<PAGE>
[*]   CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY
      BRACKETS, HAS BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
      EXCHANGE COMMISSION.



                                                                    EXHIBIT 10.7

                               FOURTH AMENDMENT TO
                               HEMOPHILIA PRODUCT
                           VOLUME COMMITMENT AGREEMENT

Fourth Amendment to Hemophilia Product Volume Commitment Agreement ("Fourth
Amendment") effective as of the 1st day of July, 2004 ("Effective Date"), by and
between Baxter Healthcare Corporation, a Delaware corporation, through its
BioScience business unit, with offices at One Baxter Parkway, Deerfield,
Illinois 60015 (hereinafter referred to as "Baxter"), and Coram, Inc., with
offices at 1675 Broadway, Suite 900, Denver, Colorado 80202 ("Purchaser").
Baxter and Purchaser are collectively referred to hereinafter as the "Parties."

                                    RECITALS

WHEREAS, Baxter and Purchaser entered into a Hemophilia Product Volume
Commitment Agreement effective December 19, 2001 ("VCC Agreement") and amended
from time to time (collectively, the VCC Agreement and all of its amendments are
referred to herein as the "Agreement");

WHEREAS, the Parties desire to amend the Agreement for the purpose of:

      1. revising Section 1;

      2. revising Section 5;

      3. revising Schedule A-1; and

      4. revising Schedule C-2.

Now therefore, it is hereby agreed as follows:

      1.    Section 1. Definitions is hereby amended to add Paragraph 1.16, as
            follows:

                  "1.16 'Additional Recombinant Base Level Product Volume' shall
                  mean Recombinant Hemophilia Product and rAHF-PFM as set forth
                  in Schedule A-2 before Purchaser specifies its Base Level
                  Product Volumes for Recombinant Hemophilia Product and
                  rAHF-PFM." Except as set forth in Section 5.1.1(c) below, such
                  Additional Recombinant Base Level Product Volume shall consist
                  of such IUs of Recombinant Hemophilia Product or rAHF-PFM as
                  Purchaser shall determine, in its sole discretion.

      2.    Section 5 Minimum Supply/Purchase Commitments is hereby amended to
            (a) delete and restate Paragraphs 5.1 Recombinant Hemophilia Product
            Minimum Supply/Purchase Commitments and 5.7 Purchase Commitment, as
            follows and (b) to add new paragraph 5.9 as follows:

            "5.1  Recombinant Hemophilia Product and rAHF-PFM Minimum
                  Supply/Purchase Commitments.For each year this Agreement
                  remains in effect, Baxter will supply Purchaser, and Purchaser
                  will purchase from Baxter, the annual Base Level Product
                  Volumes of Recombinant Hemophilia Product and rAHF-PFM set
                  forth in Schedule A-2. At the end of any year that this
                  Agreement is in effect, if Purchaser' purchases have not met
                  such minimum purchase thresholds, Baxter shall provide
                  Purchaser with written notice of the unit amount of the
                  shortfall. At Purchaser's request, Baxter shall provide
                  Purchaser with reasonable documentation showing any such
                  shortfall. Purchaser shall have [*] days from receipt
                  of such notice to make such purchases of Recombinant
                  Hemophilia Product and/or rAHF-PFM necessary to meet the
                  minimum unit purchase

                                  Page 1 of 7
<PAGE>


                  requirements. In the event Purchaser breaches this Agreement
                  by failing to satisfy their unit purchase commitments for
                  Recombinant Hemophilia Product and/or rAHF-PFM, as set forth
                  under this Section 5.1, unless such failure is due to Baxter's
                  failure to supply product or such failure is due to a force
                  majeure event, then Purchaser shall pay to Baxter an amount
                  equal to [*] of the then applicable invoice price for the
                  Therapeutic Products involved as liquidated damages, which
                  figure shall include both incidental and consequential
                  damages. In the event Baxter fails to make delivery or
                  repudiates or Purchaser rightfully reject or justifiably
                  revoke acceptance, then with respect to the Therapeutic
                  Products involved, Baxter shall either (i) promptly offer
                  substitute therapeutics (recombinant derived product for
                  Recombinant Hemophilia Product or rAHF-PFM, plasma derived
                  product for Plasma Based Hemophilia Products), as an
                  accommodation, or (ii) Baxter shall pay to Purchaser an amount
                  equal to [*] of the then applicable invoice price for the
                  Therapeutic Products involved as liquidated damages, which
                  figure shall include both incidental and consequential
                  damages. Baxter shall in each quarter tender delivery and
                  Purchaser will purchase at least [*] of the then applicable
                  Quarterly Base Level Product Volume of Recombinant Hemophilia
                  Product and rAHF-PFM for such quarter and shall tender
                  delivery of the full amount by the end of the calendar year.

