CELGENE CORPORATION

                              AMENDED AND RESTATED

                           CERTIFICATE OF DESIGNATION

                                       OF

                              SERIES A CONVERTIBLE

                                 PREFERRED STOCK

        (Pursuant to Section 151 of the Delaware General Corporation Law)

                   We, John W. Jackson and Sanford  Kaston,  the Chairman of the
Board and Chief Executive Officer and the Assistant Secretary,  respectively, of
Celgene Corporation,  a Delaware corporation,  in accordance with the provisions
of Section 103 of the Delaware General Corporation Law do hereby certify that:

               1.  The  name  of  the   corporation   (hereinafter   called  the
"Corporation") is CELGENE CORPORATION, a corporation duly organized and existing
under the laws of the State of Delaware.

               2. The Certificate of Incorporation  (as amended)  authorizes the
issuance of 5,000,000  shares of Preferred Stock of a par value of $.01 each and
expressly  vests in the Board of  Directors  of the  Corporation  the  authority
provided therein to issue any or all of said shares in one or more series and by
resolution or resolutions to establish the designation,  number, full or limited
voting  powers,  or the  denial  of voting  powers,  preferences  and  relative,
participating,  optional,  and  other  special  rights  and the  qualifications,
limitations,  restrictions,  and other  distinguishing  characteristics  of each
series to be issued.

               3. A  Certificate  of  Designation  setting  forth the rights and
privileges with respect to the Series A Convertible  Preferred  Stock,  $.01 par
value per share, of the Corporation and designating Four Hundred Twenty (420) of
the 5  Million  (5,000,000)  authorized  shares of  Preferred  Stock as Series A
Convertible  Preferred  Stock,  $.01 par value  per  share,  was filed  with the
Secretary  of State of the State of Delaware on March 6, 1996.  This Amended and
Restated  Certificate  of  Designation  amends and restates the  Certificate  of
Designation that was filed on March 6, 1996.

               4.  The   following  is  a  true  and  correct  copy  of  certain
resolutions  duly adopted by the Board of Directors of the  Corporation on March
11, 1996, which  constituted all necessary action on the part of the Company for
adoption of such resolutions.


                                        1




 





               RESOLVED,  that Five  Hundred  and Twenty  (520) of the 5 Million
(5,000,000)  authorized  shares of Preferred Stock of the  Corporation  shall be
designated  Series A Convertible  Preferred Stock, $.01 par value per share, and
shall possess the rights and privileges set forth below:

               Section 1.  Designation  and  Amount.  The shares of such  series
shall be  designated as "Series A  Convertible  Preferred  Stock" (the "Series A
Convertible Preferred Stock") and the number of shares constituting the Series A
Convertible  Preferred  Stock (the "Shares") shall be 520; such number of shares
may be increased or decreased by resolution of the Board of Directors; provided,
that no  decrease  shall  reduce the number of Shares to a number  less than the
number of shares then outstanding.


               Section 2. Rank. The Series A Convertible  Preferred  Stock shall
rank:  (i) prior to all of the  Corporation's  Common Stock,  par value $.01 per
share  ("Common  Stock");  (ii) prior to any class or series of capital stock of
the Corporation  hereafter created  specifically  ranking by its terms junior to
the Series A Convertible  Preferred Stock (collectively,  with the Common Stock,
"Junior Securities");  (iii) on parity with any class or series of capital stock
of the Corporation hereafter created specifically ranking by its terms on parity
with the Series A Convertible  Preferred  Stock ("Parity  Securities")  and (iv)
junior  to any class or series of  capital  stock of the  Corporation  hereafter
created  specifically  ranking by its terms  senior to the Series A  Convertible
Preferred  Stock  ("Senior  Securities");  in each case as to  distributions  of
assets upon liquidation,  dissolution or winding up of the Corporation,  whether
voluntary or involuntary (all such distributions  being referred to collectively
as "Distributions");

               Section 3.  Dividends.  The Series A Convertible  Preferred Stock
will bear no dividends,  and the holders of the Series A  Convertible  Preferred
Stock  shall not be entitled to receive  dividends  on the Series A  Convertible
Preferred Stock.

               Section 4. Liquidation Preference.

