Exhibit 10.24

THIRD AMENDMENT TO SUPPLY AGREEMENT

THIS THIRD AMENDMENT TO SUPPLY AGREEMENT (the “Amendment”) is dated as of
February 28 2007, by and between Novacea, Inc., a Delaware corporation
previously known as D-NOVO Therapeutics, Inc. (“Novacea”) and Plantex USA, Inc.,
a New Jersey corporation (“Plantex”).

WHEREAS:

Novacea and Plantex are parties to a certain Supply Agreement dated December 27,
2001, as amended on January 24, 2006 and March 21, 2006 (the “Supply
Agreement”); and

Novacea and Plantex wish to amend the Supply Agreement as expressly set forth in
this Amendment, leaving the Supply Agreement otherwise in full force and effect.

NOW, THEREFORE, Novacea and Plantex agree as follows:

1.     All instances of “D-NOVO Therapeutics, Inc.” in the Supply Agreement are
deleted and the following text is submitted in lieu thereof: “Novacea, Inc.”

2.     All instances of “D-NOVO” in the Supply Agreement are deleted and the
following text is submitted in lieu thereof: “Novacea.”

3.     Section 4 of the Supply Agreement is deleted in its entirety and the
following text is submitted in lieu thereof:

“Novacea agrees at its sole cost and expense to use its best efforts to obtain
Approval to market Finished Product in such countries in the Territory as shall
be reasonably determined by Novacea, except that Novacea shall use its best
efforts to obtain FDA Approval to market Finished Product in the United States
based upon a NDA or ANDA, as shall be determined by Novacea. In connection with
such FDA Approval, Novacea shall at its sole cost and expense conduct all tests
and studies reasonably required to enable Novacea to apply for, obtain and
maintain FDA Approval for Finished Product. In connection with the development
of Finished Product and securing any Approvals, Novacea agrees, on behalf of
itself, its Affiliates and their respective licensees or contract manufacturing
vendors, if any, to use only API obtained from PLANTEX (or its Affiliates) and
purchase all their respective requirements of API from PLANTEX (or its
Affiliates). Upon the execution and delivery of this Agreement, PLANTEX shall
provide and deliver to Novacea without charge two grams (2 gms.) of API.
Thereafter, Novacea shall be charged [*] dollars ($[*]) per gram for
Developmental Orders (as herein defined) of API sold hereunder and such price
shall not be subject to increase or decrease. Notwithstanding Section 6.2
hereinbelow, such payment shall be due and payable upon delivery to Novacea of
any Developmental Order or portion thereof. As used herein, “Developmental
Orders” means orders placed prior to Approval by a Regulatory Authority and not
in connection with commercial production in connection with commercial launch
following any such Approval. After January 1, 2008, all Developmental Orders
shall be minimum noncancellable orders for quantities of not less than [*] grams
([*] gms.) each and currently

 

[*] Certain information on this page has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

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forecast by Novacea at [*] grams for 2008, [*] grams for 2009 and [*] grams for
2010. For Developmental Orders on an annual basis after 2010, Novacea shall
notify Plantex of its minimum noncancellable quantities for the applicable year
(not to be less than [*] grams each year) no later than September 30 of the
preceding calendar year. Each of the Developmental Orders shall be deliverable
over periods not exceeding twelve (12) months, in partial shipments of not less
than [*] grams each and not greater than [*] grams each; provided that PLANTEX
shall use commercially reasonable efforts to deliver to Novacea or its designee
quantities set forth in a Developmental Order quarterly shipments of no less
than [*] percent ([*]%) of the applicable Developmental Order.

4.     Section 5.2 of the Supply Agreement is deleted in its entirety and the
following text is submitted in lieu thereof:

“Exception. During any period in which PLANTEX, for any reason, including, but
not limited to, force majeure as provided for in Section 15, fails to supply, is
unable to supply or anticipates that it will not supply, the quantities of API
to Novacea included within any Firm Purchase Order (as defined below) or any
other purchase order confirmed in writing by PLANTEX, Novacea shall be free to
fill such specific purchase order for API (or any unfilled portion) from an
alternative source. This shall be the sole remedy for Novacea in the event that
PLANTEX advises that it is unable to supply API. PLANTEX shall notify Novacea
promptly upon becoming aware of any facts or circumstances which causes it to
believe that it will be unable to meet shipment obligations hereunder. For
clarity, for purposes of exercising Novacea’s rights under this Section 5.2,
Novacea may enter into discussions with potential alternative sources and
conduct any and all activities necessary to validate and qualify an alternative
source as a suitable alternative source supplier, at any time during the term of
this Agreement, so that a qualified alternative source supplier will be
available for the manufacture of API as permitted by this Section 5.2.”

