Document:

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                                                                   Exhibit 10.01

                            THIRD AMENDMENT TO LEASE

     This Third Amendment to Lease (this "Amendment") is executed by and between
David E. Clem and David M. Roby, Trustees (the "Landlord") of 21 Erie Realty
Trust u/d/t dated May 16, 1996, recorded with the Middlesex South District
Registry of Deeds (the "Registry") in Book 26325, Page 504, as amended and
restated pursuant to an Amended and Restated Declaration of Trust dated May 26,
1999, recorded with the Registry in Book 30231, Page 306, and filed with the
Middlesex South Registry District of the Land Court as Document No. 1126128, and
Curis, Inc. ("Tenant"), a Delaware corporation, successor by merger to
Reprogenesis, Inc. ("Reprogenesis"), a Texas corporation, in amendment of a
Lease dated September, 1997 by and between Landlord and Reprogenesis, as amended
by First Amendment to Lease dated October 1, 1998 (the "First Amendment") by and
between Landlord and Reprogenesis and a Second Amendment to Lease dated June 29,
2000 (the "Second Amendment") by and between Reprogenesis and Landlord (as
amended by the First Amendment and the Second Amendment, the "Lease") with
respect to a portion of the building known as and numbered 21 Erie Street,
Cambridge, Massachusetts (the "Building").

     For good and valuable consideration, the receipt and legal sufficiency of
which is hereby acknowledged, Landlord and Tenant hereby agree as follows:

     1.  Each capitalized term which is used but not defined herein shall have
the respective meaning ascribed thereto in the Lease.

     2.  Commencing on the later of (a) August 28, 2000 and (b) the date on
which Landlord delivers the Third Additional Premises (as hereinafter defined)
to Tenant (the "Third Effective Date") and continuing through and including
December 31, 2007 (the "Third Additional Premises Term"), Landlord hereby leases
and demises to Tenant, and Tenant hereby leases from Landlord, premises
consisting of approximately 3,161 rentable square feet of space on the Second
Floor of the Building (the "Third Additional Premises"), which is more
particularly shown as "HELIOTROPE" on Exhibit A attached hereto and incorporated
herein by reference thereto.  If Landlord is unable to deliver possession of the
Third Additional Premises to Tenant on the Third Effective Date, Landlord shall
use commercially reasonable efforts to obtain possession of the Third Additional
Premises.  In such event, the Third Effective Date shall not occur until the
delivery of possession of the Third Additional Premises to Tenant by Landlord.
Such inability to deliver possession of the Third Additional Premises, however,
shall not affect the validity of this Amendment.

     3.  The second sentence of Section 2 of the Second Amendment and the second
sentence of Section 3 of the Second Amendment are hereby deleted in their
entirety.
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     4.  Commencing as of January 1, 2001 (the "Fourth Effective Date") and
continuing through and including December 31, 2007 (the "Fourth Additional
Premises Term"), Landlord hereby leases and demises to Tenant, and Tenant hereby
leases from Landlord, premises consisting of approximately 1,645 rentable square
feet of space on the Second Floor of the Building (the "Fourth Additional
Premises"), which is more particularly shown as "VERTEX" on Exhibit A attached
hereto and incorporated herein by reference thereto.  Within six months after
the Third Effective Date, Landlord shall have Landlord's architect measure the
Second Additional Premises, the Third Additional Premises and the Fourth
Additional Premises, based upon the BOMA method for measuring floor area in an
office building for a single tenant on such floor, but in no event shall such
measured floor areas be less than 9,318 rentable square feet, 3,161 rentable
square feet and 1,645 rentable square feet, respectively.

     5.  From and after the Third Effective Date, the term "Premises" as used in
the Lease shall be deemed to include the Third Additional Premises and, except
as set forth in this Amendment, the Third Additional Premises shall be subject
to all of the terms, covenants and conditions set forth in the Lease.  From and
after the Fourth Effective Date, the term "Premises" shall include the Fourth
Additional Premises and, except as set forth in this Amendment, the Fourth
Additional Premises shall be subject to all of the terms, covenants and
conditions set forth in the Lease.

