Document:

<Page>

                                                                   Exhibit 10.18

                      FIRST AMENDMENT TO SECURITY AGREEMENT

     This First Amendment to Security Agreement (this "Amendment") is dated as
of October 15, 2003, by and between Dyax Corp. (the "Debtor") and Genzyme
Corporation (the "Secured Party").

     The following sets forth background information relevant to this Amendment:

     A.     Reference is hereby made to that certain Security Agreement dated as
of May 31, 2002, by the Debtor as debtor and the Secured Party as secured party
(the "Original Security Agreement"). Capitalized terms used in this Amendment
that are not otherwise defined herein shall have the meaning set forth in the
Original Security Agreement.

     B.     Debtor exercised the Surgical Product Option in Section 3.2 of the
Collaboration Agreement that is mentioned in Section 2(b) of the Original
Security Agreement, and accordingly, as provided in Section 2(b) of the Original
Security Agreement, the Additional Collateral was to become Collateral within
the meaning of the Original Security Agreement. Notwithstanding the foregoing,
Debtor has requested, and Secured Party has agreed, that Debtor may transfer to
a third party all of Debtor's right, title and interest in Biotage, Inc. and
therefore, such interests shall be no longer available to serve as Collateral.

     C.     Because of Debtor's transfer of the Shares of Biotage, Debtor and
Secured Party have agreed that Debtor shall grant to Secured Party the new
collateral pursuant to this Amendment.

     D.     Debtor and Secured Party wish to amend the Original Security
Agreement to, among other things, address the foregoing.

     NOW, THEREFORE, in consideration of the foregoing and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, Debtor and Secured Party hereby agree as follows:

     1.     AMENDMENTS TO SECURITY AGREEMENT.

            (a)     The term "Program" is deleted from Section 1 of the Original
     Security Agreement and is replaced by the following:

                    "'Program' means the Debtor's research, development,
            production and sales relating to human plasma Kallikrein inhibitors,
            including that certain 58-amino acid polypeptide human plasma
            Kallikrein inhibitor known as "DX-88" (formerly known as EPI-KAL-2)
            together with all analogs, homologs, derivatives and improvements
            related thereto; but specifically excludes the Debtor's research,
            development, production and sales relating to the use of human
            plasma Kallikrein inhibitors in connection with the reduction of
            blood loss and other effects of systemic inflammatory responses
            during surgery."

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            (b)     The following new term "Ladner Patents" is added to Section
     1 of the Original Security Agreement:

                    "'Ladner Patents' shall mean the patents and patent
            applications, owned or controlled by Debtor, listed on SCHEDULE C
            attached hereto and any and all foreign counterparts and any and all
            divisionals, continuations or continuations-in-part, reissues,
            renewals, reexaminations, extensions, substitutions, supplementary
            protection certificates and additions thereof."

            (c)     The following new term "Ladner Patent License Agreements" is
     added to Section 1 of the Original Security Agreement:

                    "'Ladner Patent License Agreements' shall mean license and
            similar agreements between Debtor and third parties, whether now
            existing or hereafter arising, under which (1) Debtor grants a
            license to such third parties under the Ladner Patents to practice
            phage display (the "Ladner Technology") to discover human
            antibodies, peptides and proteins; (2) the consideration received by
            Debtor is solely based upon the license granted to such third party
            to practice Ladner Technology; and (3) Debtor transfers no materials
            or technology (other than the Ladner Technology) to such third
            party, and Debtor performs no research or other services on behalf
            of such third party. A list of current Dyax Patent License
            Agreements is attached as Schedule D."

            (d)     The following new term "Records" is added to Section 1 of
     the Original Security Agreement:

                    "'Records' shall mean books, records, computer software,
            computer printouts, customer lists, manuals and similar items."

