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                                                                    EXHIBIT 4.19

(AMGEN LOGO)


       AMENDED AND RESTATED FREESTANDING DIALYSIS CENTER AGREEMENT NO. 200308358
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     The undersigned hereby agree to amend and restate Freestanding Dialysis
Center Agreement No. 200308358 (the "Agreement"), between Amgen USA Inc.
("Amgen"), a wholly-owned subsidiary of Amgen Inc., and National Medical Care,
Inc., including all subsidiaries and affiliates that are at least fifty and
one-tenth percent (50.10%) owned by National Medical Care, Inc. and listed on
Appendix B, (collectively, "NMC"), including all prior amendments thereto, as
stated below.

     WHEREAS, Amgen and NMC entered into Freestanding Dialysis Center Agreement
No. 200308358 effective January 1, 2004 (including all prior amendments thereto,
the "Original Agreement");

     WHEREAS, the Agreement sets forth the terms and conditions for the purchase
of EPOGEN(R) (Epoetin alfa) and Aranesp(R) (darbepoetin alfa) (collectively,
"Products") by NMC, exclusively for the treatment of dialysis patients.

     WHEREAS, the parties wish to amend and restate the Original Agreement to
modify the term of that agreement, offer a Commitment Incentive for the period
Amended Date through December 31, 2004, modify rebate programs for the period
January 1, 2005 through December 31, 2005, and offer new rebate programs for the
period January 1, 2005 through December 31, 2005.

     NOW, THEREFORE, in consideration of the premises and the mutual promises
and undertakings herein contained, the parties hereto agree as follows:

     SECTION 1.  AMENDMENT AND RESTATEMENT OF THE GENERAL TERMS AND CONDITIONS
-- THE GENERAL TERMS AND CONDITIONS OF THE ORIGINAL AGREEMENT SHALL BE AMENDED
AND RESTATED IN THEIR ENTIRETY EFFECTIVE AS FOLLOWS ON DECEMBER 1, 2004 PROVIDED
NMC EXECUTES THIS AMENDED AGREEMENT ON OR BEFORE DECEMBER 1, 2004 ("AMENDED
DATE"). IF NMC EXECUTES THIS AMENDED AGREEMENT AFTER DECEMBER 1, 2004, THE
AMENDED DATE SHALL BE THE DATE ON WHICH THE PARTY LAST TO EXECUTE THIS AMENDED
AGREEMENT HAS EXECUTED THIS AMENDED AGREEMENT. THIS AMENDED AND RESTATED
AGREEMENT SHALL SUPERSEDE AND REPLACE IN ITS ENTIRETY THE ORIGINAL AGREEMENT
INCLUDING ALL AMENDMENTS, EXHIBITS AND APPENDICES THERETO.

          1.  TERM OF AGREEMENT.  The "Term" of this Agreement shall be defined
     as January 1, 2004 ("Commencement Date") through December 31, 2005
     ("Termination Date").

          2.  QUALIFIED PURCHASES.  All terms contained herein apply only to
     purchases made hereunder, as confirmed by Amgen ("Qualified Purchases"), by
     NMC and, subject to the terms of Section 11, all Affiliates (as such term
     is defined in Section 11 below) opened, acquired, or managed by NMC during
     the Term, for so long as such Affiliates remain at least fifty and
     one-tenth percent (50.10%) owned or managed by National Medical Care, Inc.,
     through wholesalers chosen by NMC and authorized by Amgen to participate in
     the program ("Authorized Wholesalers") or directly from Amgen. In addition,
     and also subject to the terms of Section 11, Renaissance Health Care, Inc.,
     Optimal Renal Care, L.L.C., Integrated Renal Care of the Pacific, LLC
     and/or any joint venture of NMC in which NMC holds at least a fifty and
     one-tenth percent (50.10%) ownership interest, will also be eligible to
     participate, although not required to purchase under this Agreement. Amgen
     agrees to reasonably approve Authorized Wholesalers requested by NMC. The
     option to purchase on a direct basis from Amgen is subject to receipt and
     approval, not to be unreasonably withheld, of an "Application for Direct
     Ship Account".

          3.  PRICING.  See Appendix A.

          4.  PAYMENT TERMS.  The terms and conditions of this Agreement shall
     apply whether NMC and/or Affiliates purchase Products through an Authorized
     Wholesaler or from Amgen directly.

          5.  DISCOUNT.  NMC shall qualify for discounts and incentives subject
     to material compliance with the terms and conditions of this Agreement as
     well as the schedules and terms set forth in Appendix A.

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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
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     Discounts in arrears will be paid by Amgen in the form of a [*] to NMC's
     corporate headquarters, and Amgen Inc. hereby guarantees Amgen's obligation
     to pay all discounts earned by NMC hereunder. Discounts in arrears will be
     calculated in accordance with the terms set forth in Appendix A. For
     purposes of all of the discounts paid in arrears contained herein,
     including, without limitation, those discounts and incentives provided in
     Appendix A, if any Affiliates are added to or deleted from this Agreement
     during any quarter, Amgen shall appropriately adjust NMC's purchases for
     the relevant periods (i) for deleted Affiliates, by excluding purchases by
     such Affiliates effective from the effective date of their deletion and
     during the relevant quarter used for comparison, or (ii) for added
     Affiliates, by including any purchases made by acquired Affiliates
     effective from the date they are added to the list of Affiliates on
     Appendix B and during the relevant quarter used for comparison, and by
     including any purchases made by any de novo Affiliates commencing in the
     quarter in which they commence operations. Amgen and NMC agree that, for
     purposes of determining eligibility for and calculation of all discounts
     and all incentives provided in this Agreement (including, without
     limitation, all discounts and incentives as are set forth in Appendix A), a
     Qualified Purchase of EPOGEN(R) or Aranesp(R) shall be deemed made on the
     date of invoice to NMC from an Authorized Wholesaler. Upon any termination
     of this Agreement, Amgen shall pay to NMC all discounts and incentives
     earned by NMC through the date of termination. Failure of NMC to qualify
     for or receive any particular discount or incentive hereunder shall not
     automatically affect its qualification for or receipt of any other discount
     or incentive provided under this Agreement.

