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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 March 31, 2000

                                       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  0-17999

                                 ImmunoGen, Inc.
             (Exact name of registrant as specified in its charter)


       Massachusetts                                     04-2726691
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
 incorporation or organization)


                             333 Providence Highway
                                Norwood, MA 02062
          (Address of principal executive offices, including zip code)

                                 (781) 769-4242
              (Registrant's telephone number, including area code)


              (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

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

     At May 12, 2000 there were  33,037,659  shares of common  stock,  par value
$.01 per share, of the registrant outstanding.


                           Exhibit Index at Page: 22


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                                 IMMUNOGEN, INC.
                                TABLE OF CONTENTS

                                                                         Page
                                                                         ----
PART I. FINANCIAL INFORMATION

Item 1. Condensed Consolidated Financial Statements:

     a.  Condensed Consolidated Balance Sheets as of
         March 31, 2000 and June 30, 1999............................     3

     b.  Condensed Consolidated Statements of Operations
         for the three months and nine months ended
         March 31, 2000 and 1999.....................................     4

     c.  Condensed Consolidated Statements of Stockholders'
         Equity for the year ended June 30, 1999 and the
         nine months ended March 31, 2000............................     5

     d.  Condensed Consolidated Statements of Cash Flows
         for the nine months ended March 31, 2000 and 1999...........     6

     e.  Notes to Condensed Consolidated Financial Statements........     7

Item 2.  Management's Discussion and Analysis of Financial Condition
         and Results of Operations...................................     12

Item 3.  Quantitative and Qualitative Disclosures about Market Risk..     17

PART II. OTHER INFORMATION ..........................................     18

SIGNATURES...........................................................     21




                                       2
  3


                                IMMUNOGEN, INC.
                     CONDENSED CONSOLIDATED BALANCE SHEETS
                     AS OF MARCH 31, 2000 AND JUNE 30, 1999
                                  (UNAUDITED)


                                                              MARCH 31,        JUNE 30,
                                                                2000             1999
                                                            ------------    -------------
                                                                      
ASSETS
Cash and cash equivalents.................................  $  2,127,386    $  4,225,580
Marketable securities.....................................    11,193,647              -
Due from related parties..................................       857,956         910,108
Current portion of note receivable........................           -           350,000
Prepaid and other current assets..........................       106,756          57,915
                                                            ------------    ------------
       Total current assets...............................    14,285,745       5,543,603
                                                            ------------    ------------
Property and equipment, net of accumulated depreciation...     1,458,563       1,583,350
Other assets..............................................        43,700          43,700
                                                            ------------    ------------

          Total assets....................................  $ 15,788,008    $  7,170,653
                                                            ============    ============

LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable..........................................  $    839,239    $    869,996
Accrued compensation......................................       258,940         282,390
Other current accrued liabilities.........................       398,442         528,969
Current portion of deferred lease and
 capital lease obligations................................        62,826          91,911
                                                            ------------    ------------
       Total current liabilities..........................     1,559,447       1,773,266
                                                            ------------    ------------
Capital lease obligations.................................        20,309          68,220
                                                            ------------    ------------
          Total liabilities...............................     1,579,756       1,841,486
                                                            ------------    ------------

Commitments and contingencies
Stockholders' equity:
 Preferred stock, $.01 par value; authorized 5,000,000
  shares as of March 31, 2000 and June 30, 1999:
   Convertible preferred stock, Series E, $.01 par
     value; issued and outstanding 0 and 2,400 shares
     as of March 31, 2000 and June 30, 1999,respectively
     (liquidation preference - stated value)..............           -                24
 Common stock, $.01 par value;  authorized  50,000,000
  shares  as of  March  31,  2000  and June 30,  1999;
  issued  and  outstanding 33,035,509 and 25,668,797
  shares as of March 31, 2000 and June 30 1999,
  respectively ...........................................       330,355         256,687

Additional paid-in capital................................   168,330,397     158,790,821
Accumulated deficit.......................................  (154,667,397)   (153,718,365)
Accumulated other comprehensive income....................       214,897             -
                                                            ------------    ------------
       Total stockholders' equity.........................    14,208,252       5,329,167
                                                            ------------    ------------
          Total liabilities and stockholders' equity......  $ 15,788,008    $  7,170,653
                                                            ============    ============

          The accompanying notes are an integral part of the condensed
                       consolidated financial statements.

                                       3

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                                 IMMUNOGEN, INC.
                 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
      FOR THE THREE MONTHS AND NINE MONTHS ENDED MARCH 31, 2000 AND 1999
                                   (UNAUDITED)




                                                         THREE MONTHS ENDED          NINE MONTHS ENDED
                                                              MARCH 31,                  MARCH 31,
                                                     ------------------------    ------------------------
                                                         2000        1999           2000         1999
                                                     -----------  -----------    -----------  -----------
                                                                                  
Revenues:
  Revenue earned under collaboration agreement....           -    $ 1,000,000    $ 6,500,000  $ 1,000,000
  Development fees................................           -        115,310          4,800      377,605
  Interest........................................   $   120,095       45,494        254,184      189,407
  Licensing.......................................           -            329            485        1,157
                                                     -----------  -----------    -----------  -----------
       Total revenues.............................       120,095    1,161,133      6,759,469    1,568,169
                                                     -----------  -----------    -----------  -----------
Expenses:
  Research and development........................     2,262,513    1,417,456      5,984,229    4,263,538
  General and administrative......................       689,167      432,287      1,835,445    1 249,417
  Interest........................................         4,134          754         14,265        3,182
                                                     -----------  -----------    -----------  -----------
       Total expenses.............................     2,955,814    1,850,497      7,833,939    5,516,137
                                                     -----------  -----------    -----------  -----------
Earnings/(loss) from operations...................    (2,835,719)    (689,364)    (1,074,470)  (3,947,968)
                                                     -----------  -----------    -----------  -----------

  Gain on the sale of assets......................            50          -            1,538        4,200
  Other income/(expense)..........................         6,000         (800)        48,030       24,480
                                                     -----------  -----------    -----------  -----------
Net earnings/(loss) before minority interest......    (2,829,669)    (690,164)    (1,024,902)  (3,919,288)
                                                     -----------  -----------    -----------  -----------
  Minority interest in net loss of consolidated
   subsidiary.....................................        25,290       25,290         75,870       75,870
                                                     -----------  -----------    -----------  -----------
Net earnings/(loss)...............................    (2,804,379)    (664,874)      (949,032)  (3,843,418)
                                                     -----------  -----------    -----------  -----------
  Non-cash dividends on convertible
   preferred stock................................           -            -              -       (917,583)
                                                     -----------  -----------    -----------  -----------

Net earnings/(loss) to common stockholders........   $(2,804,379)  $ (664,874)   $  (949,032) $(4,761,001)
                                                     ===========  ===========    ===========  ===========

Earnings/(loss) per common share
  Basic and Diluted...............................   $     (0.09) $     (0.03)   $     (0.03)  $    (0.19)
                                                     ===========  ===========    ===========  ===========
Average common shares outstanding
  Basic and Diluted...............................    32,051,859   25,514,229     28,356,336   25,497,183
                                                     ===========  ===========    ===========  ===========


          The accompanying  notes are an integral part of the condensed
                       consolidated financial statements.

