<PAGE>

                                                                   Exhibit 10.27

          Confidential Materials omitted and filed separately with the
        Securities and Exchange Commission. Asterisks denote omissions.



                                SUPPLY AGREEMENT


This Supply Agreement (the "AGREEMENT") is entered into by and between:

NXSTAGE MEDICAL, INC., a company organized and existing under the laws of
Delaware, and having offices at 439 S. Union Street, 5th Floor, Lawrence, MA
01843 (together with its Affiliates (as defined below), hereafter referred to as
"NXSTAGE")

and

MEMBRANA GMBH, a company organized and existing under the laws of Germany having
offices at Ohder Str. 28, D-42289 Wuppertal, Germany (together with its
Affiliates, hereinafter referred to as "MEMBRANA")

WHEREAS, NxStage is engaged, inter alia, in the manufacture and sale of products
that deliver therapeutic renal care solutions including filters containing
membranes ("dialyzers");

WHEREAS, Membrana is engaged in the manufacture and sale of membranes for
various applications including without limitation, synthetic membranes for
hemodialysis;

WHEREAS, NxStage and Membrana are parties to that certain Supply Agreement with
an effective date of October 1, 2004 (the "OLD CONTRACT");

WHEREAS, Membrana and NxStage wish to replace the Old Contract in its entirety
with this Agreement;

WHEREAS, Membrana and NxStage wish to enter into this Agreement for the supply
of the hemodialysis membranes listed on Annex 1 (hereinafter referred to as the
"MEMBRANES"). Other types of membranes may be added to this list by the mutual
agreement of the parties;


NOW, THEREFORE, the parties agree as follows:


ARTICLE 1: SCOPE OF AGREEMENT

This Agreement replaces in its entirety the Old Contract and shall govern all
orders for Membranes provided to Membrana by NxStage from January 1, 2007 (the
"EFFECTIVE DATE") through December 31, 2016 (the "EXPIRATION DATE") unless
sooner terminated pursuant to this Agreement. Section 8.1 of the Old Contract
shall be superseded by Article 9 of this Agreement and Confidential Information
covered by such Section 8.1 shall be covered by Article 9 of this Agreement.
Purchases made prior to the Effective Date shall continue to be governed by the
Old Contract. Except as set forth in this Article 1, the Old Contract is
superseded in its entirety by this Agreement.


<PAGE>

ARTICLE 2: SPECIFICATIONS

Membranes will be manufactured according to the specifications set forth in
Annex 2 (the "SPECIFICATIONS"). NxStage shall have the right to periodically
make changes to the Specifications and/or add additional Specifications, subject
to the prior written consent of Membrana, which shall not be unreasonably
withheld. Changes in Specifications initiated by NxStage may result in changes
to pricing. NxStage shall consider in good faith all changes to the
Specifications proposed by Membrana, but shall not be required to accept such
proposed changes if (i) products containing membranes meeting the existing
Specifications are being sold by Membrana to third parties who are not being
required to move to new specifications, (ii) such proposed changes reduce, in
any way, the performance or manufacturability of the Membranes being supplied to
NxStage hereunder, as determined in the sole and reasonable discretion of
NxStage, or (iii) such proposed changes increase, in any way, the prices paid by
NxStage for Membranes hereunder. Further, even if none of the conditions set
forth in subsections (i), (ii) and (iii) occur, NxStage shall not be required to
accept such proposed changes until it has obtained all regulatory approvals
required to market products containing such modified Membranes in the
territories in which NxStage's products are then marketed. NxStage agrees that
it shall seek to obtain promptly any such required regulatory approvals. In the
event NxStage elects to purchase a new membrane type from Membrana, a signed
supplement will be added to this Agreement before the first shipment of such
membranes, detailing the pricing and membrane specifications, which shall be
agreed to in good faith by the parties hereto. Without limiting any of the
foregoing, Membrana shall make available to NxStage all high-flux membranes for
use in renal replacement or fluid overload therapies manufactured by Membrana
during the term of this Agreement, including without limitation membranes
developed after the Effective Date hereof, but excluding any such membranes
co-developed with a third party, except upon the written consent of such third
party, which Membrana shall use commercially reasonable efforts to obtain. In
the event NxStage elects to purchase a new membrane type from Membrana, a signed
supplement will be added to this Agreement before the first shipment of such
membranes, detailing the pricing and membrane specifications, which shall be
agreed to in good faith by the parties hereto. In determining the pricing for
any new membrane types, Membrana agrees to provide NxStage with competitive
pricing. All other terms of the Agreement will remain unchanged. If NxStage
declines to purchase a new membrane type introduced to it by Membrana, Membrana
shall be free to enter into an exclusive sales arrangement with a third party
for that membrane type.

ARTICLE 3: EXCLUSIVITY AND PRODUCT ORDERING

NxStage agrees to purchase from Membrana under this Agreement 100% of its
       requirements for blood contacting membranes used in dialyzers used with
       the NxStage System One or successor NxStage products. NxStage further
       agrees that Membrana shall have the right of first refusal with respect
       to the supply of membranes for other products used with the NxStage
       System One or successor products. In the event Membrana supplies such
       membranes, a separate agreement will be entered into by the parties to
       govern such sales.

3.1    NxStage shall submit purchase orders for Membranes at least [**] weeks
       prior to the desired shipment date. Membrana shall accept within [**]
       days of receipt of the applicable purchase order through a written order
       confirmation, and timely supply all purchase orders




                                      -2-
<PAGE>

       that are consistent with NxStage's then-current accepted Forecast (as
       defined in Section 6.3 below) and are in compliance with this Agreement.

3.2    Without limiting any other rights of NxStage hereunder, if Membrana
       cannot meet NxStage's volume requirements for any reason, other than due
       to a Force Majeure Event or due to breach of this Agreement by NxStage,
       and NxStage has placed valid purchase orders for such Membranes, Membrana
       will reserve production capacity for NxStage according to the ratio
       between [**].

3.3    Membrana shall use commercially reasonable efforts to accept and timely
       supply all orders in excess of NxStage's forecasted amount for the period
       or requesting delivery in less than [**] weeks from the order date, and
       shall notify NxStage in writing if Membrana anticipates that it will not
       be able to satisfy such orders by the delivery dates indicated.

3.4    NxStage shall duly examine all deliveries of Membrane bundles received
       for any apparent defects. Deviations with regard to the color shade of
       the Membranes shall not be deemed to be defects unless they lead to any
       deterioration in the quality or marketability (from NxStage's customers'
       perspectives) of the products made therefrom. NxStage shall notify
       Membrana of any defects discovered in writing within [**] months after
       the respective installment of Membranes has been received; provided that
       in the case of hidden defects, notice of defects shall be given by
       NxStage immediately after discovery, but no later than [**] years after
       the date of delivery of the Membranes (the "Membrane Expiration Date").
       In its notice, NxStage shall specify the quantity found defective, the
       corresponding invoice, packing units, fabrication numbers and production
       days of the Membrane bundles in question. NxStage makes no representation
       that it will inspect all Membranes delivered. Membrana understands that
       it is fully responsible for ensuring that its Membranes meet the
       Specifications. NxStage agrees that Membrana shall not be responsible for
       defects to Membranes caused directly by NxStage's (i) manufacturing
       processes; (ii) storage of Membranes in unsuitable conditions; or (iii)
       negligence or willful misconduct. Any claims by NxStage relating to
       defects in the Membranes not made within the timeframes described in this
       Section 3.4 shall be deemed waived provided, however, that any obligation
       of Membrana to provide indemnity under Section 10 shall apply to claims
       brought after the Membrane Expiration Date for incidents that occur prior
       to the Membrane Expiration Date where such claims are brought prior to
       the expiration of the applicable statute of limitations period or other
       applicable claim period contractually agreed between NxStage and the
       party bringing the claim, whichever occurs first.

3.5    For all timely claims, Membrana shall reimburse NxStage for the cost of
       [**] and shall replace all out--of-Specification Membranes not yet
       incorporated into finished product if requested by NxStage in lieu of a
       refund for such Membranes pursuant to Article 8. In addition, regardless
       of whether the limits described in Article 8 are met by payments made
       pursuant to the immediately preceding sentence, Membrana shall reimburse
       NxStage for all




                                      -3-
<PAGE>

       recall expenses incurred by NxStage pursuant to a recall under the
       supervision of a government agency, whether voluntary or involuntary, and
       relating to products incorporating out-of-Specification Membranes to the
       extent that such Membranes are the direct cause of the recall, up to [**]
       for the out-of-Specification Membranes.

