EXHIBIT 3.3
 
                          SIXTH AMENDED AND RESTATED
                         CERTIFICATE OF INCORPORATION
                                      OF
                              CELL PATHWAYS, INC.


                                      I.

     The name of the corporation is Cell Pathways, Inc. (the "Corporation").

                                      II.

     The address of the registered office of the Corporation in the State of
Delaware is 1013 Centre Road, City of Wilmington, County of New Castle, and the
name of the registered agent of the Corporation in the State of Delaware at such
address is Corporation Service Company.

                                     III.

     The purpose of the Corporation is to engage in any lawful act or activity
for which a corporation may be organized under the General Corporation Law of
the State of Delaware.

                                      IV.

     A.   Upon the effectiveness of this Sixth Amended and Restated Certificate
of Incorporation, every 1.8157 outstanding shares of Common Stock of the
Corporation shall be combined into one share of Common Stock (the "Reverse
Split").  No fractional shares of Common Stock shall be issued in connection
therewith, and each stockholder otherwise entitled to receive a fractional share
shall receive the next lower whole number of shares of Common Stock.

     B.   Upon the effectiveness of the Reverse Split, the Corporation shall be
authorized to issue two classes of stock to be designated, respectively, "Common
Stock" and "Preferred Stock".  The total number of shares that the Corporation
shall be authorized to issue is twenty-seven million (27,000,000) shares.
Twenty-five million (25,000,000) shares shall be Common Stock, each having a par
value of One Cent ($.01).  Two million (2,000,000) shares shall be Preferred
Stock, each having a par value of One Cent ($.01).

     C.   The Preferred Stock may be issued from time to time in one or more
series.  The Board of Directors is hereby authorized, by filing a certificate (a
"Preferred Stock Designation") pursuant to the Delaware General Corporation Law,
to provide for such 

                                       1.

 
issuance, and to fix or alter from time to time the designation, powers,
preferences and rights of the shares of each such series and the qualifications,
limitations or restrictions of any wholly unissued series of Preferred Stock,
and to establish from time to time the number of shares constituting any such
series or any of them; and to increase or decrease the number of shares of any
series subsequent to the issuance of shares of that series, but not below the
number of shares of such series then outstanding. In case the number of shares
of any series shall be decreased in accordance with the foregoing sentence, the
shares constituting such decrease shall resume the status that they had prior to
the adoption of the resolution originally fixing the number of shares of such
series.

     D.   Subject to the rights of any Preferred Stock then outstanding, each
issued and outstanding share of Common Stock shall entitle the Holder thereof to
receive such dividends as may be declared from time to time by the Board of
Directors of the Corporation out of funds legally available therefor, and shall
entitle the Holder thereof to share ratably with other Holders of Common Stock
in all assets available for distribution in the event of any liquidation,
dissolution or winding up of the Corporation.  Each issued and outstanding share
of Common Stock shall be identical to all other shares of that class, and shall
entitle the Holder thereof to cast one vote on each matter submitted to a vote
of the Corporation's stockholders.  No Holder of Common Stock shall be entitled
to any cumulative voting rights or to any preemptive rights upon the issuance or
sale of any Securities.

                                      V.

     For the management of the business and for the conduct of the affairs of
the Corporation, and in further definition, limitation and regulation of the
powers of the Corporation, of its directors and of its stockholders or any class
thereof, as the case may be, it is further provided that:

     A.   1.  The business and affairs of the Corporation shall be managed by or
under the direction of the Board of Directors.  The number of directors that
shall constitute the whole Board of Directors shall be fixed exclusively by one
or more resolutions adopted by the Board of Directors.

          2.  Subject to the rights of the holders of any series of Preferred
Stock to elect additional directors under specified circumstances, following the
closing of the initial public offering pursuant to an effective registration
statement under the Securities Act covering the offer and sale of Common Stock
to the public (the "Initial Public Offering"), the directors shall be divided
into three classes designated as Class I, Class II and Class III, respectively.
Directors shall be assigned to each class in accordance with a resolution or
resolutions adopted by the Board of Directors.  At the first annual meeting of
stockholders following the closing of the Initial Public Offering, the term of
office of 

                                       2.

 
the Class I directors shall expire and Class I directors shall be elected for a
full term of three years. At the second annual meeting of stockholders following
the Closing of the Initial Public Offering, the term of office of the Class II
directors shall expire and Class II directors shall be elected for a full term
of three years. At the third annual meeting of stockholders following the
Closing of the Initial Public Offering, the term of office of the Class III
directors shall expire and Class III directors shall be elected for a full term
of three years. At each succeeding annual meeting of stockholders, directors
shall be elected for a full term of three years to succeed the directors of the
class whose terms expire at such annual meeting.

          Each director shall serve beyond the term specified until his
successor is duly elected and qualified or until his death, resignation or
removal.  No decrease in the number of directors constituting the Board of
Directors shall shorten the term of any incumbent director.