                                       4

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                                 IMMUNOGEN, INC.
            CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
   FOR THE YEAR ENDED JUNE 30, 1999 AND THE NINE MONTHS ENDED MARCH 31, 2000
                                   (UNAUDITED)



                                                                                                         ACCUMULATED
                                     COMMON STOCK      PREFERRED STOCK    ADDITIONAL                       OTHER         TOTAL
                                 --------------------  ----------------    PAID-IN      ACCUMULATED    COMPREHENSIVE  STOCKHOLDERS'
                                   SHARES     AMOUNT    SHARES   AMOUNT    CAPITAL        DEFICIT         INCOME         EQUITY
                                 ----------  --------  -------  -------  ------------  -------------   -------------  ------------
                                                                                              
Balance at June 30, 1998.......  25,419,552  $254,195    1,200  $    12  $152,782,585  $(148,725,822)  $        -     $  4,310,970
                                 ==========  ========  =======  =======  ============  =============   =============  ============

Comprehensive loss:
  Net loss.....................         -         -        -        -             -       (4,074,960)           -       (4,074,960)
                                                                                                                      ------------
  Comprehensive loss...........         -         -        -        -             -              -              -       (4,074,960)


Issuances of Common Stock......     174,245     1,742      -        -         313,545            -              -          315,287
Issuance of Series E
 Convertible Preferred Stock,
 net of financing costs........         -         -      1,200       12     1,495,193            -              -        1,495,205
Issuance of Common Stock in
 exchange for Series E
 Preferred Stock placement
 services......................      75,000       750      -        -            (750)           -              -              -
Value of Common Stock
 purchase warrants issued......         -         -        -        -         917,583            -              -          917,583
Compensation for stock
 option vesting acceleration
 for retired director..........         -         -        -        -          13,275            -              -           13,275
Value ascribed to ImmunoGen
 warrants issued to BioChem,
 net of financing costs........         -         -        -        -       3,269,390            -              -        3,269,390
Non-cash dividends on
 convertible preferred stock...         -         -        -        -             -         (917,583)           -         (917,583)
                                 ----------  --------  -------  -------  ------------  -------------   -------------  ------------
Balance at June 30, 1999.......  25,668,797  $256,687    2,400  $    24  $158,790,821  $(153,718,365)  $        -     $  5,329,167
                                 ==========  ========  =======  =======  ============  =============   =============  ============

Comprehensive loss:
  Net loss.....................         -         -        -        -             -         (949,032)           -         (949,032)
  Unrealized gains on
   marketable securities, net..         -         -        -        -             -              -          214,897        214,897
                                                                                                                      ------------
Comprehensive loss.............         -         -        -        -             -              -              -         (734,135)

Issuance of Common Stock.......   4,543,184    45,432      -        -       7,101,239            -              -        7,146,671
Conversion of Series E
  Convertible Preferred Stock
  into Common Stock............   2,823,528    28,236   (2,400)     (24)      (28,212)           -              -              -
Tax benefit from stock options
 exercised.....................         -         -        -        -          13,419            -              -           13,419
Value ascribed to ImmunoGen
 warrants issued to BioChem,
 net of financing costs........         -         -        -        -       2,453,130            -              -        2,453,130
                                 ----------  --------  -------  -------  ------------  -------------   -------------  ------------
Balance at March 31, 2000......  33,035,509  $330,355      -    $   -    $168,330,397  $(154,667,397)  $     214,897  $ 14,208,252
                                 ==========  ========  =======  =======  ============  =============   =============  ============


          The accompanying notes are an integral part of the condensed
                       consolidated financial statements.

                                       5
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                                 IMMUNOGEN, INC.
                CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
               FOR THE NINE MONTHS ENDED MARCH 31, 2000 AND 1999
                                  (UNAUDITED)


                                                            NINE MONTHS ENDED
                                                                MARCH 31,
                                                        -------------------------
                                                           2000           1999
                                                        -----------   -----------
                                                                
CASH FLOWS FROM OPERATING ACTIVITIES:
 Net earnings/(loss) to common stockholders..........   $  (949,032)  $(4,761,001)
 Adjustments to reconcile net loss to net cash
  used for operating activities:
   Depreciation and amortization.....................       367,574       444,803
   Gain on sale of property and equipment............        (1,538)       (4,200)
   Interest earned on note receivable................           -         (67,439)
   Compensation for stock option vesting
    acceleration for retired director................           -          13,275
   Tax benefit from stock options exercised..........        13,419           -
   Non-cash dividend on convertible preferred stock..           -         917,583
   Minority interest in net loss of consolidated
    subsidiary.......................................       (75,870)      (75,870)
   Amortization of deferred lease....................       (35,172)      (39,572)
   Changes in operating assets and liabilities:
    Due from related parties.........................        52,152        53,047
    Prepaid and other current assets.................       (48,841)       (5,359)
    Accounts payable.................................       (30,757)       14,310
    Accrued compensation.............................       (23,450)      (54,065)
    Other current accrued liabilities................      (130,527)      (53,476)
                                                        -----------   -----------
        Net cash used for operating activities.......      (862,042)   (3,617,964)
                                                        -----------   -----------
CASH FLOWS FROM INVESTING ACTIVITIES:
  Payments received on note receivable...............       350,000       610,000
  Purchase of marketable securities..................   (12,172,990)          -
  Proceeds from maturities of marketable securities..     1,194,240           -
  proceeds from sale of property and equipment.......         1,795         4,200
  Capital expenditures...............................      (243,044)      (18,570)
                                                        -----------   -----------
        Net cash (used for) provided by investing
         activities..................................   (10,869,999)      595,630
                                                        -----------   -----------
CASH FLOWS FROM FINANCING ACTIVITIES:
  Common Stock issuances.............................     7,146,671        99,199
  Proceeds from convertible preferred stock, net.....           -       1,495,205
  Proceeds from issuance of subsidiary
   convertible preferred stock, net..................     2,529,000     2,527,550
  Principal payments on capital lease obligations....       (41,824)          -
                                                        -----------   -----------
        Net cash provided by financing activities....     9,633,847     4,121,954
                                                        -----------   -----------
NET CHANGE IN CASH AND CASH EQUIVALENTS..............    (2,098,194)    1,099,620
                                                        -----------   -----------
CASH AND CASH EQUIVALENTS, BEGINNING BALANCE.........     4,225,580     1,741,825
                                                        -----------   -----------
CASH AND CASH EQUIVALENTS, ENDING BALANCE............   $ 2,127,386   $ 2,841,445
                                                        ===========   ===========

SUPPLEMENTAL DISCLOSURE OF NONCASH FINANCING ACTIVITIES:
  Due from related party for quarterly investment
   payment...........................................   $   843,000   $   843,000
                                                        ===========   ===========
  Issuance of Common Stock in exchange for
   Series E Preferred Stock placement services.......   $       -     $   107,812
                                                        ===========   ===========

          The accompanying notes are an integral part of the condensed
                       consolidated financial statements.

                                       6
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                                IMMUNOGEN, INC.
             NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS


A.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NATURE OF BUSINESS

     ImmunoGen,   Inc.  ("ImmunoGen"  or  the  "Company")  was  incorporated  in
Massachusetts in 1981 to develop,  produce and market commercial anti-cancer and
other pharmaceuticals  based on molecular  immunology.  The Company continues to
research and develop its various products and technologies,  and does not expect
to  derive  revenue  from   commercially   approved  product  sales  within  the
foreseeable  future.  It is  anticipated  that the  Company's  existing  capital
resources,  enhanced by collaborative agreement funding, will enable current and
planned  operations  to be  maintained  through  at least the next  twelve-month
period. However, if the Company is unable to achieve subsequent milestones under
its collaborative agreements (see Notes B and E), the Company may be required to
pursue additional strategic partners,  secure alternative financing arrangements
and/or defer or limit some or all of its research,  development  and/or clinical
projects.

     The Company is subject to risks common to  companies  in the  biotechnology
industry  including,  but not limited to, the  development by the Company or its
competitors  of new  technological  innovations,  dependence  on key  personnel,
protection of proprietary  technology,  manufacturing and marketing limitations,
collaboration  arrangements,  third-party  reimbursements,  the  need to  obtain
additional funding, and compliance with governmental regulations.