          6.  PAYMENT OF DISCOUNTS.  Any discount (hereinafter defined as
     including a discount at time of purchase, rebate, incentive or other
     concession impacting the total pricing of a Product) earned hereunder which
     is applicable to purchases of EPOGEN(R) shall be calculated in accordance
     with this Agreement, based on Qualified Purchases, using the [*] as the
     basis for the calculation price, and shall be paid in the form of a [*] to
     NMC's corporate headquarters, except as otherwise provided hereunder. Any
     discount earned hereunder which is applicable to purchases of Aranesp(R)
     used to treat dialysis patients shall be calculated in accordance with this
     Agreement, based on Qualified Purchases, using the [*] as the basis for the
     calculation price. NMC and Affiliates shall make available to Amgen any
     records concerning NMC's and Affiliates' purchase amounts that Amgen or its
     auditors may reasonably request for purposes of verifying discounts. Amgen
     shall make available to NMC any records concerning NMC's and Affiliates'
     purchase amounts that NMC or its auditors may reasonably request for
     purposes of verifying discounts. In the event of a discrepancy between data
     provided by NMC and that provided by an Authorized Wholesaler, verifiable
     data submitted by NMC shall be used. Amgen will use its best efforts to
     make any discount (excluding discounts at time of purchase) pursuant to
     this Agreement available in accordance with the terms referenced in
     Appendix A. Availability of discounts is contingent upon Amgen receiving
     all relevant purchase data from all Authorized Wholesalers designated by
     NMC, in a form reasonably acceptable to Amgen, detailing NMC's and
     Affiliates' Qualified Purchases of Products for the relevant period, along
     with any other data required by the terms of Appendix A. In the event of
     any purchases directly from Amgen, all such purchase data shall be included
     in the calculation of all discounts. In no event shall Amgen pay any
     discount on Products distributed by NMC or Affiliates to non-Affiliates of
     NMC. In the event that Amgen is notified in writing that National Medical
     Care, Inc. and/or any of its subsidiaries or Affiliates (the "Acquiree") is
     acquired by another entity or a change of control otherwise occurs with
     respect to the Acquiree, any discount or rebate which may have been earned
     and vested hereunder prior to the effective date of the acquisition shall
     be paid in the form of a [*] to Fresenius Medical Care North America's
     corporate headquarters subject to the conditions described herein.

          7.  TREATMENT OF DISCOUNTS.  (a) The parties agree that they will
     account for any discount or rebate earned hereunder in a way that complies
     with all applicable federal, state, and local laws and regulations,
     including without limitation, Section 1128B(b) of the Social Security Act
     and its implementing regulations, and if required by such statutes or
     regulations (1) claim the benefit of such discount received, in whatever
     form, in the fiscal year in which such discount was earned or the year
     after, (2) fully and accurately report the value of such discount in any
     cost reports filed under Title XVIII or Title XIX of the Social Security
     Act,

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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
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     or a state health care program, and (3) provide, upon request by the U.S.
     Department of Health and Human Services or a state agency or any other
     federally funded state health care program, the information furnished by
     Amgen concerning the amount or value of such discount. NMC agrees that it
     will advise all Affiliates, in writing, of any discount received by NMC's
     corporate headquarters hereunder with respect to purchases made by such
     Affiliates and that NMC will advise said Affiliates as to their requirement
     under the Agreement to account for any such discount in accordance with the
     above stated requirements.

             (b) In order to assist NMC in its compliance with its obligations
        as set forth in Section 7(a) immediately above, Amgen agrees that, along
        with the quarterly delivery of its payment of the discounts earned
        hereunder, it will provide to NMC on a quarterly basis a statement
        stating the incentives and discounts earned by NMC for such quarter.

          8.  [*]

          9.  OWN USE.  NMC hereby certifies that Products purchased hereunder
     will be for the "own use" by NMC and the Affiliates of NMC. NMC hereby
     further certifies that all of the Products purchased hereunder shall be for
     the exclusive use of treating dialysis patients.

          10.  AUTHORIZED WHOLESALERS.  A complete list of NMC's and Affiliates'
     current Authorized Wholesalers, through which NMC and Affiliates may
     purchase Products hereunder is attached as Appendix C. NMC and Affiliates
     agree to promptly provide Amgen with any additions, deletions, or changes
     to the initial list of Authorized Wholesalers. Amgen requires no less than
     thirty (30) days notice before the effective date of change for any
     addition or deletion by NMC of Authorized Wholesalers hereunder. Any
     proposed changes by NMC to the initial list of Authorized Wholesalers must
     be in writing by NMC and are subject to reasonable approval by Amgen.

          11.  SUBSIDIARIES AND AFFILIATES.  Attached as Appendix B is a current
     listing of all Affiliates, and other entities, that will be participating
     in this Agreement, designating which affiliates are owned and/or managed by
     NMC. Affiliates listed in Appendix B, as so designated by NMC and approved
     by Amgen, will be deemed "Affiliates" for the purposes of this Agreement.
     Subsequent to approval and acceptance by Amgen, a list of Affiliates shall
     be attached to this Agreement as Appendix B and incorporated herein. Only
     those Affiliates approved by Amgen and referenced in Appendix B will be
     eligible to participate under this Agreement. Any NMC managed Affiliate, or
     other entity with an existing contract, may participate in either their
     existing agreement with Amgen, or this Agreement, but not both. Each
     managed Affiliate or entity must declare under which single Amgen contract
     it will participate. Only Qualified Purchases under this Agreement will be
     used in the calculation of pricing, discounts or other incentives under
     this Agreement. NMC will notify Amgen monthly of changes to Appendix B.,
     and the effective date of change. Such effective date of change may not be
     earlier than the date the notice is received by Amgen. Any proposed change
     to Appendix B will be subject to the reasonable approval of Amgen based
     upon Amgen's then current legal and contractual requirements, and such
     proposed Affiliate's classification as a freestanding dialysis center or a
     home dialysis support facility.