               (a) In the event of any liquidation, dissolution or winding up of
the Corporation,  either  voluntary or involuntary ("an Event"),  the holders of
Shares  shall be entitled to receive,  immediately  after any  distributions  to
Senior  Securities  and prior and in  preference to any  distribution  to Junior
Securities but in parity with any distribution to Parity  Securities,  an amount
per  share  equal to the sum of (i)  $50,000  for each  outstanding  Share  (the
"Original  Series  A Issue  Price")  and  (ii) an  amount  equal  to 4.9% of the
Original Series A Issue Price per annum for the period that has passed since the
date of issuance of any Series A Convertible  Preferred Stock (such amount being
referred to herein as the  "Accretion").  If upon the  occurrence of such Event,
the  assets  and funds  thus  distributed  among  the  holders  of the  Series A
Convertible  Preferred  Stock and Parity  Securities  shall be  insufficient  to
permit the payment to such holders of the full  preferential  amounts due to the
holders of the Series A Convertible  Preferred Stock and the Parity  Securities,
respectively,  then the  entire  assets  and  funds of the  Corporation


                                       2

 


legally available for distribution shall be distributed among the holders of the
Series A Convertible Preferred Stock and the Parity Securities,  pro rata, based
on the  respective  liquidation  amounts to which  each such  series of stock is
entitled   by  the   Corporation's   Certificate   of   Incorporation   and  any
Certificate(s) of Designation.

               (b)  Upon  the  completion  of  the   distribution   required  by
subsection 4(a), if assets remain in this Corporation, they shall be distributed
to holders of Junior Securities in accordance with the Corporation's Certificate
of Incorporation including any duly adopted Certificate(s) of Designation.

               (c) A consolidation or merger of the Corporation with or into any
other corporation or corporations,  or a sale,  conveyance or disposition of all
or substantially all of the assets of the Corporation or the effectuation by the
Corporation  of a transaction  or series of related  transactions  in which more
than 50% of the voting  power of the  Corporation  is disposed  of, shall not be
deemed to be a liquidation, dissolution or winding up within the meaning of this
Section 4, but shall instead be treated pursuant to Section 5(f)(ii) hereof.

               Section 5.  Conversion.

The record  Holders of this  Series A  Convertible  Preferred  Stock  shall have
conversion rights as follows (the "Conversion Rights"):

               (a)  Right  to  Convert.  The  record  holder  of  the  Series  A
Convertible  Preferred Stock shall be entitled, as set forth below, and, subject
to the Company's right of redemption set forth in Section 6 and the restrictions
on  conversion  set forth in Section  5(b) below,  to convert the Shares held by
such holder  into that  number of  fully-paid  and  nonassessable  shares of the
Common Stock at the  Conversion  Rate as set forth below.  The minimum number of
Shares that may be  converted is the lesser of (i) Two Shares or (ii) all of the
Holder's remaining Shares. The rate at which Shares may be converted into shares
of Common  Stock is  hereinafter  referred  to as the  "Conversion  Rate" and is
computed as follows:

Number  of  shares  of  Common  Stock  issued  upon  conversion  of one share of
Preferred Stock = Principal Conversion Rate + Accretion Conversion Rate, where

"Principal Conversion Rate" =                  Issue Price
                                             ----------------
                                             Conversion Price

and "Accretion Conversion Rate =     (.049)(N/365)(Issue Price)
                                     --------------------------
                                     Accretion Conversion Price

where

                                        3



 





           N = the number of days between (i) the date that,  in connection with
           the  consummation of the initial purchase of the Preferred Stock from
           the  Company,  the escrow  agent  first had in its  possession  funds
           representing   full  payment  for  the  Preferred   Stock  for  which
           conversion is being elected, and (ii) the Date of Conversion;

           Issue  Price = the  Original  Series A Issue  Price,  as  defined  in
           Section 4(a);

           Accretion  Conversion  Price equals the average Closing Price for the
           Common Stock as that term is defined below,  for the 30 calendar days
           prior to the Date of Conversion; and

           Conversion  Price = the lesser of (x) $18.81 (the  "Fixed  Conversion
           Price")(which  equals  110% of $17.1,  which is the  average  closing
           price for the seven (7) trading days ending on February 29, 1996), or
           (y) 90% of the average  Closing Price, as that term is defined below,
           of the  Company's  Common  Stock  for  the  seven  (7)  trading  days
           immediately  preceding the Date of Conversion.  For purposes  hereof,
           the  term  "Closing  Price"  shall  mean  the  closing  price  of the
           Company's  Common Stock as reported by NASDAQ (or, if not reported by
           NASDAQ, as reported by such other exchange or market where traded).