BASIS OF PRESENTATION

     The accompanying  condensed  consolidated financial statements at March 31,
2000 and June 30, 1999 and for the  three-month  and  nine-month  periods  ended
March  31,  2000  and  1999   include  the  accounts  of  the  Company  and  its
subsidiaries, ImmunoGen Securities Corp. and Apoptosis Technology, Inc. ("ATI").
Although the condensed  consolidated  financial  statements are unaudited,  they
include all of the adjustments, consisting only of normal recurring adjustments,
which management  considers  necessary for a fair  presentation of the Company's
financial position in accordance with generally accepted  accounting  principles
for interim financial information.  Certain information and footnote disclosures
normally  included  in the  Company's  annual  financial  statements  have  been
condensed or omitted.  The preparation of interim financial  statements requires
the use of  management's  estimates  and  assumptions  that affect the  reported
amounts  of assets and  liabilities  and  disclosure  of  contingent  assets and
liabilities  at the date of the interim  financial  statements  and the reported
amounts of revenues and expenditures during the reported period. The Company has
been unprofitable since inception and expects to incur significant  research and
development  expenses  that may result in a net loss for the  fiscal  year ended
June 30, 2000. The results of the interim periods are not necessarily indicative
of  the  results  for  the  entire  year.  Accordingly,  the  interim  financial
statements should be read in conjunction with the audited  financial  statements
and notes thereto  included in the Company's  Annual Report on Form 10-K for the
year ended June 30, 1999.

ACCOUNTING PROUNCEMENTS

     In December 1999, the  Securities  and Exchange  Commission  ("SEC") issued
Staff  Accounting  Bulletin 101 ("SAB 101"),  "Revenue  Recognition in Financial
Statements,"  which provides  guidance related to revenue  recognition  based on
interpretations  and practices  followed by the SEC. The effective  date of this
bulletin was deferred to no later than the second fiscal quarter beginning after
December 31, 1999.  SAB 101 requires  companies to report any changes in revenue
recognition  as a  cumulative  change  in  accounting  principle  at the time of
implementation  in accordance with Accounting  Principles  Board Opinion No. 20,
"Accounting  Changes." The Company is currently in the process of evaluating the
impact,  if any, that SAB 101 will have on its financial  position or results of
operations.
                                       7
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     In  March  2000,  the  Financial  Accounting  Standards  Board  issued FASB
Interpretation  No. 44,  "Accounting  for Certain  Transactions  Involving Stock
Compensation  - an  interpretation  of APB Opinion  No. 25" ("FIN  44").  FIN 44
clarifies the application of APB Opinion No. 25 and among other issues clarifies
the  following:  the  definition  of an employee  for  purposes of applying  APB
Opinion No. 25; the  criteria  for  determining  whether a plan  qualifies  as a
noncompensatory plan; the accounting consequence of various modifications to the
terms of previously  fixed stock options or awards;  and the  accounting  for an
exchange  of stock  compensation  awards in a  business  combination.  FIN 44 is
effective July 1, 2000, but certain  conclusions in FIN 44 cover specific events
that occurred  after either  December 15, 1998 or January 12, 2000.  The Company
does not  expect  the  application  of FIN 44 to have a  material  impact on the
Company's financial position or results of operations.

CASH AND CASH EQUIVALENTS

     The Company  considers all  investments  purchased  with maturity  dates of
three months or less from the date of acquisition to be cash equivalents.

MARKETABLE SECURITIES

     In  accordance  with  the  Company's  investment  policy,  surplus  cash is
invested in  investment-grade  corporate  and U.S.  Government  debt  securities
typically with maturity dates of less than one year. The Company  determines the
appropriate  classification of marketable securities at the time of purchase and
reevaluates  such  designation  as  of  each  balance  sheet  date.   Marketable
securities which meet the criteria for classification as available-for-sale  are
carried at fair value based on quoted market prices.  Net  unrealized  gains and
losses are reported as comprehensive  income within  shareholders'  equity.  The
cost of debt  securities is adjusted for  amortization of premiums and accretion
of discounts to maturity  with all  amortization/accretion  included in interest
income.

     As of June 30, 1999, $4,225,580 in cash and overnight government repurchase
agreements  were  classified as cash and cash  equivalents.  The Company's cash,
cash equivalents and marketable securities as of March 31, 2000 are as follows:


                                                 GROSS       GROSS
                                   AMORTIZED   UNREALIZED  UNREALIZED   ESTIMATED
                                      COST       GAINS       LOSSES    FAIR VALUE
                                  -----------  ----------  ----------  ----------
                                                           

 Cash and money market funds....  $ 2,127,386  $      -    $      -    $ 2,127,386
 Commercial paper...............    6,330,150     216,800         (30)   6,546,920
 Government treasury notes......    4,648,600         270      (2,143)   4,646,727
                                  -----------  ----------  ----------  -----------
   Total........................   13,106,136     217,070      (2,173)  13,321,033
 Less amounts classified as
  cash and cash equivalents.....   (2,127,386)        -           -     (2,127,386)
                                  -----------  ----------  ----------  -----------
   Total marketable securities..  $10,978,750  $  217,070  $   (2,173) $11,193,647
                                  ===========  ==========  ==========  ===========


     No  realized  gains  or  losses  on   available-for-sale   securities  were
recognized during the three-month and nine-month periods ended March 31, 2000.

COMPUTATION OF LOSS PER COMMON SHARE

     Basic and diluted  earnings/(loss)  per share is calculated  based upon the
weighted average number of common shares outstanding during the period.  Diluted
earnings per share  incorporates the dilutive effect of stock options,  warrants
and  other  convertible  securities.  As of March 31,  2000 and 1999,  the total
number  of  stock  options,  warrants  and  other  securities  convertible  into
ImmunoGen  Common Stock,  as calculated  in accordance  with the  treasury-stock
accounting method, equaled 5,009,091 and 7,198,981, respectively.  Components of
calculating net earnings/(loss) per share are set forth in the following table:

                                       8
  9


                                                         NINE MONTHS ENDED
                                                             MARCH 31,
                                                    --------------------------
                                                        2000           1999
                                                    -----------    -----------
                                                             
  Net earnings/(loss) to common shareholders.....   $  (949,032)   $(4,761,001)
                                                    ===========    ===========
  Weighted  average common shares
   outstanding, basic...........................     28,356,336     25,497,183
  Net effect of dilutive instruments:
   Convertible preferred stock.................         927,083      6,269,307
   Options.....................................       2,289,142        783,381
   Warrants....................................       1,792,866        146,293
                                                    -----------    -----------
  Weighted average common shares
   outstanding, diluted.........................     33,365,427     32,696,164
                                                    ===========    ===========

  Earnings/(loss) per common share, basic.......    $     (0.03)   $     (0.19)
                                                    ===========    ===========
  Earnings/(loss) per common share, dilutive *..    $     (0.03)   $     (0.19)
                                                    ===========    ===========

     * The  dilutive  effects of common stock  equivalents  were not included in
either March 31, 2000 or 1999 calculation, as their effect was antidilutive.

COMPREHENSIVE INCOME

     The Company presents  comprehensive  income in accordance with Statement of
Financial Accounting Standard No. 130, "Reporting Comprehensive Income." For the
nine-month period ended March 31, 2000,  comprehensive  income totaled $214,897.
No  comprehensive income was recorded in the  nine-month  period ended March 31,
1999. Accumulated other comprehensive income is comprised entirely of unrealized
gains recognized on available-for-sale debt securities.

B.  AGREEMENTS

     In February 1999, the Company entered into an exclusive  license  agreement
with  SmithKline  Beecham  plc,  London  and  SmithKline  Beecham,  Philadelphia
(collectively,  "SB")  to  develop  and  commercialize  ImmunoGen's  lead  tumor
activated prodrug ("TAP"),  huC242-DM1/SB-408075 (the "SB Agreement"). Under the
terms  of the  agreement,  the  Company  could  receive  up to a total  of $41.5
million,   subject  to  the   achievement  by  the  Company  of   predetermined,
nonrefundable  scientific  and/or  regulatory  milestones.  The  Company is also
entitled to receive  royalty  payments on future product sales, if and when they
commence.

     Under a separate Stock Purchase  Agreement,  ImmunoGen was also granted the
right to sell up to $5.0 million of ImmunoGen Common Stock to SB in two separate
transactions, subject to certain conditions (the "put options"). On September 1,
1999,  the  Company  exercised  the first of these two put  options  and  issued
1,023,039 shares of Common Stock to SB in exchange for $2.5 million.