          12.  TERMINATION.  If either party materially breaches this Agreement
     the other party may terminate this Agreement upon thirty (30) days advance
     written notice specifying the breach, provided that such breach remains
     uncured at the end of the thirty (30) day period unless such breach is in
     violation of state, federal, or other applicable laws. In the event that
     NMC materially breaches any provision of this Agreement and the breach
     remains uncured for thirty (30) days following Amgen's notice of such
     breach, Amgen shall have no obligation to continue to offer the terms
     described herein or pay any further unvested discounts to NMC. However, any
     rebates or discounts that have been earned and vested at the time of
     termination shall still be paid pursuant to the applicable terms of
     Appendix A.

          In the event of an amendment or termination by Amgen for a reason
     other than breach or threatened breach by NMC, Amgen will immediately vest
     any unvested rebates as of the effective date of any amendment or
     termination.

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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
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          13.  CONFIDENTIALITY.  Both Amgen and NMC agree that this Agreement
     represents and contains confidential information which will not be
     disclosed to any third party, or otherwise made public, without prior
     written authorization of the other party, except where such disclosure is
     contemplated hereunder or required by law or court order. In the event NMC
     believes it is obligated to disclose any such information as required by
     law or court order, NMC will provide Amgen with prior written notice and an
     opportunity to seek a protective order and NMC shall furnish only that
     portion of the information that its counsel advises is required to be
     disclosed by law. Amgen acknowledges and agrees that NMC may file this
     Agreement as an exhibit to its parents' periodic reports to the Securities
     and Exchange Commission.

          14.  WARRANTIES.  Each party represents and warrants to the other that
     this Agreement (a) has been duly authorized, executed, and delivered by it,
     (b) constitutes a valid, legal, and binding agreement enforceable against
     it in accordance with the terms contained herein, and (c) does not conflict
     with or violate any of its of the contractual obligations, expressed or
     implied, to which it is a party or by which it may be bound. The party
     executing this Agreement on behalf of NMC specifically warrants and
     represents to Amgen that it is authorized to execute this Agreement on
     behalf of and has the power to bind NMC and the Affiliates to the terms set
     forth in this Agreement. The parties executing this on behalf of Amgen and
     Amgen Inc. specifically warrant and represent to NMC that they are
     authorized to execute this Agreement on behalf of and have the power to
     bind Amgen and Amgen Inc. to the terms set forth in this Agreement. Amgen
     warrants that the Products purchased pursuant to this Agreement (a) are
     manufactured and labeled in accordance with all applicable federal, state
     and local laws and regulations pertaining to the manufacturing of the
     Products including without limitation, the Federal Food, Drug, and Cosmetic
     Act and implementing regulations, and meet all specifications for
     effectiveness and reliability as required by the United States Food and
     Drug Administration, and (b) when used in accordance with the directions on
     the labeling, are fit for the purposes and indications described in the
     labeling. Amgen agrees that it will promptly notify NMC once it determines
     that there has been any material defect in any of the Products delivered to
     NMC.

          15.  GOVERNING LAW.  This Agreement will be governed by the laws of
     the State of Delaware and the parties submit to the jurisdiction of
     Delaware courts, both state and federal.

          16.  NOTICES.  Any notice or other communication required or permitted
     hereunder (excluding purchase orders) shall be in writing and shall be
     deemed given or made five (5) days after deposit in the United States mail
     with proper postage for first-class registered or certified mail prepaid,
     return receipt requested, or when delivered personally or by facsimile
     (Receipt verified and confirmed by overnight mail), or one (1) day
     following traceable delivery to a nationally recognized overnight delivery
     service with instructions for overnight delivery, in each case addressed to
     the parties as follows (or at such other addresses as the parties may
     notify each other in writing):

     If to NMC:
                           Fresenius Medical Care Holdings, Inc.
                           95 Hayden Avenue
                           Lexington, MA 02420
                           Attn: Robert McGorty, Senior Vice President
                           Fax: 781-402-9718

     with a copy to:
                           Fresenius Medical Care Holdings, Inc.
                           95 Hayden Avenue
                           Lexington, MA 02420
                           Attn: General Counsel
                           Fax: (781) 402-9713

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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
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     If to Amgen:
                           Amgen USA Inc.
                           One Amgen Center Drive, M/S 37-2-B
                           Thousand Oaks, CA 91320-1789
                           Attn: Allison Wright, Sr. Contract and Pricing
                           Analyst
                           Fax: (805) 499-6933

     with a copy to:
                           Amgen USA Inc.
                           One Amgen Center Drive, M/S 27-4-A
                           Thousand Oaks, CA 91320-1789
                           Attn: General Counsel
                           Fax: (805) 447-1000

     If to Amgen, Inc.:
                           Amgen Inc.
                           One Amgen Center Drive, M/S 37-2-B
                           Thousand Oaks, CA 91320-1789
                           Attn: Allison Wright, Sr. Contract and Pricing
                           Analyst
                           Fax: (805) 499-6933

     with a copy to:
                           Amgen Inc.
                           One Amgen Center Drive, M/S 27-4-A
                           Thousand Oaks, CA 91320-1789
                           Attn: General Counsel
                           Fax: (805) 447-1000