ARTICLE 4: PRICES/PAYMENT

4.1    The parties agree to pricing as described in the sections that follow and
       agree that allowable adjustments to price will include: NxStage annual
       chronic Therapy Average Sales Price ("TASP", as such term is hereafter
       defined), actual annual fiber volume purchased, and Euro to US dollar
       exchange rates. Beginning in 2007 and annually thereafter, NxStage will
       provide a forecast of the volume of Membranes that it will purchase for
       the next calendar year by [**] and a forecast of the expected TASP for
       the next calendar year (an "Annual Forecast"). For convenience of
       invoicing and payments over 2008 and subsequent years, NxStage and
       Membrana will use the Annual Forecasts to mutually agree on an
       appropriate calculated invoice price for the next calendar year, using
       the pricing matrix below and the procedures detailed in this Article 4.
       The parties acknowledge that at the end of each year the invoiced price
       for Membranes shall be reconciled based on actual Membrane volumes
       purchased and actual TASP. Appropriate adjusting payments will be made
       between the parties, no later than March 1st following the end of the
       preceding calendar year, to reconcile the actual net price paid, per
       Section 4.4.3 below. For purposes hereof, "TASP" shall mean the average
       monthly total sales price paid by NxStage chronic customers prescribing
       monthly treatment with the NxStage System One, or its successor products.

4.2    The pricing for all Membranes ordered and received at NxStage during the
       period August 10, 2006 through December 31, 2006, and for the first
       shipment received in January, 2007, shall be [**] Euros per km. This
       price represents an equal split of the savings due to new Membrane
       pricing vs. applicable pricing from the Old Contract, retroactive to
       August 10, 2006.

4.3    For the calendar year 2007, the pricing shall be according to Figure 1
       below. This pricing matrix assumes a TASP of $[**] per patient per month
       and a baseline exchange rate as of the Effective Date of the contract of
       [**] US Dollars to 1 Euro for the same period.

Figure 1. Pricing for Calendar Year 2007



                                      -4-
<PAGE>

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
   A. Annual      B. % of TASP for      C. Minimum Price       D. Base Euro
    Volume,        all Membranes            (Euro/km)         Price per km at
   ([**] Km)          purchased                                 TASP of [**]
                                                                 (US$/month)
--------------------------------------------------------------------------------
<S>               <C>                   <C>                   <C>
      [**]              [**]                  [**]                   [**]
--------------------------------------------------------------------------------
      [**]              [**]                  [**]                   [**]
--------------------------------------------------------------------------------
      [**]              [**]                  [**]                   [**]
--------------------------------------------------------------------------------
</TABLE>

       Note: The exchange rate of [**] US Dollars to 1.00 Euro is only used as
       the basis for establishing the percentages and prices listed in the
       table. This exchange rate is used to determine the applicable Base Euro
       pricing for each year and shall not be modified over the Term of this
       Agreement. Price adjustments for fluctuations in actual exchange rates
       will be handled as set forth in section 4.5 below.

       Note: All calculations taking place under this Section 4 will be carried
       out to 4 decimal places.

4.4    Pursuant to the Annual Forecasts and for calendar years beginning in
       2008, the parties shall create a new price matrix substantially
       equivalent to Figure 2 below. The price matrix shall be completed during
       the month of December of the prior year (beginning in December 2007) and
       shall incorporate the forecasted TASP for the forthcoming year in its
       derivation. The Base Euro Price (column D.) shall be calculated for each
       year using the % of TASP (Column B) provided that the price is not less
       than the "Minimum Price" (Column C). The values in Figure 2 assume a
       monthly therapy consisting of [**] treatments per month and [**] km of
       Membranes per treatment. As set forth in Section 4.4.3 below, changes to
       either of these baseline assumptions will require changes to Figure 2 and
       a formal amendment to this agreement. See Example A below for the
       completion of Column D for each year.

Figure 2.  Pricing for Calendar Years 2008 and Beyond

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
  A. Annual      B. % of TASP for      C. Minimum Price       D. Base Euro
   Volume,        all Membranes            (Euro/km)        Price per km at
  ([**] Km)         purchased                               treatment fee of
                                                             TBD (US$/month)
--------------------------------------------------------------------------------
<S>              <C>                   <C>                  <C>
    [**]               [**]                  [**]
--------------------------------------------------------------------------------
    [**]               [**]                  [**]
--------------------------------------------------------------------------------
    [**]               [**]                  [**]
--------------------------------------------------------------------------------
</TABLE>

       4.4.1    Once Figure 2 has been completed for the specific calendar year,
                i.e. once Column D. has been derived, the forecasted fiber
                volume shall be used to derive the invoice price for the
                forthcoming year using linear interpolation [**]. The invoice
                price shall be the same for all Membranes shipped in a



                                      -5-
<PAGE>

                calendar year. See Example D below for the specifics of linear
                interpolation.

Example A -- Calculation of Base Euro Price (Column D)
If the forecasted and agreed TASP is $[**], then the Base Euro Price is
calculated as follows:

Therapy definition: [**] treatments per month x [**] km per treatment = [**] km
per month

$[**]/US$[**]/Euro = Euro [**]

Euro [**] x % of TASP (as set based on Annual Volumes) / [**] km per month =
Base Euro Price

<TABLE>
<CAPTION>
Annual Volume:    TASP              % of TASP     Therapy       Base Euro Price
-------------------------------------------------------------------------------
<S>               <C>               <C>           <C>           <C>
[**] Km           Euro [**]    x    [**]%  /      [**] km/month =     [**]
    ------------------     ---------    -----------------------------
[**] Km           Euro [**]    x    [**]%  /      [**] km/month =     [**]
    -------------------    ---------    ------------------------------
[**] Km           Euro [**]    x    [**]%  /      [**] km/month =     [**]
    -------------------    ---------    ------------------------------
</TABLE>



<TABLE>
<CAPTION>
-----------------------------------------------------------------------------
  A. Annual      B. % of TASP for       C. Minimum Price     D. Base Euro
   Volume,         all Membranes           (Euro/km)        Price per km at
  ([**] Km)          purchased                               TASP of [**]
                                                              (US$/month)
-----------------------------------------------------------------------------
<S>              <C>                    <C>                 <C>
    [**]                   [**]                   [**]               [**]
-----------------------------------------------------------------------------
    [**]                   [**]                   [**]               [**]
-----------------------------------------------------------------------------
    [**]                   [**]                   [**]               [**]
-----------------------------------------------------------------------------
</TABLE>


Example B -- Calculation of Base Euro Price (Scenario 1) for Example Year
(Column D)
If the forecasted and agreed TASP is $[**], then the Base Euro Price is
calculated as follows:

Therapy definition: [**] treatments per month x [**] km per treatment = [**] km
per month

$[**]/US$[**]/Euro = Euro[**]

Euro[**] x % of TASP/[**] km per month = Base Euro Price

<TABLE>
Annual Volume:          TASP e          % of TASP      Therapy   Base Euro Price
--------------------------------------------------------------------------------
<S>            <C>                <C>            <C>             <C>
[**]           Euro [**]     x   [**]%  /        [**] km/month = [**]
    ----------------    ---------    ----------------------------
[**]           Euro [**]     x   [**]%  /        [**] km/month = [**]
    ----------------    ---------    ----------------------------
[**]           Euro [**]     x   [**]%  /        [**] km/month = [**]
    ----------------    ---------    ----------------------------
</TABLE>




                                      -6-
<PAGE>



Example B -- Continued -- Calculation of Base Euro Price for Example Year


<TABLE>
<CAPTION>
-------------------------------------------------------------------------------
  A. Annual      B. % of TASP for       C. Minimum Price     D. Base Euro
   Volume,         all Membranes           (Euro/km)         Price per km at
  ([**] Km)          purchased                              treatment fee of
                                                            [**] (US$/month)
-------------------------------------------------------------------------------
<S>              <C>                    <C>                 <C>
     [**]                    [**]                   [**]                  [**]
-------------------------------------------------------------------------------
     [**]                    [**]                   [**]                  [**]
-------------------------------------------------------------------------------
     [**]                    [**]                   [**]                  [**]
-------------------------------------------------------------------------------
</TABLE>


Example C -- Calculation of Base Euro Price (Scenario 2) for Example Year
(Column D)
If the forecasted and agreed TASP is $[**], then the Base Euro Price is
calculated as follows:

Therapy definition: [**] treatments per month X [**] km per treatment = [**] km
per month