            (e)     Section 2 of the Original Security Agreement is deleted in
     its entirety and the following shall be substituted therefore:

            "2.     COLLATERAL. To secure the full and prompt payment and
            performance of the Obligations (as defined below), the Debtor grants
            the Secured Party a continuing security interest in all of the
            Debtor's right, title and interest in and to the following property,
            whether now owned or existing or hereafter acquired or arising:

                    (a)    all tangible and intangible personal property arising
                    from, related to or used in connection with the Program,
                    including, but not limited to, the following: (i) all goods,
                    accounts, and general intangibles (as those terms are
                    defined in the UCC), (ii) all Intellectual Property
                    including, but not limited to, the patents issued or
                    assigned to and all patent applications made by the Debtor
                    relating to human plasma Kallikrein inhibitors, including
                    that certain 58-amino acid polypeptide human plasma
                    Kallikrein inhibitor known as "DX-88" (formerly known as
                    EPI-KAL-2), including, without limitation, the patents,
                    patent applications and exclusive licenses listed on
                    SCHEDULE A hereto, but specifically excluding Intellectual
                    Property relating to the use of human plasma Kallikrein
                    inhibitors, including DX-88, in connection with the
                    reduction of blood loss and other effects of systemic
                    inflammatory

                                      - 2 -
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                    responses during surgery; (iii) all infringement claims with
                    regard to such Intellectual Property; and (iv) all rights to
                    revenue, income, profits, royalties, damages, licenses or
                    other rights related to such Intellectual Property;

                           (b)    (i) all accounts (as defined in the UCC)
                    arising from or related to the Ladner Patent License
                    Agreements and (ii) all rights to revenue, income, profits,
                    royalties, damages, licenses and other rights related to the
                    Ladner Patent License Agreements; and

                           (c)    all Records and all proceeds (as defined by
                    the UCC) and products of the foregoing set forth in
                    subsections (a) and (b) above (collectively, the
                    "COLLATERAL").

            Notwithstanding anything to the contrary, the Collateral shall not
            include any equipment."

            (f)     The Secured Party consents to Debtor's transfer of Biotage,
     Inc. Accordingly, (i) the fourth sentence of Section 4(a) of the Security
     Agreement is hereby deleted; (ii) Section 7(e) of the Original Security
     Agreement is hereby deleted; and (iii) references in the Original Security
     Agreement to the "Additional Collateral" shall be of no further force or
     effect.

            (g)     All references in the Security Agreement, as amended by this
     Amendment, to Schedule A, Schedule B, Schedule C and Schedule D, shall mean
     the Schedule A, Schedule B, Schedule C and Schedule D attached hereto.

            (h)     All references in the Note to the Security Agreement shall
     mean the Original Security Agreement, as amended by this Amendment.

     2.     REPRESENTATIONS AND WARRANTIES. Debtor hereby ratifies and confirms
all of the representations and warranties in the Original Security Agreement as
of the date of this Amendment and agrees that such representations and
warranties apply to the Debtor Collateral after giving effect to this Amendment.
Debtor hereby represents and warrants that as of the date of this Amendment, the
Collateral is free from any right or claim of any person or any Lien.

     3.     ADDITIONAL COVENANTS. The following shall be added as Section 7B. of
the Original Security Agreement:

            "7B.    NOTIFICATION TO ACCOUNT DEBTORS AND OTHER PERSONS OBLIGATED
     ON COLLATERAL. If an Event of Default shall have occurred and be
     continuing, the Debtor shall, at the request and option of the Secured
     Party, notify account debtors and other persons obligated on any of the
     Collateral of the security interest of the Secured Party in any account,
     general intangible, or other Collateral and that payment thereof is to be
     made directly to the Secured Party or to any financial institution
     designated by the Secured Party as the Secured Party's agent therefor, and
     the Secured Party may itself, if an Event of Default shall have occurred
     and be continuing, following five (5) business days written notice to
     Debtor, so notify account debtors and other persons obligated on
     Collateral. After the making of such a request or the giving of any such
     notification, the Debtor shall hold any proceeds of collection of accounts,
     general intangibles, and other Collateral received by the Debtor as trustee
     for the Secured Party without commingling

