<PAGE>   1

                                                                   EXHIBIT 10.41

   CERTAIN PORTIONS OF THIS EXHIBIT HAVE BEEN OMITTED BASED UPON A REQUEST FOR
   CONFIDENTIAL TREATMENT PURSUANT TO RULE 24B-2 UNDER THE SECURITIES EXCHANGE
      ACT OF 1934. THE OMITTED PORTIONS HAVE BEEN FILED SEPARATELY WITH THE
                       SECURITIES AND EXCHANGE COMMISSION.

                                      AMGEN

          AMENDMENT #1 DATED FEBRUARY 10, 1999 TO AGREEMENT NO. 980202

Agreement No. 980202, between Amgen Inc. ("Amgen") and Renal Care Group, Inc.,
shall be amended and restated in its entirety to read as stated below. Provided
this Amendment is signed on or before March 26, 1999, this Amendment shall
become effective on April 1, 1999. If this Amendment is not signed on or before
March 26, 1999, this Amendment shall be null and void, and the original
Agreement and all of the terms described therein shall remain in force through
the original expiration date of March 31, 1999.

This Agreement ("Agreement") between Amgen Inc. ("Amgen") and Renal Care Group,
Inc., including the freestanding dialysis center affiliate(s) listed on 
Appendix B, (collectively, "Dialysis Center"), sets forth the terms and 
conditions for the purchase of EPOGEN(R) (Epoetin alfa) by Dialysis Center.

1.       TERM OF AGREEMENT. The "Term" of this Agreement shall be defined as
         April 1, 1999 ("Commencement Date") through March 31, 2000
         ("Termination Date").

2.       DIALYSIS CENTER AFFILIATES. Dialysis Center must provide Amgen with a
         complete list of its dialysis center affiliates ("Affiliates") on or
         before the date this Agreement is executed by Dialysis Center.
         Modifications to the dialysis center Affiliates listed on Appendix B
         may be made pursuant to the request of Dialysis Center's corporate
         headquarters and are subject to approval and acknowledgment by Amgen in
         writing. Amgen requires no less than 30 days notice before the
         effective date of change for any addition or deletion of Affiliates
         hereunder. Amgen reserves the right to accept, reject, or immediately
         terminate any Affiliates with regard to participation in this
         Agreement.

3.       OWN USE. Dialysis Center hereby certifies that EPOGEN(R) purchased
         hereunder shall be for Dialysis Center's "own use."

4.       AUTHORIZED WHOLESALERS. Dialysis Center must provide Amgen with a
         complete list of its current wholesalers, from whom Dialysis Center
         intends to purchase EPOGEN(R), and must provide the list to Amgen on or
         before the date this Agreement is executed by Dialysis Center's
         corporate headquarters. The list must include the name and complete
         address of each designated wholesaler. Wholesalers designated by
         Dialysis Center and approved by Amgen to participate in this program
         will be deemed "Authorized Wholesalers." A current listing of Dialysis
         Center's Authorized Wholesalers is referenced in Appendix B.
         Notification of proposed changes to the list of Authorized Wholesalers
         must be provided to Amgen in writing at least 30 days before the
         effective date of the proposed change. Amgen reserves the right to
         accept, reject, or immediately terminate any wholesaler with regard to
         participation in this Agreement. Dialysis Center agrees to require all
         Authorized Wholesalers to submit product sales information to a
         third-party sales reporting organization designated by Amgen.

5.       QUALIFIED PURCHASES. EPOGEN(R) purchased under this Agreement by
         Dialysis Center *.

*Omitted information is the subject of a request for confidential treatment
pursuant to Rule 24b-2 under the Securities Exchange Act of 1934 and has been
filed separately with the Securities and Exchange Commission.




<PAGE>   2


6.       COMMITMENT TO PURCHASE. Dialysis Center agrees to purchase EPOGEN(R)
         for all of its dialysis use requirements for recombinant human
         erythropoietin. Dialysis Center may purchase another brand of
         recombinant human erythropoietin for its dialysis use requirements only
         for the time, and only to the extent, that Amgen has notified Dialysis
         Centers corporate headquarters in writing that Amgen cannot supply
         EPOGEN(R) within and for the time period reasonably required by
         Dialysis Center.