$[**]/US$[**]/Euro = Euro[**]

Euro[**] * % of TASP/[**] km per month = Base Euro Price

<TABLE>
<CAPTION>
Annual Volume:       TASP            % of TASP       Therapy     Base Euro Price
--------------------------------------------------------------------------------
<S>             <C>              <C>            <C>              <C>
[**]            Euro [**]   x    [**]% /        [**] km/month =  [**]
---------------------    --------    -----------     ------------
[**]            Euro [**]   x    [**]% /        [**] km/month =  [**]
    -----------------    --------    -----------     ------------
[**]            Euro [**]   x    [**]% /        [**] km/month =  [**]
    -----------------    --------    -----------     ------------
</TABLE>

HOWEVER, THE MINIMUM PRICE (COLUMN C) WILL BE APPLIED AS DEFINED BY SECTION 4.4


<TABLE>
<CAPTION>
-----------------------------------------------------------------------------
  A. Annual      B. % of TASP for       C. Minimum Price     D. Base Euro
   Volume,        all Membranes           (Euro/km)         Price per km at
  ([**] Km)         purchased                               treatment fee of
                                                            [**] (US$/month)
-----------------------------------------------------------------------------
<S>              <C>                    <C>                 <C>
     [**]                    [**]                   [**]                [**]
-----------------------------------------------------------------------------
     [**]                    [**]                   [**]                [**]
-----------------------------------------------------------------------------
     [**]                    [**]                   [**]                [**]
-----------------------------------------------------------------------------
</TABLE>


         4.4.2    At the end of each year (beginning on December 31, 2007), the
                  parties will determine the difference between the invoice
                  price used for the then ending calendar year and the correct
                  invoice price for such year based on actual volumes purchased
                  and the actual TASP recorded for the year, applying the same
                  price to all Membranes shipped during the calendar year. Such
                  interpolation using the actual volumes purchased must be
                  applied to the pricing matrix for the just-completed year,
                  using the actual TASP and volumes to establish the fixed price
                  to be paid for that year. See Example D below for the
                  specifics of linear interpolation.

Example D -- Linear Interpolation


                                      -7-
<PAGE>

Referring to pricing table for 2007; if actual volume is [**] km then the
interpolated actual price would be:

[**]

The difference between the invoice price applied during the calendar year and
the actual price will be rebated to the appropriate party by March 1 of each
year.

         4.4.3    From time to time new bundle configurations (km/tx) and/or
                  treatment protocols based on less than [**] treatments per
                  month may be introduced. Once such alternative treatment
                  protocols reach [**]% or more of NxStage's total chronic
                  treatment sales, the parties shall agree upon the calculations
                  to be used in these situations it being understood that these
                  situations will be handled in an analogous fashion to the
                  calculations stated in this Section 4.1 to arrive at
                  appropriate base prices.

4.5 QUARTERLY EXCHANGE RATE ADJUSTMENT

All prices in this Agreement are in Euro unless otherwise stated. Foreign
exchange risk shall not affect the net invoice prices set forth in this Article
4 so long as the exchange rate between the US dollar and the Euro remains within
the range of 1 Euro to US$ [**] to US$ [**]. Exchange rate exposure sharing will
be calculated and applied quarterly using the average of published U.S. Federal
Reserve Board monthly figures (month 1 + month 2 + month 3)/3) for the calendar
quarter. The monthly exchange rate figure is currently accessible at
http://www.federalreserve.gov/releases/g5/, however if not available at that
address, the monthly exchange rate may be obtained directly from the U.S.
Federal Reserve Board. If the exchange rate goes outside the range of 1 Euro to
US$ [**] to US$ [**], then Membrana and NxStage will [**] the amount by which
the average published exchange rate differs from US$1.29 per Euro.
Notwithstanding the published exchange rate, for purposes of calculating the
risk sharing amount under this Article 4.3, the exchange rate value to be used
by the parties shall never be lower than US$ [**] to 1.00 Euro nor higher than
US$[**] to 1.00 Euro. For illustration purposes only, examples are set forth
below:

All adjusting payments to be made under this article 4.5 shall be made to the
receiving party in Euro and shall be converted to Euro at the quarterly average
exchange rate as defined here where necessary.

Example E -- Quarterly Exchange Rate Adjustment -- Scenario 1



                                      -8-
<PAGE>

Given an invoice price of Euro [**] for the calendar year (based upon [**] km
annual volume and linearly interpolated as in Example D) and a quarterly average
exchange rate of US$ [**] per Euro, then the currency risk sharing adjustment
will be as follows:

Risk-Shared Currency Exchange Rate:

($1.29 + $[**]  = [**] $/ Euro

Actual NxStage Price Paid in US$

Euro [**]/ Km x $[**] = $[**] / km

Currency-Adjusted NxStage Price in $US

Euro [**] / km x $[**] = $[**] / km

Net adjusting payment due to NxStage = $[**] - $[**] = $[**] / km

Net adjusting payment due to NxStage in Euros = $[**]) = [**] Euros / km


Example F -- Quarterly Exchange Rate Adjustment -- Scenario 2

Given an invoice price of Euro [**] for the calendar year (based upon [**] km
annual volume) and a quarterly average exchange rate of US$ [**] per Euro, then
the currency risk sharing adjustment will be as follows:

Risk-Shared Currency Exchange Rate:

($1.29 + $[**] = [**] $/Euro

However, the agreed exchange rate limit for risk sharing is $[**] to the Euro,
therefore the risk-shared exchange rate will be calculated as follows:

($1.29 + $[**]= [**] $/Euro

Actual NxStage Price Paid in US$

Euro [**] / Km  x $[**] = $[**] / km

Currency-Adjusted NxStage Price in $US



                                      -9-
<PAGE>

Euro [**] / km x $[**] = $[**] / km

Net adjusting payment due to Membrana = $[**] - $[**] = $[**] / km

Net adjusting payment due to Membrana in Euros = $[**] = [**] Euros / km

Example G -- Quarterly Exchange Rate Adjustment -- Scenario 3

Given an invoice price of Euro [**] for the calendar year (based upon [**] km
annual volume) and a quarterly average exchange rate of US$ [**] per Euro, then
the currency risk sharing adjustment will be as follows:

Risk-Shared Currency Exchange Rate:

 ($1.29 + $[**] = [**] $/Euro

However, the agreed exchange rate limit for risk sharing is $[**] to the Euro,
therefore the risk-shared exchange rate will be calculated as follows:

($1.29 + $[**] = [**] $/Euro

Actual NxStage Price Paid in US$

Euro [**]/Km  x $[**] = $[**] / km

The calculated Currency-Adjusted NxStage Price in $US

Euro [**] / km x $[**] = $[**] / km

The calculated Net adjusting payment due to NxStage = $[**] - $[**] = $[**] / km

However, the Minimum Price from column C of Figure 1, linearly interpolated to
an annual volume of [**] km will apply in this case.

The Currency-Adjusted NxStage Price in $US

Euro [**] x $[**] = $[**] / km

Net Adjusting payment due to NxStage = $[**] = $[**] / km

4.6 If NxStage fails to purchase a minimum of [**] km of Membranes in a calendar
year (the "BASE AMOUNT"), Membrana may terminate this Agreement upon 45 days'
written notice, provided that NxStage shall have the opportunity to purchase the
shortfall




                                      -10-
<PAGE>

amount, by submitting a purchase order for such volume during this 45 day
period. In the event of a Change of Control of NxStage (as defined below), the
Base Amount for the successor or acquirer shall be the higher of (i) the Base
Amount stated above, or (ii) [**] percent ([**]%) of the amount of the highest
past volume of Membranes purchased by NxStage in any calendar year of this
Agreement, which shall be annualized from the intervening months in the event
that a Change of Control happens prior to the conclusion of the first calendar
year (the "New Base Amount"). In addition to Membrana's other available
remedies, if the successor or acquirer of NxStage fails to purchase the New Base
Amount, the successor or acquirer will be required to purchase the shortfall
amount by submitting a purchase order for such volume within 45 days of the end
of the calendar year in which the New Base Amount was not achieved.
Notwithstanding the foregoing, the successor or acquirer of NxStage will not be
held liable for market forces or other factors outside of its control that drive
its requirements below the New Base Amount. In such an event Membrana and the
successor or acquirer of NxStage will agree upon an appropriate volume for the
New Base Amount in good faith.