     The SB Agreement is expected to provide the Company  with  sufficient  cash
funding to carry out its responsibilities in developing huC242-DM1/SB-408075. To
that end, the Company is  responsible  for costs  associated  with the currently
ongoing  huC242-DM1/SB-408075  clinical  study,  which was initiated in December
1999. All costs subsequent to this clinical study will be the  responsibility of
SB. The SB  Agreement,  assuming  milestones  continue to be achieved  under the
Agreement,  is also  expected  to  provide  enough  additional  funding  to help
subsidize  further  development  of the  Company's  other  current  and  planned
research  and  development  efforts.  As of March  31,  2000,  the  Company  had
recognized four milestones under the SB Agreement,  resulting in $9.5 million in
collaboration revenue. Pursuant to the SB Agreement,  these payments represented
nonrefundable, unrestricted cash transfers where no future obligation to perform
exists.
                                      9

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C.  MINORITY INTEREST

     In July 1997,  ATI entered  into a  collaboration  agreement  with  BioChem
Pharma  Inc.  ("BioChem"),  a large  Canadian  biopharmaceutical  company.  This
agreement  grants BioChem an exclusive  worldwide  license to ATI's  proprietary
screens  based on two  families of proteins  involved in  apoptosis,  for use in
identifying  leads for anti-cancer drug development.  As of April 2000,  BioChem
has fulfilled all of its funding obligations under the agreement by purchasing a
total  of  $11.125  million  in  non-voting,   non-dividend-bearing  convertible
preferred stock of ATI.

     In April  2000,  BioChem  informed  ATI of its  decision  not to extend the
agreement  beyond its scheduled July 31, 2000  termination  date.  Consequently,
under the terms of the  agreement,  rights to all screens  delivered  to BioChem
will  revert  to ATI  effective  August 1,  2000.  However,  certain  provisions
pertaining to the license of any products  resulting from the collaboration will
remain in force.  Although no compound leads have yet been identified,  should a
product candidate result,  BioChem remains obligated to make milestone  payments
up to $15.0  million for each  product  over the course of its  development.  In
addition, if and when product sales commence,  ATI will receive royalties on any
future worldwide sales of products resulting from the collaboration.  Until July
31, 2000, all remaining  proceeds of the $11.125 million  BioChem  investment in
ATI are  restricted  to support the research and  development  activities of the
collaboration.   After  that  date,   all  residual   proceeds  will   represent
unrestricted  assets  of ATI.  Of the  Company's  $13.3  million  in cash,  cash
equivalents  and  marketable  securities  as of March  31,  2000,  $1.5  million
represents funds restricted to support ATI's research and development activities
under the BioChem agreement.

     The preferred stock issued to BioChem is convertible  into ATI common stock
at any time after three years from the date of first  issuance,  at a conversion
price equal to the then current market price of the ATI common stock, but in any
event at a price that will result in BioChem  acquiring at least 15% of the then
outstanding  ATI common  stock.  Through  March 31, 2000,  11,125  shares of ATI
preferred stock were issued or issuable to BioChem,  representing a 15% minority
interest (on an if-converted and fully-diluted  basis) in the net equity of ATI.
This minority  interest  portion of ATI's loss reduced  ImmunoGen's  net loss in
each of the nine-month  periods ended March 31, 2000 and 1999 by $75,870.  Based
upon an independent appraisal,  approximately 3% of the $11.125 million invested
to date, or approximately  $334,000, has been allocated to the minority interest
in ATI, with the remainder,  or approximately  $10.791 million  allocated to the
Company's equity.

     As part  of the  BioChem  agreement,  BioChem  also  received  warrants  to
purchase  shares of ImmunoGen  Common Stock equal to the amount  invested in ATI
during the  three-year  research term.  Beginning July 31, 2000,  these warrants
will be exercisable for a number of shares of ImmunoGen  Common Stock determined
by dividing $11.125 million,  the amount of BioChem's  investment in ATI, by the
market price of ImmunoGen Common Stock on the exercise date,  subject to certain
limitations  imposed by the Nasdaq Stock Market  rules,  which limit the sale or
issuance by an issuer of certain  securities at a price less than the greater of
book or market  value.  Consequently,  BioChem's  ability to convert  all of its
ImmunoGen  warrants into ImmunoGen  Common Stock is limited to a total of 20% of
the number of shares of ImmunoGen's  Common Stock outstanding on the date of the
initial  transaction to the extent that the conversion  price would be less than
the market price of  ImmunoGen  Common  Stock on that date,  unless  stockholder
approval for such conversion is obtained, if required, or unless the Company has
obtained a waiver of that requirement.  The exercise price is payable in cash or
shares of ATI's preferred stock, at BioChem's option.  The warrants are expected
to be  exercised  only in the event that the  shares of ATI common  stock do not
become publicly traded.  In such event,  ImmunoGen expects that BioChem will use
its shares of ATI preferred stock, in lieu of cash, to exercise the warrants.

D.  CAPITAL STOCK

     In January 2000,  holders of the Company's  Series E Convertible  Preferred
Stock  ("Series E Stock")  exercised  their right to convert all 2,400 shares of
Series E Stock into 2,823,528 shares of the Company's Common Stock.

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  11
     In February 2000, a holder of warrants originally issued in connection with
a private  placement  of the  Company's  Series A  Convertible  Preferred  Stock
exercised his right to acquire 50,000 shares of Common Stock at $3.11 per share.
Proceeds from this warrant exercise will be used to fund current operations.

     In  February  and March  2000,  holders of  warrants  originally  issued in
connection  with a  private  placement  of the  Company's  Series B  Convertible
Preferred  Stock  exercised  their rights to acquire 239,069 and 5,000 shares of
Common Stock at $3.68 per share and $5.49 per share, respectively. Proceeds from
these warrant exercises will be used to fund current operations.

     Between January and March 2000,  holders of warrants  originally  issued in
connection  with a  private  placement  of the  Company's  Series C  Convertible
Preferred Stock exercised their rights to acquire 654,368 shares of Common Stock
at $2.31 per share.  Proceeds from these warrant  exercises will be used to fund
current operations.

     In January 2000, holders of warrants originally issued in connection with a
private  placement  of  the  Company's  Series  D  Convertible  Preferred  Stock
exercised  their rights to acquire  427,272  shares of Common Stock at $1.94 per
share.  Proceeds  from  these  warrant  exercises  will be used to fund  current
operations.

     During the  three-month  period  ended March 31,  2000,  holders of options
issued  through the  Company's  1986  Incentive  Stock Option Plan,  as amended,
exercised  their  rights to acquire  an  aggregate  of 111,750  shares at prices
ranging from $0.84 per share to $11.25 per share.  The total proceeds from these
option exercises, $204,058, will be used to fund current operations.

     In July 1997, the Company's majority-owned subsidiary,  ATI, entered into a
collaboration with BioChem. As part of the agreement,  BioChem received warrants
to purchase  shares of  ImmunoGen  Common  Stock equal to $11.125  million,  the
amount  invested in ATI by BioChem  during the three-year  research term.  These
warrants will be  exercisable  at any time on or after July 31, 2000,  until and
including  July 31,  2002,  into a number of shares of  ImmunoGen  Common  Stock
determined  by dividing  $11.125  million by the market  price of the  ImmunoGen
Common Stock on the exercise date, subject to certain  limitations.  As of March
31, 2000,  the last  quarterly  investment  of $843,000 was due to ATI. In April
2000,  this amount due was received and  warrants  corresponding  to that amount
were issued.  Until July 31, 2000,  proceeds from this investment are restricted
to fund the ongoing ATI research collaboration.

E.    SUBSEQUENT EVENTS

     In May 2000, the Company  executed two separate  licensing  agreements with
Genentech, Inc. of South San Francisco,  California.  The first agreement grants
an exclusive license to Genentech for ImmunoGen's  maytansinoid  tumor-activated
prodrug (TAP) for use with antibodies such as  Herceptin(R).  Under the terms of
the  agreement,   Genentech   will  receive   exclusive   worldwide   rights  to
commercialize  anti-HER2  targeting products using ImmunoGen's  maytansinoid TAP
platform.  Genentech will be responsible for manufacturing,  product development
and marketing of any products  resulting from the  agreement;  ImmunoGen will be
reimbursed for any  preclinical  and clinical  materials that it makes under the
agreement. ImmunoGen is due a $2.0 million non-refundable,  up-front payment for
execution of the agreement,  for which no further  performance  is required.  In
addition  to  royalties  on  net  sales,  the  terms  of the  agreement  include
achievement-based  milestone  payments,  assuming  all  benchmarks  are met, for
potentially up to $40.0 million.