            "5.1.1 Additional Recombinant Base Level Product Volumes Minimum
                  Supply/Purchase Commitment.

                  "a.   In addition to the annual Base Level Product Volumes of
                        rAHF-PFM described in Paragraph 5.1, in calendar year
                        2004, Baxter will supply to Purchaser and Purchaser will
                        purchase from Baxter [*] of the Additional Recombinant
                        Base Level Product Volume. Purchaser will designate a
                        quantity up to [*] of the Additional Recombinant Base
                        Level Product Volumes as rAHF-PFM. The balance of said
                        [*], if any, shall be Recombinant Hemophilia Product.
                        Designation of the number of IUs of the Additional
                        Recombinant Base Level Product Volume that shall be
                        Recombinant Hemophilia Product and the number of IUs of
                        the Additional Recombinant Base Level Product Volume
                        that shall be rAHF-PFM for the period of July 1, 2004
                        through September 30, 2004 will be made on or before
                        [*]. Designation of the number of IUs of the Additional
                        Recombinant Base Level Product Volume that shall be
                        Recombinant Hemophilia Product and the number of IUs of
                        the Additional Recombinant Base Level Product Volume
                        that shall be rAHF-PFM for the period of October 1, 2004
                        through December 31, 2004 will be made on or before [*].

                  "b.   In calendar year 2005, Baxter will supply to Purchaser
                        and Purchaser will purchase from Baxter the Additional
                        Recombinant Base Level Product Volume set forth in
                        Schedule A-2. No later than [*], Baxter will supply to
                        Purchaser and Purchaser will purchase from Baxter [*] of
                        the Additional Recombinant Base Level Product Volume.
                        Purchaser will designate a quantity up to [*] of the
                        Additional Recombinant Base Level Product Volume as
                        rAHF-PFM. The balance of said [*], if any, shall be
                        Recombinant Hemophilia Product. Designation of the
                        number of IUs of the Additional Recombinant Base Level
                        Product Volume that shall be Recombinant Hemophilia
                        Product and the number of IUs that shall be rAHF-PFM for
                        the period of January 1, 2005 through March 31, 2005
                        will be made on or before [*]. Designation of the number
                        of IUs of the Additional Recombinant Base Level Product
                        Volume that shall be Recombinant Hemophilia Product and
                        the number of IUs that shall be rAHF-PFM for the period
                        of April 1, 2005 through June 30, 2005 will be made on
                        or before [*].

                                   Page 2 of 7
<PAGE>

                        "As to the remaining [*] of Additional Recombinant Base
                        Level Product Volume, no later than [*], Baxter will
                        supply to Purchaser and Purchaser will purchase from
                        Baxter [*] of the Additional Recombinant Base Level
                        Product Volume. Purchaser will designate a quantity up
                        to [*] of the Additional Recombinant Base Level Product
                        Volumes as rAHF-PFM. The balance of said [*], if any,
                        shall be Recombinant Hemophilia Product. Designation of
                        the number of IUs of the Additional Recombinant Base
                        Level Product Volume that shall be Recombinant
                        Hemophilia Product and the number of IUs that shall be
                        rAHF-PFM for the period of July 1, 2005 through
                        September 30, 2005 will be made on or before [*].
                        Designation of the number of IUs of the Additional
                        Recombinant Base Level Product Volume that shall be
                        Recombinant Hemophilia Product and the number of IUs
                        that shall be rAHF-PFM for the period of October 1, 2005
                        through December 31, 2005 will be made on or before [*].

                  "c.   If Purchaser fails to specify the Base Level Product
                        Volumes for Recombinant Hemophilia Product and rAHF-PFM
                        by the dates specified above, then Baxter will deliver
                        to Purchaser and Purchaser will purchase from Baxter the
                        Additional Recombinant Base Level Product Volume as
                        follows:

<TABLE>
<CAPTION>
                                     RECOMBINANT
                                     HEMOPHILIA          RAHF-PFM
           DATE                     PRODUCT (IN IUS)     (IN IUS)
           ----                    ------------------   -----------
<S>                                <C>                  <C>
July 1, 2004 through September
30, 2004                                     [*]               [*]

October 1, 2004 through
December 31, 2004                            [*]               [*]

January 1, 2005 through March
31, 2005                                     [*]               [*]

April 1, 2005 through June 30,
2005                                         [*]               [*]

July 1, 2005 through September
30, 2005                                     [*]               [*]

October 1, 2005 through
December 31, 2005                            [*]               [*]
</TABLE>

"Specification of respective quantities of Recombinant Hemophilia Product and
rAHF-PFM will be negotiated as set forth above. Pricing will be established at
the then current price as of [*] of each subsequent year for each therapy for
the quantity of that therapy for which Purchaser commit to purchase in each
year.

