FIRST AMENDMENT TO SUBLEASE AND PARKING SUBLICENSE AGREEMENTS

Exhibit 10.54

FIRST AMENDMENT TO
SUBLEASE AND PARKING SUBLICENSE AGREEMENTS

     This First Amendment to Sublease and Parking Sublicense Agreements (this “ First Amendment ”) is made and entered into as of July 21, 2008, by and between ESS SUSA HOLDINGS, LLC, a Delaware limited liability company (“ Landlord ”), and GTx, Inc., a Delaware corporation (“ Tenant ”).

     WHEREAS, Landlord and Tenant entered into that certain Sublease Agreement (the “ Sublease ”) as of December 17, 2007, regarding the subleasing of certain Premises in the Building, and that certain Parking Sublicense Agreement (the “ Sublicense ”, and collectively with the Sublease, the “ Agreements ”) as of December 17, 2007, regarding the sublicensing of the right to use certain parking spaces in the Parking Facility, as such terms are defined, and on such additional terms and conditions set forth, in the Agreements; and

     WHEREAS, in Section 15 of the Sublease, Landlord granted Tenant certain rights of first refusal to lease the third and fourth floor space of the Building; and

     WHEREAS, Landlord has offered, and Tenant has accepted, an offer to sublease the fourth floor space on certain terms and conditions, all as more particularly set forth herein.

     NOW THEREFORE, in consideration of the premises and the mutual covenants of the parties, more particularly hereinafter set forth, the adequacy and sufficiency of which are hereby acknowledged, it is agreed as follows:

     1.  Offer Space . The text of Sections 1(b) and 1(e) of the Sublease are hereby deleted in their entirety and replaced with the following, respectively:

     (b) “ Premises ”: Fourth, Seventh and Eighth floors of the Building

     (e) “ Rentable Area of Premises ”: approximately 52,248 , comprised of 21,500 square feet on the fourth floor, 21,500 square feet on the seventh floor, and 9,248 square feet on the eighth floor.

     2.  Fourth Floor Terms. The text of Sections 1(g), 1(i), 1(m), 1(n), 4 and 13 of the Sublease and Sections 2 and 4.c. of the Sublicense are hereby amended in all respects to reflect that the Term, termination dates and fees, Base Rent, parking provisions, and Rent Commencement Date set forth therein apply or relate exclusively to the seventh and eighth floor portions of the Premises, and that as to the fourth floor portion of the Premises only, the following shall apply:

     “ Term ” shall mean August 1, 2008 through April 30, 2015. Tenant shall have the option to cancel the Sublease, as to the fourth floor Premises only, effective December 31, 2012 upon six months prior written notice and payment of $103,916.68.

     “ Base Rent ”: The monthly rent schedule shall be as follows:

     “ Parking ”: During the Term, Tenant shall sublicense from Landlord the following number of additional unreserved parking spaces at a monthly cost of $0.00 dollars per space: (i) through December 31, 2008, 20 spaces, (ii) thereafter, through December 31, 2009, 40 spaces, and (iii) thereafter, through the end of the Term, 50 spaces. The foregoing number of parking spaces shall reduce, space for space, the number of any additional parking spaces to be sublicensed by Tenant upon Tenant’s actual occupancy of the fourth floor portion of the Premises pursuant to the second paragraph of Section 13 of the Sublease and Sections 2 and 4.c. of the Sublicense. In all other respects, Tenant’s sublicensing and use of any such spaces shall be subject to the terms and conditions relating to such sublicensed parking spaces as set forth in the Agreements.

     “ Rent Commencement Date ”: August 1, 2008, payable in accordance with the schedule set forth in the definition of “Base Rent” above regarding the fourth floor portion of the Premises.

     “ Tenant Improvements ”: No tenan