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                                                                   Exhibit 10.11

UNIVERSITY OF CALIFORNIA

BERKELEY - DAVIS - IRVINE - LOS ANGELES - MERCED - RIVERSIDE - SAN DIEGO - SAN
                     FRANCISCO - SANTA BARBARA - SANTA CRUZ

                       (THE UNIVERSITY OF CALIFORNIA LOGO)

OFFICE OF THE SENIOR VICE PRESIDENT--            OFFICE OF TECHNOLOGY TRANSFER
BUSINESS & FINANCE                               1111 Franklin Street, 5th Floor
                                                 Oakland, California 94607-5200
                                                 Web Site: www.ucop.edu/ott/
                                                 Tel: (510) 587-6000
                                                 Fax: (510) 587-6090

                                                               February 14, 2005

Robert Zerbe, M.D.
Chief Executive Officer
QuatRx Pharmaceuticals
777 E. Eisenhower Pkwy, Suite 100
Ann Arbor, MI 48108

Dear Dr. Zerbe,

     In recognition of the desire expressed by EndoChem, Inc., the prospective
licensee for the license agreement covering UC Case Nos. ****** and ******
(the "Agreement"), to grant a sublicense under the Agreement, The Regents hereby
reaffirms the following provisions of the Agreement that pertain to certain
rights that accrue to QuatRx Pharmaceuticals Company under the Agreement. The
Regents further states that notwithstanding the termination or expiration of the
Agreement, The Regents shall permit QuatRx to exercise all rights granted to
EndoChem under the Agreement and sublicensed to QuatRx by EndoChem, provided
that the conditions set forth in (a) through (c) in Paragraph 3.1.2 below have
been fulfilled.

PARAGRAPH 3.1.2 (SUBLICENSES)

     The Regents acknowledges that Licensee may grant a sublicense under this
Agreement to QUATRx Pharmaceuticals Company ("QUATRx"). If Licensee grants such
a sublicense, then notwithstanding anything else to the contrary herein, upon
any expiration or termination of this Agreement for any reason, upon written
request by QUATRx to The Regents and to Licensee, all sublicensed rights
licensed hereunder and granted pursuant to this Article 3 which have been
conveyed to QUATRx and its further sublicensees will remain in effect and will
be recognized by The Regents as binding license obligations, provided that (a)
QUATRx and its further sublicensees are not in breach of their respective
sublicenses at the time of expiration or termination of this Agreement; (b) all
of the terms of this Agreement are agreed to fully in writing by QUATRx; and (c)
QUATRx acquires no rights from or the ability to enforce any obligations on the
part of The Regents (and The Regents do not assume any obligations) other than
those that are specifically granted under this Agreement and QUATRx assumes all
liability and obligations to The Regents required of Licensee by this Agreement
with respect to The Regents' sublicensed rights, including past due obligations
existing at the time of such written request by QUATRx following such expiration
or termination. If QUATRx as a Sublicensee

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QuatRx Pharmaceuticals
February 14, 2005
Page 2


fails to meet the above provisions described in this Paragraph 3.1.2 (a)-(c)
then The Regents may terminate its sublicense upon expiration or termination of
this Agreement, notwithstanding any such request by a Sublicensee, in accordance
with Article 15 (Termination by The Regents). The Regents will not be bound to
perform any duties or obligations set forth in any sublicense with QUATRx that
extend beyond the duties and obligations of The Regents set forth in this
Agreement, and the Licensee's obligations to The Regents hereunder will be
binding upon QUATRx. Notwithstanding the above, in the event that any sublicense
granted to QUATRx under this Agreement terminates or expires while this
Agreement remains in effect, all further sublicenses granted by QUATRx shall
automatically terminate or expire, as appropriate.