"5.7  Purchase Commitment.

                                   Page 3 of 7
<PAGE>

                  "a.   As to Hemofil M AHF only, the Base Level Product Volume
                        is set forth in Schedule C-3. No later than [*] of each
                        subsequent year this Agreement is in effect, the Parties
                        will commence good-faith discussions between their
                        designees toward setting the Base Level Product Volume
                        for Hemofil M AHF.

                        "Should the Parties fail to reach an agreement as to the
                        Base Level Product Volume for Hemofil M AHF for any
                        period of time that this Agreement is in effect prior to
                        [*] of said year, the Parties agree that the Base Level
                        Product Volume for the previous year, as set forth in
                        Schedule C-2 (as then amended), shall be effective for
                        said year.

                  "b.   As to Recombinant Hemophilia Product and/or rAHF-PFM
                        only, the Base Level Product Volumes are set forth in
                        Schedule A-2. Thereafter, no later than [*] of each
                        subsequent year this Agreement is in effect, the Base
                        Level Product Volume for Recombinant Hemophilia Product
                        and/or rAHF-PFM will be set pursuant to Paragraph 5.1.

                        "The Additional Recombinant Base Level Product Volume
                        for calendar year 2005 shall be designated as set forth
                        in Paragraph 5.1.1. Notwithstanding the foregoing,
                        should the Parties fail to reach an agreement as to the
                        Base Level Product Volume(s) for Recombinant Hemophilia
                        Product and/or rAHF-PFM for any additional period of
                        time that this Agreement remains in effect prior to [*]
                        of said year, the Parties agree that the Base Level
                        Product Volume(s) for the previous year, as set forth in
                        Schedule A-2 (as then amended), shall be effective for
                        said year.

            5.9   Recombinant Hemophilia Product Pricing and Commitment.

                  Should Purchaser purchase recombinant from any Baxter
                  authorized distributor at a price lower than the price for
                  Recombinant Hemophilia Product set forth on Schedule C-3, then
                  Purchaser shall certify to Baxter in writing (i) the quantity
                  recombinant purchased, (ii) the price at which recombinant was
                  purchased, (iii) the date recombinant was delivered to
                  Purchaser, and (iv) the Baxter authorized distributor from
                  which recombinant was purchased. Upon receipt of such
                  certification, Baxter will credit the quantity of said
                  purchase to Purchaser's current year Base Level Product
                  Volume. If, at any time during the term of this Agreement,
                  Baxter discontinues its distribution of Recombinant Hemophilia
                  Product, Purchaser's purchase commitments for both Recombinant
                  Hemophilia Product and Additional Base Level Product Volume
                  under the Agreement [*].

      3.    Schedule A-1 is hereby deleted, and the Agreement is hereby amended
            so that all references to such Schedule shall be to the new Schedule
            A-2 of the Agreement attached hereto.

      4.    Schedule C-2 is hereby deleted, and the Agreement is hereby amended
            so that all references to such Schedule shall be to the new Schedule
            C-3 of the Agreement attached hereto.

      5.    The Parties agree that in consideration of this Fourth Amendment,
            each Party expressly waives any claim of antecedent breach or claims
            for monetary damages, liquidated or otherwise, arising out of the
            other Party's breach of the Agreement.

      6.    This Fourth Amendment will be effective until the expiration of the
            term of the Agreement (unless further amended in accordance with the
            terms of the Agreement).

                                   Page 4 of 7
<PAGE>
      7.    In the event of any conflict between the Agreement and its
            associated schedules and this Fourth Amendment and its associated
            schedules, the provisions of this Fourth Amendment and its
            associated schedules shall be controlling. Except as specifically
            modified herein, the terms and conditions of the Agreement are
            hereby affirmed, confirmed and ratified.