7.       CONFIDENTIALITY. Both Amgen and Dialysis Center agree that this
         Agreement represents and contains confidential information which shall
         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.

8.       DISCOUNTS. Dialysis Center may qualify for discounts in accordance with
         the schedules and terms set forth in Appendix A. Discounts in arrears
         will be paid in the form of a check payable to Dialysis Center's
         corporate headquarters. Discounts in arrears will be calculated in
         accordance with Amgen's discount calculation policies based on * using
         the prevailing * (*) as the calculation price, except as otherwise
         provided hereunder. Upon vesting, Amgen will use its best efforts to
         make such discounts available within 60 days after receipt by Amgen of
         data, in a form acceptable to Amgen, detailing all * during the
         applicable period. Payment amounts, as calculated by Amgen, must equal
         or exceed $100.00 for the applicable period to qualify. Subject to the
         section entitled "Breach of Agreement," in the event that Amgen is
         notified in writing that Dialysis Center, legally known as Renal Care
         Group, Inc., and/or any Affiliates (the "Acquiree") is acquired by
         another entity or a change of control otherwise occurs with respect to
         the Acquiree, any discounts which may have been earned hereunder shall
         be paid in the form of a check payable to the Acquiree's corporate
         headquarters subject to the conditions described herein. If any
         Affiliates are added to or deleted from this Agreement during any of
         the periods used for comparison, for any of the discounts paid in
         arrears contained herein, Amgen reserves the right in its sole
         discretion to appropriately adjust Dialysis Center's discounts for the
         relevant periods, by including or excluding any purchases made by those
         Affiliates during any of those periods.

9.       TREATMENT OF DISCOUNTS. Dialysis Center agrees that it will properly
         disclose and account for any discount or other reduction in price
         earned hereunder, in whatever form, (i.e. pricing, discount, or
         incentive), in a way that complies with all applicable federal, state,
         and local laws and regulations, including without limitation, Section
         11286(b) of the Social Security Act and its implementing regulations.
         Section 1126B(b) requires that a provider of services will properly
         disclose and appropriately reflect the value of any discount or other
         reduction in price earned in the costs claimed or charges made by the
         provider under a federal health care program, as that term is defined
         in Section 1128B(f). Dialysis Center also agrees that it will (a) claim
         the benefit of such discount received, in whatever form, in the fiscal
         year in which such discount was earned or the year after, (b) 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, or a state
         health care program, and (c) 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. Dialysis
         Center's corporate headquarters agrees that it will advise all
         Affiliates, in writing, of any discount received by Dialysis Center's
         corporate headquarters hereunder with respect to purchases made by such
         Affiliates and that said Affiliates will account for any such discount
         in accordance with the above stated requirements.

*Omitted information is the subject of a request for confidential treatment
pursuant to Rule 24b-2 under the Securities Exchange Act of 1934 and has been
filed separately with the Securities and Exchange Commission.





                                      -2-
<PAGE>   3

10.      DISCOUNT LIMITATION. Notwithstanding anything contained herein to the
         contrary, the amount of any discount available to Dialysis Center from
         Amgen, under this Agreement or otherwise, shall be limited to *, taking
         into account the aggregate value of all discounts ultimately available
         to Dialysis Center for the relevant quarter.

11.      DATA COLLECTION. Dialysis Center agrees that all data to be provided to
         Amgen pursuant to this Agreement, shall be in a form that does not
         disclose the identity or name of any patient or other
         patient-identifying information such as address, telephone number, or
         social security number. Dialysis Center acknowledges that the data to
         be supplied to Amgen pursuant to this Agreement shall be used 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. Dialysis Center shall consistently use a unique
         alpha-numeric code (which shall not be the same as 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, Dialysis
         Center 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 that it will
         maintain data supplied under this agreement in confidence and that 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.

12.      BREACH OF AGREEMENT. Either party may terminate this Agreement for
         breach upon 30 days advance written notice. In addition, in the event
         that Dialysis Center breaches any provision of this Agreement, Amgen
         shall have no obligation to continue to offer the terms described
         herein or pay any further discounts to Dialysis Center.