5.     Section 5.5 of the Supply Agreement as amended is deleted in its entirety
and the following text is submitted in lieu thereof:

“Commencing [*] months prior to the date on which Novacea, in good faith,
anticipates Approval, Novacea will provide Plantex with [*] month rolling
forecasts of its requirements by calendar quarter for API. Thereafter, such
rolling forecasts shall be delivered to Plantex on or before the fifteenth
(15th) day of each calendar quarter during the Term. The first calendar quarter
of each [*] month rolling forecast shall be binding on Plantex and Novacea and
shall constitute a firm purchase order (“Firm Purchase Order”) for the API
indicated for such calendar quarter. Plantex shall supply Novacea with (i) the
quantities set forth on each such Firm Purchase Order and (ii) such additional
amounts as Novacea may order in excess of its forecasted amounts for such
calendar quarter, provided that Plantex shall have confirmed and accepted such
additional orders within thirty (30) days of Plantex’s receipt of Novacea’s
written request for such additional amounts. Plantex agrees to use commercially
reasonable efforts to meet any such additional orders. In the event that Plantex
determines for any reason (other than force majeure as provided for in
Section 15, below) to discontinue the manufacture of API, Plantex shall have the
right to terminate its delivery obligations hereunder by giving to Novacea not
less than [*] months prior written notice. The terms and conditions of this
Agreement shall apply to all

 

[*] Certain information on this page has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

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purchase orders hereunder and if any terms and conditions contained in such
purchase orders shall conflict with any terms and conditions contained herein,
the terms of this Agreement shall control. No additional terms or conditions set
forth in any such purchase order (other than the quantities and delivery dates
set forth therein and conforming to the provisions of this Agreement) shall be
binding upon Plantex, unless agreed to in writing by Plantex. Any additional
terms therein contained shall be deemed to be a proposed offer of amended terms
that shall be deemed rejected by Plantex and of no force or effect,
notwithstanding any action or inaction by Plantex other than its express written
approval of such additional terms.

6.     Section 14.2 of the Supply Agreement as amended is deleted in its
entirety and the following text is submitted in lieu thereof:

“Termination by PLANTEX. This Agreement may be terminated by PLANTEX on the
giving of thirty-six (36) months prior written notice in the event that either:
(i) a phase 3 Clinical Trial of a Finished Product has not been initiated on or
before December 31, 2006 (or thereafter discontinued prior to successful
completion), or (ii) FDA approval of Finished Product shall not have been
obtained by Novacea, Inc. on or before December 31, 2011.”

7.     Except as expressly set forth in this Amendment, the Supply Agreement
shall remain in full force and effect.

8.     This Amendment and the Supply Agreement, as amended by this Amendment,
constitute the entire agreement and understanding between the parties hereto and
supersede all prior negotiations, representation or agreements, whether written
or oral, relating to the subject matter hereof.

9.     The validity, performance and construction of this Amendment shall be
governed by, and construed in accordance with the laws of the State of New
Jersey, without regard to its choice of law or conflict of law rules.

 

[*] Certain information on this page has been omitted and filed separately with
the Securities and Exchange Commission. Confidential treatment has been
requested with respect to the omitted portions.

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10.   This Amendment may be executed in multiple counterparts, each of which
shall be deemed an original but all of which, taken together, shall constitute
one and the same instrument.

 

PLANTEX USA, INC.       NOVACEA, INC. F/K/A D-NOVO THERAPEUTICS, INC.

/s/    George Svokos

        /s/    John P. Walker

By: George Svokos

Its: President

     

By: John. P. Walker

Its: Chairman and Interim CEO

/s/    Allen Lefkowitz

     

By: Allen Lefkowitz

Its: CFO