     In addition to the  Herceptin(R)  agreement  described  above,  the Company
announced  in May 2000 that it has entered  into an  additional  agreement  with
Genentech.  This second  collaboration  provides  Genentech with broad access to
ImmunoGen's  maytansinoid  TAP technology for use with  Genentech's  proprietary
antibodies.  The  multi-year  agreement  provides  Genentech  with a license  to
utilize  ImmunoGen's  maytansinoid TAP platform in its antibody product research
efforts and an option to obtain product licenses for a limited number of antigen
targets over the  agreement's  five-year  term.  This agreement  provides for an
up-front  technology access fee of $3.0 million,  potential  milestone  payments
- --assuming benchmarks are met--of up to nearly $40.0 million per antigen target,

                                       11
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and royalties on net sales of resulting products.  Genentech will be responsible
for manufacturing,  product  development and marketing of any products developed
through this  collaboration;  ImmunoGen will be reimbursed  for any  preclinical
materials  that it makes under the  agreement.  The agreement can be renewed for
one subsequent three-year period, for an additional technology access fee.

     Also in May 2000, the Company entered into a development, commercialization
and license  agreement with British Biotech  Pharmaceuticals  Limited  ("British
Biotech"),  a biotechnology  company located in Oxford,  England, to develop and
commercialize the Company's  huN901-DM1 TAP for the treatment of small-cell lung
cancer.  The agreement  grants British Biotech  exclusive  rights to develop and
commercialize  huN901-DM1 in the European Union and Japan.  The Company  retains
the rights to commercialize  huN901-DM1 in the United States and the rest of the
world,  as well as the right to  manufacture  the product  worldwide.  Under the
terms of the agreement,  British  Biotech will be responsible for conducting the
clinical trials  necessary to achieve  marketing  approval in the United States,
European Union and Japan. ImmunoGen is responsible for the remaining preclinical
development,  and will be reimbursed for  manufacturing the product for clinical
trials. British Biotech paid an up-front fee of $1.5 million for its territorial
rights.  Upon  approval of the product for marketing in the United  States,  the
Company will pay to British Biotech a one-time milestone payment. ImmunoGen will
receive royalties on sales of huN901-DM1 in the European Union and Japan.


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

OVERVIEW

     Since inception, ImmunoGen has been principally engaged in the research and
development  of  immunoconjugate   products  which  the  Company  believes  have
significant commercial potential as human therapeutics.  The Company's 97%-owned
subsidiary,  Apoptosis  Technology,  Inc.  ("ATI"),  focuses  its efforts on the
discovery and development of anti-cancer and anti-viral  therapeutics based upon
regulation of programmed cell death, or apoptosis.

     In February 1999, the Company entered into an exclusive  license  agreement
with  SmithKline  Beecham  plc,  London  and  SmithKline  Beecham,  Philadelphia
(collectively,  "SB")  to  develop  and  commercialize  ImmunoGen's  lead  tumor
activated   prodrug   ("TAP"),   huC242-DM1/SB-408075,   for  the  treatment  of
colorectal,  pancreatic and non-small-cell lung cancers (the "SB Agreement"). In
December  1999,  the  Company  began  a  single-dose  human  clinical  study  of
huC242-DM1/SB-408075.  The start of this clinical study triggered a $2.5 million
milestone  payment to ImmunoGen,  which  represented the fourth  milestone to be
achieved in ImmunoGen's  collaboration  with SB to date. Through March 31, 2000,
the Company  received  $12.0  million  under the SB  Agreement - $9.5 million in
milestone-based  collaborative  agreement revenue and $2.5 million upon issuance
of ImmunoGen Common Stock to SB.

     In May 2000, the Company  executed two separate  licensing  agreements with
Genentech, Inc. of South San Francisco,  California.  The first agreement grants
an exclusive license to Genentech for ImmunoGen's  maytansinoid  tumor-activated
prodrug (TAP) for use with antibodies such as  Herceptin(R).  Under the terms of
the  agreement,   Genentech   will  receive   exclusive   worldwide   rights  to
commercialize  anti-HER2  targeting products using ImmunoGen's  maytansinoid TAP
platform.  Genentech will be responsible for manufacturing,  product development
and marketing of any products  resulting from the  agreement;  ImmunoGen will be
reimbursed for any  preclinical  and clinical  materials that it makes under the
agreement. ImmunoGen is due a $2.0 million non-refundable,  up-front payment for
execution of the agreement,  for which no further  performance  is required.  In
addition  to  royalties  on  net  sales,  the  terms  of the  agreement  include
achievement-based  milestone  payments,  assuming  all  benchmarks  are met, for
potentially up to $40.0 million.

     In addition to the  Herceptin(R)  agreement  described  above,  the Company
announced  in May 2000 that it has entered  into an  additional  agreement  with
Genentech.  This second  collaboration  provides  Genentech with broad access to
ImmunoGen's  maytansinoid  TAP technology for use with  Genentech's  proprietary
antibodies.  The  multi-year  agreement  provides  Genentech  with a license  to
utilize  ImmunoGen's  maytansinoid TAP platform in its antibody product research
efforts and an option to obtain product licenses for a limited number of antigen
targets over the  agreement's  five-year  term.  This agreement  provides for an
up-front  technology access fee of $3.0 million,  potential  milestone  payments
- --assuming benchmarks are met--of up to nearly $40.0 million per antigen target,
and royalties on net sales of resulting products.  Genentech will be responsible

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  13
for manufacturing,  product  development and marketing of any products developed
through this  collaboration;  ImmunoGen will be reimbursed  for any  preclinical
materials  that it makes under the  agreement.  The agreement can be renewed for
one subsequent three-year period, for an additional technology access fee.

     Also in May 2000, the Company entered into a development, commercialization
and license  agreement with British Biotech  Pharmaceuticals  Limited  ("British
Biotech"),  a biotechnology  company located in Oxford,  England, to develop and
commercialize the Company's  huN901-DM1 TAP for the treatment of small-cell lung
cancer.  The agreement  grants British Biotech  exclusive  rights to develop and
commercialize  huN901-DM1 in the European Union and Japan.  The Company  retains
the rights to commercialize  huN901-DM1 in the United States and the rest of the
world,  as well as the right to  manufacture  the product  worldwide.  Under the
terms of the agreement,  British  Biotech will be responsible for conducting the
clinical trials  necessary to achieve  marketing  approval in the United States,
European Union and Japan. ImmunoGen is responsible for the remaining preclinical
development,  and will be reimbursed for  manufacturing the product for clinical
trials. British Biotech paid an up-front fee of $1.5 million for its territorial
rights.  Upon  approval of the product for marketing in the United  States,  the
Company will pay to British Biotech a one-time milestone payment. ImmunoGen will
receive royalties on sales of huN901-DM1 in the European Union and Japan.

     As of March 31, 2000, the Company had  approximately  $13.3 million in cash
and cash equivalents.  In addition, in May 2000, an additional $7.35 million was
received from the following sources:  $5.0 million from Genentech,  $1.5 million
from British Biotech, and $843,000 from BioChem. No revenues have been generated
from product  sales and the Company does not  anticipate  having a  commercially
approved  product  within  the  foreseeable  future.  Research  and  development
expenses are expected to increase  significantly in the near term as the Company
continues  its  development  efforts.  Moreover,  the  Company  expects to spend
approximately  $2.0 million to upgrade its development  and pilot  manufacturing
facility in Norwood, Massachusetts. It is anticipated that the increase in total
cash expenditures will be offset by collaboration-derived proceeds. Accordingly,
period-to-period  operational  results may fluctuate  dramatically.  The Company
believes  that  its  established  collaborative  agreements,  while  subject  to
specified milestone achievements, will provide funding sufficient to allow it to
meet its obligations under all collaborative  agreements while also allowing the
aggressive  development  of those product  candidates and  technologies  outside
current collaborative agreements.  However, no assurances can be given that such
collaborative  agreement funding will, in fact, be realized.  Should the Company
not meet some or all of the terms and  conditions  of its various  collaboration
agreements,  it may be required to pursue additional strategic partners,  secure
alternative  financing  arrangements,  and/or  defer or limit some or all of its
research, development and/or clinical projects.