IN WITNESS WHEREOF, the Parties have caused this Fourth Amendment to be executed
by their duly authorized representatives:

    PURCHASER:                          BAXTER:

    Coram, Inc.                         Baxter Healthcare Corporation
                                        Through its BioScience business unit
                                        Sales and Marketing North America region

    By: /s/ FRANK GEIGER                By: /s/ PETER O'MALLEY
        ------------------------------      --------------------------------
    Name:   Frank Geiger                Name:   Peter O'Malley
    Title:  SRVP, Materials Management  Title:  VP/GM
    Date:   June 28, 2004               Date:   7/2/04

                                   Page 5 of 7
<PAGE>


                                  SCHEDULE A-2

                         RECOMBINANT HEMOPHILIA PRODUCT

                                RECOMBINATE RAHF
                           BASE LEVEL PRODUCT VOLUMES

<TABLE>
<CAPTION>
Year                  Base Level Volumes (In Units)
----                  -----------------------------
<S>                   <C>
2004                              [*]

2005                              [*]
</TABLE>

                                     ADVATE RAHF-PFM
                               BASE LEVEL PRODUCT VOLUMES

<TABLE>
<CAPTION>
Year                  Base Level Volumes (In Units)
----                  -----------------------------
<S>                   <C>
2004                             [*]

2005                             [*]
</TABLE>

                                 ADDITIONAL RECOMBINANT
                               BASE LEVEL PRODUCT VOLUMES

<TABLE>
<CAPTION>
Year                  Base Level Volumes (In Units)
----                  -----------------------------
<S>                   <C>
2004                              [*]

2005                              [*]
</TABLE>

                                   Page 6 of 7
<PAGE>

                                  SCHEDULE C-3

                          PRICES AND VOLUME COMMITMENTS

                    JANUARY 1, 2004 THROUGH DECEMBER 31, 2004

<TABLE>
<CAPTION>
      THERAPEUTIC PROTEIN                LIST NUMBER              PRICE/UNIT         VOLUME COMMITMENT
      -------------------                -----------              ----------         -----------------
<S>                                <C>                           <C>                 <C>
Factor VIII Hemofil** M AHF        060-792: 060-793: 060-795:
                                        060-796                       [*]                 [*]
</TABLE>

                     JULY 1, 2004 THROUGH DECEMBER 31, 2004

<TABLE>
<CAPTION>
                                                                                   NEW STOCKING          VOLUME
      THERAPEUTIC PROTEIN                LIST NUMBER              PRICE/UNIT          ORDER            COMMITMENT
      -------------------                -----------              ----------          -----            ----------
<S>                                 <C>                         <C>                 <C>               <C>
Factor VIII Recombinate** rAHF      060-351: 060-352: 060-353         [*]              N/A                 [*]

Factor VIII ADVATE***  (rAHF-PFM).     060-110:060-111
                                       060-112:060-113                [*]              N/A                 [*]

FEIBA*** VH Anti-Inhibitor                922204                      [*]              N/A                 [*]
Coagulation Concentrate

Bebulin VH Factor IX Complex              924402                      [*]              N/A                 [*]

Proplex T Factor IX                      060-739                      [*]              N/A                 [*]
</TABLE>

               EFFECTIVE JANUARY 1, 2005 THROUGH DECEMBER 31, 2005

<TABLE>
<CAPTION>
                                                                                   NEW STOCKING          VOLUME
      THERAPEUTIC PROTEIN                LIST NUMBER              PRICE/UNIT          ORDER             COMMITMENT
      -------------------                -----------              ----------          -----             ----------
<S>                                 <C>                         <C>                <C>                <C>
Factor VIII Recombinate** rAHF      060-351: 060-352: 060-353         [*]              N/A                 [*]


                                        060-110:060-111
Factor VIII ADVATE***  (rAHF-PFM).      060-112:060-113               [*]              N/A                 [*]

Factor VIII Hemofil** M AHF             060-792:060-793:
                                        060-795:060-796               [*]              N/A                 [*]

FEIBA*** VH Anti-Inhibitor
Coagulation Concentrate                     922204                    [*]              N/A                 [*]

Bebulin VH Factor IX Complex                924402                    [*]              N/A                 [*]

Proplex T Factor IX                        060-739                    [*]              N/A                 [*]
</TABLE>

**Hemofil, Proplex, Recombinate and ADVATE are trademarks of Baxter
International, Inc. Hemofil and Proplex are registered with the US Patent and
Trademark Office.

*** FEIBA and Bebulin are trademarks of Baxter AG and are registered with the US
Patent and Trademark Office.

                                   Page 7 of 7