          17.  COMPLIANCE WITH HEALTH CARE PRICING AND PATIENT PRIVACY
     LEGISLATION AND STATUTES; DATA USE AGREEMENT.

             (a) Notwithstanding anything contained herein to the contrary, at
        any time following the enactment of any federal, state, or local law,
        regulation, rule, policy, program memorandum or other interpretation,
        modification or utilization guideline by any governmental payer that
        materially reforms, modifies, alters, restricts, or otherwise affects
        the pricing of or reimbursement available for any of the Products and/or
        results in material increase in Aranesp usage in dialysis clinics in the
        United States, including a reimbursement or use decision by Centers for
        Medicare and Medicaid Services ("CMS") or one of its contractors
        (Carriers or Fiscal Intermediaries), upon thirty (30) days notice, (i)
        either party may terminate this Agreement, (ii) Amgen may, in its sole
        discretion, modify any pricing or discount terms contained herein, or
        (iii) Amgen may, in its sole discretion, exclude any Affiliates from
        participating in this Agreement. Without limiting the foregoing, any
        change, modification or further clarification to the Medicare
        Modernization Act or any rules or regulations promulgated thereunder, or
        the [*] that occurs subsequent to the Amended Date would specifically
        trigger the right to the termination or modification referenced herein.
        Additionally, in order to assure compliance with any existing federal,
        state or local statute, regulation or ordinance, Amgen reserves the
        right, in its sole discretion, to exclude any Affiliates from the
        pricing, discount, and incentive provisions of this Agreement and/or to
        reasonably modify any pricing or discount terms contained herein. In the
        event there is a future change in Medicare, Medicaid, or other federal
        or state statutes or regulations or in the interpretation thereof, which
        renders any of the material terms of this Agreement unlawful or
        unenforceable, this Agreement shall continue only if amended by the
        parties as a result of good faith negotiations as necessary to bring the
        Agreement into compliance with such statute and regulation.

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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
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             (b) Notwithstanding anything contained herein to the contrary, in
        order to assure compliance, as determined by either party in its
        reasonable discretion, with any existing federal, state or local
        statute, regulation or ordinance relating to patient privacy of medical
        records, or at any time following the enactment of any federal, state,
        or local law or regulation relating to patient privacy of medical
        records that in any manner reforms, modifies, alters, restricts, or
        otherwise affects any of the data received or to be received in
        connection with any of the incentives contemplated under this Agreement,
        either party may upon thirty (30) days' notice, seek to modify this
        Agreement with respect to the affected incentive. NMC and Amgen shall
        meet and in good faith seek to mutually agree to modify this Agreement
        to accommodate any such change in law or regulation, [*] If the parties,
        after a reasonable time, are unable to agree upon such a modification,
        Amgen shall be entitled to terminate the affected incentive upon thirty
        (30) days' notice or upon the date such change in law or regulation goes
        into effect, whichever is earlier. [*]

        Notwithstanding anything contained herein to the contrary, this
        Agreement is effective only as of the date the parties hereto execute a
        mutually agreeable Data Use Agreement pursuant to which NMC may disclose
        a Limited Data Set of patient information to Amgen (as specified in the
        Data Use Agreement and which shall include, at a minimum, the data
        fields to be received by Amgen in connection with this Agreement) for
        purposes of Amgen's Research and Public Health analyses and NMC Health
        Care Operations. Unless otherwise specifically defined in this
        Agreement, each capitalized term used in this Section 17(c) shall have
        the meaning assigned to such term by the Health Insurance Portability
        and Accountability Act codified under 45 C.F.R. parts 160 and 164
        ("HIPAA"). If NMC terminates the Data Use Agreement for any reason,
        Amgen shall be entitled to terminate the incentives described in
        Appendix A.

          18.  INSURANCE AND INDEMNITY.  During the Term of this Agreement,
     Amgen shall insure coverage of its obligations hereunder consistent with
     Amgen corporate policy through such programs of self-insurance and/or
     policies of general liability insurance through third-party carriers as
     Amgen shall determine in its sole discretion. Amgen agrees to indemnify,
     defend and hold harmless NMC and its Affiliates and their respective
     employees, officers and directors from and against any and all liabilities,
     losses, claims, or costs, including reasonable attorneys' fees, which
     result directly from Product which as of the date of shipment by Amgen: (i)
     contain defects in material and workmanship, (ii) are adulterated or
     misbranded within the meaning of applicable provisions of the Federal Food,
     Drug and Cosmetic Act (the "FDC Act"), or (iii) are prohibited from being
     introduced into interstate commerce by Section 301 of the FDC Act or
     Section 351 of the Public Health Service Act; provided that such indemnity
     shall not apply to claims arising out of the negligent or willful actions
     or omissions of NMC or its agents, employees, representatives, successors
     or assigns or due to defects in the Product caused by persons other than
     Amgen which result from neglect, misuse, unauthorized adulteration or
     modification, improper testing, handling or storage or any cause beyond the
     range of normal usage; and further provided that (a) Amgen is promptly
     notified in writing of any such claim, (b) Amgen shall have sole control of
     the defense and settlement thereof, and (c) NMC reasonably cooperates and
     gives Amgen all requested information and reasonable assistance for such
     defense. Notwithstanding the foregoing, Amgen shall not be liable for loss
     of profit or loss of use, incidental or consequential damages arising out
     of any claim asserted by NMC under this Agreement or otherwise. This
     paragraph sets forth NMC's sole indemnity remedy for claims of Product
     defect, adulteration or misbranding.

          19.  [*]

          20.  DIRECT PURCHASE OF PRODUCTS.  NMC may purchase EPOGEN(R) M20,
     20,000U, 1mL vials, NDC 55513-478-10 packaged as ten (10) vials per pack
     and four (4) packs per case; S4, 4,000U, 1mL vials, NDC 55513-148-10
     packaged as ten (10) vials per pack and ten (10) packs per case; and
     Aranesp(R) 25 mcg, 1.0 mL vials, NDC 55513-010-04 packaged as four (4)
     vials per pack and ten (10) packs per case; 40 mcg, 1.0 mL vials, NDC
     55513-011-04 packaged as four (4) vials per pack and ten (10) packs per
     case; 60 mcg,