                                      - 3 -
<Page>

     the same with other funds of the Debtor and shall turn the same over to the
     Secured Party in the identical form received, together with any necessary
     endorsements or assignments. The Secured Party shall apply the proceeds of
     collection of accounts, general intangibles, and other Collateral received
     by the Secured Party to the Obligations, such proceeds to be immediately
     credited after final payment in cash or other immediately available funds
     for the items giving rise to them. Debtor irrevocably directs and requires
     all licensees and account debtors to honor Secured Party's request for
     direct payment and comply with any such request, notwithstanding any
     directions or instructions to the contrary that may be given by Debtor and
     agrees that the compliance by such licensee or account debtor with the
     provisions of this Section shall not be deemed a violation of such party's
     contractual agreements with Debtor."

     4.     SECURITY AGREEMENT; RATIFIED AND CONFIRMED. From and after the
effective date of this Amendment, the term "Security Agreement" shall mean the
Original Security Agreement, as amended by this Amendment. Except as expressly
amended hereby, the Security Agreement shall remain in full force and effect and
is hereby ratified and confirmed.

     5.     COUNTERPARTS. This Amendment may be executed in one or more
counterparts, each of which shall be deemed an original and all of which shall
constitute one and the same instrument.

     6.     CAPTIONS. The captions are headings in this Amendment are for
convenience only and in no way define, limit or describe the scope or intent of
any provisions or sections hereof.

     7.     GOVERNING LAW. This Amendment shall be governed by the laws of the
Commonwealth of Massachusetts.

     8.     SECURED PARTY'S EXPENSES. The Debtor agrees that it shall pay to the
Secured Party within twenty (20) days of the Secured Party's request, all legal
fees and expenses incurred by the Secured Party in connection with this
Amendment up to a maximum of $2,500.00.

     IN WITNESS WHEREOF, the parties have executed this Amendment under seal as
of the date first above written.

GENZYME CORPORATION                            DYAX CORP.

By: /s/ Richard Douglas                        By: /s/ Henry E. Blair
   -------------------------------------          ------------------------------
   Name: Richard Douglas                          Name: Henry E. Blair
   Title: SVP of Corporate Development            Title: Chairman & CEO

                                      - 4 -
<Page>

                                   SCHEDULE A

                                  DX-88 PATENTS

<Table>
<Caption>
                         APPLICATION
    COUNTRY                NUMBER              FILING DATE               STATUS
------------------  ---------------------  -------------------  ------------------------
<S>                 <C>                    <C>                  <C>
     U.S.                08/179,964              1/11/94        ABANDONED IN FAVOR OF US
                                                                        08/208,264

   U.S. CIP              08/208,264              3/10/94              U.S. 6,057,287
                                                                      ISSUED 5/20/00

   U.S. CIP              08/676,125              9/25/96             U.S. 5,795,865
                                                                      ISSUED 8/18/98

U.S. CIP - DIV           09/136,012              8/17/98              U.S. 5,994,125
                                                                     ISSUED 11/30/99

U.S. CIP - DIV           09/421,097             10/19/99              U.S. 6,333,402
                                                                     ISSUED 12/25/01

U.S. CIP - DIV           10/016,329             10/26/01                 PENDING

    CANADA               2,180,950               1/11/95                 PENDING

      EPO               95/909223.0              1/11/95                 PENDING
                    PUBLISHED EP0739355    PUB. DATE: 10/30/96

    JAPAN               518726/1995              1/11/95                 PENDING
                    PUBLISHED JP9-511131   PUB. DATE: 11/11/97

     PCT                  US95/00299             1/11/95              NATIONAL PHASE
                     PUBLISHED WO95/21601  PUB. DATE: 8/17/95
</Table>

                                      - 5 -
<Page>

                                   SCHEDULE B

Existing Indebtedness:
---------------------

Capital Lease Obligations
-------------------------

Master Lease Agreement between General Electric Capital Corporation and Dyax
Corp. (indebtedness under lease line as of September 30, 2003 of $2,559)