13.      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 other 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 Dialysis Center
         specifically warrants and represents to Amgen that it is authorized to
         execute this Agreement on behalf of and has the power to bind Dialysis
         Center and the Affiliates to the terms set forth in this Agreement.

14.      GOVERNING LAW. This Agreement shall be governed by the laws of the
         State of California and the parties submit to the jurisdiction of the
         California courts, both state and federal.

15.      NOTICES. Any notice or other communication required or permitted
         hereunder shall be in writing and shall be deemed given or made when
         delivered in person or when sent to the other party by first class mail
         or other means of written communication at the respective party's
         current address or at such other address as the party shall have
         furnished to the other in accordance with this provision.

16.      COMPLIANCE WITH HEALTH CARE PRICING LEGISLATION AND STATUTES.
         Notwithstanding anything contained herein to the contrary, at any time
         following the enactment of any federal, state, or local law or
         regulation that in any manner reforms, modifies, alters, restricts, or
         otherwise affects


*Omitted information is the subject of a request for confidential treatment
pursuant to Rule 24b-2 under the Securities Exchange Act of 1934 and has been
filed separately with the Securities and Exchange Commission.



                                      -3-
<PAGE>   4


         the pricing of or reimbursement available for EPOGEN(R), Amgen may, in
         its sole discretion, upon 30 days notice (a) terminate this Agreement,
         or (b) exclude any Affiliates from participating in this Agreement
         unless such Affiliate(s) certifies in writing that they are, or will
         be, exempt from the provisions thereunder. 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.

17.      FORCE MAJEURE. Neither party will be liable for delays in performance
         or nonperformance of this Agreement or any covenant contained herein if
         such delay or nonperformance is a result of Acts of God, civil or
         military authority, civil disobedience, epidemics, war, failure of
         carriers to furnish transportation, strike, lockout or other labor
         disturbances, inability to obtain material or equipment, or any other
         cause of like or different nature beyond the control of such party.

18.      MISCELLANEOUS. No modification of this Agreement will be effective
         unless made in writing and executed by a duly authorized representative
         of each party, except as otherwise provided hereunder. Neither party
         may assign this Agreement to a third party without the prior written
         consent of the other party. 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.

19.      ENTIRE AGREEMENT. This Agreement constitutes the entire understanding
         between the parties and supersedes all prior written or oral proposals,
         agreements, or commitments pertaining to the subject matter herein.

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

The parties executed this Amendment as of the dates set forth below.

AMGEN INC.                                  RENAL CARE GROUP, INC.

Signature:   /s/ Tom Green                  Signature:   /s/ Gary Brukardt
          ----------------------------                 -------------------------
Print Name:  Tom Green                      Print Name:  Gary Brukardt
           ---------------------------                  ------------------------
Print Title: National Account Manager       Print Title: EVP-COO
             -------------------------                   -----------------------
Date:        03/19/99                       Date:        03/26/99
     ---------------------------------            ------------------------------


                                      -4-
<PAGE>   5





                APPENDIX A. DISCOUNT PRICING, SCHEDULE, AND TERMS

1.       PRICING. Dialysis Center may purchase EPOGEN(R) through Authorized
         Wholesalers at a guaranteed * off of the prevailing *. Amgen reserves
         the right to change the * at any time. *

2.       OPTIONAL HEMATOCRIT/HEMOGLOBIN INCENTIVE. Each individual Affiliate may
         qualify for an Optional Hematocrit/Hemoglobin Incentive ("OHI")
         provided the following requirements are met.

A.       REQUIREMENTS: Dialysis Center's aggregate * of EPOGEN(R) purchases by
         all Affiliates as listed on Appendix B on the Commencement Date of this
         Agreement for each calendar quarter during the Term must equal or
         exceed * of the aggregate * of EPOGEN(R) purchases by those same
         Affiliates for the same time period from the previous year. In
         addition, at least * of Dialysis Centers patients must have Average
         Patient Hematocrits (as defined in Section 2(b) below) greater than or
         equal to * during each calendar quarter of the Term. If either of these
         criteria is not met during any given calendar quarter of the Term, none
         of Dialysis Center's Affiliates will qualify for the OHI during that
         quarter.

