Document:

[REGIS TECHNOLOGIES, INC. LETTERHEAD]

February 28, 2003

Rostyk Mandzij
Immtech International, Inc.
150 Fairway Drive, Suite 150
Vernon Hills, IL  60061

Dear Rostyk:

Thank you for the opportunity to review your project, cGMP synthesis of DB289
using the new chemistry. Regis understands that Immtech is interested in
production of a batch of approximately 8 kg. Based on our recent R & D
activities on this chemistry, we offer the following proposal.

Price and Scope of Work

The price for cGMP production of approximately 8 kg DB289 is $198,500. We
understand that Regis will provide all raw materials. Activities will include:

      1. Conducting scale-up experiments, as necessary;

      2. Running a full-scale cGMP batch to produce approximately 8 kg of
         product; and

      3. Carrying out analytical testing on the final product, based on the
         specifications previously established.

Documentation

Documentation for this batch will be carried out in a batch record. After
completion of the analytical testing on each intermediate and the final product,
a batch record package will be assembled, including the completed operating
procedure and all analytical data for raw materials and the product. A copy of
this package will be provided to Immtech and the original kept at Regis. In
addition, any related laboratory notebook pages can be provided upon request.

A Certificate of Analysis will accompany the product and include the results
from the assays established on July 31, 2000. Please advise if any changes have
been made since that date. Any other testing requirements or formal method
transfer may incur additional charges.

Regulatory

Regis operates in compliance with all applicable local, state and federal codes
and standards. The facility is considered to be a 90-day generator of hazardous
wastes. No waste treatment is performed on site: wastes are collected and
treated by a licensed waste disposal hauler. The primary disposition is fuel
reblending.

The FDA inspects Regis at least biennially. The most recent inspection took
place in October 2002. A copy of the FDA 483 and Regis' response is attached for
your review.

Communications

Your primary Regis contact for this work will be the author of this document,
Lori A. Hoffman. When work commences, weekly updates will be provided via phone,
fax, or e-mail, whichever the customer prefers. In addition, conference calls or
on-site meetings can be established to discuss progress and issues. Immtech
personnel are welcome on site at any time to observe the synthesis and audit the
facility.

                                   Page 1 of 2
<PAGE>

Qualifications

Until recently, Regis has primarily served as a source of preclinical and
clinical trial quantities of a wide range of bulk pharmaceutical intermediates
and ingredients. We are currently the commercial supplier of seven approved bulk
active pharmaceutical ingredients. Regis maintains an active contract with the
GMP Institute and GlobePharm providing ongoing cGMP training and internal
audits. Our facility and personnel are prepared for a preapproval inspection.

Please note that as contractor, Regis maintains the sole responsibility for
providing, approving and retaining key personnel for this project. Immtech will
be informed of any changes that may impact the project.

Technology Ownership and Documentation

Immtech will own all technology developed during the course of the work. Upon
completion of each chemical step, a batch record package will be assembled,
including the completed production log (either lab notebook pages or a batch
record) and all analytical data for raw materials and the product of that step.
A copy of this document will be provided to Immtech and the original kept at
Regis.

Delivery

Several raw materials have a 2-3 week lead time. The 4-bromobenzonitrile,
however, has a 6-7 week lead time. Another source can offer the material with a
4-6 week lead time, but the price for the project would increase to $212,400.
Please advise if this option is appealing. We will provide estimated timing upon
issuance of a purchase order and firmer scheduling as the materials arrive. Once
work commences, we anticipate production to require approximately 7-8 weeks to
complete. Weekly updates will keep Immtech up-to-date as to the progress of the
project.

Terms and Conditions

Regis will require a down payment of $40,000 to initiate work. The remainder,
$158,500, will invoice upon completion of the batch record package and/or
shipment of product. Prices are FOB Morton Grove, IL. Shipping charges are
prepaid and added to the invoice. Payment is due 30 days after receipt of
invoice. The customer's QA review of documentation should be completed within
that 30-day timeframe.

Please contact me if you have any questions or concerns about this proposal. To
indicate acceptance, please sign and date this letter and return a copy to me by
fax, along with any purchase order information. We look forward to working with
Immtech again on this project.

Best regards,

Lori A. Hoffman
Senior Project Manager

ACCEPTED BY:

/s/ T. Stephen Thompson       President and CEO             March 4, 2003
-------------------------     -------------------------     ------------------
Signature                     Title                         Date

_________________________
Purchase Order Number

                                   Page 2 of 2<PAGE>

                                                                     EXHIBIT 4.3

               AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

         This Registration Rights Agreement (this "Agreement") is made and
entered into as of August 7, 2003 among GTX, INC., a Tennessee corporation (the
"Company") and ORACLE PARTNERS, L.P., a Delaware limited partnership (the
"Purchaser").

         This Agreement is being entered into pursuant to that certain purchase
agreement dated as of the date hereof between the Company and the Purchaser and
the other purchasers described therein (the "Purchase Agreement") pursuant to
which the Purchaser is acquiring shares of the Company's Series E Preferred
Stock (as hereinafter defined).

         The Company and the Purchaser hereby agree as follows:

         1.       Definitions.

                  (a)      Capitalized terms used and not otherwise defined
herein shall have the meanings given such terms in the Purchase Agreement. As
used in this Agreement, the following terms shall have the following meanings:

         "Advice" shall have the meaning set forth in Section 4(c).

         "Affiliate" means, with respect to any Person, any other Person that
directly or indirectly controls or is controlled by or under common control with
such Person. For the purposes of this definition, "control," when used with
respect to any Person, means the possession, direct or indirect, of the power to
direct or cause the direction of the management and policies of such Person,
whether through the ownership of voting securities, by contract or otherwise;
and the terms of "affiliated," "controlling" and "controlled" have meanings
correlative to the foregoing.

         "Business Day" means any day except Saturday, Sunday and any day which
shall be a legal holiday or a day on which banking institutions in the State of
Tennessee generally are authorized or required by law or other government
actions to close.

         "Commission" means the Securities and Exchange Commission.

         "Common Stock" means the Company's common stock, no par value per
share.

         "Demand" has the meaning set forth in Section 2 hereof.

         "Demand Date" means the last date of the Demand Period in which at
least a majority of the Holders of Registrable Securities demand the
registration of any Registrable Securities pursuant to Section 2 hereof.

         "Demand Period" shall have that meaning set forth in Section 2.

         "Effectiveness Date" means, with respect to the Registration Statement,
the 180th day following the Demand Date.

<PAGE>

         "Effectiveness Period" shall have the meaning set forth in Section 2.

         "Event" shall have the meaning set forth in Section 8(e).

         "Exchange" means, at any time and from time to time hereafter, any
securities exchange, automated interdealer quotation system or other
over-the-counter market on which any of the Company's securities are listed or
regularly traded or quoted.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended.

         "Filing Date" shall mean the 60th day following the Demand Date.

         "Holder" or "Holders" means the holder or holders, as the case may be,
from time to time of Registrable Securities.

         "Hyde Holders" means the holders of the Hyde Registrable Securities.

         "Hyde Registrable Securities" means the "Registrable Securities" as
defined in the Hyde Registration Rights Agreement.

         "Hyde Registration Rights Agreement" means that certain amended and
restated registration rights agreement between the Company and J.R. Hyde, III,
dated as of the date of this Agreement.