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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
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     1.0 mL vials, NDC 55513-012-04 packaged as four (4) vials per pack and ten
     (10) packs per case; 100 mcg, 1.0 mL vials, NDC 55513-013-04 packaged as
     four (4) vials per pack and ten (10) packs per case; 200 mcg, 1.0 mL vials,
     NDC 55513-014-01 packaged as one (1) vial per pack and four (4) packs per
     case; 150mcg, 0.75mL single-use vials, NDC 55513-054-04 packaged as four
     (4) vials per pack and ten (10) packs per case; 300mcg, 1.0mL single-use
     vials, NDC 55513-015-01 packaged as one (1) vial per pack and four (4)
     packs per case; Aranesp(R) SingleJect(R) Prefilled Syringe 60 mcg, 0.3 mL
     (200 mcg/mL), single-use syringe, NDC 55513-039-04 packaged as 4 syringes
     per pack; 10 packs per case; Aranesp(R) SingleJect(R) Prefilled Syringe 100
     mcg, 0.5 mL (200 mcg/mL), single-use syringe, NDC 55513-041-04 packaged as
     4 syringes per pack; 10 packs per case; Aranesp(R) SingleJect(R) Prefilled
     Syringe 200 mcg, 0.4 mL (500 mcg/mL), single-use syringe, NDC 55513-044-01,
     packaged as 1 syringe per pack; 4 packs per case; and Aranesp(R)
     SingleJect(R) Prefilled Syringe 300 mcg, 0.6 mL (500 mcg/mL), single-use
     syringe, NDC 55513-046-01, packaged as 1 syringe per pack; 4 packs per
     case, NDC 55513-043-04 single-use syringe; four (4) syringes per pack; ten
     (10) packs per case, 150 mcg, 0.3 mL (500 mcg/mL) (the "Direct Product") on
     a direct basis from Amgen in accordance with the terms set forth in
     Appendix D which is incorporated herein by reference.

          21.  DATA COLLECTION.  NMC agrees all data to be provided to Amgen
     pursuant to this Agreement shall be in a form that does not disclose the
     identity of any patient or any other patient-identifying information such
     as name, address, telephone number, birth date, all or part of a social
     security number, medical record number or prescription number. NMC and
     Amgen agree to use and accept only those patient identifiers compliant with
     HIPAA. Amgen and NMC acknowledge and agree that the data to be supplied to
     Amgen pursuant to this Agreement shall be used by Amgen solely to support
     verification of the discounts and incentives referenced herein, as well as
     for Amgen-sponsored research concerning the role of EPOGEN(R) in improving
     treatment outcomes and quality of life of dialysis patients.
     Notwithstanding the foregoing or any other provision of this Agreement,
     Amgen shall not obtain hereby any legal title to any NMC data and shall not
     sell or sublicense any data obtained hereunder. Any use by Amgen of such
     data shall be in a format that will not identify NMC or any Affiliates as
     the source of such data. NMC shall consistently use a unique alpha-numeric
     code (which shall not be the same as part or all of the patient's social
     security number) as a "case identifier" to track the care rendered to each
     individual patient over time, and such case identifier shall be included in
     the data provided to Amgen. The key or list matching patient identities to
     their unique case identifiers shall not be provided to Amgen personnel. In
     furtherance of Amgen research, NMC may agree from time to time to use its
     key to update the patient care data by linking it with information
     concerning health outcomes, quality of life, and other pertinent data that
     may become available to Amgen from other sources. Any such linking of data
     sources shall not provide the identity of any patient to Amgen. Amgen
     agrees it will maintain data supplied under this Agreement in confidence
     and it will not use such data to identify or contact any patient. No
     reports by Amgen concerning analyses of the data or the results of such
     research shall disclose the identity of any patient. Nothing in this
     Agreement shall limit NMC's use of its patient data, including without
     limitation, any data to be supplied to Amgen hereunder. For purposes of
     this Agreement, including Appendix A, NMC shall only be obligated to
     provide Amgen data with respect to its "Permanent" patients, as such term
     is defined in NMC's database. Generally, Permanent patients are those
     patients for whom NMC is the primary provider of dialysis services.

          22.  ACCESS.  Amgen and NMC agree that it and its agents and employees
     shall, at all times, comply with all applicable laws and regulations.

          23.  MISCELLANEOUS.  No modification of this Agreement shall be
     effective unless mutually agreed upon, made in writing and signed by a duly
     authorized representative of each party. This Agreement constitutes the
     entire agreement of the parties pertaining to the subject matter hereof and
     supersedes all prior written and oral agreements and understandings
     pertaining hereto including without limitation, any previous or existing
     contract, amendment, or agreement for the purchase of Products for use in
     the treatment of dialysis patients. Neither party shall have the right to
     assign this Agreement to a third party without the prior written consent of
     the other party provided, however, that Amgen may assign this Agreement to
     any of its

                                        7
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

     subsidiaries or affiliates without the written consent of NMC. Neither
     party shall be liable for delays in performance and nonperformance of this
     Agreement or any covenant contained herein caused by fire, flood, storm,
     earthquake or other act of God, war, terrorist acts, rebellion, riot,
     failure of carriers to furnish transportation, strike, lockout or other
     labor disturbances, act of government authority, inability to obtain
     material or equipment, or any other cause of like or different nature
     beyond the control of such party. The parties shall execute and deliver all
     documents, provide all information, and take or refrain from taking action
     as may be necessary or appropriate to achieve the purposes of this
     Agreement. This Agreement may be executed in one or more counterparts, each
     of which is deemed to be an original but all of which taken together
     constitutes one and the same agreement. Upon expiration or early
     termination of this Agreement, the rights and obligations set forth in
     Sections 5, 6, 7, 13,14, 18 and 22 shall survive such expiration or
     termination. In the event that the outcomes data proves to not serve and
     yield the beneficial results intended by both parties, Amgen and NMC will
     agree to meet, and negotiate in good faith.

             (a) [*]

          24.  PRODUCT INTEGRITY.  Amgen and NMC shall reasonably cooperate with
     each other in connection with each party's efforts to ensure the
     genuineness and integrity of Products purchased hereunder.

     Please retain one fully executed original for your records and return the
other fully executed original to Amgen.