ACCOUNTING PROUNCEMENTS

     In December 1999, the  Securities  and Exchange  Commission  ("SEC") issued
Staff  Accounting  Bulletin 101 ("SAB 101"),  "Revenue  Recognition in Financial
Statements,"  which provides  guidance related to revenue  recognition  based on
interpretations  and practices  followed by the SEC. The effective  date of this
bulletin was deferred to no later than the second fiscal quarter beginning after
December 31, 1999.  SAB 101 requires  companies to report any changes in revenue
recognition  as a  cumulative  change  in  accounting  principle  at the time of
implementation  in accordance with Accounting  Principles  Board Opinion No. 20,
"Accounting  Changes." The Company is currently in the process of evaluating the
impact,  if any, that SAB 101 will have on its financial  position or results of
operations.

     In  March  2000,  the  Financial  Accounting  Standards  Board  issued FASB
Interpretation  No. 44,  "Accounting  for Certain  Transactions  Involving Stock
Compensation  - an  interpretation  of APB Opinion  No. 25" ("FIN  44").  FIN 44
clarifies the application of APB Opinion No. 25 and among other issues clarifies
the  following:  the  definition  of an employee  for  purposes of applying  APB
Opinion No. 25; the  criteria  for  determining  whether a plan  qualifies  as a
noncompensatory plan; the accounting consequence of various modifications to the
terms of previously  fixed stock options or awards;  and the  accounting  for an
exchange  of stock  compensation  awards in a  business  combination.  FIN 44 is
effective July 1, 2000, but certain  conclusions in FIN 44 cover specific events
that occurred  after either  December 15, 1998 or January 12, 2000.  The Company
does not  expect  the  application  of FIN 44 to have a  material  impact on the
Company's financial position or results of operations.

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RESULTS OF OPERATIONS

    THREE MONTHS ENDED MARCH 31, 2000 AND 1999

    Revenues

     Revenues  for the  three-month  period ended March 31, 2000  ("2000")  were
$120,000 compared with $1.16 million for the three-month  period ended March 31,
1999  ("1999").  The  significant  decrease  in  revenues  from  1999 to 2000 is
primarily   attributable  to  the  timing  of  milestone  payments  received  in
connection with the Company's collaboration with SB. During the third quarter of
1999, the Company  recorded a $1.0 million SB  agreement-signing  milestone;  no
collaboration-related revenue was recognized during the three months ended March
31, 2000. Additional  substantial  collaboration  revenues will be earned if the
Company  achieves the  predetermined  milestones set forth in the respective SB,
Genentech and British Biotech agreements.  Accordingly,  historically recognized
collaboration  revenues should not be used as indicators of the timing or extent
of future milestone payments,  and the recognition of such milestones will cause
period-to-period results to fluctuate dramatically.

     In the three-month  period ended March 31, 1999,  revenues of $115,000 were
also derived from development fees received under the Small Business  Innovation
Research Program ("SBIR") of the National Cancer Institute. As of July 1999, all
funds available under authorized SBIR programs had been recognized and received.
Accordingly,  no material development fees are expected to be earned through the
remainder of fiscal year 2000.

     Interest  income was  $120,000  in 2000  compared  to $45,000 in 1999.  The
increase  in  interest  income  from 1999 to 2000  primarily  resulted  from the
increase in funds available for investment.

    Research and Development Expenses

     Research  and  development   expenses,   which  constituted  the  principal
component of the Company's total operational  expenditures (77% in both quarters
ended March 31,  2000 and 1999),  were $2.26  million in 2000  compared to $1.42
million in 1999. The $840,000,  or 59%, increase from 1999 to 2000 was primarily
due to increased costs  associated with the  development  and  manufacturing  of
huC242-DM1/SB-408075  clinical  components,  as well as the further  preclinical
development of huN901-DM1. Future research and development expenses are expected
to  significantly  increase in  connection  with the Company's  ongoing  initial
clinical study of huC242-DM1/SB-408075.  The Company also anticipates additional
development  costs will result from both the  advancement  of huN901-DM1  toward
human  clinical  trials  as  well  as  the  development  of  other  TAP  product
candidates.

    General and Administrative Expenses

     General and  administrative  expenses  were  $689,000  in 2000  compared to
$432,000 in 1999. The $257,000,  or 59%, increase was primarily due to increased
administrative  and  business  development   staffing,   as  well  as  increased
expenditures  associated with investor relations,  business  development and the
Company's  information  system.  Future general and administrative  expenses are
also  expected to increase  congruently  with the continued  development  of the
Company's product candidates and technologies.

   Minority Interest

     ATI operating  losses of $25,290 in each of the  three-month  periods ended
March 31, 2000 and 1999 were allocated to ATI's minority  stockholder within the
Company's condensed consolidated financial statements.

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    NINE MONTHS ENDED MARCH 31, 2000 AND 1999

    Revenues

     Revenues  for the nine  months  ended March 31,  2000  ("2000")  were $6.76
million,  compared  with $1.57  million for the nine months ended March 31, 1999
("1999").  The  significant  increase in revenues from 1999 to 2000 is primarily
attributable   to  the  $6.5  million  in  milestone   payments   recognized  as
collaboration  revenue under the SB Agreement in 2000 compared with $1.0 million
recognized in 1999. The collaboration revenues recognized in 2000 were comprised
of the following:  $4.0 million on acceptance by the United States Food and Drug
Administration  of  the  Company's  Investigational  New  Drug  application  for
huC242-DM1/SB408075,  and $2.5 million on initiation  of the  currently  ongoing
clinical  study.  The 1999  collaboration  revenue  represented  a $1.0  million
agreement-signing milestone.

     In 1999,  revenues of $378,000  were also  derived  from  development  fees
received  under the SBIR grant  program.  As of July 1999,  all funds  available
under  authorized  SBIR  programs had been  received.  Accordingly,  no material
development  fees are expected to be earned through the remainder of fiscal year
2000.

     Interest  income was  $254,000 in 2000  compared  to $189,000 in 1999.  The
increase  in  interest  income  from 1999 to 2000  primarily  resulted  from the
increase in funds available for investment.

    Research and Development Expenses

     Research and  development  expenses  were $5.98 million in 2000 compared to
$4.26 million in 1999. The $1.72 million,  or 40%, increase from 1999 to 2000 is
due to the increased costs  associated  with supporting the Company's  currently
ongoing  huC242-DM1/SB-408075  human  clinical  trial,  as well as the continued
development of huN901-DM1 in advance of human clinical studies.

    General and Administrative Expenses

     General and administrative  expenses were $1.84 million in 2000 compared to
$1.25  million in 1999.  Similar to the results for the three months ended March
31, 2000 and 1999, the $590,000, or 47%, increase was primarily due to increased
administrative   and  business   development   staffing  as  well  as  increased
expenditures  associated with investor relations,  business  development and the
Company's information system.

    Minority Interest

     ATI  operating  losses of $75,870 in 2000 and 1999 were  allocated to ATI's
minority  stockholder  within the  Company's  condensed  consolidated  financial
statements.

    Non-cash Dividends

     Non-cash  dividends  were  approximately  $918,000 in the nine months ended
March 31, 1999. No such non-cash  dividends were recognized in nine months ended
March 31, 2000. The $918,000  non-cash  dividends  represented the Black-Scholes
option  pricing  model  derived  fair value of warrants to purchase  1.4 million
shares of ImmunoGen Common Stock issued in connection with the July 1998 sale of
the Company's Series E Convertible Preferred Stock.