         "Indemnified Party" shall have the meaning set forth in Section 6(c).

         "Indemnifying Party" shall have the meaning set forth in Section 6(c).

         "Losses" shall have the meaning set forth in Section 6(a).

         "MBV Holders" means the holders of the MBV Registrable Securities.

         "MBV Registrable Securities" means the "Registrable Securities" as
defined in the Registration Rights Agreement.

         "MBV Registration Rights Agreement" means that certain amended and
restated registration rights agreement between the Company and Memphis Biomed
Ventures I, L.P., dated as of the date of this Agreement.

         "Other Securities" has the meaning set forth in Section 8(d)(i).

         "Person," whether or not capitalized, means a natural person,
corporation, partnership, trust, incorporated or unincorporated association,
joint venture, partnership (including a limited partnership), limited liability
company, joint stock company, government (or an agency or political subdivision
thereof) or other entity of any kind.

                                       2

<PAGE>

         "Proceeding" means an action, claim, suit, investigation or proceeding
(including, without limitation, an investigation or partial proceeding, such as
a deposition), whether commenced or threatened.

         "Prospectus" means the prospectus included in the Registration
Statement (including, without limitation, a prospectus that includes any
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A promulgated under the
Securities Act), as amended or supplemented by any prospectus supplement, with
respect to the terms of the offering of any portion of the Registrable
Securities covered by the Registration Statement, and all other amendments and
supplements to the Prospectus, including post-effective amendments, and all
material incorporated by reference in such Prospectus.

         "Purchase Agreement" as the meaning set forth in the second
introductory paragraph of this Agreement.

         "Purchaser Stock" means (i) Series C Preferred Stock issued to
Purchaser's Affiliate pursuant to that certain purchase agreement dated as of
October 5, 2001, as amended, by and among the Company, the Purchaser, Oracle
Investment Management, Inc., J. R. Hyde, III, and Pittco Associates, LP; (ii)
Series D Preferred Stock issued to Purchaser or its Affiliates pursuant to that
certain purchase agreement, dated as of July 17, 2002, by and among the Company,
the Purchaser, Oracle Institutional Partners, L.P., J. R. Hyde, III, and Memphis
Biomed Ventures, L.P.; (iii) Series E Preferred Stock and issued to Purchaser or
its Affiliates pursuant to the Purchase Agreement; and (iv) any security issued
as a dividend to a beneficial owner of the preferred stock identified in
subsections (i), (ii) and (iii) above.

         "Registrable Securities" means (i) the shares of Common Stock now or at
any time hereafter issuable upon conversion of the Purchaser Stock and (ii) any
other securities which may hereafter become receivable by the Holders upon
conversion of the Purchaser Stock, including any dividend or other distribution
with respect to, conversion or exchange of, or in replacement of, Registrable
Securities.

         "Registration Statement" means the registration statements and any
additional registration statements contemplated by Section 2, including (in each
case) the Prospectus, amendments and supplements to such registration statement
or Prospectus, including pre- and post-effective amendments, all exhibits
thereto, and all material incorporated by reference in such registration
statement.

         "Rule 144" means Rule 144 promulgated by the Commission pursuant to the
Securities Act, as such Rule may be amended from time to time, or any similar
rule or regulation hereafter adopted by the Commission having substantially the
same effect as such Rule.

         "Rule 158" means Rule 158 promulgated by the Commission pursuant to the
Securities Act, as such Rule may be amended from time to time, or any similar
rule or regulation hereafter adopted by the Commission having substantially the
same effect as such Rule.

                                       3

<PAGE>

         "Rule 415" means Rule 415 promulgated by the Commission pursuant to the
Securities Act, as such Rule may be amended from time to time, or any similar
rule or regulation hereafter adopted by the Commission having substantially the
same effect as such Rule.

         "Securities Act" means the Securities Act of 1933, as amended.

         "Series C Preferred Stock" means the 8% Series C Cumulative Convertible
Preferred Stock of the Company.

         "Series D Preferred Stock" means the 8% Series D Cumulative Convertible
Preferred Stock of the Company.

         "Series E Preferred Stock" means the 8% Series E Cumulative Convertible
Preferred Stock of the Company.

         "Special Counsel" means the special counsel designated by a majority of
the Holders pursuant to Section 5.

         "Unsold Securities" shall have the meaning set forth in Section 8(e).

                  (b)      Use of the singular or of the plural shall be
construed to include both the singular and the plural unless the context clearly
indicates that only the singular or only the plural is intended. Use of any
gender shall be construed to include all other genders unless the context
clearly indicates that less than all the genders is intended.

         2.       Demand Registration. At any time after the Company has filed
any Registration Statement under the Securities Act, during which there is no
effective registration statement relating to the Registrable Securities, the
Holders of not less than a majority of the Registrable Securities may make up to
two (2) requests in writing (each a "Demand") requiring the Company to effect a
registration under the Securities Act of Registrable Securities. Upon receipt of
such a Demand, the Company shall, not later than the Filing Date, prepare and
file with the Commission a "shelf" Registration Statement covering all
Registrable Securities for which such Demand is made for an offering to be made
on a continuous basis pursuant to Rule 415. The Registration Statement shall be
on a form appropriate for such registration in accordance herewith; provided,
however, that only the first Registration Statement (and amendments thereto)
made pursuant to a Demand need be on Form S-1. The Company shall (i) not permit
any securities other than the Registrable Securities to be included in the
Registration Statement (unless such requirement is waived in writing by the
Holders of a majority in interest of the Registrable Securities to be included
in such Registration Statement, or as provided pursuant to Section 8(c)(ii)
hereof) and (ii) use its best efforts to cause the Registration Statement to be
declared effective under the Securities Act (including filing with the
Commission a request for acceleration of effectiveness in accordance with Rule
461 promulgated under the Securities Act within five (5) Business Days of the
date that the Company is notified (orally or in writing, whichever is earlier)
by the Commission that a Registration Statement will not be "reviewed," or not
be subject to further review, and to keep such Registration Statement
continuously effective under the Securities Act until such date as is the
earlier of (x) the date when all Registrable Securities covered by such
Registration Statement have been sold or (y) the date on which the Registrable
Securities may be

                                       4

<PAGE>

sold without any restriction pursuant to Rule 144(k) as determined by the
counsel to the Company pursuant to a written opinion letter, addressed to the
Company's transfer agent to such effect (the "Effectiveness Period"). If the
Company receives a Demand from one or more Holders (whether or not such Holders
constitute Holders of a majority of the Registrable Securities), the Company
shall, not later than one business day thereafter, give notice thereof (the
"Demand Notice") to all other Holders, who shall then have 30 days (the "Demand
Period") to serve their own Demands for registration. At the end of the Demand
Period, if the Holders of a majority in interest of the Registrable Securities
have served Demands to the Company, the Company shall proceed with the
registration of all the Registrable Securities for which such a Demand is made
and keep such Registration Statement continuously effective throughout the
Effectiveness Period as required by this Agreement. Notwithstanding the
foregoing, the Company shall be entitled to postpone for up to 90 days the
filing, effectiveness, supplementing or amending of any registration statement
otherwise required to be prepared and filed pursuant to this Agreement, if the
Board of Directors of the Company determines that such registration or the offer
and sale of Registrable Securities contemplated thereby would interfere with, or
require premature disclosure of, any material financing, acquisition,
disposition, reorganization or other transaction involving the Company or any of
its subsidiaries and the Company promptly gives the Holder notice of such
determination. The Holders hereby acknowledge that any notice given by the
Company pursuant to this Section 2 shall constitute material non-public
information and that the United States securities laws prohibit any Person who
has material non-public information about a company from purchasing or selling
securities of such company or from communicating such information to any other
Person under circumstances in which it is reasonably foreseeable that such
Person is likely to purchase or sell such securities.