          3.  Subject to the rights of the holders of any series of Preferred
Stock, a director may be removed only for cause and only by the affirmative vote
of the holders of a majority of the voting power of all the then-outstanding
shares of voting stock of the Corporation, entitled to vote at an election of
directors (the "Voting Stock").

          4.  Subject to the rights of the holders of any series of Preferred
Stock, any vacancies on the Board of Directors resulting from death,
resignation, disqualification, removal or other causes and any newly created
directorships resulting from any increase in the number of directors, shall,
unless the Board of Directors determines by resolution that any such vacancies
or newly created directorships shall be filled by the stockholders, be filled
only by the affirmative vote of a majority of the directors then in office, even
though less than a quorum of the Board of Directors, and not by the
stockholders.  Any director elected in accordance with the preceding sentence
shall hold office for the remainder of the full term of the director for which
the vacancy was created or occurred and until such director's successor shall
have been elected and qualified.

          5.  The Board of Directors shall designate and empower committees of
the Board of Directors, shall elect and empower the officers of the Corporation,
may appoint and empower other officers and agents of the Corporation, and shall
determine the time, place and notice of Board meetings, quorum and voting
requirements, and the manner of taking Board action.  Subject to the other
provisions of this Article V, the Board of Directors shall determine the rights,
powers, duties, rules and procedures that shall affect the directors' power to
manage and direct the business and affairs of the Corporation.  Notwithstanding
any other provision of this Certificate of Incorporation, the powers specified
in this Article V shall be exercised only by or under the direction of the Board
of Directors and may be exercised or expressed in the form of resolution, Bylaw
or 

                                       3.

 
other form of determination or exercise; and the form of the exercise of the
power shall not derogate the status of the power exercised.

     B.   1.  Subject to paragraph (h) of Section 43 of the Bylaws, the Bylaws
may be altered or amended or new Bylaws adopted by the affirmative vote of at
least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of
the then-outstanding shares of the Voting Stock.  The Board of Directors shall
also have the power to adopt, amend, or repeal Bylaws.

          2.  The directors of the Corporation need not be elected by written
ballot unless the Bylaws so provide.

          3.  No action shall be taken by the stockholders of the Corporation
except at an annual or special meeting of stockholders called in accordance with
the Bylaws or by written consent of stockholders in accordance with the Bylaws
prior to the closing of the Initial Public Offering, and following the closing
of the Initial Public Offering no action shall be taken by the stockholders by
written consent.

          4.  Special meetings of the stockholders of the Corporation may be
called, for any purpose or purposes, by (i) the Chairman of the Board of
Directors, (ii) the Chief Executive Officer, or (iii) the Board of Directors
pursuant to a resolution adopted by a majority of the total number of authorized
directors (whether or not there exist any vacancies in previously authorized
directorships at the time any such resolution is presented to the Board of
Directors for adoption), and shall be held at such place, on such date, and at
such time as the Board of Directors shall fix.

          5.  Advance notice of stockholder nominations for the election of
directors and of business to be brought by stockholders before any meeting of
the stockholders of the Corporation shall be given in the manner provided in the
Bylaws of the Corporation.

                                      VI.

     A.   A director of the Corporation shall not be personally liable to the
Corporation or its stockholders for monetary damages for any breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the Corporation or its stockholders, (ii) for acts or
omissions not in good faith or that involve intentional misconduct or a knowing
violation of law (iii) under Section 174 of the Delaware General Corporation
Law, or (iv) for any transaction from which the director derived an improper
personal benefit.  If the Delaware General Corporation Law is amended after
approval by the stockholders of this Article to authorize corporate action
further eliminating or limiting the personal liability of directors, then the
liability of a 

                                       4.

 
director shall be eliminated or limited to the fullest extent permitted by the
Delaware General Corporation Law, as so amended.

     B.   Any repeal or modification of this Article VI shall be prospective and
shall not affect the rights under this Article VI in effect at the time of the
alleged occurrence of any act or omission to act giving rise to liability or
indemnification.

                                     VII.

     A.   The Corporation reserves the right to amend, alter, change or repeal
any provision contained in this Certificate of Incorporation, in the manner now
or hereafter prescribed by statute, except as provided in Section B of this
Article VII, and all rights conferred upon the stockholders herein are granted
subject to this reservation.

     B.   Notwithstanding any other provisions of this Certificate of
Incorporation or any provision of law that might otherwise permit a lesser vote
or no vote, but in addition to any affirmative vote of the holders of any
particular class or series of the Voting Stock required by law, this Certificate
of Incorporation or any Preferred Stock Designation, the affirmative vote of the
holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting
power of all of the then-outstanding shares of the Voting Stock, voting together
as a single class, shall be required to alter, amend or repeal Articles V, VI
and VII.

                                       5.