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                                                                  EXHIBIT 3.1A

                            CERTIFICATE OF AMENDMENT
                                       TO
                          CERTIFICATE OF INCORPORATION
                                       OF
                          IMCLONE SYSTEMS INCORPORATED

                Under Section 242 of the General Corporation Law
                            Of the State of Delaware

      The undersigned, being the President and CEO of IMCLONE SYSTEMS
INCORPORATED, a Delaware corporation (the "Corporation") DOES HEREBY CERTIFY as
follows:

      FIRST:            The Certificate of Incorporation of the Corporation is
hereby amended so that Article FOURTH (a) shall read in its entirety as
follows:

            "FOURTH: (a) The total number of shares of capital stock which the
      Corporation shall have the authority to issue is one hundred and twenty
      million (120,000,000) shares of Common Stock with a par value of one
      tenth of one cent ($.001) per share and four million (4,000,000) shares
      of Preferred Stock with a par value of one dollar ($1.00) per share."

      SECOND:     That such amendment was duly adopted by the Board of
Directors of the Corporation and by the Stockholders of the Corporation in
accordance with Section 242 of the General Corporation Law of the State of
Delaware.

      IN WITNESS THEREOF, this Certificate of Amendment to the Certificate of
Incorporation of the Corporation has been signed, and the statements made
herein affirmed as true under the penalties of perjury, this 12th day of June,
2000.

                                  /s/ Samuel D. Waksal
                                  Samuel D. Waksal,
                                  President and CEO

/s/ John B. Landes
-------------------------
John B. Landes, Secretary