         3.       Registration Procedures. In connection with the Company's
registration obligations pursuant to Section 2 hereof, the Company shall:

                  (a)      Prepare and file with the Commission on or prior to
the Filing Date, a Registration Statement in accordance with the method or
methods of distribution thereof as specified by the majority of Holders that
have served the Company with a Demand to include Registrable Securities on such
Registration Statement, and cause the Registration Statement to become effective
and remain effective during the Effectiveness Period; provided, however, that
not less than five (5) Business Days prior to the filing of the Registration
Statement or any related Prospectus or any amendment or supplement thereto
(including any document that would be incorporated therein by reference), the
Company shall (i) furnish to the Holders and the Special Counsel, copies of all
such documents proposed to be filed, which documents (other than those
incorporated by reference) will be subject to the review of such Holders and the
Special Counsel, and (ii) at the request of the majority of Holders that have
served the Company with a Demand cause its officers and directors, counsel and
independent certified public accountants to respond to such inquiries as shall
be necessary, in the reasonable opinion of the Special Counsel, to conduct a
reasonable investigation within the meaning of the Securities Act. The Company
shall not file the Registration Statement or any such Prospectus or any
amendments or supplements thereto to which the Holders of a majority of the
Registrable Securities or the Special Counsel shall reasonably object in writing
within three (3) Business Days of their receipt thereof.

                                       5

<PAGE>

                  (b)      (i) Prepare and file with the Commission such
amendments, including post-effective amendments, to the Registration Statement
as may be necessary to keep the Registration Statement continuously effective as
to the applicable Registrable Securities for the Effectiveness Period; (ii)
cause the related Prospectus to be amended or supplemented by any required
Prospectus supplement, and as so supplemented or amended to be filed pursuant to
Rule 424 (or any similar provisions then in force) promulgated under the
Securities Act; and (iii) respond as promptly as practicable to any comments
received from the Commission with respect to the Registration Statement or any
amendment thereto and as promptly as practicable provide the Holders true and
complete copies of all correspondence from and to the Commission relating to the
Registration Statement.

                  (c)      Notify the Holders of Registrable Securities to be
sold and the Special Counsel as promptly as possible but in no event less than
five (5) Business Days prior to such filing, and confirm such notice in writing
no later than one (1) Business Day following the day when a Prospectus or any
Prospectus supplement or post-effective amendment to the Registration Statement:
(A) is proposed to be filed; (B) when the Commission notifies the Company
whether there will be a "review" of such Registration Statement and whenever the
Commission comments in writing on such Registration Statement; and (C) with
respect to the Registration Statement or any post-effective amendment, when the
same has become effective, and during the Effectiveness Period: (i) of any
request by the Commission or any other Federal or state governmental authority
for amendments or supplements to the Registration Statement or Prospectus or for
additional information; (ii) of the issuance by the Commission of any stop order
suspending the effectiveness of the Registration Statement covering any or all
of the Registrable Securities or the initiation of any Proceedings for that
purpose; (iii) of the receipt by the Company of any notification with respect to
the suspension of the qualification or exemption from qualification of any of
the Registrable Securities for sale in any jurisdiction, or the initiation or
threatening of any Proceeding for such purpose; and (iv) of the occurrence of
any event that makes any statement made in the Registration Statement or
Prospectus or any document incorporated or deemed to be incorporated therein by
reference untrue in any material respect or that requires any revisions to the
Registration Statement, Prospectus or other documents so that, in the case of
the Registration Statement or the Prospectus, as the case may be, it will not
contain any untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements therein,
in the light of the circumstances under which they were made, not misleading.

                  (d)      Use its best efforts to avoid the issuance of, or, if
issued, obtain the withdrawal of, (i) any order suspending the effectiveness of
the Registration Statement or (ii) any suspension of the qualification (or
exemption from qualification) of any of the Registrable Securities for sale in
any jurisdiction, at the earliest practicable moment.

                  (e)      If requested by the Holders of a majority in interest
of the Registrable Securities to be sold pursuant to the Registration Statement,
(i) promptly incorporate in a Prospectus supplement or post-effective amendment
to the Registration Statement such information as the Company reasonably agrees
should be included therein and (ii) make all required filings of such Prospectus
supplement or such post-effective amendment as soon as practicable after the
Company has received notification of the matters to be incorporated in such
Prospectus supplement or post-effective amendment.

                                       6

<PAGE>

                  (f)      Furnish to each Holder and the Special Counsel,
without charge, at least one conformed copy of each Registration Statement and
each amendment thereto, including financial statements and schedules, all
documents incorporated or deemed to be incorporated therein by reference, and
all exhibits to the extent reasonably requested by such Person (including those
previously furnished or incorporated by reference) promptly after the filing of
such documents with the Commission.

                  (g)      Promptly deliver to each Holder and the Special
Counsel, without charge, as many copies of the Prospectus or Prospectuses
(including each form of prospectus) and each amendment or supplement thereto as
such Persons may reasonably request; and the Company hereby consents to the use
of such Prospectus and each amendment or supplement thereto by each of the
selling Holders in connection with the offering and sale of the Registrable
Securities covered by such Prospectus and any amendment or supplement thereto.

                  (h)      Prior to any public offering of Registrable
Securities, use its best efforts to register or qualify or cooperate with the
selling Holders and the Special Counsel in connection with the registration or
qualification (or exemption from such registration or qualification) of such
Registrable Securities for offer and sale under the securities or Blue Sky laws
of such jurisdictions within the United States as the Holders of a majority in
interest of Registrable Securities included in the Registration Statement
request in writing, to keep each such registration or qualification (or
exemption therefrom) effective during the Effectiveness Period and to do any and
all other acts or things reasonably necessary or advisable to enable the
disposition in such jurisdictions of the Registrable Securities covered by a
Registration Statement; provided, however, that the Company shall not be
required to qualify generally to do business in any jurisdiction where it is not
then so qualified or to take any action that would subject it to general service
of process in any such jurisdiction where it is not then so subject or subject
the Company to any material tax in any such jurisdiction where it is not then so
subject.

                  (i)      Cooperate with the Holders to facilitate the timely
preparation and delivery of certificates representing Registrable Securities to
be sold pursuant to a Registration Statement, which certificates shall be free
of all restrictive legends, and to enable such Registrable Securities to be in
such denominations and registered in such names as any Holder may request at
least two (2) Business Days prior to any sale of Registrable Securities.

                  (j)      Upon the occurrence of any event contemplated by
Section 3(c)(iv), as promptly as practicable, prepare a supplement or amendment,
including a post-effective amendment, to the Registration Statement or a
supplement to the related Prospectus or any document incorporated or deemed to
be incorporated therein by reference, and file any other required document so
that, as thereafter delivered, neither the Registration Statement nor such
Prospectus will contain an untrue statement of a material fact or omit to state
a material fact required to be stated therein or necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading.

