-Registered Trademark- and mitomycin manufacturing processes and
      sources of bulk drugs for certain of its Extra and generic products.
      However, it has yet to receive marketing approval for any of its
      internally developed products. There can be no assurance that any of the
      Company's products currently under development will be successfully
      developed, receive required governmental regulatory approvals, become
      commercially viable or achieve market acceptance.
 
    - ADDITIONAL FINANCING REQUIREMENTS. The Company's need for additional
      funding is expected to be substantial and will be determined by the
      progress and cost of the acquisition, development and commercialization of
      its products and other activities. Based on the Company's current
      operating plan, additional funds will be needed after approximately twelve
      months. If the Company experiences unanticipated cash requirements during
      that twelve month period, the Company could require funds much sooner.
      There can be no assurance that additional funds will be available at terms
      favorable to the Company, if at all. Failure to obtain adequate financing
      in a timely manner would have a material adverse effect on the Company's
      business, results of operations and cash flows.
 
    - DEPENDENCE ON KEY PERSONNEL. The Company's success is dependent on certain
      key management and scientific personnel, including Dr. Joseph Rubinfeld,
      the loss of whose services could significantly affect the ability of the
      Company to achieve its planned objectives. The loss of key personnel, or
      the inability to attract and retain the additional, highly skilled
      personnel required for the expansion of the Company's activities, could
      have a material adverse effect upon the Company's business, results of
      operations and cash flows.
 
    - MANUFACTURING LIMITATIONS; RELIANCE ON THIRD PARTIES. The Company
      currently relies on foreign and domestic manufacturers and vendors for
      Nipent-Registered Trademark- related manufacturing activities, for storage
      of crude concentrate, for production of certain of its bulk Extra and
      generic formulations and for production of sufficient quantities of
      compounds to conduct clinical trials for its proposed proprietary
      products. There can be no assurance that these manufacturers or vendors
      will perform satisfactorily or that relationships with these manufacturers
      or vendors will continue on terms favorable to the Company or that the
      Company will be able to retain other qualified manufacturers or vendors in
      the event that current manufacturers or vendors do not perform
      satisfactorily. Failure of one or more of these manufacturers or vendors
      to satisfactorily perform could have a material adverse effect upon the
      Company's business, results of operations and cash flows, as could the
      failure of the Company to retain other qualified manufacturers or vendors
      in the event of a termination of a relationship with a current
      manufacturer or vendor.
 
    - NEED TO COMPLY WITH GOVERNMENTAL REGULATION AND TO OBTAIN PRODUCT
      APPROVALS. The research, testing, manufacturing, labeling, distribution,
      marketing and advertising of the Company's existing and proposed products
      are subject to extensive regulation by governmental and regulatory
      authorities in the U.S. and other countries. The Company cannot predict
      with certainty if or when it might
 
                                       12
<PAGE>
      submit its products currently under development for regulatory review.
      Once the Company submits its potential products for review, there can be
      no assurance that FDA or other regulatory approvals for any pharmaceutical
      products developed by the Company will be granted on a timely basis or at
      all. Failure to obtain FDA and other regulatory approvals would delay
      product sales and would have a material adverse affect on the Company's
      business, results of operations and cash flows.
 
    - PATENTS AND PROPRIETARY TECHNOLOGY; UNCERTAINTY OF PROTECTION THEREOF. The
      Company has licenses to or assignments of numerous issued U.S. patents.
      However, there can be no assurance that the Company's patent position will
      provide it with significant protection against competitors. Failure to
      comply with the terms of licenses and agreements could result in loss of
      the Company's underlying rights to one or more of its potential
      proprietary products. There can be no assurance that claims against the
      Company will not be raised based on patents held by others or that, if
      raised, such claims will not be successful. If the Company becomes
      involved in any litigation, that process could consume a substantial
      portion of the Company's resources regardless of the outcome of such
      litigation.
 
    - COMPETITION. There are many companies, both public and private, including
      well-known pharmaceutical companies that are engaged in the development
      and sale of products for many of the applications being pursued by the
      Company. The industry in which the Company competes is highly competitive
      and is characterized by extensive research and development efforts and
      rapid technological progress. Price erosion is also characteristic of this
      industry, particularly with regard to products such as the Company's
      proposed Extra and generic drugs. The Company's competitive position will
      be affected by many factors, including but not limited to:
 
     - discoveries by others,
 
     - the ability of the Company to establish or maintain proprietary
       positions,
 
     - the Company's ability to obtain necessary government approvals,
 
     - the number of competitors, and
 
     - market selling prices and their effects upon the Company's gross margins.
 
    The above factors are not intended to be inclusive and there are numerous
other factors which could contribute to the business risk inherent in the
Company's operations. Some of these factors are described in the Company's 1997
Annual Report on Form 10-K. Failure to satisfactorily achieve any of the
Company's objectives or avoid any of these risks may have a material adverse
effect on the Company's business, results of operations and cash flows.
 
                                       13
<PAGE>
                                 SUPERGEN, INC.
 