4.7 If Membrana's actual direct material and utilities cost to manufacture
Membranes increases Membrana's cost to manufacture Membranes for NxStage by more
than [**]% after the Effective Date, then Membrana may, no more than [**] per
annum, and no more than [**] times over the term of this Agreement, propose to
raise the Membrane prices by the amount necessary to reflect only such direct
material or utilities costs increases subject to section 13.1 below. The parties
will discuss and agree to price increases in good faith.

4.8 Payments for all Membranes shall be due and payable by NxStage within [**]
days from the date of shipment of the Membranes. Membrana shall have the option
to change the payment terms if, in Membrana's reasonable discretion, NxStage
experiences a material adverse change in creditworthiness such as a decline in
credit rating applied by a third-party rating agency or repeatedly making late
payments for product.

4.9 Time is of the essence with regard to payments for Membranes. Late payments
shall bear interest at the lower of [**]% per month or the maximum amount
allowable under applicable law. In addition, late payments on undisputed
invoices that carry over the end of a calendar quarter shall automatically incur
a special administrative charge of [**]% of the past due balance of such late
payments.

4.10 From time to time, the parties shall work together on agreed upon joint
projects to identify and implement cost saving measures related to logistics.
Any savings that are



                                      -11-
<PAGE>

realized through these joint efforts shall be shared fairly between the parties
based upon each party's contribution to the project irrespective of whether the
implementation occurs at Membrana or NxStage's facilities.

ARTICLE 5: CAPACITY INSTALLATION

If, during the term of this Agreement, Membrana's capacity becomes insufficient
to meet NxStage's Membrane requirements, Membrana will consider adding
additional capacity and NxStage shall in good faith consider assisting Membrana
in obtaining the capital necessary to fund such additional capacity. Any capital
assistance provided by NxStage shall be returned to NxStage through price
decreases or such other terms agreed upon by the parties prior to NxStage
providing capital assistance. NxStage shall also consider agreeing to guaranteed
minimum volumes to assist Membrana in obtaining the capital necessary to fund
increased capacity. All additional capacity funded with NxStage assistance shall
be dedicated to supplying NxStage requirements on a first priority basis until
the capital assistance is repaid. Nothing herein shall limit Membrana's
obligation to supply Membranes to NxStage hereunder consistent with NxStage's
then-current forecasted requirements pursuant to Section 6.3.

ARTICLE 6: CONDITIONS

6.1    The resale of Membrane bundles in the form purchased by NxStage under
       this Agreement shall require Membrana's prior written consent.

6.2    Delivery of Membranes shall be free carrier (as defined in Incoterms
       2000) at Membrana's facility in Wuppertal, Germany. As soon as the
       Membranes leave Membrana's facility or are made available to NxStage for
       shipping, all transport risks shall pass to NxStage. A delivery period or
       a delivery date shall be deemed to have been adhered to if the goods have
       left Membrana's facility in Wuppertal, Germany by the expiry of the
       delivery period. Without limiting its obligations to fulfill all accepted
       purchase orders, Membrana shall be entitled to effect partial deliveries
       and to invoice for each such partial delivery, as far as a partial
       delivery is tolerable for NxStage. Membrana may deliver against any
       accepted purchase order up to [**]% more or less than the quantity
       ordered. The quantity actually delivered will be invoiced.
       Notwithstanding the foregoing, the parties agree that the preceding
       sentence shall not impact any of the percentages set forth in Sections
       6.5 and 6.6 hereof, and that in determining the percentages set forth in
       Sections 6.5 and 6.6 hereof, the parties shall calculate quantities of
       Membranes actually delivered compared to quantities ordered under NxStage
       accepted purchase orders.

6.3    Each month, NxStage shall provide Membrana with a rolling [**] month
       forecast (the "Forecast") with the first [**] months being a binding
       order. If Membrana produces Membranes in reliance on any of these binding
       portions of a forecast, NxStage agrees it



                                      -12-
<PAGE>

       will purchase those quantities of Membranes within [**] months of the
       date of the relevant forecast. Notwithstanding the foregoing, NxStage
       intends that the other [**] months of the forecast shall be nonbinding
       and that such months shall only be used by Membrana for planning
       purposes.

6.4    Shipment dates confirmed by Membrana are the dates ex warehouse
       Wuppertal, Germany.

6.5    Notwithstanding the foregoing, in the event that more than [**]% of
       NxStage's accepted purchase orders over any [**]-month period are not
       shipped within [**] days of the agreed upon shipment date, NxStage shall
       have the right to source the unavailable quantities from a third party
       and such volumes shall count towards the Base Amount and the volumes
       necessary to achieve certain pricing under Article 4.1, without penalty;
       provided that, in the case of a Force Majeure Event, such volumes shall
       not count towards the volumes necessary to achieve certain pricing under
       Article 4.1. If the cost of obtaining Membranes from another source is
       higher than the Membrane prices set forth herein, other than in the case
       of a Force Majeure Event, Membrana shall reimburse NxStage for the
       difference between the [**] and the [**] paid by NxStage hereunder;
       provided that Membrana shall have the [**], on behalf of NxStage, and to
       [**], upon the prior written consent of NxStage, which shall not be
       unreasonably withheld. Membrana understands that, in such event, time
       will be of the essence, and that Membrana must [**] thereof in order to
       preserve its rights of [**] under this Section 6.5. Once Membrana is able
       to supply the shortfall amount, and to meet 100% of NxStage's
       then-forecasted requirements, on a go-forward basis, NxStage shall resume
       purchasing 100% of its requirements from Membrana, except to the extent
       NxStage is then contractually prohibited from so doing by any third party
       from whom Membranes were purchased pursuant to the terms hereof.

6.6    In the event that (i) more than [**]% of NxStage's accepted purchase
       orders over any [**] month period (which months need not be consecutive)
       in the same [**] month period are not shipped within [**] days of the
       agreed upon shipment date, other than due to a Force Majeure Event, or
       (ii) more than [**]% of NxStage's accepted purchase orders over any (A)
       [**] consecutive months over the term of this Agreement, or (B) [**]
       month period, which months need not be consecutive, over the term of this
       Agreement, are not shipped within [**] days of the agreed upon ship date,
       other than due to a Force Majeure Event, or (iii) more than [**]% of
       NxStage's accepted purchase orders over any consecutive [**] month period
       over the term of this Agreement are not shipped within [**] days of the
       agreed upon ship date, due to a Force Majeure Event, then, in each case,
       the Base Amount requirements of Section 4.6 and the exclusivity
       requirements of Section 3 shall be terminated, and NxStage shall be free
       to obtain Membranes from another source thereafter (hereinafter
       collectively referred to, in each case, as an "Exclusivity Termination
       Event"), without liability. Following a Change of Control of Membrana (as
       defined below), in addition to the foregoing terms, the successor or
       acquirer of Membrana shall also pay to



                                      -13-
<PAGE>

       NxStage, in any of the scenarios set forth in subsections (i) and (ii)
       above, damages equal to [**] the Membrane Price for that volume of
       Membranes equal to NxStage's forecasted requirements for the [**], on an
       annualized basis, for the period of [**]. Any payments required pursuant
       to the preceding sentence must be made within [**] days of the date on
       which such payment is triggered.

6.7    In addition to the agreed prices, NxStage must pay any applicable
       statutory value-added or turnover tax. All other fees and taxes relating
       to NxStage's purchase of Membranes hereunder, which fees and taxes which
       were not known at the time of purchase, shall be borne by NxStage.
       Retention of due payments or offsetting shall be possible only on the
       basis of claims by NxStage which have been the subject of non-appealable
       court decisions or that have been acknowledged and agreed to by Membrana
       in writing.

ARTICLE 7: QUALITY DATA & TECHNICAL & SCIENTIFIC SUPPORT, REGULATORY MATTERS

7.1    Membrana shall provide NxStage with each shipment of Membranes the 'QC
       Data List' and the 'Attachment to QC-Specification' as shown by example
       in Annex 3. This shall include, among other things, a certification that
       the Membranes meet the Specification, and that the Membranes have been
       manufactured in accordance with applicable laws and regulations.

7.2    Membrana shall provide reasonable assistance to NxStage in connection
       with all regulatory filings made by NxStage or its affiliates relating to
       products incorporating the Membranes supplied by Membrana. Membrana,
       however, shall not be liable for any damages resulting from the given
       technical advice or the provided assistance.

7.3    NxStage and its representatives and affiliates shall have the right upon
       a minimum of [**] days' prior written notice to Membrana, during regular
       business hours, to audit Membrana's facilities where the Membranes are
       manufactured, packaged and stored and to make any further examination
       reasonably necessary to ascertain compliance with the Membrane
       Specifications.