                  (k)      Use its best efforts to cause all Registrable
Securities relating to such Registration Statement to be listed on each
Exchange.

                                       7

<PAGE>

                  (l)      Comply in all material respects with all applicable
rules and regulations of the Commission and make generally available to its
security holders earning statements satisfying the provisions of Section 11(a)
of the Securities Act and Rule 158 not later than 45 days after the end of any
12-month period (or 90 days after the end of any 12-month period if such period
is a fiscal year) commencing on the first day of the first fiscal quarter of the
Company after the effective date of the Registration Statement, which statement
shall conform to the requirements of Rule 158.

                  (m)      Require each selling Holder to furnish to the Company
information regarding such Holder and the distribution of such Registrable
Securities as is required by law to be disclosed in the Registration Statement,
and the Company may exclude from such registration the Registrable Securities of
any such Holder who fails to furnish such information within a reasonable time
prior to the filing of each Registration Statement, supplemented Prospectus
and/or amended Registration Statement.

                  (n)      If the Registration Statement refers to any Holder by
the name or otherwise as the holder of any securities of the Company, then such
Holder shall have the right to require (if such reference to such Holder by name
or otherwise is not required by the Securities Act or any similar federal
statute or regulation then in force) the deletion of the reference to such
Holder in any amendment or supplement to the Registration Statement filed or
prepared subsequent to the time that such reference ceases to be required.

         4.       Holder Obligations. In connection with the Company's
registration obligations hereunder, each Holder:

                  (a)      Covenants and agrees that it will not sell any
Registrable Securities under the Registration Statement until it has received
copies of the Prospectus as then amended or supplemented as contemplated in
Section 3(g) and notice from the Company that such Registration Statement and
any post-effective amendments thereto have become effective as contemplated by
Section 3(c).

                  (b)      Covenants and agrees that it and its officers,
directors or Affiliates, if any, will comply with the prospectus delivery
requirements of the Securities Act as applicable to them in connection with
sales of Registrable Securities pursuant to the Registration Statement.

                  (c)      Agrees by its acquisition of the Registrable
Securities that, upon receipt of a notice from the Company of the occurrence of
any event of the kind described in Section 3(c)(i), Section 3(c)(ii), Section
3(c)(iii) or Section 3(c)(iv), such Holder will forthwith discontinue
disposition of such Registrable Securities under the Registration Statement
until such Holder's receipt of the copies of the supplemented Prospectus and/or
amended Registration Statement contemplated by Section 3(j), or until it is
advised in writing (the "Advice") by the Company that the use of the applicable
Prospectus may be resumed, and, in either case, has received copies of any
additional or supplemental filings that are incorporated or deemed to be
incorporated by reference in such Prospectus or Registration Statement.

         5.       Registration Expenses. All fees and expenses incident to the
performance of or compliance with this Agreement by the Company shall be borne
by the Company whether or not

                                       8

<PAGE>

the Registration Statement is filed or becomes effective and whether or not any
Registrable Securities are sold pursuant to the Registration Statement. The fees
and expenses referred to in the foregoing sentence shall include, without
limitation, (i) all registration and filing fees (including, without limitation,
fees and expenses (A) with respect to filings required to be made with any
Exchange on which Registrable Securities are required hereunder to be listed,
(B) with respect to filings required to be made with the Commission, (C) with
respect to filings required to be made under the rules of any Exchange and (D)
in compliance with state securities or Blue Sky laws (including, without
limitation, reasonable fees and disbursements of the Special Counsel for the
Holders in connection with Blue Sky qualifications of the Registrable Securities
and determination of the eligibility of the Registrable Securities for
investment under the laws of such jurisdictions as the Holders of a majority in
interest of the Registrable Securities included in the Registration Statement
may designate)), (ii) printing expenses (including, without limitation, expenses
of printing certificates for Registrable Securities and of printing prospectuses
if the printing of prospectuses is requested by the Holders of a majority of the
Registrable Securities included in the Registration Statement), (iii) messenger,
telephone and delivery expenses, (iv) Securities Act liability insurance, if the
Company so desires such insurance, and (v) fees and expenses of all other
Persons retained by the Company in connection with the consummation of the
transactions contemplated by this Agreement, including, without limitation, the
Company's independent public accountants (including the expenses of any comfort
letters or costs associated with the delivery by independent public accountants
of a comfort letter or comfort letters) and legal counsel. In addition, the
Company shall be responsible for all of its internal expenses incurred in
connection with the consummation of the transactions contemplated by this
Agreement (including, without limitation, all salaries and expenses of its
officers and employees performing legal or accounting duties), the expense of
any annual audit, the fees and expenses incurred in connection with the listing
of the Registrable Securities on any securities exchange as required hereunder.
Notwithstanding the foregoing, the Company shall not be responsible for the
payment of (i) underwriting discounts or commissions or (ii) any expenses of any
registration proceeding began pursuant to Section 2 if the registration is
subsequently withdrawn at the request of the Holder Representative (in which
case all Holders shall bear all such expenses pro rata).

         6.       Indemnification.

                  (a)      Indemnification by the Company. The Company shall,
notwithstanding any termination of this Agreement, indemnify and hold harmless
each Holder, the officers, directors, agents, brokers (including brokers who
offer and sell Registrable Securities as principal as a result of a pledge or
any failure to perform under a margin call of Common Stock), investment advisors
and employees of each of them, each Person who controls any such Holder (within
the meaning of Section 15 of the Securities Act or Section 20 of the Exchange
Act) and the officers, directors, agents and employees of each such controlling
Person, to the fullest extent permitted by applicable law, from and against any
and all losses, claims, damages, liabilities, costs (including, without
limitation, reasonable costs of preparation and reasonable attorneys' fees) and
expenses (collectively, "Losses"), as incurred, arising out of or relating to
any untrue or alleged untrue statement of a material fact contained in the
Registration Statement, any Prospectus or any form of prospectus or in any
amendment or supplement thereto or in any preliminary prospectus, or arising out
of or relating to any omission or alleged omission of a material fact required
to be stated therein or necessary to make the statements therein (in the case

                                       9

<PAGE>

of any Prospectus or form of prospectus or supplement thereto, in the light of
the circumstances under which they were made) not misleading, except to the
extent, but only to the extent, that such untrue statements or omissions are
based solely upon information regarding such Holder furnished in writing to the
Company by such Holder expressly for use therein, which information was
reasonably relied on by the Company for use therein or to the extent that such
information relates to such Holder or such Holder's proposed method of
distribution of Registrable Securities and was reviewed and expressly approved
in writing by such Holder expressly for use in the Registration Statement, such
Prospectus or such form of Prospectus or in any amendment or supplement thereto.
The Company shall notify the Holders promptly of the institution, threat or
assertion of any Proceeding of which the Company is aware in connection with the
transactions contemplated by this Agreement. Such indemnity shall remain in full
force and effect regardless of any investigation made by or on behalf of an
Indemnified Party (as defined in Section 6(c) to this Agreement) and shall
survive the transfer of the Registrable Securities by the Holders.