         In order to participate in the OHI, Dialysis Center must provide the
         following to Amgen or to a data collection vendor specified by Amgen,
         on a monthly basis, and no later than 30 days after the end of each
         month:

         i)       all hematocrit test results for each dialysis patient, the
                  date of each test, and a consistent, unique, alpha-numeric
                  identifier (sufficient to consistently track an individual
                  patient without in any way disclosing the identity of the
                  patient), along with the name, address and phone number of the
                  particular Affiliate at which each patient received treatment
                  (collectively the "Data"). Amgen may utilize the Data for any
                  purpose, and reserves the right to audit all Data. Under no
                  circumstances should the Data include any patient identifiable
                  information including, without limitation, name, complete
                  social security number, address or birth date. The identity of
                  the account submitting the Data and any association with the
                  Data will remain confidential. The hematocrit test results
                  must be derived from blood samples taken immediately before
                  dialysis treatment using any automated red blood cell counter
                  testing method (e.g. Coulter-counter, Bayer-Technicon, Sysmex,
                  CellDyne), must be reported to the nearest tenth of one
                  percent, and must be submitted directly from the clinical
                  laboratory in a format acceptable to Amgen. Hand written
                  reports are not acceptable; electronic submission of the Data
                  is preferred, and

         ii)      a properly executed "Certification Letter," a sample of which
                  is attached hereto as Exhibit #1, that will be provided to
                  Dialysis Center's corporate headquarters, unless otherwise
                  requested, before each payment period.

B.       CALCULATION: Assuming Dialysis Center has fulfilled all requirements as
         described in Section 2(a) above, the OHI for each individual Affiliate
         will be calculated as follows:

         The "Average Patient Hematocrit" for each dialysis patient will be
         based upon the average of all hematocrit test results gathered for each
         patient during each calendar quarter of the Term. The Average Quarterly
         Percentage of all dialysis patients with Average Patient Hematocrits
         greater than or equal to * will be determined for each Affiliate by
         dividing the total number of dialysis patients with Average Patient
         Hematocrits greater than or equal to *, by the total number of dialysis
         patients treated by that Affiliate.

*Omitted information is the subject of a request for confidential treatment
pursuant to Rule 24b-2 under the Securities Exchange Act of 1934 and has been
filed separately with the Securities and Exchange Commission.




<PAGE>   6

         C.       PAYMENT: The OHI for each Affiliate will be calculated on a
                  quarterly basis and paid to Dialysis Center's corporate
                  headquarters, except as otherwise provided hereunder. Payment
                  is contingent upon receipt by Amgen of the Certification
                  Letters and all required Data for the corresponding quarter.
                  If the Data from any given Affiliate is received more then 30
                  days after the last day of any relevant month, such Affiliate
                  will not qualify for the OHI for that quarter. Quarterly OHI
                  payments for each individual Affiliate will be based upon the
                  Data received for that Affiliate from the previous quarter *
                  governed by the OHI schedule listed below. Notwithstanding the
                  foregoing, payment for any period during the Term that is not
                  equivalent to a complete calendar quarter, will be based on an
                  average of the Data that is available for that period. If
                  requested by Amgen, Dialysis Center will provide any
                  information necessary * 30 days of Amgen's written request. If
                  Dialysis Center is unable to provide detailed * for each
                  Affiliate, Amgen may calculate the OHI based on Dialysis
                  Center's *. Amgen reserves the right to modify the OHI if the
                  EPOGEN(R)package insert language changes.

<TABLE>
<CAPTION>
                                                                                              Optional 
                     Average Quarterly Percentage of all dialysis patients at each           Hematocrit 
                 Affiliate with Average Patient Hematocrits greater than or equal to *       Incentive 
                     Please direct your attention to the EPOGEN(R) package insert            Percentage

                 <S>                                                                         <C>
                                    *       .................................................... *
                                    *       .................................................... *
                                    *       .................................................... *
                                    *       .................................................... *
                                    *       .................................................... *
</TABLE>


D        VESTING: The OHI for each Affiliate will vest on the last day of the
         corresponding quarter.