7.4    Membrana shall give NxStage prompt notice if Membrana becomes aware of
       any defect or condition which in any way alters the Membrane
       Specifications or the quality of any of the Membranes supplied.

7.5    Membrana shall trace and maintain records regarding the source and lot
       number of each Membrane shipment for a period of [**] years after
       shipment of the Membranes to which the records pertain. These records
       shall be delivered to NxStage upon NxStage's request or upon the
       termination of this Agreement.

7.6    Membrana shall promptly notify NxStage of the occurrence of any changes
       in regulatory status related to its production of Membranes and of the
       outcome of any regulatory



                                      -14-
<PAGE>

       inspections which suggest a material weakness or deficiency in the
       quality of Membrana's Membrane manufacturing processes, documentation or
       facilities.

ARTICLE 8: LIMITED WARRANTY, LIABILITY AND DEFECTIVE MEMBRANES

8.1    NxStage and Membrana each hereby represent and warrant as follows:

       8.1.1     It is a corporation duly organized, validly existing and in
                 good standing under the laws of the jurisdiction of its
                 incorporation and has the full corporate power and authority to
                 enter into this Agreement and perform its agreements and
                 covenants to be performed hereunder.

       8.1.2     The execution and delivery of this Agreement and its
                 performance of the covenants and agreements hereunder have been
                 duly authorized by all necessary corporate action and, when
                 executed and delivered, shall be valid and binding upon it.

       8.1.3     Neither the execution and delivery of this Agreement nor the
                 performance by it of the transactions contemplated herein will
                 violate any provision of its certificate of incorporation or
                 bylaws or any rule, law, regulation, judgment, decree or other
                 order of any court, government, or governmental agency or
                 instrumentality, or conflict with or result in any breach of
                 any of the terms of, or the creation or imposition of any
                 charge or encumbrance pursuant to, any contract or agreement to
                 which it is a party or by which it, or any of its assets and
                 properties are bound.

Membrana warrants that the Membranes shipped to NxStage pursuant to this
Agreement shall meet the Specifications. EXCEPT AS SET FORTH IN THIS ARTICLE 8,
MEMBRANA EXPRESSLY DISCLAIMS AND EXCLUDES ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. EXCEPT AS SET FORTH IN ARTICLE 10 AND IN SECTION 3.5, IN THE EVENT OF
ANY CLAIMED OR ACTUAL BREACH OF WARRANTY, NXSTAGE'S SOLE AND EXCLUSIVE REMEDY IS
THE [**] OR [**]. EXCEPT AS SET FORTH IN ARTICLE 10, ARTICLE 6, OR, WITH RESPECT
TO RECALL EXPENSES, SECTION 3.5, OR IN THE CASE OF WILFUL REFUSAL TO SUPPLY
MEMBRANES WITHIN FORECAST ON A TIMELY BASIS (NOT DUE TO A FORCE MAJEURE EVENT),
MEMBRANA'S TOTAL LIABILITY UNDER THIS AGREEMENT REGARDLESS OF THE NATURE OF THE
CLAIM SHALL NOT EXCEED [**] TIMES THE INVOICE PRICE OF THE MEMBRANES THAT GAVE
RISE TO THE CLAIM. EXCEPT AS SET FORTH IN ARTICLE 10, IN NO EVENT SHALL EITHER
PARTY BE LIABLE FOR ANY INCIDENTAL, CONSEQUENTIAL, STATUTORY, PUNITIVE,
EXEMPLARY OR OTHER INDIRECT DAMAGES, INCLUDING, WITHOUT LIMITATION, LOSS OF
PROPERTY,



                                      -15-
<PAGE>

AND LOSS OF BUSINESS OR PROFITS OR OTHER ECONOMIC LOSSES, REGARDLESS OF THE
NATURE OF THE CLAIM OR THEORY OF RECOVERY.

Membrana shall not be liable for minor violations of the Agreement which do not
result in material harm to NxStage or physical injury to a person (it being
specifically understood without limitation that the delivery of
out-of-Specification Membranes shall constitute a major violation of the
Agreement), unless such minor violations are the result of Membrana's or its
agents' or affiliates' gross negligence or willful misconduct. Without limiting
the terms of this Agreement, including without limitation Article 3, the parties
agree to share adverse product yield impacts as measured by NxStage's Fiber leak
rate in NxStage's filter manufacturing plant, as. follows: Membrana will credit
NxStage [**] times the invoice price of Membrane bundles rejected over [**]% of
Membrane bundles incorporated by NxStage in dialyzers in a calendar month if
such fiber leaks are proven to be present in the Membranes as shipped by
Membrana. NxStage will supply Membrana with regular leak rate updates and
whenever a leak rate of over [**]% is reached. Membrana may request samples of
defective bundles prior to payment of a leak rate claim to confirm the accuracy
of the claim and to assist in investigations. Any payments to be made pursuant
to the foregoing paragraph shall be calculated and made [**] at the end of each
calendar [**]. For the avoidance of doubt, this Section is not intended to cover
fiber leaks incorporated in finished goods dialyzers.

ARTICLE 9: CONFIDENTIALITY, INTELLECTUAL PROPERTY, INFRINGEMENT MATTERS

9.1    NxStage shall keep strictly confidential any information disclosed by
       Membrana during the term of this Agreement or that was disclosed under
       the Old Contract which is confidential by nature or expressly marked as
       confidential, and Membrana will keep strictly confidential all
       information disclosed by NxStage during the term of this Agreement or
       that was disclosed under the Old Contract which is confidential by nature
       or expressly marked as confidential. Without limiting the foregoing,
       Membrana shall treat NxStage purchase orders, forecasts, and complaint
       investigation information as strictly confidential, especially prices,
       quantities and Membrane Specifications. The Parties' obligations to keep
       information confidential shall survive for [**] years following the
       termination of this Agreement.

For purposes of this Agreement, confidential information shall not include:

         -        Information, which was, or becomes, in the public domain
                  through no fault or action of the non-disclosing party;

         -        Information which was already known by the non-disclosing
                  party, as shown by its written records;

         -        Information which becomes known by the non-disclosing party
                  from a third party not under an obligation of confidentiality
                  to the disclosing party; or



                                      -16-
<PAGE>

         -        Information which is independently developed by the
                  non-disclosing party.

         The parties further agree that the terms of this Agreement shall be
         treated as confidential; provided that either party may disclose the
         terms hereof if required by law, including without limitation, pursuant
         to the requirements of United States Securities laws.

9.2    All ideas, developments and inventions which are made or conceived by
       Membrana jointly with representatives of NxStage during the term of this
       Agreement relating to dialysis equipment but excluding membranes shall be
       the sole and exclusive property of NxStage. All ideas, developments and
       inventions made or conceived by NxStage jointly with representatives of
       Membrana during the term of this Agreement relating to membranes
       including membrane manufacturing technology but excluding dialysis
       equipment shall be the sole and exclusive property of Membrana. In the
       event that a joint patent application is filed based on this Section 9.2,
       the parties will seek to negotiate in good faith an exclusive license
       agreement that will state which claims each party will have exclusive
       freedom to practice should the patent be granted; it being understood
       that such license shall contemplate that those claims relating to
       dialysis equipment shall be licensed exclusively to NxStage and those
       claims relating exclusively to membranes and membrane manufacturing
       technology shall be licensed exclusively to Membrana.

9.3    Membrana represents and warrants that, as of the Effective Date, it is
       not aware of any third party patent rights which are infringed by
       Membranes supplied to NxStage hereunder in the condition in which they
       are shipped to NxStage. In the event that such a right is asserted
       against either party, however, the respective party shall immediately
       inform the other party and both parties shall discuss subsequent actions.

         a)       If after due evaluation Membrana or NxStage decides to reduce
                  or stop the supply or use of Membranes in compliance with such
                  assertion, then Membrana will buy back from NxStage up to [**]
                  months of unused inventories of Membranes, as the case may be,
                  at the same price as NxStage has paid for Membranes.

         b)       If the parties agree to continue the supply and use of
                  Membranes in spite of such an assertion, they shall jointly
                  organize their defense and shall agree on a fair sharing of
                  costs required for an appropriate defense.

9.4      NxStage represents and warrants that, as of the Effective Date, it is
         not aware of any third party patent rights which are infringed by the
         dialyzers with the incorporation of the Membranes supplied to NxStage.
         In the event that such a right is asserted against either party,
         however, the respective party shall immediately inform the other party
         and both parties shall discuss subsequent actions.