        (b)  Restrictions  on  Conversion.  No shares  of  Series A  Convertible
Preferred  Stock may be  converted  prior to 60 days after the Last  Closing (as
defined  in  the   Subscription   Agreement).   Thereafter,   (subject   to  the
effectiveness of the S-3  Registration  Statement as defined in the Subscription
Agreement)  each  Holder of Series A  Convertible  Preferred  Stock may  convert
one-third of his shares of Series A Convertible  Preferred Stock on or after the
60th day after the Last Closing,  an  additional  one-third on or after the 90th
day after the Last Closing,  and all additional  remaining  Series A Convertible
Preferred Stock on or after the 120th day after the Last Closing.

        (c) Mechanics of  Conversion.  In order to convert  Series A Convertible
Preferred Stock into shares of Common Stock,  the holder shall (i) fax a copy of
the fully executed  notice of conversion in the form attached hereto ("Notice of
Conversion")  to the Company at the office of the Company and to American  Stock
Transfer & Trust  Company (the  "Exchange  Agent") that he elects to convert the
same,  which notice shall  specify the number of shares of Series A  Convertible
Preferred  Stock  to be  converted  and  shall  contain  a  calculation  of  the
Conversion  Rate (together with a copy of the first page of each  certificate to
be  converted)  prior to Midnight,  New York City time (the  "Conversion  Notice
Deadline") on the Date of Conversion  specified on the Notice of Conversion  and
(ii) surrender the original certificate or certificates therefor, duly endorsed,
and the original  Notice of  Conversion,  no later than  Midnight (New York City
Time) the next business day, to a common  courier for overnight  delivery or (if
overseas)  2-day  delivery  to the  Exchange  Agent.  The  Company  shall not be
obligated to issue  certificates  evidencing the shares


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of Common Stock  issuable upon such  conversion  unless either the  certificates
evidencing  such  Series A  Convertible  Preferred  Stock are  delivered  to the
Exchange Agent as provided above, or the Holder notifies the Exchange Agent that
such  certificates  have been lost, stolen or destroyed and such Holder provides
such  indemnity as is reasonably  acceptable to the Company with respect to such
lost,  stolen  or  destroyed  certificate.  In the case of a  dispute  as to the
calculation of the Conversion  Rate, the Company's  calculation  shall be deemed
conclusive  absent manifest error. No fractional shares of Common Stock shall be
issued upon conversion of this Series A Convertible  Preferred Stock. In lieu of
any  fractional  share to which the Holder  would  otherwise  be  entitled,  the
Company shall round up to the nearest whole share.

        The Company  shall issue and deliver or cause to be issued and delivered
within three (3)  business  days after  delivery to the  Exchange  Agent of such
certificates,  or after the holder has furnished  such  indemnity such holder of
Series A Convertible  Preferred  Stock at the address of the Holder on the books
of the Company, a certificate or certificates for the number of shares of Common
Stock to which the Holder  shall be entitled as provided in Section  5(a) above.
The date on which conversion  occurs (the "Date of Conversion")  shall be deemed
to be the date set forth in such  Notice of  Conversion,  provided  (i) that the
advance  copy of the  Notice  of  Conversion  is  faxed to the  Company  and the
Exchange  Agent before  midnight,  New York City time, on the Date of Conversion
and (ii)  that the  stock  certificates  (the  "Preferred  Stock  Certificates")
representing  the  Series A  Convertible  Preferred  Stock to be  converted  are
received by the Exchange  Agent within five (5) business  days  thereafter.  The
person or persons  entitled to receive the shares of Common Stock  issuable upon
such  conversion  shall be treated  for all  purposes  as the  record  holder or
holders of such shares of Common Stock on such date.  If the  original  Series A
Convertible Preferred Stock Certificates to be converted are not received by the
Exchange  Agent or the Company  within five (5) business  days after the Date of
Conversion,  the Company may, at its option,  treat the Notice of  Conversion as
null and void.