E.       HEMOGLOBIN CONVERSION: Dialysis Center may choose to submit hemoglobin
         test results rather than hematocrit test results as a measurement of
         anemia. If during the Term, Dialysis Center elects to use hemoglobin
         test results, Dialysis Center must: i) submit a "Notification Letter"
         to Amgen, a sample of such Notification Letter is attached hereto as
         Exhibit #2, and ii) begin submitting all hemoglobin test results for
         all dialysis patients along with all other information described in
         Section 2(a) above, rather than hematocrit test results for all
         dialysis patients at each Affiliate for purposes of participating in
         the OHI.

         Amgen will accept the hemoglobin test results, multiply each test
         result by *, and apply the converted results to the same schedule,
         requirements and calculations described above in place of the
         hematocrit test results.

         For the calendar quarter in which Dialysis Center submits its
         Notification Letter ("Grace Period"), Amgen will apply each Affiliate's
         Average Quarterly Percentage from the last calendar quarter in which
         complete hematocrit test results were received ("AQP-Hematocrit") to
         the OHI schedule listed above in order to determine the applicable OHI
         Percentage earned for each Affiliate. If Dialysis Center's overall
         performance on the OHI after the Grace Period does not equal or exceed
         the overall performance by Dialysis Center prior to conversion to
         hemoglobin, Amgen will continue to apply each Affiliate's
         AQP-Hematocrit through the remainder of the Term, provided that during
         the time period the AQP-Hematocrit is applied *.

*Omitted information is the subject of a request for confidential treatment
pursuant to Rule 24b-2 under the Securities Exchange Act of 1934 and has been
filed separately with the Securities and Exchange Commission.




                                      -2-
<PAGE>   7

         In the event any Affiliates still earning the OHI based on hematocrit
         test results are added to this Agreement after Dialysis Center has
         converted to hemoglobin, each such Affiliate's OHI payment for the
         calendar quarter in which they were added, shall be determined based on
         each such Affiliate's hematocrit test result for that quarter. All
         subsequent OHI payments to such added Affiliates must be based solely
         on hemoglobin test results. Hematocrit test results will not be
         accepted for any subsequent OHI payment calculations.

3.       ADDITIONAL OHI INCENTIVE. In addition to the OHI referenced above,
         beginning with the quarter commencing October 1, 1999, each Affiliate
         may be eligible to quality to receive an additional * incentive payment
         of their *. In order to qualify for the Additional OHI Incentive, each
         Affiliate must first meet all of the requirements for the OHI as
         described in this Appendix A, Section 2a, and for the quarters
         beginning October 1, 1999 through December 31, 1999 and January 1, 2000
         through March 31, 2000, such Affiliate must have at least * of its
         patients with Average Patient Hematocrits greater than or equal to *.
         If such Affiliate meets these requirements for both quarters referenced
         herein, such Affiliate will qualify for the Additional OHI Incentive.
         If such Affiliate has at least * of its patients with Average Patient
         Hematocrits greater than or equal to * for only one of the quarters
         described above, such Affiliate will not qualify for the Additional OHI
         Incentive. The Additional * incentive payment will be calculated as *
         during the quarter beginning October 1, 1999 through December 31, 1999
         and for the quarter beginning January 1, 2000 through March 31, 2000.

4.       ELECTRONIC DATA INCENTIVE. Each Affiliate may be eligible to receive an
         additional * incentive payment if certain data elements are transmitted
         to Amgen electronically. The additional * will be calculated as a
         percentage of each * during that quarter. In order to qualify for the
         additional *, the following EPOGEN(R) Related Patient Data must be
         submitted by all Affiliates in an electronic format acceptable to
         Amgen: Facility ID, Patient ID, Draw Date, Hematocrit, Hemoglobin,
         Transferrin Saturation, and Ferritin. Such EPOGEN(R) Related Patient
         Data must be submitted, on a monthly basis, and no later than 30 days
         after the end of each month. If such EPOGEN(R) Related Patient Data is
         not submitted by any Affiliate for any given calendar quarter of the
         second year of the Term, such Affiliate will not qualify for the
         Electronic Data Incentive.