                                      -17-
<PAGE>

         a)       If after due evaluation Membrana or NxStage decides to reduce
                  or stop the supply or use of Membranes in compliance with such
                  assertion, then NxStage will buy from Membrana up to [**]
                  months of unused inventories of Membranes, as the case may be,
                  at then-current pricing, to the extent quantities of inventory
                  are consistent with any then-current forecasts.

         b)       If the parties agree to continue the supply and use of
                  Membranes in spite of such an assertion, they shall jointly
                  organize their defense and shall agree on a fair sharing of
                  costs required for an appropriate defense.

ARTICLE 10: INDEMNIFICATION

10.1   Each party ("the Indemnifying Party") agrees to indemnify and hold the
       other party (the other party and its affiliates and the officers,
       employees and directors of the other party and its affiliates,
       collectively hereinafter referred to as the "Indemnified Party") harmless
       from any and all third party claims, damages, costs and expenses that may
       be claimed or asserted against the Indemnified Party, arising out of the
       negligence of the Indemnifying Party in performing its obligations
       hereunder or the breach of the Indemnifying Party of any terms hereunder,
       or the supply of a defective product or component (including, in the case
       of NxStage, its dialyzers) by the Indemnifying Party. The obligation of
       the Indemnifying Party to indemnify the Indemnified Party pursuant to
       this Section shall be conditioned upon the Indemnified Party giving
       reasonably prompt notice of any such claim for indemnification to the
       Indemnifying Party, and giving the Indemnifying Party authority to
       conduct the defense of any action in its sole discretion including
       deciding on settlement of any action; provided, however, that the
       Indemnified Party may retain additional counsel at its own expense and
       participate in any such litigation.

10.2   In order to discharge the obligations set forth in Section 10.1, Membrana
       and NxStage each agree to obtain and keep in force during the term of
       this Agreement, product liability insurance with a limit of liability of
       not less than $5,000,000. The insurance policies evidencing such
       insurance shall be endorsed to name NxStage and Membrana, as the case may
       be, as an additional insured and provide that the insurer will endeavor
       to provide written notification to the other party by the insurer of not
       less than thirty (30) days prior to cancellation, expiration or material
       modification of such insurance. A certificate of insurance from
       Membrana's and NxStage's insurers evidencing compliance with the
       requirements of this Section shall be given to NxStage and Membrana,
       respectively, upon the execution of this Agreement.

ARTICLE 11: TRADEMARK LICENSE

       NxStage shall co-brand any products it sells containing Membrana's
       Membranes with Membrana's trademark(s) related to such Membranes. Product
       containing PUREMA(R) Membranes shall include the Purema(R) trademark on
       brochures and publications as set



                                      -18-
<PAGE>

       forth in the trademark license agreement attached hereto as Annex 4 (the
       "Trademark Agreement"). NxStage shall not be required to put the PUREMA
       mark on product labels where it is not reasonably practical to do so.


ARTICLE 12: APPLICABLE LAW AND JURISDICTION

12.1   This Agreement shall be governed and construed in accordance with the
       laws of the state of Delaware, USA. The United Nations Convention on
       Contracts for the International Sales of Goods and any related subsequent
       Conventions shall not apply to sales hereunder.

ARTICLE 13: MISCELLANEOUS PROVISIONS

13.1   NxStage shall have the right, at its option and expense, to have a third
       party audit Membrana's records regarding its increased costs pursuant to
       Section 4.7 above once a year. Membrana shall have the right, at its
       option and expense, to have a third party audit NxStage's records with
       respect to its Treatment Fees once a year. Third party auditors may only
       report whether the value of cost or fees declared by a party is correct
       or incorrect and, if incorrect, the amount of the difference. If an audit
       uncovers errors in the value of costs or fees claimed by either party,
       appropriate rebates or other payments will be made using the corrected
       values. Further, the party with the uncovered error, if such uncovered
       error exceeds $[**], shall bear the cost of the third party audit.

13.2   This Agreement constitutes the entire Agreement between the parties.

13.3   Amendments and/or supplements to this Agreement must be in writing signed
       by both parties.

13.4   If any of the provisions of this Agreement should be or become invalid,
       this shall in no way interfere with the validity of the other provisions.
       The parties to this Agreement shall then replace the invalid provision by
       a new provision which comes the closest possible to the spirit of the
       provision declared to be invalid. Neither party shall be entitled to any
       compensation in case that any of the provisions of this Agreement is or
       becomes invalid.

13.5   This Agreement is not assignable or transferable by either party except
       to its successor or the transferee of all or substantially all of said
       party's business and assets to which this Agreement relates, and shall be
       binding upon and inure to the benefit of the parties, their current and
       future Affiliates, and their successors and permitted assigns.
       "AFFILIATE" means any person or entity directly or indirectly
       controlling, controlled by or under common control with the party in
       question. Each party will cause its Affiliates, successors and assigns to
       abide by the terms and conditions of this Agreement. The parties
       specifically agree that if a majority of their ownership or dialysis
       assets or Membrane manufacturing capacity is acquired by any third party
       (a "Change of Control"), that such third party will



                                      -19-
<PAGE>

       be bound by this Agreement and shall be required to fulfill the
       obligations of its predecessor as though such third party was an original
       party hereto. Membrana agrees that the exclusivity obligations set forth
       herein shall only apply to a successor (or acquirer) of NxStage's
       business following a Change of Control with respect to Membranes used in
       dialyzers used with the NxStage System One, or a successor product, and
       not to any other dialyzers manufactured by such successor (or acquirer).

13.6   Except as otherwise set forth in this Agreement, if either party is in
       breach or violation of any term or condition contained in this Agreement
       other than breaches related to payments of invoices, the other party
       shall provide written notice of such alleged breach to the breaching
       party. The breaching party shall then have a reasonable time to cure such
       breach of no less than [**] days. If it does so in a timely manner, then
       such breach shall be of no further effect and the parties shall resume
       their performance of this Agreement. In the event the breach is not so
       timely cured, then the non-breaching party shall have the ability to
       terminate this Agreement upon 30 days prior written notice to the
       breaching party.

13.7   Neither party shall be liable to the other party for any actual or
       threatened Act of God, war, the public enemy, mobilization, riot, strike,
       lockout, drought, fire, flood, explosion, accident, shortage of raw
       materials, delays of carriers, embargoes, the acts or orders of
       governments or political subdivisions thereof, or any other contingency
       or cause beyond the reasonable control of the affected party, which
       prevents or materially hinders such party's performance under this
       Agreement (a "FORCE MAJEURE EVENT"). The party undergoing the Force
       Majeure Event will provide written notice to the other party of such
       event and shall also inform the other party in writing when the affected
       party is able to resume its performance under this Agreement.

This Agreement may be executed in one or more counterparts, each of which will
       be deemed to be an original, but all of which will constitute one and the
       same instrument.


                            [signature page follows]



                                      -20-
<PAGE>



IN WITNESS WHEREOF, the undersigned parties have caused their duly authorized
representatives to execute this Agreement as of the Effective Date.


NXSTAGE MEDICAL, INC.                           MEMBRANA GMBH



By: /s/ Jeffrey H. Burbank                      By: /s/ Ulf Seidel
    -----------------------------------------       ----------------------------
    Name: Jeffrey H. Burbank                        Name: Ulf Seidel
    Title: President & Chief Executive Officer      Title: VP Sales & Marketing
    Date: 1/4/07                                    Date: 05-01-07
    Place: Lawrence, MA                             Place: Wuppertal, Germany


                                                By: /s/ Anthony W. Mancusi
                                                    ----------------------------
                                                    Name: Anthony W. Mancusi
                                                    Title: Key Account Manager
                                                    Date: 1/5/2007
                                                    Place: Charlotte, NC






                                      -21-
<PAGE>



                                     Annex 1
                                    Membranes


Membrana's PUREMA(R) membranes as specified on Annex 2.

