     6.  Subject to Section 9 hereof, (i) during the Third Additional Premises
Term the Annual Base Rent Rate for the Third Additional Premises shall be $30.00
per rentable square foot (the "Third Additional Premises Annual Base Rent Rate")
and (ii) during the Fourth Additional Premises Term the Annual Base Rent Rate
for the Fourth Additional Premises shall be $30.00 per rentable square foot (the
"Fourth Additional Premises Annual Base Rent Rate").  Upon measurement of the
Second Additional Premises, the Third Additional Premises and the Fourth
Additional Premises, any overpayment by Tenant to Landlord of Annual Base Rent
or Annual Additional Rent for the Second Additional Premises, the Third
Additional Premises and the Fourth Additional Premises, respectively, shall be
credited to Annual Base Rent for the Premises and any underpayment of Annual
Base Rent and Annual Additional Rent for the Third Additional Premises and the
Fourth Additional Premises, respectively, shall be paid by Tenant to Landlord
within ten (10) days after written notice thereof.  Annual Base Rent and Annual
Additional Rent for the Third Additional Premises and the Fourth Additional
Premises shall be made in the same manner and at the same time as Annual Base
Rent and Annual Additional Rent for the remainder of the Premises.

     7.  The word "Share" set forth in Section 4 of the Second Amendment is
hereby deleted and the word "Fraction" is inserted in place thereof.  From and
after the Third Effective Date and the Fourth Effective Date, respectively, the
term "Tenant's Proportionate Fraction" set forth in Article I of the Lease shall
be determined by dividing the total rentable square footage of the Premises, as
determined from time to time, by the total rentable square footage of the
Building, as determined from time to time.

     8.  Each of the Third Additional Premises and the Fourth Additional
Premises shall be delivered to Tenant by Landlord on an "As Is, Where Is" basis
with all faults and without representation, warranty or guaranty of any kind by
Landlord to Tenant.

                                       2
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     9.  On the Adjustment Date (as defined in Section 4.1(b) of the Lease), the
Third Additional Premises Annual Base Rent Rate and the Fourth Additional
Premises Annual Base Rent Rate shall be increased by multiplying each of said
rates by a fraction, the numerator of which shall be the Price Index (as defined
in Section 4.1(b) of the Lease), and the denominator of which shall be the
Second Additional Premises Base Price Index (as defined in the Second
Amendment), compounded monthly over the then elapsed period of the Third
Additional Premises Term and the first two years of the Fourth Additional
Premises Term, respectively.

     10.  Simultaneously with the execution hereof, Tenant shall pay to Landlord
$15,805.00 representing the security deposit for the Third Additional Premises
(the "Third Additional Premises Security Deposit Amount").  On or before January
1, 2001, Tenant shall pay to Landlord $8,225.00 representing the security
deposit for the Fourth Additional Premises (the "Fourth Additional Premises
Security Deposit Amount").  Upon receipt of the Third Additional Premises
Security Deposit Amount and Fourth Additional Premises Security Deposit Amount,
respectively, references in the Lease to "Security Deposit Amount" shall include
the Security Deposit Amount, the Third Additional Premises Security Deposit
Amount and the Fourth Additional Premises Security Deposit Amount, all of which
shall be subject to all of the provisions of the Lease, including Section 10.11
thereof.

     11.  Each party warrants and represents to the other party that it has had
no dealings with any broker or agent in connection with this Third Amendment and
covenants to defend with counsel reasonably approved by such other party, hold
harmless and indemnify such other party from and against any and all cost,
expense or liability arising from any breach of the foregoing warranty and
representation.

     12  During the Third Additional Premises Term and the Fourth Additional
Premises Term, Tenant shall be entitled to lease that number of parking spaces
determined pursuant to Section 10.16 of the Lease at the fair market rent from
time to time established by Landlord.

     13.  The Lease, as amended hereby, is hereby ratified, confirmed and
approved in all respects.

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     WITNESS the execution hereof under seal as of the 31st day of July, 2000.

                    LANDLORD:

                              /s/ David E. Clem
                              ------------------------------------
                              David E. Clem, Trustee as aforesaid
                              and not individually

                              /s/ David M. Roby
                              ------------------------------------
                              David M. Roby, Trustee as aforesaid
                              and not individually

                    TENANT:

                              CURIS, INC.

                              By: /s/ James S. Sigler
                                  --------------------------------
                                 Title: Vice President, Manufacturing
                                        --------------------------
                                 hereunto duly authorized

                                       4<PAGE>

                                                                   EXHIBIT 10.02

  CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
               EXCHANGE COMMISSION.  ASTERISKS DENOTE OMISSIONS.