PARAGRAPH 3.3 (SUBLICENSES)

     The Licensee will identify each Sublicensee to The Regents and will notify
The Regents of each sublicense granted hereunder (including, without limitation,
any sublicenses granted by any Sublicensee and any sublicense granted to or by
QUATRx) and will provide The Regents with a complete copy of each such
sublicense and each amendment to such sublicense within thirty (30) days of
issuance of such sublicense or such amendment. The Licensee will pay to The
Regents all fees, payments, royalties and the cash equivalent of any
consideration due The Regents on account of the grant or exercise of any such
sublicenses. The Licensee will guarantee all monies due The Regents with respect
to amounts that accrue due to actions by Sublicensees. For clarity, if the
Licensee or a Sublicensee grants a sublicense that contains a provision for
payment of royalties by any Sublicensee in an amount that is less than the
Sublicensee Royalty required to be paid under Paragraph 8.2 below, then the
Licensee will pay to The Regents a total amount equal to the Sublicensee Royalty
based on the Sublicensees' Net Sales as provided for in Paragraph 8.2. The
Licensee will require Sublicensees to provide it with copies of all progress
reports and royalty reports in accordance with the provisions herein and the
Licensee will collect and deliver all such reports due The Regents from
Sublicensees.

PARAGRAPH 3.6 (SUBLICENSES)

     Sublicensees who have received a direct sublicense from Licensee under this
Article 3 may grant further sublicenses (without further rights to sublicense
except to the extent specified below with respect to QUATRx) in connection with
Licensee's and its direct Sublicensee's development, manufacture and
commercialization of Licensed Products; provided, however that (a) such further
sublicenses shall not be granted on a stand-alone basis, where the term
"standalone" means that a sublicense is granted to an entity for the
development, manufacture or commercialization of Licensed Products without
Licensee or such direct Sublicensee participating or having participated in the
development or commercialization of Licensed Products in material part (i.e.,
without Licensee or such direct Sublicensee having incurred more than ** ****
($****) in costs related to the development, manufacture or commercialization of
Licensed Products); (b) Sublicensees of any direct Sublicensee of Licensee shall
have no further rights to sublicense the rights granted hereunder (except to the
extent specified below with respect to QuatRx); and (c) such sublicenses (and
Licensee's and Sublicensee's obligations with respect to such sublicenses) shall
be in full compliance with the provisions of this Article 3. For the avoidance
of doubt, any Sublicensee's right to further sublicense the rights granted to it
hereunder shall be limited solely to sublicenses granted in

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QuatRx Pharmaceuticals
February 14, 2005
Page 3


conjunction with and solely for the purpose of developing, manufacturing and/or
commercializing, in collaboration with Licensee or a direct Sublicensee,
Licensed Products developed and/or commercialized in material part by Licensee
and/or such direct Sublicensee, For the further avoidance of doubt, Licensee and
any permitted Sublicensee can engage independent contractors such as
manufacturers, clinical trial organizations, and work-for-hire research
laboratories (such as those who conduct assays on a fee for service basis) so
long as the work conducted by such entities is being conducted on Licensee or
such Sublicensee's behalf and such contracting entity does not receive rights to
develop, manufacture, use or commercialize Licensed Products outside of, or
after it completes, its services. Notwithstanding the foregoing, The Regents
agree that QuatRx, upon becoming a direct Sublicensee of Licensee, shall have
the right to grant further direct sublicenses as if QuatRx were the Licensee
under Paragraph 3.1 and this Paragraph 3.6 (i.e., QuatRx shall have the right to
grant sublicenses to the extent Licensee is permitted to grant sublicenses under
Paragraph 3.1, and such direct Sublicensees of QuatRx shall have the right to
grant further sublicenses as if such direct Sublicensee of QuatRx were a direct
Sublicensee of Licensee for the purpose of this Paragraph 3.6), provided that,
for clarity, no further sublicensing by any Sublicensee of a direct Sublicensee
of QuatRx shall be permitted (but such Sublicensee may engage subcontractors as
described above).

                                       Sincerely,


                                       /s/ Y. M. Vaishnav
                                       -----------------------------
                                       Yashwant Vaishnav, Ph.D.
                                       Business Development &
                                       Intellectual Property Manager


                                       Approved as to legal form


                                       /s/ P. Martin Simpson, Jr.      2-14-2005
                                       -----------------------------   Date
                                       P. Martin Simpson, Jr.
                                       University Counsel
                                       Office of General Counsel