                                      -22-
<PAGE>



                                     Annex 2
                                 Specifications
                                   (attached)



















                                      -23-
<PAGE>


<TABLE>
<CAPTION>
<S>              <C>                                      <C>  <C>     <C>              <C>              <C>

                                                                                        --------------------------
                                                                                        MEDICAL MEMBRANE
                                                                                        --------------------------

MEMBRANA                                                               DATA SHEET
UNDERLINING PERFORMANCE                                                PRELIMINARY

PUREMA(R)                                                              INTENDED USE:    HEMODIALYSIS

                                                                       SHEET NO.        084/0126/000      OF 06/06
CAPILLARY MEMBRANE                                                     SUPERSEDES       084/0126/000      OF 12/04
TYPE H


CHEMICAL COMPOSITION                                                                                   TEST REF.NO:
                 --------------------------------------------------------------------------------------------------
                 Polymer                                  Polyethersulfone
-------------------------------------------------------------------------------------------------------------------
PHYSICAL PROPERTIES
                 --------------------------------------------------------------------------------------------------
                 Wall thickness                           m               30      (mu)m                  701/017
                                                          d          +/-  5       (mu)m
                 --------------------------------------------------------------------------------------------------
                 Inner diameter                           m               200     (mu)m                  701/017
                                                          d          +/-  15      (mu)m
-------------------------------------------------------------------------------------------------------------------
MEMBRANE PERFORMANCE CHARACTERISTICS
                 --------------------------------------------------------------------------------------------------
                 [**]                                     [**]       [**]         [**]                   [**]
                 [**]
                 [**]
                 --------------------------------------------------------------------------------------------------
                 [**]                                                                                    [**]
                 [**]
                 [**]                                     [**]       [**]
                 [**]                                     [**]       [**]
-------------------------------------------------------------------------------------------------------------------
AVAILABLE MAKE-UP CONFIGURATIONS
                 --------------------------------------------------------------------------------------------------
                                                          Bundles (customer specified), with P.E.T.(R)
                 --------------------------------------------------------------------------------------------------


The information contained in this data sheet reflects the      m = mean value; d = deviation of the mean value;
company's knowledge and experience at the time of issue.       a)mmHg = 1.333 mber = 133.3 Pa
No guarantee can, however, be given as to its                  (R) = reg. trade mark
completeness. Neither must it be construed to embody any       P.E.T. = Performance Enhancing Technology
liability on the part of Membrana GmbH beyond the
company's "General Conditions of Sale".
For questions related to handling and manufacturing please     MEMBRANA GMBH
refer to our separate "Instructions for handling and           Oehder Strabe 28, D - 42289 Wuppertal, Germany
processing (PUREMA(R))".                                       Postal address: Postfach 20 01 51, D - 42201 Wuppertal
This product is delivered non-sterile.                         Phone  (+49) (202) 6099-1
                                                               Fax    (+49) (202) 60 70 296
                                                               www.membrane.com

                                                               A POLYPORE COMPANY
</TABLE>



                                      -24-


<PAGE>

<TABLE>
<CAPTION>
<S>              <C>                                      <C>  <C>     <C>              <C>              <C>

                                                                                        --------------------------
                                                                                        MEDICAL MEMBRANE
                                                                                        --------------------------

MEMBRANA                                                               DATA SHEET
UNDERLINING PERFORMANCE                                                PRELIMINARY

PUREMA(R)                                                              INTENDED USE:    HEMODIALYSIS

                                                                       SHEET NO.        084/0000/000      OF 12/04
CAPILLARY MEMBRANE                                                     SUPERSEDES       084/0000/000      OF 08/04
PRIMARY BUNDLES


------------------------------------------------------------------------------------------------------------------
BUNDLE DIMENSIONS                                                                                     TEST REF.NO:
                 ----------------------------------------- -------------------------------------------------------
                 Length                                    nominal value                                  [**]
                                                           [**]       [**]        mm
                 -------------------------------------------------------------------------------------------------
                 Diameter                                  nominal value                                  [**]
                                                           [**]       [**]        mm
                 -------------------------------------------------------------------------------------------------
                 Number of capillaries                     nominal value
                                                                                                          --------
                                                           [**]       [**]        mm
---------------------------------------------------------- ---------- --------------------------------------------









The information contained in this data sheet reflects the      d = deviation of the mean value;
company's knowledge and experience at the time of issue.       (R) = reg. trade mark
No guarantee can, however, be given as to its
completeness. Neither must it be construed to embody
any liability on the part of Membrana GmbH beyond
the company's "General Conditions of Sale".
This product is delivered non-sterile.                         MEMBRANA GMBH
                                                               Oehder Strabe 28, D - 42289 Wuppertal, Germany
                                                               Postal address: Postfach 20 01 51, D - 42201 Wuppertal
                                                               Phone  (+49) (202) 6099-1
                                                               Fax    (+49) (202) 60 70 296
                                                               www.membrane.com

                                                               A POLYPORE COMPANY
</TABLE>


                                      -25-

<PAGE>



                                     Annex 3
                         QC Data and Data List Examples

















                                      -26-


<PAGE>



MEMBRANA
UNDERLINING PERFORMANCE


PUREMA(R) QC DATA LIST

DATE              28.11.2006
DELIVERY TO       NxStage GmbH & Co. KG
CONFIRMATION      0000011354
WEIGHT SPEC.      0080015502
INVOICE-NO.       007463019


PUREMA(R) CAPILLARY MEMBRANE                 TYPE: PUREMA H             [**]
                                             FIBERS/BUNDLE      :  [**]
                                             LENGTH/FIBERS (MN) :  [**]
                                             FINAL LENGTH ACCORDING TO CUSTOMERS
                                             SEPARATE SPECIFICATION
CRATE-NO.: 131536/2006255059-2006260077

<TABLE>
<CAPTION>
DATE     F-        JUL.           MEAN VALUE            SC         SC
TE       NO        DAY               UFR               CYTC       BSA

<S>      <C>       <C>            <C>                  <C>        <C>
SEP
12.      2085      06-255           [**]               [**]       [**]
13.                06-256           [**]               [**]       [**]
14.                06-257           [**]               [**]       [**]
15.                06-258           [**]               [**]       [**]
16.                06-259           [**]               [**]       [**]

16.      2086      06-259           [**]               [**]       [**]
17.                06-260           [**]               [**]       [**]
</TABLE>


QUALITY CONTROL MANAGEMENT

THIS QC DATA LIST HAS BEEN MADE BY ELECTRONIC DATA PROCESSING AND, THEREFORE,
HAS NOT BEEN SIGNED.

THIS QC DATA LIST HAS BEEN PREPARED WITH CARE AND TO THE BEST KNOWLEDGE AS PART
OF THE QUALITY ASSURANCE SYSTEM OF MEMBRANA GMBH. HOWEVER, IT DOES NOT RELIEVE
OUR CUSTOMERS OF THEIR OBLIGATION TO INSPECT THE GOODS UPON RECEIPT OR ESTABLISH
ANY WARRANTIES TO THIRD PARTIES TO WHOM IT MIGHT BE PASEED. NO ADDITIONAL
WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, IS LINKED HERETO.

                                                       MEMBRANA GMBH

                                                       Oehder Strabe 28
                                                       D - 42289 Wuppertal
                                                       Germany
                                                       Fon +49 (0) 2 02 60 99-0
                                                       Fax +49 (0) 2 02 60 57 15

                                                       www.membrane.com

Registered office: Wuppertal, Registry: Wuppertal Reg. 8 No. 9318


                                      -27-
<PAGE>

MEMBRANA
UNDERLINING PERFORMANCE

ATTACHMENT QC-SPECIFICATION

DATE              28.11.2006
DELIVERY TO       NxStage GmbH & Co. KG
CONFIRMATION      0000011354
WEIGHT SPEC.      0080015502
INVOICE-NO.       007463019


PUREMA(R) CAPILLARY MEMBRANE        TYPE: PUREMA H             UFR APP. 37


<TABLE>
<CAPTION>
ALMK/         PACK-           F-NO.      PROD.-       QTY         QTY OF        LENGTH      COMMER.
MATHR         NO.                        DATE         BUND.       FIBRES        IN MM       QTY./KM

<S>           <C>             <C>        <C>          <C>         <C>           <C>         <C>
04/131536     2006255059      2085       06255        [**]         [**]         [**]          [**]
                                         06256        [**]
              2006256060      2085       06256        [**]                                    [**]
              2006256061      2085       06256        [**]                                    [**]
              2006256062      2085       06256        [**]                                    [**]
              2006256063      2085       06256        [**]                                    [**]
                                         06257        [**]
              2006257064      2085       06257        [**]                                    [**]
              2006257063      2085       06257        [**]                                    [**]
              2006257066      2085       06257        [**]                                    [**]
                                         06258        [**]
              2006257067      2085       06257        [**]                                    [**]
              2006258068      2085       06258        [**]                                    [**]
              2006258069      2085       06258        [**]                                    [**]
              2006258070      2085       06258        [**]                                    [**]
              2006258071      2085       06258        [**]                                    [**]
                                         06259        [**]
              2006259072      2085       06259        [**]                                    [**]
              2006259073      2085       06259        [**]                                    [**]
              2006359074      2085       06259        [**]                                    [**]
              2006259075      2086       06259        [**]                                    [**]
                                         06260        [**]
              2006260076      2086       06260        [**]                                    [**]
              2006260077      2086       06260        [**]                                    [**]
</TABLE>