        (d) Reservation of Stock Issuable Upon Conversion.  The Company shall at
all times reserve and keep available out of its  authorized but unissued  shares
of Common  Stock,  solely for the purpose of  effecting  the  conversion  of the
Series A Convertible  Preferred Stock, such number of its shares of Common Stock
as shall from time to time be  sufficient  to effect the  conversion of all then
outstanding  shares of Series A Convertible  Preferred Stock; and if at any time
the  number of  authorized  but  unissued  shares of Common  Stock  shall not be
sufficient to effect the conversion of all then  outstanding  shares of Series A
Convertible  Preferred Stock, the Company will take such corporate action as may
be necessary to increase its authorized  but unissued  shares of Common Stock to
such number of shares as shall be sufficient for such purpose.

        (e) Automatic  Conversion.  Each share of Series A Convertible Preferred
Stock  outstanding  two years  from the Date of the Last  Closing  automatically
shall be converted into Common Stock on such date at the  Conversion  Price then
in effect  and two years


                                       5

 


from the Date of the Last Closing  shall be deemed the Date of  Conversion  with
respect to such Shares then  outstanding  provided  that,  if such date is not a
business day, the next following business day shall be the operative date.

        (f)    Adjustment to Fixed Conversion Price.

               In computing the Fixed  Conversion  Price for purposes of Section
5(a):

               (i)  If,  prior  to  the  conversion  of  all  of  the  Series  A
Convertible Preferred Stock, the number of outstanding shares of Common Stock is
adjusted by a stock split stock  dividend,  or other  similar  event,  the Fixed
Conversion Price shall be proportionately adjusted.

               (ii) If,  prior to the  conversion  of all  Series A  Convertible
Preferred Stock, there shall be any merger,  consolidation,  exchange of shares,
recapitalization,  reorganization,  or other similar event, as a result of which
shares of Common Stock shall be changed  into the same or a different  number of
shares of the same or another  class or classes  of stock or  securities  of the
Company or another  entity,  then the Holders of Series A Convertible  Preferred
Stock shall thereafter have the right to purchase and receive upon conversion of
Series A  Convertible  Preferred  Stock,  upon the  basis and upon the terms and
conditions  specified  herein  and  in  lieu  of  the  shares  of  Common  Stock
immediately  theretofore  issuable upon conversion,  such shares of stock and/or
securities  as may be issued or payable  with  respect to or in exchange for the
number of  shares  of  Common  Stock  immediately  theretofore  purchasable  and
receivable  upon the conversion of Series A Convertible  Preferred Stock held by
such  Holders  had the Holders  converted  their  Series A  Preferred  to Common
immediately   prior  to  such   merger,   consolidation,   exchange  of  shares,
recapitalization or reorganization,  and in any such case appropriate provisions
shall be made with  respect to the rights and  interests  of the  Holders of the
Series A  Convertible  Preferred  Stock to the end  that the  provisions  hereof
(including,   without  limitation,   provisions  for  adjustment  of  the  Fixed
Conversion  Price and of the number of shares  issuable  upon  conversion of the
Series A Convertible Preferred Stock) shall thereafter be applicable,  as nearly
as may be  practicable  in  relation  to  any  shares  of  stock  or  securities
thereafter be deliverable upon the conversion of Series A Convertible  Preferred
Stock. The Company shall not effect any transaction described in this subsection
5(f) unless the  resulting  successor or  acquiring  entity (if not the Company)
assumes by written  instrument  the  obligation to deliver to the Holders of the
Series A Convertible  Preferred Stock such shares of stock and/or securities as,
in  accordance  with the  foregoing  provisions,  the  Holders  of the  Series A
Convertible Preferred Stock may be entitled to purchase.

               (iii) If any  adjustment  under this  Section 5(f) would create a
fractional  share of Common  Stock or a right to acquire a  fractional  share of
Common Stock, such fractional share (on an aggregate basis) shall be disregarded
and the  number of shares of Common  Stock  issuable  upon  conversion  shall be
rounded to the next higher number of shares.


                                       6

 




               Section 6. Redemption by Company; Lock Up.

        (a)  Company's  Right to  Redeem or Lock Up  Conversion  in the Event of
Conversion.

               (i) Redemption Upon Receipt of Notice of Conversion. In the event
the average  Closing Price of the  Company's  Common Stock on the NASDAQ for the
seven (7) trading days immediately  preceding the Date of Conversion shall be at
or less than the Fixed  Conversion  Price,  the Company shall have the right, in
its sole discretion,  upon receipt of a Notice of Conversion pursuant to Section
5, to  redeem  in whole or in part any  Series  A  Convertible  Preferred  Stock
submitted for conversion, immediately prior to conversion. If the Company elects
to  redeem  some,  but not all,  of the  Series A  Convertible  Preferred  Stock
submitted  for  conversion,  the  Company  shall  redeem from among the Series A
Convertible Preferred Stock submitted by the various shareholders for conversion
on the applicable  date, a pro-rata  amount from each  shareholder so submitting
Series A Convertible Preferred Stock for conversion.