     THE PARTIES EXECUTED THIS AMENDMENT AND RESTATEMENT OF THE AGREEMENT AS OF
THE DATES SET FORTH BELOW.

<Table>
<S>         <C>                                  <C>         <C>

AMGEN USA INC.                                   NATIONAL MEDICAL CARE, INC.

Signature:  /s/ Fred Manak                       Signature:  /s/ Robert J. McGorty
            -------------------------------                  -------------------------------

Print       Fred Manak                           Print       Robert J. McGorty
  Name:     -------------------------------      Name:       -------------------------------

Print       Dir. U.S. Corporate Pricing          Print       VP Finance and Administration
  Title:    -------------------------------      Title:      -------------------------------

Date:       12/1/04                              Date:       12/01/04
            -------------------------------                  -------------------------------


AMGEN INC.

Signature:  /s/ Helen Torley
            -------------------------------

Print       Helen Torley
  Name:     -------------------------------

Print       VP and General Manager
  Title:    -------------------------------

Date:       12/01/04
            -------------------------------
</Table>

                                        8
<PAGE>
                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

     SECTION 2.  AMENDMENT AND RESTATEMENT OF APPENDIX A:  [*]

                                        9
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

              APPENDIX B: LIST OF NMC SUBSIDIARIES AND AFFILIATES

                                 SUBSIDIARIES:

                                  AFFILIATES:

                           See Contract List Attached

                                        10
<PAGE>
                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

                 APPENDIX C: LIST OF NMC AUTHORIZED WHOLESALERS

     TO ENSURE NMC RECEIVES THE APPROPRIATE DISCOUNT, IT IS IMPORTANT AMGEN
RECEIVES NMC'S CURRENT LIST OF AUTHORIZED WHOLESALERS. THE FOLLOWING LIST
REPRESENTS THE WHOLESALERS AMGEN CURRENTLY HAS ASSOCIATED WITH NMC'S CONTRACT.
PLEASE UPDATE THE LIST BY ADDING OR DELETING WHOLESALERS AS NECESSARY.

                                        11
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

                APPENDIX D: TERMS FOR PURCHASE OF DIRECT PRODUCT

     Pursuant to Section 20 of the Agreement, the terms under which NMC may
purchase Direct Product on a direct basis from Amgen are as follows:

          1.  ORDERS/INVOICES.  NMC shall place Direct Product orders with NMC
     Distribution Center. NMC Distribution Center shall transmit orders and
     receive corresponding invoices via electronic data interchange ("EDI") in a
     format specified by Amgen.

          Orders may be submitted via facsimile, mail, or telephone to the
     address and telephone/fax numbers listed below. [*]

          Amgen Customer Service may be reached at the following address and
     phone numbers:

               Amgen USA Inc.
               Customer Service Department Fax: 1-800-292-6436
               One Amgen Center Drive Tel: 1-800-282-6436
               Thousand Oaks, CA 91320-1799

          2.  SHIPPING, TRANSPORTATION AND CHARGES.  [*]

          3.  TITLE AND RISK OF LOSS.  [*]

          4.  PRICING FOR DIRECT PRODUCT.  [*]

          5.  TERMS OF PAYMENT.  NMC Distribution Center agrees to pay a [*] for
     Direct Product ordered, at terms of [*]

          6.  CREDIT.  NMC Distribution Center shall send annually, within one
     hundred twenty (120) days of Fresenius Medical Care Holdings, Inc.'s
     ("FMCH") fiscal year end, or more frequently as requested by Amgen, copies
     of FMCH's audited financial statements for such fiscal year to:

               Amgen USA Inc.
               Customer Finance Department
               One Amgen Center Drive
               Thousand Oaks, CA 91320-1799

     If no audited financial statements are available, NMC Distribution Center
     shall send unaudited financial statements which are certified by NMC
     Distribution Center's principal financial officer as being accurate in all
     material respects. Amgen shall not be obligated to ship Direct Product to
     NMC Distribution Center if there are any amounts past due on NMC
     Distribution Center's account or if NMC Distribution Center's outstanding
     balance due exceeds NMC Distribution Center's predetermined credit limit.
     NMC Distribution Center shall supply Amgen written notice of the sale or
     transfer of all or substantially all of its assets of, or a controlling
     interest in, NMC Distribution Center at least thirty (30) days prior to
     such action if not otherwise prohibited by law or contractual obligations.
     Amgen reserves the right in its sole discretion to modify its credit
     policies and to require prepayment or satisfactory security at any time.

          7.  SALES DATA.  NMC Distribution Center shall submit all Direct
     Product sales data, including Customer returns, rebillings and associated
     credits to IMS America, Ltd. ("IMS") and to any other third-party sales
     reporting organization as reasonably requested by Amgen, on a monthly
     basis, and within two (2) weeks after the close of each month. NMC
     Distribution Center shall provide all information and assistance reasonably
     required by Amgen to determine and verify Medicaid, other government, or
     third-party rebate claims or obligations. If NMC Distribution Center is
     unable to report such sales data to the agreed upon independent third-party
     sales reporting organization(s) due to unwillingness of the third party to
     deal with NMC Distribution Center, Amgen's sole recourse shall be to
     terminate the Direct Product purchase components of this Agreement.

                                        12
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
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          8.  CONTRACTS AND CHARGEBACKS.  NMC Distribution Center agrees to
     service contracts that Amgen has entered into with Customers in accordance
     with the terms specified in bid award notifications sent by Amgen to NMC
     Distribution Center. [*] Adjustments or credits will be made in accordance
     with Amgen's Chargeback Policy (See Article One) attached hereto and
     incorporated herein. NMC Distribution Center further agrees to submit
     chargebacks to Amgen via EDI in a format acceptable to Amgen at least once
     per week, and in accordance with Amgen's Chargeback Policy. NMC
     Distribution Center shall retain all documentation supporting such
     chargebacks for a period of eighteen (18) months from the date of sale and
     permit Amgen employees or contractors (who shall not be compensated by
     Amgen on a contingency basis) to review this documentation upon request.