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  16
LIQUIDITY AND CAPITAL RESOURCES

     Since July 1, 1999,  the Company has  financed the net cash used to support
operating activities primarily from various collaborative and financing sources.
These sources include:

 - $6.5 million from milestone revenues earned under the Company's SB agreement;

 - $5.0 million from equity issuances to SB and BioChem and;

 - $4.6 million  from the  exercise of warrants  and options to purchase  Common
   Stock.

To a lesser  extent,  the Company  also  received  proceeds  from the SBIR grant
program as well as the final  principal  payment on a note  receivable  from the
prior  assignment of facilities  and  equipment.  Cash used in operations in the
nine months  ended March 31, 2000  primarily  supported  the  Company's  various
research and development efforts.

     Net cash used in operations during the nine months ended March 31, 2000 was
$862,000  compared to $3.62 million used in the nine months ended March 31,1999.
This 76% decrease in operational  cash use is largely due to the recognition and
receipt of $5.5 million more collaboration  revenue in 2000 as compared to 1999.
Offsetting the increase in collaboration  revenue was a $2.3 million increase in
total operational expenses.

     Net cash used in  investing  activities  was  $10.87  million  for the nine
months   ended  March  31,  2000,   and   primarily   represents   purchases  of
higher-yielding, investment-grade corporate and U.S. Government debt securities.
Net cash used in investing  activities  during the nine-month period ended March
31, 1999 was $595,000 and primarily  resulted  from payments  received on a note
receivable  originally issued in connection with the assignment of the Company's
former Canton, Massachusetts facility.

     Capital  purchases  were $243,000 for the nine months ended March 31, 2000,
and consisted  primarily of information  system  upgrades along with  scientific
equipment  purchases  associated with the Company's  clinical  manufacturing and
development functions.  As a result of the recently signed Genentech and British
Biotech collaborative agreements, the Company expects to expend significant cash
resources to update its existing  Norwood,  Massachusetts  development and pilot
manufacturing  facility.  The Company anticipates that such capital expenditures
could  approximate  $2.0 million over the next twelve  months.  Certain  capital
outlays are expected to be reimbursed  pursuant to the  Company's  collaborative
agreements.

     Net cash provided  by financing  activities increased from $4.12 million in
the nine months ended March 31, 1999 to $9.63 million in same nine-month  period
ended  March 31,  2000.  The  increase  is largely  due to the  exercise of 1.49
million  warrants and options during the nine-month  period ended March 31, 2000
and to the September 1999 issuance of 1.02 million shares of Common Stock to SB.
Total proceeds from of all ImmuniGen Common Stock issuances occurring within the
nine-month period totaled $7.15 million.  In fiscal 1999, $1.5 million in Series
E  Convertible  Preferred  Stock  was  issued in a  private  placement.  No such
issuance of ImmunoGen convertible preferred occurred during fiscal 2000. In each
of the nine-month  periods ended March 31, 1999 and 2000,  $2.5 million was also
received in connection  with ATI's  issuance of convertible  preferred  stock to
BioChem.  The  BioChem  research  collaboration  expires  on July 31,  2000;  no
additional preferred stock will be issued.

     As of March 31, 2000, the Company had  approximately  $13.3 million in cash
and cash  equivalents.  In addition,  in April and May 2000, an additional $7.35
million was received from the following  sources:  $5.0 million from  Genentech,
$1.5 million from  British  Biotech,  and  $843,000  from  BioChem.  The Company
anticipates  that these  capital  resources  will enable the Company to meet its
operational  expenses  and  capital  expenditures  at  least  through  the  next
twelve-month  period.  The Company  believes that its established  collaborative
agreements,  while  subject to specified  milestone  achievements,  will provide
funding  sufficient  to allow  the  Company  to meet its  obligations  under all
collaborative agreements while also allowing the Company to aggressively develop
product  candidates and technologies  not covered by  collaborative  agreements.
However,  no assurances can be given that such  collaborative  agreement funding
will, in fact, be realized. Should the Company not meet some or all of the terms

                                       16
  17
and conditions of its various  collaboration  agreements,  it may be required to
pursue additional strategic partners, secure alternative financing arrangements,
and/or defer or limit some or all of its research,  development  and/or clinical
projects.

CERTAIN FACTS THAT MAY AFFECT FUTURE RESULTS OF OPERATIONS

     This report  contains  certain  forward-looking  statements as that term is
defined in the Private Securities Litigation Reform Act of 1995. Such statements
are based on management's  current  expectations  and are subject to a number of
factors and uncertainties  which could cause actual results to differ materially
from those described in the  forward-looking  statements.  The Company  cautions
investors  that  there can be no  assurance  that  actual  results  or  business
conditions will not differ  materially from those projected or suggested in such
forward-looking  statements as a result of various factors,  including,  but not
limited to, the following: the uncertainties associated with preclinical studies
and  clinical  trials;   the  early  stage  of  the  Company's  initial  product
development  and lack of product  revenues;  the Company's  history of operating
losses and accumulated  deficit;  the Company's limited financial  resources and
uncertainty as to the availability of additional capital to fund its development
on acceptable  terms, if at all; the Company's lack of commercial  manufacturing
experience  and  commercial  sales,  distribution  and  marketing  capabilities;
reliance on suppliers of key materials  necessary for production of the products
and technologies; the potential development by competitors of competing products
and   technologies;   the   Company's   dependence  on  existing  and  potential
collaborative  partners, and the lack of assurance that the Company will receive
any  funding  under  such   relationships  to  develop  and  maintain  strategic
alliances;  the lack of assurance  regarding patent and other protection for the
Company's  proprietary  technology;  governmental  regulation  of the  Company's
activities, facilities, products and personnel; the dependence on key personnel;
uncertainties as to the extent of  reimbursement  for the costs of the Company's
potential  products and related  treatments  by  government  and private  health
insurers   and   other   organizations;   the   potential   adverse   impact  of
government-directed  health care reform;  the risk of product  liability claims;
unreported Year 2000 problems; and economic conditions, both generally and those
specifically related to the biotechnology  industry.  As a result, the Company's
future  development   efforts  involve  a  high  degree  of  risk.  For  further
information,  refer to the  more  specific  risks  and  uncertainties  discussed
throughout  the  Company's  Annual Report on Form 10-K for the fiscal year ended
June 30, 1999 as filed with the Securities and Exchange Commission.

YEAR 2000 ISSUES

     Prior to January 1, 2000, the Company had completed all upgrades  necessary
to ensure that its information systems,  facilities and research and development
equipment  containing   date-sensitive  hardware  and  software  was  Year  2000
compliant. Also prior to January 1, 2000, the Company sent questionnaires to its
then engaged  third-party  suppliers,  vendors,  administrators  and custodians,
inquiring  of their  progress  in  identifying  and  addressing  their Year 2000
issues. The Company received responses from all surveyed vendors and, based upon
the information  contained in those  responses,  the Company  believes that Year
2000 issues have been addressed by the Company's critical vendors.  To date, the
Company  has not  encountered  any  problems  as a result of Year  2000  issues.
Expenses  related to Year 2000  issues have not been  material,  and the Company
does not expect to incur any significant Year 2000 expenses in the future.


ITEM 3.  QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

     In the normal course of business,  the financial position of the Company is
subject to certain risks,  including  market risk  associated with interest rate
movements.  The  Company  regularly  assesses  these  risks and has  established
policies and business practices designed to mitigate such exposures. The Company
invests surplus cash in low-risk debt securities, typically maturing in one year
or less,  pending use in operations.  The Company manages these funds by seeking
principal  preservation  while  concurrently  enhancing  rates  of  return.  The

                                       17
  18
Company's interest income is therefore sensitive to changes in the general level
of  domestic  interest  rates.  Based on the  Company's  overall  interest  rate
exposure  at March 31,  1999,  a near-term  change in  interest  rates would not
materially affect the fair value of interest rate sensitive instruments.

                           PART II. OTHER INFORMATION


Item 1.  Legal Proceedings.

           The Company is not a party to any material legal proceedings.


Item 2.  Changes in Securities and Use of Proceeds.