5.       VOLUME PERFORMANCE INCENTIVE. Dialysis Center may qualify for the
         Volume Performance Incentive ("VPI") as described below.

A.       CALCULATION: Dialysis Center's VPI Will be calculated in accordance
         with the following formula.

                                        *
                           where

                                        *

         Estimated payments will be made quarterly using Amgen's discount
         calculation policies, and the VPI will be reconciled at the end of the
         Term.

         Vesting:  Dialysis Center's VPI will vest quarterly.


*Omitted information is the subject of a request for confidential treatment
pursuant to Rule 24b-2 under the Securities Exchange Act of 1934 and has been
filed separately with the Securities and Exchange Commission.



                                      -3-
<PAGE>   8



                 Appendix B: List of Dialysis Center Affiliates

                          (See attached Contract List)


<PAGE>   9


To ensure you receive the appropriate discount it is important that we have your
current list of Authorized Wholesalers. The following list represents the
Wholesalers Amgen currently has associated with your contract. Please update the
list by adding or deleting Wholesalers as necessary,

Henry Schein, Incorporated
5 Harbor Park Drive
Port Washington, NY  11050

Metro Medical Supply, Incorporated
3332 Powell Road
Nashville, TN  37204

Priority Healthcare Corporation
Charise Charles Division
285 West Central Parkway, Suite 1704
Altamonte Springs, FL  32714




                                      -5-
<PAGE>   10


                                                                      EXHIBIT #1

                           SAMPLE CERTIFICATION LETTER

Month X, 199X

FSDC Legal Name
Street Address
City, ST  Zip

RE:      Amgen Agreement No. XXXX)(X

Dear _____________________:

Thank you for your participation in the Optional Hematocrit/Hemoglobin Incentive
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 (805)
447-5745. Thank you for your assistance in returning this certification.

Sincerely,

Steve Todd
FSDC Market Segment Manager

CERTIFICATION:

On behalf of FSDC Legal Name and all eligible Affiliates participating in the
Optional Hematocrit/Hemoglobin Incentive Program under Agreement No. XXXXXX, the
undersigned hereby certifies that the hematocrit/hemoglobin data submitted for
each eligible Affiliate during this calendar quarter includes the required
hematocrit/hemoglobin results from all dialysis patients of such Affiliate, and
does not include hematocrit/hemoglobin results from non-patients. The party
executing this document also represents and warrants that it (i) has no reason
to believe that the submitted hematocrit/hemoglobin data is incorrect, and (ii)
is authorized to make this certification on behalf of all eligible Affiliates
submitting hematocrit/hemoglobin data.

FSDC LEGAL NAME

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

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

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

Date:                                                
     ----------------------------------




                                      -6-
<PAGE>   11


                                                                      EXHIBIT #2

                           Sample Notification Letter

Month X, 199X

Steve Todd
FSDC Market Segment Manager
Amgen Inc,
One Amgen Center Drive
Thousand Oaks, CA  91320

RE:      Amgen Agreement No. XXXXXX

Dear Mr. Todd:

This letter serves as notification that FSDC Legal Name and all eligible
Affiliates participating in the Optional Hematocrit/Hemoglobin Incentive Program
under Agreement No. XXXXXX, will begin using hemoglobin test results as a
measurement of anemia as of Month X, 199X, and will begin submitting hemoglobin
test results rather than hematocrit test results for purposes of participating
in the Optional Hematocrit/Hemoglobin Incentive Program.

We understand that any discount under the Optional Hematocrit/Hemoglobin
Incentive Program will now be based solely on hemoglobin test results and that
hematocrit test results will no longer be accepted. We also understand that such
hemoglobin test results will be converted and applied to the same schedule,
requirements, and calculations described in the Optional Hematocrit/Hemoglobin
Incentive Program outlined in the Agreement,

Sincerely,

Name of Administrator
Title







                                      -7-