        In the case of a redemption under this Section  6(a)(i),  the redemption
        price shall  equal the sum of the  Principal  Redemption  Price plus the
        Accretion, where:

               Principal Redemption Price =

                          Issue Price x Closing Price on Date of Conversion
                          -------------------------------------------------
                                           Conversion Price

        In the event of redemption,  the Accretion is payable,  at the Company's
option,  in cash or Common Stock. If the Accretion is paid in Common Stock,  the
number of shares for such payment shall be  calculated  in  accordance  with the
following formula:

                                    Accretion
                                    ---------
                           Accretion Conversion Price


               where "N," "Issue Price," "Closing Price",  "Accretion Conversion
               Price" and  "Conversion  Price"  have the  meanings  set forth in
               Section 5, and  "Accretion"  has the meaning set forth in Section
               4.

               (ii)  Redemption  or Lockup Below Soft Floor Price.  In the event
the  Closing  Price per share  shall be at or less than  $11.50 (the "Soft Floor
Price"),  for each of the five (5) trading days preceding the date of submission
of a Notice of Conversion by a Holder,  the Company shall have the right, in its
sole discretion,  upon receipt of such Notice of Conversion  pursuant to Section
5, to elect, in lieu of conversion, either (A) or (B), as follows:

                      A. The Company may elect to declare such  conversion  null
                      and



                                       7

 


                      void,  and declare  that no  conversion  of any  Preferred
                      Stock that is  included in the Notice of  Conversion  (the
                      "Affected  Preferred  Stock")  shall be permitted  for the
                      subsequent  ninety  (90) day  period  (the "90 Day Lock Up
                      Period").  In the event the Company declares a 90 Day Lock
                      Up Period,  the  Company  shall  issue  within 10 business
                      days,  to the  Holder  of  the  Affected  Preferred  Stock
                      warrants ("90 Day Lock Up Warrants"),  to purchase  Common
                      Stock of the Company, as follows:

                                    Terms of 90 Day Lock Up Warrant

                             - the 90 Day  Lock Up  Warrant  shall  entitle  the
                             holder  to  purchase  a number  of shares of common
                             stock  equal  to 10% of the  number  of  shares  of
                             Common  Stock  that  would  have been  issued  upon
                             conversion of the Affected  Preferred  Stock at the
                             Soft Floor Price.

                             - the  strike  price of the 90 Day Lock Up  Warrant
                             shall equal the Soft Floor Price.

                             - the term of the 90 Day Lock Up  Warrant  shall be
                             two (2) years.

                      The Company may, in its  discretion,  offer ("180 Day Lock
                      Up Offer") to provide  another  warrant  ("180 Day Lock Up
                      Warrant"),  in addition to the 90 Day Lock Up Warrant,  to
                      purchase  Common  Stock of the  Company,  to the Holder of
                      Affected  Preferred  Stock in exchange  for such  Holder's
                      agreement  to  forebear  from   converting   its  Affected
                      Preferred  Stock for an  additional  90 days beyond the 90
                      Day Lockup Period (a "180 Day Lockup Period"). The Holder,
                      in its  discretion,  may accept or reject the 180 Day Lock
                      Up Offer. The Company shall issue to the Holder, within 10
                      business days of Holder's written  acceptance of a 180 Day
                      Lock Up  Offer,  a 180 Day Lock Up  Warrant,  the terms of
                      which shall be equivalent to the terms of a 90 Day Lock Up
                      Warrant.

                      After  any 90 Day Lock Up Period or 180 Day Lock Up Period
                      (as  applicable),  the Investor shall again be entitled to
                      convert the Affected Preferred Stock pursuant to the terms
                      of  Section  5  above,   without  any   further   lock  up
                      restrictions.