Master Lease Agreement between Transamerica Business Credit Corporation and
Dyax Corp. (indebtedness under lease line as of September 30, 2003 of
$534,965)

Master Lease Agreement between Dyax SA and Locabel (indebtedness under lease
line as of September 30, 2003 of Eur 1,204,521)

Master Lease Agreement between Access National and Biotage Inc. (indebtedness
under lease line as of September 30, 2003 of $167,667)

Capital Lease for equipment in the Netherlands (indebtedness under lease line
as of September 30, 2003 of Eur 94,121)

Various capital leases with Dell Computer Leasing (indebtedness under lease
lines as of September 30, 2003 of $32,948)

Other Debt
----------

Loan obligation of Massachusetts Institute of Technology to Dyax Corp. under
Lease Agreement to loan up to $35 per rentable square foot to fund portion of
Tenant's Work (indebtedness under loan as of September 30, 2003 of $2,179,747)

Promissory note to Virginia National Bank given by Biotage Real Estate LLC to
Industrial Development Authority of Albermarle County, Virginia to fund land
acquisition and construction of new facility for Biotage, Inc. (indebtedness
under note as of September 30, 2003 of $4,232,087)

Promissory note to Virginia National Bank to fund the purchase of fixed
assets (indebtedness under note as of September 30, 2003 of $331,083)

Existing Liens:
--------------

Letter of Credit for benefit of Massachusetts Institute of Technology
($4,279,932) to secure obligations under Lease Agreement for 300 Technology
Square

All Equipment acquired pursuant to Master Lease Agreements and other lease
agreements under 6 Existing Capital Lease Obligations listed above

Real Estate located in Albermarle County, Virginia to secure obligations
under Promissory Note held by Virginia National Bank

                                      - 6 -
<Page>

                                   SCHEDULE C

                                 LADNER PATENTS

<Table>
<Caption>
             APPLICATION/                      PATENT      ISSUE
COUNTRY        PATENT NO.        FILING DATE   NO.         DATE/STATUS
-----------  ------------------  ------------  ----------  --------------
<S>          <C>                 <C>           <C>         <C>
US           07/664,989          3/1/91        5,223,409   6/29/93

US           08/009,319          1/26/93       5,403,484   4/4/95

US           08/057,667          6/18/93       5,571,698   11/5/96

US           08/415,922          4/3/95        5,837,500   11/17/98

US           Div. of 08/415,922  02/14/01                  Pending

US           Div of 08/415,922   03/05/01                  Pending

US           Div of 08/415,922   06/29/01                  Pending

US           Div of 08/415,922   06/29/01                  Pending

US           Div of 08/415,922   04/22/02                  Pending

US           Div of 08/415,922   04/22/02                  Pending

PCT          US89/03731          9/1/89                    National Phase
             W09002809 pub       3/22/90

EPO          96/112867.5         9/1/89                    Pending
             0 768 377 pub       4/16/97 pub

EPO          00/106289.2         9/1/89                    Pending
             1 026 240 pub       9/8/00 pub

Japan        89510087            9/1/89                    Pending
             JP4502700 (pub)     5/21/92

Canada       610,176             9/1/89        1,340,288   1/27/99

Ireland      IR89/2834           9/4/89                    Pending

Israel       91501               9/1/89        91501       6/11/98

Israel       3 Divisionals       5/29/97                   Pending

PCT          US92/01456          2/27/92                   National Phase
             W09215677 (pub)     9/17/92