          9.  PRODUCT RETURNS.  NMC Distribution Center shall comply with
     Amgen's Product Return Policy (See Article Two) and all requirements of the
     Prescription Drug Marketing Act of 1987 (as amended from time to time).

             a.  Returns by Customer to NMC Distribution Center

     NMC Distribution Center shall notify Amgen of all Direct Product returned
     to NMC Distribution Center in the form of a negative chargeback. This will
     ensure that the proper adjustment is made to NMC Distribution Center's
     account.

             b.  Returns by NMC Distribution Center to Amgen

     Amgen shall only accept Direct Product returns from NMC Distribution Center
     that have been pre-authorized by Amgen Customer Service. Direct Product
     must be in original, unopened and undamaged cartons and returned within
     twelve (12) months post expiration and must be in full compliance with
     Amgen's Product Return Policy (See Article Two) attached hereto and
     incorporated herein. Amgen will promptly issue credit to NMC Distribution
     Center in accordance with Amgen's Product Return Policy.

             c.  Returns by Customer to Amgen

     Amgen shall accept from Customer Direct Product returns that have been
     pre-authorized by Amgen Customer Service. NMC Distribution Center agrees to
     promptly issue credit to Customer returning Direct Product directly to
     Amgen and for which Amgen has issued a credit memo to NMC Distribution
     Center.

          10.  REBILLINGS AND ASSOCIATED CREDITS.  NMC Distribution Center
     agrees to submit to Amgen all Customer rebillings and associated credits in
     conformance with Amgen's Chargeback Policy.

          11.  PRODUCT RECALL.  In the event of a recall, Amgen will promptly
     notify NMC Distribution Center and relevant Customer of such recall and
     arrange for Direct Product to be shipped directly to Amgen. Amgen will
     provide a third-party billing number (common carrier) to Customer and NMC
     Distribution Center for shipping of recalled Direct Product directly to
     Amgen. NMC Distribution Center shall provide a list of Customer names and
     addresses to Amgen who may have received recalled Direct Product. In
     consideration for NMC Distribution Center's administrative expenses, Amgen
     will pay NMC Distribution Center for a list of each Customer that may have
     received recalled Direct Product in the amount equal to $1.00 per Customer
     name up to a maximum $100.00 per distribution center. NMC Distribution
     Center shall render its services and assist Amgen in returning all recalled
     Direct Product to Amgen. Amgen shall provide reasonable compensation to NMC
     Distribution Center per HDMA standards for additional services that may be
     requested by Amgen. A credit memo will be issued to NMC Distribution Center
     for all recalled Direct Product returned to Amgen. NMC Distribution Center
     shall promptly issue credit to Customer for recalled Direct Product
     returned directly to Amgen for which Amgen has issued a credit memoranda to
     NMC Distribution Center. NMC Distribution Center may call Amgen Customer
     Service at 1-800-282-6436 for further instructions in the event of a
     recall.

          12.  APPLICABLE LAWS AND REGULATIONS.  Amgen and NMC Distribution
     Center agree to comply with all laws (local, state and federal) applicable
     to the purchase, handling, sale, and distribution of Direct

                                        13
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

     Product. NMC agrees to provide Amgen with the statutory citation of all
     local and state laws and regulations contemplated by this Section 12. In
     the event there shall be a change in federal or state statutes (including,
     but not limited to Medicare or Medicaid statutes, Federal Food, Drug and
     Cosmetic Act (the "FDC Act"), and any other statutes governing
     distribution, handling, purchasing, or sale of drugs, medical supplies and
     durable medical equipment), case laws, regulations or general instructions,
     the interpretation of any of the foregoing, the adoption of new federal or
     state legislation, or a change in any third party reimbursement system, any
     of which are reasonably likely to materially and adversely affect the
     manner in which either party may perform or be compensated for its services
     under this Agreement or which shall make this Agreement unlawful, the
     parties shall immediately enter into good faith negotiations regarding a
     new service arrangement or basis for compensation for the services
     furnished pursuant to this Agreement that complies with the law,
     regulation, or policy. If good faith negotiations cannot resolve the matter
     within thirty (30) days, the parties shall terminate the Agreement.

          13.  DIVERSION.  NMC Distribution Center shall distribute Direct
     Product only to those approved Subsidiaries and Affiliates listed on
     Exhibit B. NMC Distribution Center shall promptly notify Amgen upon
     learning of any activity that appears to be diversion of Direct Product,
     including the sale, distribution or purchase of Direct Product for uses
     beyond the provision of care for dialysis patients, or the sale or
     distribution of Direct Product outside of the United States and Puerto
     Rico. Amgen may terminate this Agreement upon written notice if it is
     determined by Amgen, in its sole discretion, that NMC Distribution Center
     has purchased Direct Product from sources other than Amgen or distributed
     Direct Product to entities not listed on Exhibit B.

                                        14
<PAGE>
                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

               APPENDIX E: LIST OF APPROVED DISTRIBUTION CENTERS

Fresenius USA Manufacturing, Inc.
d/b/a Nephromed and affiliates
95 Hayden Avenue
Lexington, MA 92420-9192

                                        15
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

                                  ARTICLE ONE

CHARGEBACK POLICY

1.  INITIAL SUBMISSIONS:

     Chargeback claims must be submitted via EDI in a format acceptable to
Amgen. Claims must be received by Amgen no later than sixty (60) calendar days
after NMC Distribution Center has invoiced the Customer. Each item must contain
the information necessary to uniquely identify the Customer, including the
Health Industry Number (HIN) and complete ship-to name and address, or other
identifier as required by Amgen.

2.  PROCESSING TIME:

     Amgen will process all initial chargeback claims received in an acceptable
format within ten (10) business days. Once the chargeback claim has been
processed, NMC Distribution Center will receive, by mail, the credit memoranda
and/or discrepancy report.