                  (b)      Indemnification by Holders. Each Holder shall,
severally and not jointly, indemnify and hold harmless the Company, its
directors, officers, agents and employees, each Person who controls the Company
(within the meaning of Section 15 of the Securities Act and Section 20 of the
Exchange Act), and its directors, officers, agents or employees of such
controlling Persons, to the fullest extent permitted by applicable law, from and
against all Losses, as incurred, arising solely out of or based solely upon any
untrue statement of a material fact contained in the Registration Statement, any
Prospectus, or any form of prospectus, or arising solely out of or based solely
upon any omission of a material fact required to be stated therein or necessary
to make the statements therein (in the case of any Prospectus or form of
prospectus or supplement thereto, in the light of the circumstances under which
they were made) not misleading, to the extent, but only to the extent, that such
untrue statement or omission is contained in or omitted from any information so
furnished in writing by such Holder to the Company specifically for inclusion in
the Registration Statement or such Prospectus and that such information was
reasonably relied upon by the Company for use in the Registration Statement,
such Prospectus or such form of prospectus or to the extent that such
information relates to such Holder or such Holder's proposed method of
distribution of Registrable Securities and was reviewed and expressly approved
in writing by such Holder expressly for use in the Registration Statement, such
Prospectus or such form of Prospectus Supplement. Notwithstanding anything to
the contrary contained herein, the Holder shall be liable under this Section
6(b) for only that amount as does not exceed the net proceeds to such Holder as
a result of the sale of Registrable Securities pursuant to such Registration
Statement.

                  (c)      Conduct of Indemnification Proceedings. If any
Proceeding shall be brought or asserted against any Person entitled to indemnity
hereunder (an "Indemnified Party"), such Indemnified Party promptly shall notify
the Person from whom indemnity is sought (the "Indemnifying Party") in writing,
and the Indemnifying Party shall assume the defense thereof, including the
employment of counsel reasonably satisfactory to the Indemnified Party and the
payment of all fees and expenses incurred in connection with defense thereof;
provided, that the failure of any Indemnified Party to give such notice shall
not relieve the Indemnifying Party of its obligations or liabilities pursuant to
this Agreement, except (and only) to the extent that it shall be finally
determined by a court of competent jurisdiction (which determination is not
subject to appeal or further review) that such failure shall have proximately
and materially adversely prejudiced the Indemnifying Party.

                                       10

<PAGE>

                  An Indemnified Party shall have the right to employ separate
counsel in any such Proceeding and to participate in the defense thereof, but
the fees and expenses of such counsel shall be at the expense of such
Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed in
writing to pay such fees and expenses; or (2) the Indemnifying Party shall have
failed promptly to assume the defense of such Proceeding and to employ counsel
reasonably satisfactory to such Indemnified Party in any such Proceeding; or (3)
the named parties to any such Proceeding (including any impleaded parties)
include both such Indemnified Party and the Indemnifying Party, and such
Indemnified Party shall have been advised by counsel that a conflict of interest
is likely to exist if the same counsel were to represent such Indemnified Party
and the Indemnifying Party (in which case, if such Indemnified Party notifies
the Indemnifying Party in writing that it elects to employ separate counsel at
the expense of the Indemnifying Party, the Indemnifying Party shall not have the
right to assume the defense thereof and such counsel shall be at the expense of
the Indemnifying Party). The Indemnifying Party shall not be liable for any
settlement of any such Proceeding effected without its written consent, which
consent shall not be unreasonably withheld. No Indemnifying Party shall, without
the prior written consent of the Indemnified Party, effect any settlement of any
pending Proceeding in respect of which any Indemnified Party is a party, unless
such settlement includes an unconditional release of such Indemnified Party from
all liability on claims that are the subject matter of such Proceeding.

                  All fees and expenses of the Indemnified Party (including
reasonable fees and expenses to the extent incurred in connection with
investigating or preparing to defend such Proceeding in a manner not
inconsistent with this Section) shall be paid to the Indemnified Party, as
incurred, within ten (10) Business Days of written notice thereof to the
Indemnifying Party (regardless of whether it is ultimately determined that an
Indemnified Party is not entitled to indemnification hereunder; provided, that
the Indemnifying Party may require such Indemnified Party to undertake to
reimburse all such fees and expenses to the extent it is finally judicially
determined that such Indemnified Party is not entitled to indemnification
hereunder).

                  (d)      Contribution. If a claim for indemnification under
Section 6(a) or Section 6(b) is unavailable to an Indemnified Party because of a
failure or refusal of a governmental authority to enforce such indemnification
in accordance with its terms (by reason of public policy or otherwise), then
each Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall
contribute to the amount paid or payable by such Indemnified Party as a result
of such Losses, in such proportion as is appropriate to reflect the relative
fault of the Indemnifying Party and Indemnified Party in connection with the
actions, statements or omissions that resulted in such Losses as well as any
other relevant equitable considerations. The relative fault of such Indemnifying
Party and Indemnified Party shall be determined by reference to, among other
things, whether any action in question, including any untrue or alleged untrue
statement of a material fact or omission or alleged omission of a material fact,
has been taken or made by, or relates to information supplied by, such
Indemnifying, Party or Indemnified Party, and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
action, statement or omission. The amount paid or payable by a party as a result
of any Losses shall be deemed to include, subject to the limitations set forth
in Section 6(c), any reasonable attorneys' or other reasonable fees or expenses
incurred by such party in connection with any Proceeding to the extent such
party would have been indemnified for such fees or expenses if the
indemnification provided for in this Section 6 was available to such party in

                                       11

<PAGE>

accordance with its terms. Notwithstanding anything to the contrary contained
herein, the Holder shall be liable or required to contribute under this Section
6(d) for only that amount as does not exceed the net proceeds to such Holder as
a result of the sale of Registrable Securities pursuant to such Registration
Statement.

                  The parties hereto agree that it would not be just and
equitable if contribution pursuant to this Section 6(d) were determined by pro
rata allocation or by any other method of allocation that does not take into
account the equitable considerations referred to in the immediately preceding
paragraph. No Person guilty of fraudulent misrepresentation (within the meaning
of Section 11(f) of the Securities Act) shall be entitled to contribution from
any Person who was not guilty of such fraudulent misrepresentation.

                  The indemnity and contribution agreements contained in this
Section are in addition to any liability that the Indemnifying Parties may have
to the Indemnified Parties

         7.       Rule 144. The Company covenants to timely file (or obtain
extensions in respect thereof and file within the applicable grace period) all
reports required to be filed by the Company after the date hereof pursuant to
Section 13(a) or 15(d) of the Exchange Act and to promptly furnish the Holders
with true and complete copies of all such filings. Upon the request of any
Holder, the Company shall deliver to such Holder a written certification of a
duly authorized officer as to whether it has complied with such requirements.

         8.       Miscellaneous.

                  (a)      Remedies. In the event of a breach by the Company or
by a Holder, of any of their obligations under this Agreement, each Holder or
the Company, as the case may be, in addition to being entitled to exercise all
rights granted by law and under this Agreement, including recovery of damages,
will be entitled to specific performance of its rights under this Agreement. The
Company and each Holder agree that monetary damages would not provide adequate
compensation for any losses incurred by reason of a breach by it of any of the
provisions of this Agreement and hereby further agrees that, in the event of any
action for specific performance in respect of such breach, it shall waive the
defense that a remedy at law would be adequate.