EPO          92/908057.0         2/27/92                   Pending

Canada       2105300             2/27/92                   Pending

Japan        92507558            2/27/92                   Pending

PCT          WO9215679           2/28/92                   National Phase

EP           92/908799.7         2/28/92                   Pending

Japan        92508216            2/28/92                   Pending
</Table>

                                      - 7 -
<Page>

                                   SCHEDULE D

                        LADNER PATENT LICENSE AGREEMENTS

<Table>
<Caption>
COMPANY                                                    EFFECTIVE DATE
<S>                                                           <C>
Affibody Technology                                           4/27/2001
Affimed                                                       8/10/2003
Affymax                                                       7/25/2001
Alexion Antibody Technologies                                 8/31/1999
Amersham Biosciences (Research Kits)                          6/30/1997
Amersham Biosciences (Affinity Separations)                   10/1/2001
Amgen                                                         2/2/2000
Ambit (formerly Aventa Biosciences)                           6/27/2001
AVIVA Antibody Corp.                                          12/20/2001
Bayer                                                         8/31/1999
BioInvent                                                     1/1/2000
Biosite Diagnostics                                           6/1/1998
Burnham Institute, The                                        7/1/1996
Cambridge Antibody Technology                                 12/31/1997
Corvas International, Inc.                                    6/30/1996
Crucell                                                       3/10/1997
Cubist Pharmaceuticals, Inc.                                  7/20/1998
Domantis                                                      2/16/2002
DuPont-Merck Corporation                                      12/31/1996
DuPont De Nemours and Company                                 10/14/2003
Genencor International                                        12/13/2002
Genentech                                                     9/19/2002
Genzyme Corporation                                           3/29/1996
Glaxo SmithKline                                              6/28/1996
GPC-Biotech                                                   3/17/1999
Idexx Laboratories                                            10/2/2000
IGEN International                                            12/31/1996
Invitrogen                                                    4/28/1997
J&J/Ortho-Clinical Diagnostics                                3/9/1998
Karo Bio                                                      3/31/1999
K&P Labs                                                      8/9/2002
Merck                                                         3/31/1996
Micromet AG                                                   10/30/2000
Millennium Biotherapeutics                                    12/31/1997
MoBiTec                                                       12/31/1998
Morphosys                                                     10/4/1996
New England Biolabs                                           3/1/1997
Novagen                                                       10/1/1996
Phage Screen Inc.                                             1/1/1999
Pharmacia Corporation                                         5/30/1997
Praecis Pharmaceuticals Inc.                                  3/30/1996
Promega Corporation                                           7/10/1998
J&J Pharmaceutical Research and Development                   9/30/1997
Stratagene                                                    3/15/1998
</Table>

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Exhibit 4.13  

 

QWEST COMMUNICATIONS INTERNATIONAL INC.,

Issuer  

 QWEST SERVICES CORPORATION,

Guarantor  

 QWEST CAPITAL FUNDING, INC.

Guarantor  

 And  

 DEUTSCHE BANK TRUST COMPANY AMERICAS,

Trustee  

 FIRST SUPPLEMENTAL INDENTURE  

 Dated as of December 26, 2002  

7.50% Senior Notes Due 2008 

 

  

 
 

FIRST SUPPLEMENTAL INDENTURE    
    

        This FIRST SUPPLEMENTAL INDENTURE, dated as of December 26, 2002 (the "Supplemental Indenture"), is by and
between: 

        QWEST
COMMUNICATION INTERNATIONAL INC., a corporation duly organized and existing under the laws of the State of Delaware (the
"Company"); 

        QWEST
SERVICES CORPORATION, a corporation duly organized and existing under the laws of the State of Colorado ("QSC"); 

        QWEST
CAPITAL FUNDING, INC., a corporation duly organized and existing under the laws of the State of Colorado, ("QCF"); and 

        DEUTSCHE
BANK TRUST COMPANY AMERICAS (formerly known as Bankers Trust Company), a banking corporation organized under the laws of the State of New York, as trustee (in such capacity,
together with it successors in such capacity, the "Trustee"). 

PRELIMINARY STATEMENT  

        The Company and the Trustee are parties to that certain Indenture dated as of November 4, 1998 (the
"Indenture") pursuant to which the following notes (the "Notes") are issued and outstanding: 7.50%
Senior Notes due 2008 and 7.50% Series B Senior Notes due 2008. 

