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                                                                    Exhibit 10.5

                            FIRST AMENDMENT TO LEASE

     This First Amendment to Lease (this "Amendment") is made as of May 6,
2004 by and between THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR
UNIVERSITY, a body having corporate powers under the laws of the State of
California ("LANDLORD"), and Incyte Corporation, a Delaware corporation
("TENANT"), in the following factual context:

     A.   Landlord and Tenant, formerly known as Incyte Pharmaceuticals, Inc.,
are the parties to that certain Lease dated as of June 19, 1997, as amended by
(i) Notice of Commencement Date dated October 28, 1998, (ii) Notice of Base Rent
and Rentable Area dated November 24, 1998, and (iii) Notice of Rent Commencement
Date and Expiration Date dated November 24, 1998 (as so amended, the "LEASE"),
under which Tenant leases from Landlord a two-story building commonly known as
3160 Porter Drive in Palo Alto, California, as more particularly described in
the Lease. Capitalized terms used in this Amendment and not otherwise defined
herein shall have the meanings given to them in the Lease.

     B.   Landlord and Tenant now desire to further amend the Lease as provided
in this Amendment.

     NOW THEREFORE, the parties hereby agree as follows:

     1.   BASIC LEASE INFORMATION. Article 1 of the Lease is hereby amended to
modify the following terms:

          Building Address/Address of Tenant:  3160 Porter Drive
                                               Palo Alto, CA 94304
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     2.   PREMISES. The last four sentences of Section 3.1 of the Lease, and all
references in the Lease (including, without limitation, in Article 14 of the
Lease) to "Ground Lease," and "Ground Lessee" are hereby deleted. The defined
term "Ground Lease Property" shall be replaced with the defined term "3160/3170
Porter Drive Site", which shall mean the total area of both the Premises and the
land and improvements adjacent to the Premises that are commonly identified as
3170 Porter Drive, and currently leased to Lockheed Martin Corporation.

     3.   USE. Section 7.1 of the Lease is hereby amended to delete the second
sentence of such section and to substitute the following:

          "For the purposes of this Lease, "research and development" means uses
          primarily related to the study, testing, engineering, design, analysis
          and experimental development of products, processes, or services
          related to current or new technologies. Research and development may
          include limited manufacturing, fabricating, processing, assembling or
          storage of prototypes, products or materials, or similar related
          activities, where such activities are incidental to research,
          development or evaluation. Examples of research and development uses
          include, but are not limited to, computer software and hardware firms,
          electronic research firms, biotechnical firms, medical device firms,
          and pharmaceutical research laboratories. Related administrative uses,
          such as (a) finance, marketing, sales, accounting, purchasing, or
          corporate offices, (b) provisions of services to others on or
          off-site, and (c) related educational uses, may also be included
          provided they remain supportive to the primary uses of research and
          development and are part of the same research and development firm.
          Related administrative uses may constitute up to ninety percent (90%)
          of the Rentable Area of the Premises so long as at least ten percent
          (10%) of such Rentable Area is devoted to the primary uses of research
          and development."


     4.   INITIAL IMPROVEMENT WORK. The parties agree that the terms and
conditions of Sections 8.1 and 8.2 have been fully performed and are no longer
applicable to the Lease; provided, however, Tenant's acceptance of the Premises
pursuant to Section 8.2 remains subject to latent defects.

     5.   LANDLORD'S INDEMNITY. Landlord's indemnity as set forth in Section 8.4
shall also benefit any assignee of Tenant's leasehold estate, and any subtenant
that subleases the entire Premises for substantially all of the remaining term
of the Lease.


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     6.   ALTERATIONS. Notwithstanding anything to the contrary in Article 9 of
the Lease or elsewhere in the Lease, Landlord hereby acknowledges and agrees
that Tenant shall not be obligated or required to remove, upon the Termination
Date, any Alterations existing in the Premises as of the date of this Amendment.
In addition, the following modifications are hereby made to Article 9 of the
Lease:

          (a) The phrase "Notwithstanding the foregoing" at the beginning of the
          second sentence of Section 9.1 is hereby deleted and replaced with the
          following: "Notwithstanding the foregoing, after completion of
          Tenant's initial improvements to the Premises, . . "

          (b) All references to the "Tenant Improvement Allowance" in Section
          9.5 are hereby deleted.

     7.   INDEMNITY. Tenant's indemnity with respect to the condition of the
Premises or any occurrence on the Premises, as set forth in clause (c) of
Section 21.1(a) of the Lease, is hereby modified to add the following words
after the word "Agents": "or to the extent of Landlord's liability pursuant to
Section 8.4 of this Lease."

     8.   CONFIDENTIALITY. The second sentence of Article 28 of the Lease is
hereby modified to add the following at the end thereof: "but does not include,
and shall not be deemed to include, disclosures by either party as required (a)
to comply with the rules of any exchange upon which the disclosing party's
shares are traded, (b) to comply with the requirements of applicable law, or (c)
to facilitate any sale or financing of the Premises or the land underlying the
Premises, so long as any party who receives any of the information described in
the first sentence of this Article 28 in connection with such sale or financing
agrees in writing to maintain the confidentiality of such information pursuant
to the first sentence of this Article 28."

     9.   EFFECT OF AMENDMENT. As modified by this Amendment, the Lease remains
in full force and effect.


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

                                THE BOARD OF TRUSTEES OF THE LELAND
                                STANFORD JUNIOR UNIVERSITY

                                By Stanford Management Company



                                By: /s/ Jean Snider
                                    -------------------------------
                                    Jean Snider, Managing Director
                                        Stanford Research Park



                                INCYTE CORPORATION


                                By: /s/ David Hastings
                                    -------------------------------

                                Its: EVP, CFO
                                     -------------------------------



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