           In  January  2000,  holders  of the  Company's  Series E  Convertible
           Preferred  Stock ("Series E Stock")  exercised their right to convert
           all  2,400  shares  of Series E Stock  into  2,823,528  shares of the
           Company's Common Stock.

           In  February  2000,  a  holder  of  warrants   originally  issued  in
           connection  with a  private  placement  of  the  Company's  Series  A
           Convertible  Preferred  Stock  exercised his right to acquire  50,000
           shares of Common Stock at $3.11 per share. Proceeds from this warrant
           exercise will be used to fund current operations.

           In February and March 2000, holders of warrants  originally issued in
           connection  with a  private  placement  of  the  Company's  Series  B
           Convertible Preferred Stock exercised their rights to acquire 239,069
           and 5,000  shares  of  Common  Stock at $3.68 per share and $5.49 per
           share,  respectively.  Proceeds from these warrant  exercises will be
           used to fund current operations.

           Between January and March 2000, holders of warrants originally issued
           in  connection  with a private  placement of the  Company's  Series C
           Convertible Preferred Stock exercised their rights to acquire 654,368
           shares  of Common  Stock at $2.31  per  share.  Proceeds  from  these
           warrant exercises will be used to fund current operations.

           In January 2000, holders of warrants  originally issued in connection
           with a  private  placement  of the  Company's  Series  D  Convertible
           Preferred  Stock  exercised their rights to acquire 427,272 shares of
           Common  Stock  at  $1.94  per  share.  Proceeds  from  these  warrant
           exercises will be used to fund current operations

           During  the  three-month  period  ended  March 31,  2000,  holders of
           options  issued  through the Company's  1986  Incentive  Stock Option
           Plan,  Option Plan, as amended,  exercised their rights to acquire an
           aggregate of 111,750 shares at prices ranging from $0.84 per share to
           $11.25 per share.  The total  proceeds  from these option  exercises,
           $204,058, will be used to fund current operations.

           In July 1997, the Company's majority-owned  subsidiary,  ATI, entered
           into a collaboration with BioChem. As part of the agreement,  BioChem
           received  warrants to purchase shares of ImmunoGen Common Stock equal
           to $11.125 million,  the amount invested in ATI by BioChem during the
           three-year  research term.  These warrants will be exercisable at any
           time on or after July 31, 2000,  until and  including  July  31,2002,
           into a number of shares  of  ImmunoGen  Common  Stock  determined  by
           dividing  $11.125 million by the market price of the ImmunoGen Common
           Stock on the exercise  date,  subject to certain  limitations.  As of
           March 31, 2000, the last quarterly  investment of $843,000 was due to
           ATI.  In April  2000,  this  amount  due was  received  and  warrants
           corresponding  to that  amount  were  issued.  Until  July 31,  2000,
           proceeds from this  investment are restricted to fund the ongoing ATI
           research collaboration.

                                      18

 19
Item 3.  Defaults Upon Senior Securities.

           Not applicable

Item 4.  Submission of Matters to a Vote of Security Holders.

           None

Item 5.  Other Information.

           Not applicable

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

         (a)      Exhibits

                  10.1     Form of Warrant  Certificate issued by the Registrant
                           to BioChem Pharma Inc.  (previously  filed as exhibit
                           10.5 to, and  incorporated  herein by reference from,
                           the Registrant's Registration Statement on Form 10-Q,
                           as  amended by form  10-Q/A,  for the  quarter  ended
                           March 31, 1997)

                  27       Financial Data Schedule

         (b)      Reports on Form 8-K

                           Form 8-K dated May 4,  2000 - Item 5:  Other  Events.
                           ImmunoGen,  Inc. and Genentech,  Inc.  announced that
                           Genentech  has   exclusively   licensed   ImmunoGen's
                           maytansinoid Tumor-Activated Prodrug (TAP) technology
                           for   use   with   anti-HER2   antibodies   such   as
                           Herceptin(R).  Under  the  terms  of  the  agreement,
                           Genentech will receive exclusive  worldwide rights to
                           commercialize   anti-HER2  targeting  products  using
                           ImmunoGen's maytansinoid TAP platform. Genentech will
                           be responsible for manufacturing, product development
                           and marketing of products resulting from the license;
                           ImmunoGen will be reimbursed for any  preclinical and
                           clinical materials that it makes under the agreement.
                           ImmunoGen  will  receive  an  up-front  payment of $2
                           million.  In addition to royalties on net sales,  the
                           terms of the agreement  include  milestone  payments,
                           assuming all benchmarks  are met, for  potentially up
                           to $40 million..

                           Form 8-K dated May 5,  2000 - Item 5:  Other  Events.
                           ImmunoGen,  Inc. and British  Biotech plc announced a
                           license   agreement  to  develop  and   commercialize
                           ImmunoGen's huN901-DM1 tumor- activated prodrug (TAP)
                           for  treatment of  small-cell  lung  cancer.  British
                           Biotech  has  been  granted  the  exclusive  right to
                           develop and commercialize  huN901-DM1 in the European
                           Union ("EU") and Japan.  ImmunoGen retains the rights
                           to commercialize  huN901-DM1 in the United States and
                           the  rest  of the  world,  as well  as the  right  to
                           manufacture  the product  worldwide.  British Biotech
                           paid  an  up-front   fee  of  $1.5  million  for  its
                           territorial  rights.  Under  the  agreement,  British
                           Biotech is  responsible  for  conducting the clinical
                           trials  necessary to achieve  regulatory  approval in
                           the US, EU and Japan.  ImmunoGen is  responsible  for
                           the remaining  preclinical  development,  and will be
                           reimbursed for manufacturing the product for clinical
                           trials.  It is  anticipated  that a Phase I  clinical
                           trial will start in the fourth  quarter of this year.
                           Upon regulatory approval of the product for marketing
                           in the US,  ImmunoGen  will  pay  British  Biotech  a
                           one-time  milestone  payment.  ImmunoGen will receive
                           royalties on sales of huN901-DM1 in the EU and Japan.

                                      19
 20
                           Form 8-K dated May 8,  2000 - Item 5:  Other  Events.
                           ImmunoGen,  Inc.  and  Genentech,  Inc.  announced  a
                           second collaboration between the two companies.  This
                           second  collaboration  provides  Genentech with broad
                           access to  ImmunoGen's  maytansinoid  Tumor-Activated
                           Prodrug (TAP)  technology  for use with  proprietary
                           antibodies.   The   multi-year   agreement   provides
                           Genentech  with  a  license  to  utilize  ImmunoGen's
                           maytansinoid  TAP  platform in its  antibody  product
                           research  efforts  and an option to obtain  exclusive
                           product  licenses  for a limited  number  of  antigen
                           targets over the agreement's five-year term.

                           The  agreement  provides  for an up-front  technology
                           access  fee of $3  million  and  potential  milestone
                           payments--assuming benchmarks are met-of up to nearly
                           $40 million per antigen target,  and royalties on net
                           sales  of  resulting  products.   Genentech  will  be
                           responsible for  manufacturing,  product  development
                           and marketing of any products  developed  through the
                           collaboration;  ImmunoGen  will be reimbursed for any
                           preclinical   materials   that  it  makes  under  the
                           agreement.  The  agreement  can be  renewed  for  one
                           subsequent   three-year  period,  for  an  additional
                           technology  access fee.  Genentech  is  developing  a
                           Herceptin(R)  TAP   conjugate   under   a   separate,
                           previously announced, agreement with ImmunoGen.









                                       20

 21



                                   SIGNATURES


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


                                 IMMUNOGEN, INC.




Date:    May 12, 2000                     By:  /s/ Mitchel Sayare
                                               -----------------------
                                                Mitchel Sayare
                                                  President and Chief Executive
                                                  Officer
                                                  (principal executive officer)



Date:    May 12, 2000                     By:  /s/ Kathleen A. Carroll
                                               -----------------------
                                                Kathleen A. Carroll
                                                  Vice President,
                                                  Finance and Administration
                                                  (principal financial officer)



                                       21
  22
                               INDEX TO EXHIBITS

EXHIBIT
  NO.           DESCRIPTION
- -------         -----------

  27            Financial Data Schedule