        QSC
has entered into that certain Indenture, dated as of the date hereof, by and among QSC, the Guarantors named therein, including QCF, and Bank One Trust Company, N.A., as trustee (the
"New QSC Indenture"), pursuant to which the following notes will be issued on the date hereof: (i) 13% Senior Subordinated Secured Notes due
2007, Series A, (ii) 131/2% Senior Subordinated Secured Notes due 2010, Series A, and (iii) 14% Senior Subordinated Secured Notes due 2014, Series A
(all such notes and
any additional notes that may be issued under the New Indenture, collectively referred to as the "New QSC Notes"). 

        The
New QSC Indenture provides that QSC shall issue the New QSC Notes and such notes shall be guaranteed by the Company and QCF. Due to issuance of the New QSC Notes and the guarantees
thereto and pursuant to Section 10.16 of the Indenture, the Company is required to simultaneously execute and deliver a supplemental indenture to the Indenture providing for a guarantee of the
Notes by QSC and QCF. 

        The
Company and the Trustee desire to modify and amend the Indenture to the extent and as set forth in this Supplemental Indenture. 

        The
Company and the Trustee are duly authorized pursuant to Section 9.01 of the Indenture to execute and deliver this Supplemental Indenture and to modify and amend the Indenture
as provided herein. 

        All
things necessary to make this Supplemental Indenture a valid agreement of each of the Company, QSC, QCF and the Trustee in accordance with its terms have been done. 

ARTICLE 1

AMENDMENTS TO INDENTURE  

        Section 1.1 Addition of Definitions to Section 1.01. Section 1.01 of the Indenture is hereby
amended by inserting the following definition, which shall be inserted in alphabetical order: 

        "Note Guarantee" means, in respect of any Guarantor, the unconditional guarantee by such Guarantor of the Company's Obligations
under the Notes. 

1

 

        Section 1.2  Addition of Article Thirteen to Indenture. The Indenture is hereby amended by inserting Article Thirteen
with the following language: 

ARTICLE THIRTEEN  

NOTES GUARANTEES  

        SECTION 13.01 Notes Guarantees. Each Guarantor hereby jointly and severally unconditionally and irrevocably
guarantees as a primary obligor and not merely as a surety, to each Holder and to the Trustee and its successors and assigns (a) the full and punctual payment of principal of, premium, if any,
and interest, on the Securities when due, whether at maturity, by acceleration, by redemption or otherwise, subject to any applicable grace period, and all other monetary obligations of the Company
under this Indenture (including obligations to the Trustee) and the Securities and (b) the full and punctual performance within applicable grace periods of all other Obligations of the Company
whether for expenses, indemnification or otherwise under this Indenture and the Securities (all of the foregoing being hereinafter collectively called the "Guaranteed
Obligations"). Each Guarantor further agrees that the Guaranteed Obligations may be extended or renewed, in whole or in part, without notice or further assent from each such
Guarantor, and that each such Guarantor shall remain bound under this Article Thirteen notwithstanding any extension or renewal of any Guaranteed Obligation. 

        Each
Guarantor waives presentation to, demand of, payment from and protest to the Company of any of the Guaranteed Obligations and also waives notice of protest for nonpayment. Each
Guarantor waives notice of any default under the Securities or the Guaranteed Obligations. The obligations of each Guarantor hereunder shall not be affected by (a) the failure of any Holder or
the Trustee to assert any claim or demand or to enforce any right or remedy against the Company or any other Person under this Indenture, the Securities or any other agreement or otherwise;
(b) any extension or renewal of any Guaranteed Obligations; (c) any rescission, waiver, amendment or modification of any of the terms or provisions of this Indenture, the Securities or
any other agreement; (d) the release of any security held by any Holder or the Trustee for the Guaranteed Obligations or any of them; (e) the failure of any Holder or Trustee to exercise
any right or remedy against any other guarantor of the Guaranteed Obligations; or (f) any change in the ownership of such Guarantor. 

        Each
Guarantor further agrees that its Note Guarantee herein constitutes a Guarantee of payment, performance and compliance when due (and not a guarantee of collection) and waives
any right to require that any resort be had by any Holder or the Trustee to any security held for payment of the Guaranteed Obligations. 