                           PART II--OTHER INFORMATION
 
ITEM 2. CHANGES IN SECURITIES AND USE OF PROCEEDS
 
    On March 13, 1996, the Company commenced its initial public offering (the
"IPO") of 4,025,000 units (a unit consisted of one share of Common Stock $0.001
par value per share, and a warrant to purchase one share of Common Stock at
$9.00), including the underwriter's over-allotment option consisting of 525,000
units at a public offering price of $6.00 per unit pursuant to a registration
statement on Form S-B (file no. 333-476 LA) filed with the Securities and
Exchange Commission. Of the units registered, 4,024,302 were sold. Paulson
Investment Company was the managing underwriter of the IPO. Aggregate gross
proceeds to the Company from the IPO (prior to deduction of underwriting
discounts and commissions and expenses of the offering and any exercises of the
warrants) were $24,146,000. All of the shares registered for the exercise of the
warrants have not yet been sold. There were no selling stockholders in the IPO.
 
    The Company paid underwriting discounts, commissions and expenses of
$1,992,000 and other expenses of approximately $623,000 in connection with the
IPO. The total expenses paid by the Company in the IPO were $2,615,000, and the
net proceeds to the Company from the IPO through June 30, 1998, including the
subsequent exercise of warrants to purchase common stock, were $23,424,000.
 
    From March 13, 1996, the effective date of the registration statement, to
June 30, 1998, (the Company's fiscal 1998 second quarter end), the approximate
amount of net proceeds used were:
 
<TABLE>
<S>                                                               <C>
Construction of plant, building and facilities..................  $1,246,000
Purchase and installation of machinery and equipment............    295,000
Purchase of real estate.........................................    744,000
Working capital used in operations..............................  16,862,000
Repurchase of common stock......................................  3,557,000
Purchase of equity investment...................................    500,000
Acquisition of developed technology.............................    220,000
</TABLE>
 
    None of such payments consisted of direct or indirect payments to directors,
officers, owners of more than 10% of the outstanding stock of the Company or
affiliates of the Company, with the exception of:
 
    - the payment to repurchase common stock, which was made to a stockholder
      that, immediately prior to the repurchase, owned more than 10% of the then
      outstanding common stock of the Company,
 
    - $279,000 which was paid to director under a consulting agreement and is
      included in working capital used in operations,
 
    - compensation to directors and officers as compensation for services
      provided to the Company.
 
                                       14
<PAGE>
ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS
 
    The Company's Annual Meeting of Stockholders was held on May 7, 1998. The
results of the voting were as follows:
 
Proposal 1: Election of the Board of Directors of the Company.
 
<TABLE>
<CAPTION>
                                           VOTES
NOMINEE                     VOTES FOR    WITHHELD
-------------------------  ------------  ---------
<S>                        <C>           <C>
Joseph Rubinfeld             16,141,714    142,457
Lawrence J. Ellison          16,141,864    142,307
Denis Burger                 16,116,964    167,207
David M. Fineman             16,124,564    159,607
J. Gregory Swendsen          16,138,364    145,807
Julius A. Vida               16,138,664    145,507
Daniel Zurr                  16,031,564    252,607
</TABLE>
 
Proposal 2: Amendment of the Company's Amended and Restated 1993 Stock Option
            Plan to increase the number of shares reserved for issuance by
            750,000 shares to 3,250,000 shares.
 
<TABLE>
<S>                                 <C>
                        Votes For:  15,187,364
                    Votes Against:    317,973
                 Votes Abstaining:    101,916
                 Broker Non-Votes:    676,918
</TABLE>
 
Proposal 3: Ratification and Approval of the 1998 Employee Stock Purchase Plan.
 
<TABLE>
<S>                                 <C>
                        Votes For:  16,091,282
                    Votes Against:    145,806
                 Votes Abstaining:     47,083
                 Broker Non-Votes:     --
</TABLE>
 
Proposal 4: Ratification of Ernst & Young LLP as the independent auditors of the
            Company for the fiscal year ending December 31, 1998.
 
<TABLE>
<S>                                 <C>
                        Votes For:  16,198,412
                    Votes Against:     33,400
                 Votes Abstaining:     52,359
                 Broker Non-Votes:     --
</TABLE>
 
ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K
 
    (b) No reports were filed on Form 8-K during the quarter for which this
report is filed.
 
                                       15
<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.
 
Date: August 7, 1998
 
<TABLE>
<S>                             <C>  <C>
                                By              /s/ JOSEPH RUBINFELD
                                     -----------------------------------------
                                              Joseph Rubinfeld, Ph.D.
                                      CHIEF EXECUTIVE OFFICER, PRESIDENT, AND
                                                      DIRECTOR
                                         (PRINCIPAL EXECUTIVE AND FINANCIAL
                                                      OFFICER)
 
                                By                /s/ KEVIN C. LEE
                                     -----------------------------------------
                                                    Kevin C. Lee
                                     CONTROLLER (PRINCIPAL ACCOUNTING OFFICER)
</TABLE>
 
                                       16