                  (b)      No Inconsistent Agreements. Except for the Hyde
Registration Rights Agreement and the MBV Registration Rights Agreement, the
Company has not, as of the date hereof, entered into any agreement currently in
effect, nor shall the Company, on or after the date of this Agreement, enter
into any agreement with respect to its securities that is inconsistent with the
rights granted to the Holders in this Agreement or otherwise conflicts with the
provisions hereof. Except for the Hyde Registration Rights Agreement and the MBV
Registration Rights Agreement, the Company has not previously entered into any
agreement currently in effect granting any registration rights with respect to
any of its securities to any Person. Without limiting the generality of the
foregoing, the Company shall not, without the written consent of the Holders of
a majority of the then outstanding Registrable Securities, grant to any Person
the right to request the Company to register any securities of the Company under
the Securities Act or any state securities laws unless the rights so granted are
subject in all respects to the prior rights in full of the Holders set forth
herein, and are not otherwise in conflict with the provisions

                                       12

<PAGE>

of this Agreement. The Company shall give prompt notice to the Holders of (i)
the Company's receipt of any demand for registration of any of its securities
(including without limitation a demand under the Hyde Registration Rights
Agreement), whether or not the Company considers such demand to be binding upon
the Company, and (ii) any decision by the Company (whether or not pursuant to
any demand) to register any of its securities for sale under the Securities Act
or any state securities laws.

                  (c)      Piggyback on Holder Registrations.

                           (i)      Except as set forth in Section 8(c)(ii)
         below, neither the Company nor any of its security holders (other than
         the Holders in such capacity pursuant hereto) may include securities of
         the Company or such security holder in a Registration Statement filed
         pursuant to a Demand, and the Company shall not after the date hereof
         enter into any agreement providing such right to any of its security
         holders, unless the right so granted is subject in all respects to the
         prior rights in full of the Holders set forth herein, and is not
         otherwise in conflict with the provisions of this Agreement.

                           (ii)     Notwithstanding the foregoing, any
         Registration Statement filed pursuant to the demand of the Holders of
         the Registrable Securities pursuant to Section 2 hereof, may, subject
         to the provisions hereof, include shares of Hyde Registrable Securities
         and MBV Registrable Securities. In the case of an underwritten public
         offering, if the Company after consultation with the managing
         underwriter should reasonably determine that the inclusion of Hyde
         Registrable Securities and/or MBV Registrable Securities would
         materially adversely affect the offering contemplated in such
         Registration Statement, and based on such determination recommends
         inclusion in such Registration Statement of fewer or none of the
         Registrable Securities, the Hyde Registrable Securities and/or the MBV
         Registrable Securities, then fewer or none of Hyde Registrable
         Securities and MBV Registrable Securities shall be included in such
         Registration Statement unless all of the Registrable Securities
         requested to be included in such Registration Statement are so
         included.

                  (d)      Piggy-Back Registrations.

                           (i)      Except as provided in (Section 8(d)(ii))
         below, if, at any time when there is not an effective Registration
         Statement covering the Registrable Shares, the Company shall determine
         to prepare and file with the Commission a registration statement
         relating to an offering for its own account or the account of others
         under the Securities Act of any of its equity securities ("Other
         Securities"), other than on Form S-4 or Form S-8 (each as promulgated
         under the Securities Act) or its then equivalents relating to equity
         securities to be issued solely in connection with any acquisition of
         any entity or business or equity securities issuable in connection with
         stock option or other employee benefit plans, then the Company shall
         send to each Holder of Registrable Securities written notice of such
         determination and, if within thirty (30) days after receipt of such
         notice, any such Holder shall so request in writing (which request
         shall specify the number of Registrable Securities intended to be
         disposed of by the Holders), the Company will cause the registration
         under the Securities Act of all Registrable Securities which the
         Company has been so requested to register by the Holders, to the extent

                                       13

<PAGE>

         required to permit the disposition of the Registrable Securities so to
         be registered, provided, however, that if at any time after giving
         written notice of its intention to register Other Securities and prior
         to the effective date of the registration statement filed in connection
         with such registration, the Company shall determine for any reason not
         to register or to delay registration of the Other Securities, the
         Company may, at its election, give written notice of such determination
         to such Holders and, thereupon, (i) in the case of a determination not
         to register, shall be relieved of its obligation to register any
         Registrable Securities in connection with such registration (but not
         from its obligation to pay expenses in accordance with Section 5
         hereof), and (ii) in the case of a determination to delay registering,
         shall be permitted to delay registering any Registrable Securities
         being registered pursuant to this Section 8(d) for the same period as
         the delay in registering the Other Securities. The Company shall
         include in such registration statement all or any part of the
         Registrable Securities which a Holder requests to be registered;
         provided, however, that the Company shall not be required to register
         any Registrable Securities pursuant to this Section 8(d) that are
         eligible for sale pursuant to Rule 144(k) of the Securities Act. In the
         case of an underwritten public offering, if the managing underwriter(s)
         or underwriter(s) should reasonably object to the inclusion of the
         Registrable Securities in such registration statement, or if the
         Company after consultation with the managing underwriter should
         reasonably determine that the inclusion of such Registrable Securities
         would materially adversely affect the offering contemplated in such
         registration statement, and based on such determination recommends
         inclusion in such registration statement of fewer or none of the
         Registrable Securities of the Holders, then (x) the number of
         Registrable Securities, Hyde Registrable Securities and MBV Registrable
         Securities included in such registration statement shall be reduced
         pro-rata among such Holders, any Hyde Holders and any MBV Holders
         seeking respectively to register Registrable Securities, Hyde
         Registrable Securities or MBV Registrable Securities, or (y) none of
         the Registrable Securities of the Holders shall be included in such
         registration statement, if the Company after consultation with the
         underwriter(s) recommends the inclusion of none of such Registrable
         Securities, Hyde Registrable Securities or MBV Registrable Securities;
         provided, however, that, in either case, if securities are being
         offered for the account of other persons or entities as well as the
         Company, such reduction shall not represent a greater fraction of the
         number of Registrable Securities intended to be offered by the Holders
         than the fraction of similar reductions imposed on such other persons
         or entities (other than the Company).

                           (ii)     If, at any time when there is not an
         effective Registration Statement covering the Registrable Shares, the
         Company is required to prepare and file with the Commission a
         registration statement pursuant to the Hyde Registration Rights
         Agreement, then the Company shall send to each Holder of Registrable
         Securities written notice of such requirement and, if within thirty
         (30) days after receipt of such notice, any such Holder shall so
         request in writing (which request shall specify the number of
         Registrable Securities intended to be disposed of by the Holders), the
         Company will cause the registration under the Securities Act of all
         Registrable Securities which the Company has been so requested to
         register by the Holders, to the extent requisite to permit the
         disposition of the Registrable Securities so to be registered. The
         Company shall include in such registration statement all or any part of
         the Registrable Securities which a Holder requests to be registered;
         provided, however, that the Company shall not

                                       14

<PAGE>

         be required to register any Registrable Securities pursuant to this
         Section 8(d) that are eligible for sale pursuant to Rule 144(k) of the
         Securities Act. In the case of an underwritten public offering, if the
         Company after consultation with the managing underwriter should
         reasonably determine that the inclusion of such Registrable Securities
         would materially adversely affect the offering contemplated in such
         registration statement, and based on such determination recommend
         inclusion in such registration statement of fewer or none of the
         Registrable Securities of the Holders, then the number of Registrable
         Securities of the Holders included in such registration statement shall
         be reduced in accordance with the Hyde Registration Rights Agreement.