                        Amendment to License Agreement

                       Effective as of September 1, 2000

                          Re:  Harvard Cases 956; 963

President and Fellows of Harvard College (hereinafter, "HARVARD") and Ontogeny,
Inc., now Curis, Inc., by virtue of Ontogeny's merger into Curis, Inc. on July
31, 2000, (hereinafter, "LICENSEE") hereby amend the License Agreement which was
effective February 9, 1995, and amended effective February 9, 1995 and January
1, 1997, and assigned by Ontogeny, Inc. to Curis, Inc. (the "Agreement") as
follows:

1. After the fourth paragraph of page 1, to insert a paragraph to read:

     Whereas HARVARD and LICENSEE have entered in and are parties to a license
     agreement dated September 1, 2000 ("the 2000 License Agreement"),
     identified and reproduced in Appendix C, which confers to LICENSEE
     commercial rights to technology that may be related to the subject matter
     of PATENT RIGHTS; and

2. To modify Section 3.3(a) to read:

   3.3(a)  LICENSEE shall pay HARVARD during the term of this license a royalty
           of [**] percent ([**]%) of NET SALES of all ROYALTY PRODUCTS sold by
           LICENSEE and its AFFILIATES; provided, however, that in the case of
           ROYALTY PRODUCTS covered by a pending patent claim, such royalty of
           [**] percent ([**]%) shall be due and payable as follows: [**]
           percent ([**]%) shall be payable to HARVARD pursuant to Section
           4.4(a), and the remainder shall accumulate and shall not be required
           to be paid by LICENSEE to HARVARD unless and until such claim is
           issued as part of a patent in the applicable jurisdiction. A ROYALTY
           PRODUCT that is a ROYALTY PRODUCT solely as a result of any such
           claim that has been abandoned, has been rejected by an administrative
           agency from which no appeal can be taken or has been pending for more
           than five years in any jurisdiction shall cease to be a ROYALTY
           PRODUCT in such jurisdiction unless and until such claim is issued as
           part of a patent.
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  CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
               EXCHANGE COMMISSION.  ASTERISKS DENOTE OMISSIONS.

           In the event that a ROYALTY PRODUCT as contemplated in this Agreement
           is also a royalty product as defined in Section 1.8 of the 2000
           License Agreement ("2000 Royalty Product"), LICENSEE may reduce the
           royalty due to HARVARD on such ROYALTY PRODUCT by [**] percent
           ([**]%) of the royalty due to HARVARD on such 2000 Royalty Product as
           specified in Section 4.2(a) of the 2000 License Agreement. In no
           event shall the royalty due to HARVARD on such ROYALTY PRODUCT be
           reduced by more than [**] percent ([**]%) as a result of such
           reduction.

           In the event that a ROYALTY PRODUCT as contemplated in this Agreement
           is also a milestone product as defined in Section 1.5 of the 2000
           License Agreement ("2000 Milestone Product"), LICENSEE may reduce the
           royalty due to HARVARD on such ROYALTY PRODUCT to [**] percent
           ([**]%) of the royalty due to HARVARD on such ROYALTY PRODUCT.

3. To modify Section 3.3(b) to read:

   3.3(b)  If LICENSEE grants a sublicense under this Agreement to a sublicensee
           (other than an AFFILIATE) for development of a product in a field as
           to which LICENSEE or an AFFILIATE has committed or provides a written
           commitment to devote within the succeeding [**] ([**]) month period
           the resources equivalent to the full time of at least [**] of its own
           FTEs, [**] having an advanced scientific degree (a "Joint Field"),
           LICENSEE shall pay to HARVARD [**] percent ([**]%) of any royalties,
           fees or other amounts received by LICENSEE or its AFFILIATES as a
           result of the sublicensee's development and/or sale of ROYALTY
           PRODUCTS or MILESTONE PRODUCTS, excluding: (i) amounts paid in
           partial or full consideration of equity of LICENSEE or its
           AFFILIATES; (ii) amounts paid to fund research and development
           activities conducted by LICENSEE or its AFFILIATES; and (iii) non-
           monetary consideration, including, without limitation, intellectual
           property rights, noncompetition covenants and the like.