                      B.  Redeem  such  Affected  Preferred  Stock  pursuant  to
                      Section 6(a)(i).


                                       8

 





               (iii)  Mechanics  of  Redemption  or  Lock  Up.  Any  shareholder
considering  submitting  Preferred  Stock  for  conversion  at such  time as the
Company's  right of redemption  under  Section  6(a)(i) or lock up under Section
6(a)(ii) is or may be in effect may provide  notice to the Company by facsimile,
of his  possible  desire to convert a  specified  number of Shares,  and ask the
Company to  determine  whether or not the Company  would  exercise  its right of
redemption or lock up if the Shares were submitted for  conversion.  The Company
shall  respond  within  two (2)  business  days of the date of  receipt  of that
notice,  and state whether it would redeem or lock up the Shares, in whole or in
part, or allow conversion into Common Stock without redemption or lock up, which
election will be applicable to conversion by such  shareholder  of the number of
Shares specified in his notice within the next five business days after the date
of the Company's response.  Failure of the Company to respond within the two (2)
business  day period shall be deemed an election by the Company not to redeem or
lock up the Shares covered by that notice if submitted for conversion within the
next five  business  days.  If the holder  does not  provide  advance  notice of
intention  to convert as  contemplated  in this section  (iii),  the Company may
effect redemption or lock up of Shares submitted for conversion by giving notice
of its  election  to redeem  or lock up, by  facsimile  within 2  business  days
following  receipt  of a Notice  of  Conversion  from a  Holder,  with a copy by
overnight or 2-day courier, to (A) the Holder of Series A Convertible  Preferred
Stock  submitted  for  conversion  at the address and  facsimile  number of such
Holder  appearing  in the  Company's  register  for  the  Series  A  Convertible
Preferred Stock and (B) the Exchange Agent.  Such notice shall indicate  whether
the  Company  will  redeem  or lock up all or part of the  Series A  Convertible
Preferred Stock submitted for conversion.

The  Company  shall not be  entitled  to  exercise  its  right to redeem  shares
submitted  for  conversion  under this  Section  6(a) unless it has (x) the full
amount  of the  redemption  price,  in  cash,  available  in a  demand  or other
immediately  available account in a bank or similar financial institution or (y)
immediately  available credit  facilities,  in the full amount of the redemption
price, with a bank or similar  financial  institution on the date the redemption
notice is sent to Holders.

        (b)  Company's  Right to Call  Redemption  if the Price of the Company's
Common Stock Is Greater Than the Fixed Strike Price.  The Company shall have the
right to redeem the Series A Convertible  Preferred Stock on the following terms
and conditions:

                      (i) at any time after nine (9) months  following  the Last
               Closing  Date,  if the  average  closing  price of the  Company's
               Common Stock for the seven (7) trading days immediately preceding
               the Notice  Date (as  defined  below) is  greater  than the Fixed
               Conversion  Price,  the  Company  may,  in its  discretion,  give
               written notice that it intends,  at least thirty (30) but no more
               than forty five (45)  business  days from the date of such notice
               ("Notice  Date") to redeem  the  Series A  Convertible  Preferred
               Stock at the  redemption  price  listed in 6(b)(iii)  below.  The
               Company  may elect to




                                       9

 


               redeem some,  but not all, of the Series A Convertible  Preferred
               Stock,  but in no event less than $1,500,000 per  redemption.  If
               the Company  elects to redeem some,  but not all, of the Series A
               Convertible  Preferred Stock, the Company shall redeem a pro-rata
               amount from among all the Series A  Convertible  Preferred  Stock
               holders.  The holders of the Preferred Stock shall have the right
               to convert their Preferred Stock until the redemption date.

                      (ii)  Mechanics of  Redemption.  The Company  shall effect
               each such  redemption by giving notice of its election to redeem,
               by facsimile with a copy by overnight or 2-day  courier,  no less
               than 30 business days prior to the intended redemption date. Such
               redemption  notice shall indicate whether the Company will redeem
               all or part of the  Series A  Convertible  Preferred  Stock,  the
               effective date of the  redemption  and the applicable  redemption
               price.  The  Company  shall not be entitled to send any notice of
               redemption and begin the redemption  procedure  unless it has (x)
               the full amount of the redemption price, in cash,  available in a
               demand  or  other  immediately  available  account  in a bank  or
               similar financial institution or (y) immediately available credit
               facilities,  in the full amount of the redemption  price,  with a
               bank or similar financial  institution on the date the redemption
               notice  is  sent  to  shareholders.  If the  Company  has met the
               requirements  of the  preceding  sentence,  and a Holder  has not
               submitted his Series A Convertible Preferred Stock for redemption
               as required by this  Section  6(c) by the  redemption  date,  the
               Company may pay the redemption price described in (iii) below and
               cancel the Series A  Convertible  Preferred  Stock subject to the
               redemption   notice,  and  such  redeemed  Series  A  Convertible
               Preferred Stock shall be of no further validity, force or effect.

