Exhibit 10.58
  th
 By email-and UPS
 Re:
    
    Mutually agreed termination of the Toremifene Collaboration and License Agreement dated 7
September 2006 as amended by First Amendment dated 22 March 2010
  Agreement GTx Ipsen Parties Amendment
  1.
    
    Subject to approval of Ipsens board of directors which Ipsen shall notify to
GTx on or before 1 March 2011 5:00 pm US EST, the Agreement and the Amendment are
hereby terminated by mutual agreement of the Parties as of 1 March 2011, except as
provided at Sections 2 to 6 below.2.
    
    In consideration of Ipsens agreement to terminate its rights and obligations
in the Ipsen Territory except as provided herein, including its rights to Right of
First Negotiation to GTx-758, GTx agrees to pay to Ipsen running royalty payments in US
dollars on US Net Sales of the Licensed Product for the ADT Indication in the amount of
3% until the later to occur of (a) the last Valid Patent Claim to expire in the US or
(b) if the expiry of a Valid Patent Claim occurs earlier than 30 November 2022 as a
result of a third party claim which shall lead to generic market penetration in the US
by more than 20% for a period of two (2) consecutive quarters, then at the end of that
second quarter. The US Royalty Payment due to Ipsen on account of US Net Sales shall
be payable by GTx to Ipsen within 60 days of the end of each Calendar Quarter for which
royalty payments are owed, accompanied by a quarterly report providing in reasonable
detail in quantity and value an accounting of the US Net Sales made during such
Calendar Quarter. Furthermore, Article 11.4 of the Agreement (i.e., records and audit
rights) shall apply mutatis mutandisto Ipsens right to verify the accuracy of GTxs
reports for the calculation of US Net Sales of the Licensed Product for the ADT
Indication.3.
    
    Except as provided herein, no party shall be entitled to receive any
compensation whatsoever as a consequence of such mutual termination.




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4.
    
    Except as provided herein, Ipsen and GTx shall be fully and entirely discharged
from any and all of their respective obligations under the Agreement and the Amendment
and shall have no liability relating thereto, except for all obligations set forth in
Article XIII Indemnification, Article XIV Dispute Resolution, and Articles 15.4
through 15.13 which shall survive this mutual termination and remain binding upon Ipsen
and GTx as applicable to this Letter Agreement until the expiry of the term mentioned
at Section 2 above and Article VIII Confidentiality, which shall survive this mutual
termination and remain binding upon Ipsen and GTx for the time-period mentioned in such
provision, provided that, the Parties agree that notwithstanding the provisions of
Section 8.4 of the Agreement, GTx shall not be required to provide to Ipsen for prior
review and approval any proposed scientific/technical publications or scientific
presentations which relate to Toremifene and/or Licensed Product as otherwise required
under Section 8.4.5.
    
    The Parties hereby agree that the Parties shall issue a press release relating
to this mutual termination of the Agreement and the Amendment on 2 March 2011. Working
draft of press releases concerning this mutual termination shall be provided to Ipsen
or GTx by the originator of the release no later than 25 February 2011 5:00 pm US EST
for the other partys written approval, which shall not unreasonably be withheld or
delayed, except to the extent required by applicable laws or stock exchange rules.
     /s/ Stéphane ThiroloixStéphane ThiroloixExecutive Vice President, Corporate Development
 Acknowledged and agreed as of February 28, 2011
GTx, Inc./s/ Mitchell S. Steiner