3.  DISCREPANCIES:

     PARTIAL REJECTIONS:  If any item cannot be validated from the claim, it
will be rejected and credit will not be issued for that item. NMC Distribution
Center will receive the credit memoranda for the validated items in conjunction
with the discrepancy report for rejected items. A reason will be given for each
rejected item.

     FULL REJECTIONS:  Submissions not in an acceptable format or with a
rejection rate greater than ten percent (10%) may be rejected in full. Upon such
notification, NMC Distribution Center must correct the error(s) and
electronically retransmit the entire claim.

4.  RESUBMISSIONS:

     Amgen will accept resubmissions for rejected chargebacks within sixty (60)
calendar days after NMC Distribution Center has been notified of the rejection.
Claims must be submitted on Amgen's discrepancy report with any corrections or
additional information necessary to validate such claim.

5.  CUSTOMER RETURNS:

     NMC Distribution Center must report its Customer returns as "negative" or
"reverse" chargebacks.

6.  CREDITS AND REBILLS:

     NMC Distribution Center shall submit simultaneously to Amgen the credits
and their associated rebills within sixty (60) calendar days after NMC
Distribution Center rebills a Customer.

7.  CONTRACT ELIGIBILITY:

     Claims will only be honored for sales made in accordance with the Bid Award
Notifications sent by Amgen to NMC Distribution Center. A facility may only
participate on one (1) contract for each product at any given time. An
individual contract will take precedence over any group purchasing organization
contract of which the facility may be a part.

                                        16
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

8.  AUDIT:

     Amgen shall have access to all information necessary to verify chargeback
claims.

9.  DEDUCTIONS:

     Deductions of chargeback claims are not permitted unless supported with a
valid credit memoranda from Amgen.

     Amgen's Chargeback Policy conforms with the guidelines set by the
Healthcare Distribution Management Association. Amgen reserves the right to
modify its Chargeback Policy upon notice to NMC pursuant to Section 16 in the
Agreement.

                                        17
<PAGE>
                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

                                  ARTICLE TWO

PRODUCT RETURN POLICY

AUTHORIZATION:

     Contact Amgen Customer Service Department at 800-282-6436 for proper
instructions and procedures for returning Direct Product.

RETURNABLE ITEMS:

     - Expired Direct Product in full pack quantity with less than one-year post
       expiration date.

     - Direct Product received in error or damaged in transit.

NON-REFUNDABLE ITEMS:  Although all Direct Product may be returned, no credit
will be issued for:

     - Direct Product twelve (12) months or more post expiration date.

     - Direct Product destroyed or damaged due to improper storage, heat, cold,
       water, and smoke, left out of refrigeration or other conditions beyond
       the control of Amgen.

     - Direct Product destroyed or losses suffered in a natural disaster (flood,
       hurricane, tornado, etc.).

     - Direct Product obtained other than through normal channels of
       distribution.

     - Direct Product that is in unsaleable condition through no fault of Amgen.

     - Direct Product shipped as a "no charge" item.

     - Unauthorized excess stock.

TRANSPORTATION CHARGES:

     - Prepaid by Customer

TERMS OF RETURN POLICY:

     - Credit, if applicable, for outdated Direct Product, will be based on
       current price less fifteen percent (15%).

     - No credit for shipping, handling and return processing fees.

     - Amgen will not be responsible for any charges associated with third party
       return processors.

     - Pre-authorized excess stock returns will be credited at eighty percent
       (80%) of the original purchase price.

     - Direct Product ordered or received in error must be reported within ten
       (10) business days of Direct Product receipt.

     - Credit for indirect Customer, for outdated Direct Product, will be issued
       in the form of a check by Capital Returns Inc. on behalf of Amgen.

     - Credit for direct Customer, for outdated Direct Product, will be issued
       by Amgen in the form of a credit invoice.

     - Unauthorized deductions from invoices are not allowed.

     - All items are subject to credit approval by Amgen Customer Service.

                                        18
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                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

THIRD PARTY RETURN PROCESSORS:

     - For all outdated Direct Product, please forward return with detail
       manifest directly to:

               CAPITAL RETURNS, INC.
               ATTN: AMGEN RETURN GOODS
               406 NORTH PORT WASHINGTON ROAD
               MILWAUKEE, WI 53212

COMPANY DISCLAIMER:

     - Direct Product returned is subject to Amgen's and or Capital Returns'
       evaluation at the time of receipt for final count and inspection.

     - Amgen may, in its sole discretion, make exceptions, changes and/or
       modifications to Returned Goods Policy.

                                        19
<PAGE>
                             AMENDMENT NO. 4 AGREEMENT NO. 200308358 (CONTINUED)
--------------------------------------------------------------------------------

                                                                      EXHIBIT #1

                          SAMPLE CERTIFICATION LETTER

Month X, 2004

FSDC Legal Name
Street Address
City, ST Zip

RE: Agreement No. __________________

Dear __________________ :

     Thank you for your participation in the [*] program. In order for us to
enroll you, we require that a duly authorized representative of your
organization sign the certification below.

     Upon receipt of this executed document, we will calculate the value of your
incentive. If we do not receive the executed certification, we cannot provide
you with this incentive.

     If you have any questions regarding this letter please contact me at [*].
Thank you for your assistance in returning this certification.

Sincerely,

---------------------------------------------------------
Outcomes Incentive Analyst

CERTIFICATION:

     On behalf of FSDC Legal Name and all eligible Affiliates participating in
the [*] program under Agreement No. ____________, the undersigned hereby
certifies that the data submitted for each eligible Affiliate includes the
required results from all dialysis patients of such Affiliate, and does not
include results from non-patients. The party executing this document also
represents and warrants that it (i) has no reason to believe that the submitted
data is incorrect, and (ii) is authorized to make this certification on behalf
of all eligible Affiliates submitting data.

<Table>
<S>         <C>                                  <C>         <C>
FSDC LEGAL NAME

Signature:
            -------------------------------

Print
  Name:
            -------------------------------

Print
  Title:
            -------------------------------

Date:
            -------------------------------
</Table>

                                        20