                      (iii)  Redemption  Price.  In  the  case  of  a redemption
               under  this  Section 6(b),  the  redemption  price  per share  of
               Series  A  Convertible Preferred Stock shall be as follows:




                         Redemption Price                 Elapsed Time since Last
Closing                  ----------------                 -----------------------
- -------
                                                      
                      130% of Stated Value                       9  months  and  1  day  -  12
months
                      125% of Stated Value                       12  months  and  1  day  - 18
months
                      120% of Stated Value                       18  months  and  1  day  - 24
months


               For purposes of this  paragraph,  the "Stated  Value" shall equal
               the Original Series A Issue Price plus the Accretion  (calculated
               as of the effective date of such redemption).


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        (c) Payment of Redemption  Price.  The redemption  price for redemptions
under either  Section 6(a) or 6(b) above shall be paid to the Holder of Series A
Convertible   Preferred   Stock  redeemed  within  5  business  days  after  the
redemption;  provided,  however,  that the  Company  shall not be  obligated  to
deliver any portion of such  redemption  price  unless  either the  certificates
evidencing  the Series A Convertible  Preferred  Stock redeemed are delivered to
the Exchange  Agent,  or the Holder  notifies the Company or the Exchange  Agent
that such  certificates  have been lost,  stolen or  destroyed  and  executes an
agreement  satisfactory  to the Company to  indemnify  the Company from any loss
incurred by it in connection with such certificates.

Section 7.  Voting  Rights.  The holders of the Series A  Convertible  Preferred
Stock have no voting rights except as required by the General Corporation Law of
the State of Delaware.

Section 8. Protective  Provision.  So long as shares of Series A Preferred Stock
are outstanding,  the Company shall not alter or change the rights,  preferences
or privileges of the shares of Series A Convertible  Preferred Stock in a manner
not  contemplated  hereby so as to affect  adversely  the  Series A  Convertible
Preferred Stock.

Section 9.  Status of Redeemed or  Converted  Stock.  In the event any shares of
Series A Convertible  Preferred Stock shall be redeemed or converted pursuant to
Section 5 or Section 6 hereof,  the shares so  converted  or  redeemed  shall be
canceled,  shall return to the status of authorized but unissued Preferred Stock
of no designated  series, and shall not be issuable by the Corporation as Series
A Convertible Preferred Stock.

               FURTHER RESOLVED,  that the statements contained in the foregoing
resolutions  creating and  designating  the said Series A Convertible  Preferred
Stock and  fixing  the  number,  powers,  preferences  and  relative,  optional,
participating,  and other special  rights and the  qualifications,  limitations,
restrictions,  and other distinguishing  characteristics thereof shall, upon the
effective date of said series,  be deemed to be included in and be a part of the
Certificate of  Incorporation  of the Corporation  pursuant to the provisions of
the General Corporation Law of the State of Delaware.

               FURTHER  RESOLVED,  that the officers of the  Corporation be, and
each acting  individually hereby is, authorized and directed to take all actions
necessary  and  advisable  to effect the  purpose  and  intent of the  foregoing
resolutions.


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        IN WITNESS WHEREOF,  Celgene  Corporation has caused this certificate to
be signed by John P.  Jackson,  its  Chairman  of the Board and Chief  Executive
Officer, and attested by Sanford Kaston, its Assistant Secretary,  this 11th day
of March, 1996.


                            CELGENE CORPORATION


                            By ____________________________
                               John W. Jackson
                               Chairman of the Board and Chief Executive Officer

Attest:


By __________________________
      Sanford Kaston
      Assistant Secretary

               Each of the  undersigned,  the  Chairman  of the  Board and Chief
Executive Officer and Assistant Secretary, respectively, of Celgene Corporation,
a Delaware  corporation,  declares under penalty of perjury that the matters set
forth in this certificate are true and correct of his own knowledge.

               Executed at Warren, New Jersey on March __, 1996.



                               ____________________________
                               John W. Jackson
                               Chairman of the Board and Chief Executive Officer


                               ____________________________
                               Sanford Kaston
                               Assistant Secretary



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