        The
obligations of each Guarantor hereunder shall not be subject to any reduction, limitation, impairment or termination for any reason, including any claim of waiver, release,
surrender, alteration or compromise, and shall not be subject to any defense of setoff, counterclaim, recoupment or termination whatsoever or by reason of the invalidity, illegality or
unenforceability of the Guaranteed Obligations or otherwise. Without limiting the generality of the foregoing, the obligations of each Guarantor herein shall not be discharged or impaired or otherwise
affected by the failure of any Holder or the Trustee to assert any claim or demand or to enforce any remedy under this Indenture, the Securities or any other agreement, by any waiver or modification
of any thereof, by any default, failure or delay, willful or otherwise, in the performance of the Guaranteed Obligations, or by any other act or thing or omission or delay to do any other act or thing
which may or might in any manner
or to any extent vary the risk of any Guarantor or would otherwise operate as a discharge of any Guarantor as a matter of law or equity. 

        Each
Guarantor further agrees that its Note Guarantee herein shall continue to be effective or be reinstated, as the case may be, if at any time payment, or any part thereof, of
principal of or interest on any Guaranteed Obligation is rescinded or must otherwise be restored by any Holder or the Trustee upon the bankruptcy or reorganization of the Company or otherwise. 

2

 

        In
furtherance of the foregoing and not in limitation of any other right which any Holder or the Trustee has at law or in equity against any Guarantor by virtue hereof, upon the failure
of the Company to pay the principal of or interest or premium, if any, on any Guaranteed Obligation when and as the same shall become due, whether at maturity, by acceleration, by redemption or
otherwise, or to perform or comply with any other Guaranteed Obligation, each Guarantor hereby promises to and shall, upon receipt of written demand by the Trustee, forthwith pay, or cause to be paid,
in cash, to the Holders or the Trustee an amount equal to the sum of (i) the unpaid principal amount of such Guaranteed Obligations, (ii) accrued and unpaid interest, premium, if any, on
such Guaranteed Obligations (but only to the extent not prohibited by law) and (iii) all other monetary Guaranteed Obligations of the Company to the Holders and the Trustee. 

        Each
Guarantor agrees that it shall not be entitled to any right of subrogation in relation to the Holders in respect of any Guaranteed Obligations guaranteed hereby until payment in
full of all Guaranteed Obligations. Each Guarantor further agrees that, as between it, on the one hand, and the Holders and the Trustee, on the other hand, (x) the maturity of the Guaranteed
Obligations guaranteed hereby may be accelerated as provided in Article Five for the purposes of any Note Guarantee herein, notwithstanding any stay, injunction or other prohibition
preventing such acceleration in respect of the Guaranteed Obligations guaranteed hereby, and (y) in the event of any declaration of acceleration of such Guaranteed Obligations as provided in
Article Five, such Guaranteed Obligations (whether or not due and payable) shall forthwith become due and payable by such Guarantor for the purposes of this Section. 

        Each
Guarantor also agrees to pay any and all costs and expenses (including reasonable attorneys' fees and expenses) incurred by the Trustee or any Holder in enforcing any rights under
this Section. 

        SECTION
13.02 Limitation on Liability; Release. Any term or provision of this Indenture to the contrary notwithstanding, the maximum,
aggregate amount of the obligations guaranteed hereunder by any Guarantor shall not exceed the maximum amount that can be guaranteed without rendering this Indenture, as it relates to any Guarantor,
voidable under applicable law relating to fraudulent conveyance or fraudulent transfer or similar laws affecting the rights of creditors generally. 

        SECTION
13.03 Successors and Assigns. This Article Thirteen shall be binding upon each Guarantor and its successors and assigns and
shall ensure to the benefit of the successors and assigns of the Trustee and the Holders and, in the event of any transfer or assignment of rights by any Holder or the Trustee, the rights and
privileges conferred upon that party in this Indenture and in the Securities shall automatically extend to and be vested in such transferee or assignee, all subject to the terms and conditions of this
Indenture. 