                  (e)      Failure to File Registration Statement and Other
Events. The Company and the Holders agree that the Holders will suffer damages
if the Registration Statement is not filed on or prior to the Filing Date and
not declared effective by the Commission on or prior to the Effectiveness Date
and maintained in the manner contemplated herein during the Effectiveness
Period. The Company and the Holders further agree that it would not be feasible
to ascertain the extent of such damages with precision. Accordingly, if (i) the
Registration Statement is not filed on or prior to the Filing Date, or is not
declared effective by the Commission on or prior to the Effectiveness Date (or
in the event an additional Registration Statement is filed because the actual
number of shares of Common Stock into which the Preferred Stock is convertible
exceeds the number of shares of Common Stock initially registered is not filed
and declared effective within the time periods set forth in Section 2 (subject
to the right of the Company under Section 2 to delay such filing), or (ii) the
Company fails to file with the Commission a request for acceleration in
accordance with Rule 461 promulgated under the Securities Act within five (5)
Business Days of the date that the Company is notified (orally or in writing,
whichever is earlier) by the Commission that a Registration Statement will not
be "reviewed," or not subject to further review, or (iii) the Registration
Statement is filed with and declared effective by the Commission but thereafter
ceases to be effective for a period in excess of ten (10) Business Days as to
the Registrable Securities for which such Registration Statement is filed at any
time prior to the expiration of the Effectiveness Period, without being
succeeded immediately by a subsequent Registration Statement filed with and
declared effective by the Commission, or (iv) trading in the Common Stock shall
be suspended or if the Common Stock is delisted from any Exchange for any reason
for more than three (3) Business Days in the aggregate, or (any such failure or
breach being referred to as an "Event"), the Company shall pay in cash as
liquidated damages for such failure and not as a penalty to any Holder whose
Registrable Securities are included on such Registration Statement (or for which
a Demand was made during the Demand Period) remain unsold (such securities being
"Unsold Securities") as a result of such Event, except as set forth below, an
amount equal to two percent (2%) of such Holder's Unsold Securities' pro rata
share of the purchase price paid by Purchaser and its Affiliates pursuant to the
Purchase Agreement for the initial thirty (30) day period until the applicable
Event has been cured, which shall be pro rated for such periods less than thirty
(30) days and two percent (2%) of such Holder's Unsold Securities' pro rata
share of the purchase price paid by Purchaser and its Affiliates for the
Preferred Stock pursuant to the Purchase Agreement for each subsequent thirty
(30) day period until the applicable Event has been cured which shall be pro
rated for such periods less than thirty days (the "Periodic Amount").
Notwithstanding the foregoing, to the extent the Event occurs for any reason not
within the control of the Company, the Company shall have an additional 60 days
to cure any Event without penalty and upon failure to cure within such 60 day
period, the 2% penalty

                                       15

<PAGE>

provided above shall then apply to such continued Event but the 2% penalty shall
be reduced to 1%. Payments to be made pursuant to this Section 8(e) shall be due
and payable immediately upon demand in immediately available cash funds. The
parties agree that the Periodic Amount represents a reasonable estimate on the
part of the parties, as of the date of this Agreement, of the amount of damages
that may be incurred by the Holders if the Registration Statement is not filed
on or prior to the Filing Date or has not been declared effective by the
Commission on or prior to the Effectiveness Date (subject to the right of the
Company under Section 2 to delay such filing) and maintained in the manner
contemplated herein during the Effectiveness Period or if any other Event as
described herein has occurred.

                  (f)      Specific Enforcement, Consent to Jurisdiction.

                           (i)      The Company and the Holders acknowledge and
         agree that irreparable damage would occur in the event that any of the
         provisions of this Agreement or the Purchase Agreement were not
         performed in accordance with their specific terms or were otherwise
         breached. It is accordingly agreed that the parties shall be entitled
         to an injunction or injunctions to prevent or cure breaches of the
         provisions of this Agreement or the Purchase Agreement and to enforce
         specifically the terms and provisions hereof or thereof, this being in
         addition to any other remedy to which any of them may be entitled by
         law or equity.

                           (ii)     Each of the Company and the Holders (i)
         hereby irrevocably submits to the exclusive jurisdiction of the state
         and federal courts located in New York City, New York for the purposes
         of any suit, action or proceeding arising out of or relating to this
         Agreement or the Purchase Agreement and (ii) hereby waives, and agrees
         not to assert in any such suit, action or proceeding, any claim that it
         is not personally subject to the jurisdiction of such court, that the
         suit, action or proceeding is brought in an inconvenient forum or that
         the venue of the suit, action or proceeding is improper. Each of the
         Company and the Holders consents to process being served in any such
         suit, action or proceeding by mailing a copy thereof to such party at
         the address in effect for notices to it under this Agreement and agrees
         that such service shall constitute good and sufficient service of
         process and notice thereof. Nothing in this Section 8(f) shall affect
         or limit any right to serve process in any other manner permitted by
         law.

                  (g)      Amendments and Waivers. The provisions of this
Agreement, including the provisions of this sentence, may not be amended,
modified or supplemented, and waivers or consents to departures from the
provisions hereof may not be given, unless the same shall be in writing and
signed by the Company and a majority of the Holders.

                  (h)      Notices. Any and all notices or other communications
or deliveries required or permitted to be provided hereunder shall be in writing
and shall be deemed given and effective on the earlier of (i) the Business Day
following the date of deposit with a nationally recognized overnight courier
service or (ii) actual receipt by the party to whom such notice is required to
be given. The addresses for such communications shall be, with respect to each
Holder, at its address as set forth in the stock transfer records of the
Company, and with respect to the Company, addressed to:

                                       16

<PAGE>

                                    GTx, Inc.
                                    3 North Dunlap Street - 3rd Floor
                                    Van Vleet Building
                                    Memphis, Tennessee 38163
                                    Attn:  Dr. Mitch S. Steiner
                                    Fax No.:  901-523-9772

or to such other address or addresses as any such party may most recently have
designated in writing to the other parties hereto by such notice. Copies of
notices to the Company shall be sent to Henry P. Doggrell, General Counsel, GTx,
Inc., 3 North Dunlap Street, 3rd Floor, Van Vleet Building, Memphis, Tennessee,
38163, Fax: 901-523-9772. Copies of notices to any Holder shall be sent to the
addresses listed on Schedule 1 attached hereto, if applicable. Copies of notices
to the Purchaser shall be sent to Kane Kessler, P.C., 1350 Avenue of the
Americas, New York, New York 10019, Attn. Robert L. Lawrence, Esq.

                  (i)      Successors and Assigns. This Agreement shall be
binding upon and inure to the benefit of the parties and their successors and
permitted assigns and shall inure to the benefit of each Holder and its
successors and assigns. The Company may not assign this Agreement or any of its
rights or obligations hereunder without the prior written consent of the
majority of the Holders. Each Holder may assign its rights hereunder in the
manner and to the Persons as permitted under the Purchase Agreement.

