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                                  EXHIBIT 10.1

                     FIFTH AMENDMENT TO EMPLOYMENT AGREEMENT


This AMENDMENT TO EMPLOYMENT AGREEMENT (the "Fifth Amendment") made as of
January 1, 2001 between ARIAD Pharmaceuticals, Inc., a Delaware corporation (the
"Company"), and John D. Iuliucci, Ph.D. (the "Employee").

The Company and the Employee have entered into an Employment Agreement dated as
of May 1, 1992, as previously amended (the "Agreement"), and the parties hereto
desire to further amend certain provisions of the Agreement.

NOW, THEREFORE, in consideration of the premises set forth herein and for other
good and valuable consideration, the receipt of which is hereby acknowledged,
the parties hereto agree to further amend the Agreement as follows:

I.     TERM OF EMPLOYMENT. The first sentence of Section 2 is hereby amended to
       read as follows:

       "The term of the Employee's employment under the Agreement is hereby
       extended to December 31, 2003 (the "Term"), unless sooner terminated
       pursuant to Section 4 or 5 of this Agreement; PROVIDED, however, that
       this Agreement shall automatically be renewed for successive one-year
       terms (the Term and, if the period of employment is so renewed, such
       additional period(s) of employment are collectively referred to herein as
       the "Term") unless terminated by written notice given by either party to
       the other at least 90 days prior to the end of the applicable Term."

II.    COMPENSATION. Section 3.1 is hereby replaced and amended in its entirety
       as follows:

       "3.1. As full compensation for all services to be rendered pursuant to
       this Agreement, the Company agrees to pay the Employee, during the Term,
       a salary at the fixed rate of $221,000 per annum during the first year of
       the Term and increased each year thereafter, by amounts, if any, to be
       determined by the Board of Directors of the Company (the "Board") in its
       sole discretion, payable in equal semi-monthly installments, less such
       deductions or amounts to be withheld as shall be required by applicable
       law and regulations."

III.   DEFINITIONS. The definition of the Company's "Field of Interest" in
       Section 14(b) of the Agreement is hereby amended to read as follows:

       The "Company's Field of Interest" is the discovery, development and
       commercialization of (i) pharmaceutical products based on (a)
       intervention in signal transduction pathways and (b) gene and cell
       therapy, and (ii) technologies to regulate genes and proteins. The
       Company's Field of Interest may be changed at any time at the sole
       discretion of the Company.

IV.    This Amendment shall be governed by and construed and enforced in
       accordance with the laws of the Commonwealth of Massachusetts applicable
       to agreements made and to be performed entirely in Massachusetts.

V.     Except as modified by this Fifth Amendment, the Agreement remains in full
       force and effect and unchanged.



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IN WITNESS WHEREOF, the parties have executed this Fifth Amendment as of the
date first written above.


                                        ARIAD PHARMACEUTICALS, INC.


                                        By: /s/ Harvey J. Berger
                                            ------------------------------------
                                            Harvey J. Berger, M.D.
                                            Chairman and Chief Executive Officer



                                        EMPLOYEE


                                            /s/ John D. Iuliucci
                                            ------------------------------------
                                            John D. Iuliucci, Ph.D.


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