           If LICENSEE grants a sublicense under this Agreement to a sublicensee
           (other than an AFFILIATE) for development of a product in a field
           other than a Joint Field, LICENSEE shall pay to HARVARD [**] percent
           ([**]%) of any royalties, fees or other amounts received by the
           LICENSEE or its AFFILIATES as a result of the sublicensee's
           development and/or sale of ROYALTY PRODUCTS or MILESTONE PRODUCTS,
           excluding: (i) amounts paid in partial or full consideration of
           equity of LICENSEE or its AFFILIATES; (ii) amounts paid to fund
           research and development activities conducted by LICENSEE or its
           AFFILIATES; and (iii) non-monetary consideration,

                                                                               2
<PAGE>

  CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
               EXCHANGE COMMISSION.  ASTERISKS DENOTE OMISSIONS.

           including, without limitation, intellectual property rights,
           noncompetition covenants and the like.

           In the event a sublicense granted under this Agreement also includes
           a sublicense to patent rights contained in the 2000 License
           Agreement, then LICENSEE may reduce the royalty on sublicense income
           due in this Section to [**] percent ([**]%)]or [**] percent ([**]%),
           respectively.

           LICENSEE shall not grant a sublicense hereunder (other than to an
           AFFILIATE) pursuant to a transaction in which LICENSEE surrenders
           substantially all of its legal rights and economic interest in the
           PATENT RIGHTS and ROYALTY PRODUCTS to a third party in exchange for
           the transfer by such third party to LICENSEE of rights to a different
           technology or products.

4. To modify Section 3.3(e) to read:

   3.3(e)  In the case of MILESTONE PRODUCTS, LICENSEE shall pay the following
           payments and shall not pay the royalties specified in Section 3.3(a).
           Such payments are in recognition of LICENSEE's early and exclusive
           use of the licensed subject matter:

           Date of First Commercial Sale of    $[**]
           MILESTONE PRODUCT

           Cumulative Sales of MILESTONE       $[**]
           PRODUCT of $[**]

           Cumulative Sales of MILESTONE       $[**]
           PRODUCT of $[**]

           If this license is terminated by LICENSEE or its AFFILIATES, or is
           converted a non-exclusive license or terminated by HARVARD for a
           financial default, the above milestone payments shall still be due
           with respect to all MILESTONE PRODUCTS identified by LICENSEE or its
           AFFILIATES prior to such termination or conversion. If this license
           is converted to a non-exclusive license or terminated by HARVARD for
           any reason other than a financial default, the above milestone
           payments will be due on only the first MILESTONE PRODUCT sold after
           such termination or conversion and identified prior to such
           termination and conversion.

                                                                               3
<PAGE>

  CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
               EXCHANGE COMMISSION.  ASTERISKS DENOTE OMISSIONS.

           In the event that a MILESTONE PRODUCT as contemplated in this
           Agreement is also a 2000 Milestone Product, LICENSEE may reduce each
           milestone payment due to HARVARD on such MILESTONE PRODUCT by [**]
           percent ([**]%) of the corresponding milestone payment due to HARVARD
           on such 2000 Milestone Product as specified in Section 4.4(a) of the
           2000 License Agreement. In no event shall any milestone payment due
           to HARVARD on such MILESTONE PRODUCT be reduced by more than [**]
           percent ([**]%) as a result of such reduction.

           In the event that a MILESTONE PRODUCT as contemplated in this
           Agreement is also a 2000 Royalty Product, LICENSEE may reduce each
           milestone payment due to HARVARD on such MILESTONE PRODUCT to [**]
           percent ([**]%) of the milestone payment due to HARVARD on such
           MILESTONE PRODUCT.

   IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
   executed by their duly authorized representatives.

           President And Fellows                       Curis, Inc.
            of Harvard College

            s/s Joyce Brinton                     s/s  Bruce A. Leicher
--------------------------------------    -------------------------------------
         Joyce Brinton, Director                        Signature
        Office for Technology and
          Trademark Licensing
                                                     Bruce A. Leicher
                                          -------------------------------------
                                                           Name

             Sept. 11, 2000                 Vice President and General Counsel
         -----------------------          -------------------------------------
                  Date                                    Title

                                                    September 8, 2000
                                          -------------------------------------
                                                           Date

                                                                               4

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