                  (j)      Assignment of Registration Rights. The rights of each
Holder hereunder shall be automatically assignable by each Holder to any
transferee of such Holder of all or a portion of the Purchaser Stock or the
Registrable Securities if: (i) the Holder agrees in writing with the transferee
or assignee to assign such rights, and a copy of such agreement is furnished to
the Company within a reasonable time after such assignment, (ii) the Company is,
within a reasonable time after such transfer or assignment, furnished with
written notice of (a) the name and address of such transferee or assignee, and
(b) the securities with respect to which such registration rights are being
transferred or assigned, (iii) following such transfer or assignment the further
disposition of such securities by the transferee or assignees is restricted
under the Securities Act and applicable state securities laws, (iv) at or before
the time the Company receives the written notice contemplated by clause (ii) of
this Section 8(j), the transferee or assignee agrees in writing with the Company
to be bound by all of the provisions of this Agreement, and (v) such transfer
shall have been made in accordance with the applicable requirements of the
Purchase Agreement. In addition, each Holder shall have the right to assign its
rights hereunder to any other Person with the prior written consent of the
Company, which consent shall not be unreasonably withheld. The rights to
assignment shall apply to the Holders (and to subsequent) successors and
assigns.

                  (k)      Counterparts. This Agreement may be executed in any
number of counterparts, each of which when so executed shall be deemed to be an
original and, all of which taken together shall constitute one and the same
Agreement. In the event that any signature is delivered by facsimile
transmission, such signature shall create a valid binding obligation of the
party executing (or on whose behalf such signature is executed) the same with
the same force and effect as if such facsimile signature were the original
thereof.

                                       17

<PAGE>

                  (l)      Governing Law. This Agreement shall be governed by
and construed in accordance with the laws of the State of New York, without
regard to principles of conflicts of law thereof. The courts of the state of New
York and the federal courts located in the Borough of Manhattan, New York City,
New York, shall have exclusive jurisdiction with respect to any action or
proceeding regarding this Agreement, and each party hereby consents to the
jurisdiction of such courts and venue in the County of New York.

                  (m)      Cumulative Remedies. The remedies provided herein are
cumulative and not exclusive of any remedies provided by law.

                  (n)      Severability. If any term, provision, covenant or
restriction of this Agreement is held to be invalid, illegal, void or
unenforceable in any respect, the remainder of the terms, provisions, covenants
and restrictions set forth herein shall remain in full force and effect and
shall in no way be affected, impaired or invalidated, and the parties hereto
shall use their reasonable efforts to find and employ an alternative means to
achieve the same or substantially the same result as that contemplated by such
term, provision, covenant or restriction. It is hereby stipulated and declared
to be the intention of the parties that they would have executed the remaining
terms, provisions, covenants and restrictions without including any of such that
may be hereafter declared invalid, illegal, void or unenforceable.

                  (o)      Headings. The headings herein are for convenience
only, do not constitute a part of this Agreement and shall not be deemed to
limit or affect any of the provisions hereof.

                  (p)      Shares Held by the Company and its Affiliates.
Whenever the consent or approval of Holders of a specified percentage of
Registrable Securities is required hereunder, Registrable Securities held by the
Company or its Affiliates (other than any Holder or transferees or successors or
assigns thereof if such Holder is deemed to be an Affiliate solely by reason of
its holdings of such Registrable Securities) shall not be counted in determining
whether such consent or approval was given by the Holders of such required
percentage.

                  (q)      Notice of Effectiveness. Within two (2) business days
after the Registration Statement which includes the Registrable Securities is
ordered effective by the Commission, the Company shall deliver, and shall cause
legal counsel for the Company to deliver, to the transfer agent for such
Registrable Securities (with copies to the Holders whose Registrable Securities
are included in such Registration Statement) confirmation that the Registration
Statement has been declared effective by the Commission in the form attached
hereto as Exhibit A.

                  (r)      Cancellation of Previous Registration Rights
Agreements. This Agreement replaces any and all existing registration rights
agreements between the Company and Purchaser (the "Previous Agreements"). The
Company and the Purchaser hereby cancel all Previous Agreements in their
entirety. Both the Company and the Purchaser agree that as of the date hereof,
neither party has any existing liability or continuing obligation or right under
any of the Previous Agreements.

                  (s)      Termination. Upon the sale of all the Registrable
Securities under a registration statement or pursuant to Rule 144(k) (as
determined by the counsel to the Company

                                       18

<PAGE>

pursuant to a written opinion letter, addressed to the Company's transfer agent)
the registration obligations of the Company under this Agreement shall
automatically terminate.

                            [Signature Pages Follow]

                                       19

<PAGE>

         In Witness Whereof, the parties hereto have caused this Registration
Rights Agreement to be duly executed by their respective authorized persons as
of the date first indicated above.

GTx, INC.                                       ORACLE PARTNERS, L.P.

By:  /s/ Marc S. Hanover                        By:   /s/ Larry Feinberg
     _________________________                      __________________________
Name:    Marc S. Hanover                        Name:   Larry Feinberg
     _________________________                  ___________________________
Title:  President - COO                         Title:   Managing Member
      ________________________                     __________________________

                                       20

<PAGE>

                                    EXHIBIT A
                         FORM OF NOTICE OF EFFECTIVENESS
                            OF REGISTRATION STATEMENT

[Name and Address of Counsel]

         Re:      GTx, Inc.

Dear [______]:

         We are counsel to GTx, Inc., a Tennessee corporation (the "Company"),
and have represented the Company in connection with that certain purchase
agreement (the "Purchase Agreement") dated as of ___________ __, 2002 by and
among the Company and the purchaser named therein (the "Holder," which term
includes its successors and assigns) pursuant to which the Company issued to the
Holder its 8% Series E Cumulative Convertible Preferred Stock, which is
convertible into shares of the Company's common stock, no par value (the "Common
Stock"). Pursuant to the Purchase Agreement, the Company has also entered into a
Registration Rights Agreement with the Holders (the "Registration Rights
Agreement") pursuant to which the Company agreed, among other things, to
register the Registrable Securities (as defined in the Registration Rights
Agreement) under the Securities Act of 1933, as amended (the "1933 Act"). In
connection with the Company's obligations under the Registration Rights
Agreement, on ____________ ___, 200_, the Company filed a Registration Statement
on Form [S-1] (File No. 333-____________) (the "Registration Statement") with
the Securities and Exchange Commission (the "SEC") relating to the Registrable
Securities which names each of the Holders as a selling stockholder thereunder.

         In connection with the foregoing, we advise you that a member of the
SEC's staff has advised us by telephone that the SEC has entered an order
declaring the Registration Statement effective under the 1933 Act at [ENTER TIME
OF EFFECTIVENESS] on [ENTER DATE OF EFFECTIVENESS] and we have no knowledge,
after telephonic inquiry of a member of the SEC's staff, that any stop order
suspending its effectiveness has been issued or that any proceedings for that
purpose are pending before, or threatened by, the SEC and the Registrable
Securities are available for resale under the 1933 Act pursuant to the
Registration Statement.

                                        Very truly yours,

                                        By:__________________________________

cc:      [LIST NAMES OF HOLDERS]

                                       21

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00057-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00057-of-00352.parquet"}]]