        SECTION
13.04 No Waiver. Neither a failure nor a delay on the part of either the Trustee or the Holders in exercising any right, power or
privilege under this Article Thirteen shall operate as a waiver thereof, nor shall a single or partial exercise thereof preclude any other or further exercise of any right, power or privilege.
The rights, remedies and benefits of the Trustee and the Holders herein expressly specified are cumulative and not exclusive of any other rights, remedies or benefits which either may have under this
Article Thirteen at law, in equity, by statute or otherwise. 

        SECTION
13.05. Modification. No modification, amendment or waiver of any provision of this Article Thirteen, nor the consent to any
departure by any Guarantor therefrom, shall in any event be effective unless the same shall be in writing and signed by the Trustee, and then such waiver or consent shall be effective only in the
specific instance and for the purpose for which given. No notice to or demand on any Guarantor in any case shall entitle such Guarantor to any other or further notice or demand in the same, similar or
other circumstances. 

        SECTION
13.06. Evidence of Guarantee. To evidence their guarantees to the Holders set forth in this Article Thirteen, each of the
Guarantors hereby agrees to execute the notation of Note Guarantee 

3

 

in
substantially the form included in Exhibit A. Each such notation of Note Guarantee shall be signed on behalf of each Guarantor by an
Officer. 

        Each
Guarantor hereby agrees that its Note Guarantee set forth in Section 13.01 shall remain in full force and effect notwithstanding any failure to endorse on each
Note a notation of such Note Guarantee. 

        If
an Officer whose signature is on this Indenture or on the Note Guarantee no longer holds that office at the time the Trustee authenticates the Note on which a
Note Guarantee is endorsed, the Note Guarantee shall be valid nevertheless. 

ARTICLE 2

MISCELLANEOUS  

        Section 2.1 Definitions. Capitalized terms used and not otherwise defined in this Supplemental Indenture
shall have the meaning ascribed thereto in the Indenture. 

        Section 2.2  Indenture in Full Force and Effect. Except to the extent expressly modified or amended by this Supplemental Indenture,
the Indenture and all of its covenants, agreements and other provisions remain in full force and effect, and are unchanged by this Supplemental Indenture. 

        Section 2.3
Effect of Heading. The Article and Section headings herein are for convenience only and shall not affect
the construction hereof. 

        Section 2.4  Successors and Assigns. All covenants and agreements in this Supplemental Indenture by the Company, QSC and QCF shall
bind their respective successors and assigns, whether so expressed or not. 

        Section 2.5
Separability. In case any provision in this Supplemental Indenture shall be invalid, illegal or unenforceable, the
validity, legality, and enforceability of the remaining provisions shall not in any way be affected or impaired thereby. 

        Section 2.6
Benefits of Supplemental Indenture. Nothing in this Supplemental Indenture, expressed or implied, shall give to any
Person, other than the parties hereto and their successors hereunder, and the Noteholders, any benefit or any legal or equitable right, remedy or claim under this Supplemental Indenture or the
Indenture. 

        Section 2.7
Governing Law. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAW OF THE STATE
OF NEW YORK. 

4

   
        IN WITNESS WHEREOF, we have set our hands on this Supplemental Indenture as of the 26th day of December 2002. 

	

 	
 	
QWEST COMMUNICATIONS INTERNATIONAL INC., as Issuer
	

 	
 	

By:	
 	

 Name:

Title:
	

 	
 	
QWEST SERVICES CORPORATION, as Guarantor
	

 	
 	

By:	
 	

 Name:

Title:
	

 	
 	
QWEST CAPITAL FUNDING, INC., as Guarantor
	

 	
 	

By:	
 	

 Name:

Title:
	

 	
 	
DEUTSCHE BANK TRUST COMPANY AMERICAS, as Trustee
	

 	
 	

By:	
 	

 Name:

Title:

S-1

   Exhibit A  

Form of
Note Guarantee 

A-1

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FIRST SUPPLEMENTAL INDENTURE

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