QUALITY CONTROL MANAGEMENT                             MEMBRANA GMBH

                                                       Oehder Strabe 28
                                                       D - 42289 Wuppertal
                                                       Germany
                                                       Fon +49 (0) 2 02 60 99-0
                                                       Fax +49 (0) 2 02 60 57 15

                                                       www.membrane.com

Registered office: Wuppertal, Registry: Wuppertal Reg. 8 No. 9318



                                      -28-
<PAGE>

                                     Annex 4
                Standard Trademark License and Quality Agreement
























                                      -29-


<PAGE>



                    NONEXCLUSIVE TRADEMARK LICENSE AGREEMENT



THIS AGREEMENT ("Agreement"), is made effective as of January 1, 2007, by and
between Membrana GmbH, a corporation organized under the laws of Germany, whose
principal place of business is located at Ohder Stra(beta)e 28, D-42289
Wuppertal, Germany (hereinafter referred to as "Licensor"), and NxStage Medical,
Inc. a Delaware corporation whose principal place of business is located at 439
South Union Street, Lawrence, MA 01843 (hereinafter referred to as "Licensee").



WHEREAS, Licensor is the owner of the entire right, title and interest in and to
the trademark "PUREMA" (hereinafter referred to as the "Trademark") for
membranes, namely membranes for therapeutic purposes, and for modules equipped
with the aforesaid membranes for use in medical apparatus especially dialysers,
registered among others in International Class 10 among others in Germany (Reg.
No. 30362253), in the United States of America (Serial No. 76/563234) and as
International Registration (IR No. 844176). Licensor is producing and selling
membranes made from synthetic polymer under said Trademark (hereinafter referred
to as the "Goods");

AND WHEREAS Licensee sells dialyzers and is interested in using the Trademark
for dialyzers containing the Goods (hereinafter referred to as the "Contract
Products");

AND WHEREAS, Licensor and Licensee are parties to a Supply Agreement dated of
even date herewith (hereinafter referred to as the "Supply Agreement").

NOW, THEREFORE, in consideration of the mutual covenants of the parties and the
sum of One Dollar ($1) herewith paid by Licensee to Licensor, the receipt of
which is hereby acknowledged by Licensor, the parties hereby agree as follows:

1. License. Licensor grants to Licensee a non-exclusive, non-royalty bearing
right to use the Trademark under the common law and under the auspices and
privileges provided by the registrations described above, covering the same
during the term of this Agreement solely in connection with Contract Products.
The License hereby granted by Licensor shall include the right of Licensee to
use said Trademark on Contract Products as well as on the packaging for the
Contract Products and promotional, sales and advertising literature in
association with the Contract Products.

2. Trademark Usage: Licensee shall be obligated to affix or otherwise display
the Trademark on the Contract Products, except where it is not reasonably
practicable to do so, packaging for the Contract Products and on promotional,
sales and advertising literature in association with the Contract Products in a
form and manner in compliance with the standards and specifications as
prescribed by Licensor (see Appendix 1). Notwithstanding the foregoing, Licensee
shall not be obligated to affix or display the Trademark on such portions of the
Contract Products where it does not place its own trademarks and where it is not
reasonably practicable to do so. Licensee shall have no obligation to affix or
otherwise display the Trademark on any finished Contract Products in inventory
as of the Effective Date that do not already bear the Trademark, which shall be
no more than six (6) months worth of inventory..

To the extent possible and reasonable from a technical and logistical
standpoint, Licensee shall be obligated to attach a notice that the Trademark is
registered to Licensor. . This notice shall be made through use of the symbol
(R) and a footnote explaining that the Trademark is registered trademark of
Licensor.



                                      -30-
<PAGE>

3. Inspection. Licensee will permit duly authorized representatives of the
Licensor to inspect Contract Products and related promotional materials of
Licensee at Licensee's premises using the Trademark at all reasonable times, in
a reasonable manner, and upon reasonable advance notice, for the sole purpose of
and strictly limited to ascertaining or determining compliance with Paragraphs
1, 2 and 4 hereof.

4. Use of Trademark. Attached hereto as Exhibit A are representative samples of
Product literature and promotional materials, including Licensor's Trademark.
Licensee agrees that its use of the Trademark in future materials developed by
Licensee shall be consistent with the appearance and placement of the Trademark
in the materials attached hereto as Exhibit A. On June 1st of every year,
Licensee shall provide Licensor with a copy of all product literature and
promotional material bearing the Trademark. Licensor shall advise Licensee of
any issues with the appearance and placement of the Trademark in the materials.
If Licensor does not approve, Licensee shall work with Licensor to promptly
address the issues and amend the materials so that they are mutually
satisfactory. If June 1st does not fall on a business day, Licensee shall
provide the materials on the first business day following June 1st.


5. Extent of License. The license granted in this Agreement shall be
nonexclusive and may not be sublicensed or transferred by Licensee without
Licensor's prior written consent, provided, however, that Licensee shall have
the right to assign this Agreement without the consent of Licensor to its
successor or the transferee of all or substantially all of its business and
assets to which this Agreement relates, provided that this Agreement shall be
binding upon any successor or permitted assign. Licensor shall have the right to
use the Trademark and to license its use to any other designee. In the event of
any pre-approved assignment, transfer, or sublicense, this Agreement, and the
rights and obligations hereunder, shall be binding upon such assignee,
transferee or sublicensee. Licensor hereby warrants and represents to Licensee
that Licensor owns the entire right, title and interest in and to the Trademark,
and that Licensor has the unrestricted right to grant the license and otherwise
enter into this Agreement.

6. Third Party Infringement. In the event any third party violates Licensor's
right, title or interest in the Trademark, Licensee shall reasonably cooperate
with Licensor in Licensor's defense of its rights at Licensor's expense.
Licensee shall notify Licensor of any violations of Licensor's right, title or
interest in the Trademark of which Licensee is aware. Licensor has the exclusive
right to prosecute and defend all suits or proceedings before governmental
agencies which involve in any way validity of, title to, or infringement of the
Trademark.

7. Termination.

      a. Except as otherwise provided herein, this Agreement shall remain in
full force and effect. This Agreement will be terminated: (i) at the will of
either party upon not less than six (6) months advance written notice to the
other party; (ii) by Licensor upon written notice if Licensee makes any
assignments of assets or business for the benefit of creditor, or a trustee or
receiver is appointed to conduct its business or affairs, or it is adjudged in
any legal proceeding to be either in voluntary or involuntary bankruptcy; or
(iii) immediately upon the expiration or termination of the Supply Agreement. In
the event this Agreement is terminated by Licensor pursuant to this subparagraph
(a), Licensee shall be able to continue for six (6) months after the effective
date to sell Contract Products then in its inventory (and related containers and
packages in connection therewith) that contain the Trademark at the time of
termination, provided, however, that in no event shall the Trademark be affixed
on such inventory, containers or packages after the effective date of
termination.


                                      -31-


<PAGE>

8. Ownership of Trademark. The Licensee and all parties to this Agreement
acknowledge Licensor's exclusive right, title and interest in and to the
Trademark and any registration that may issue thereon, and will not
intentionally at any time do or cause to be done any act or thing contesting or
in any way impairing or tending to impair part of such right, title and
interest. In connection with the use of the Trademark, neither Licensee nor any
other party hereto shall in any manner represent that he or it has any ownership
in the Trademark or registrations thereof, and all parties acknowledge that use
of the Trademark shall inure to the benefit of the Licensor. On termination of
this Agreement in any manner provided herein, except as otherwise set forth in
Section 6 above, the Licensee will cease and desist from all use of the
Trademark in any way and will deliver up to the Licensor, or its duly authorized
representatives, all material and papers upon which the Trademark appears, and
furthermore, Licensee will not at any time adopt or use without the Licensor's
prior written consent, any word or mark which is likely to be similar to or
confusing with the Trademark.

9. Notices. Any notices required or permitted to be given under this Agreement
shall be deemed sufficiently given if mailed by registered mail, postage
prepaid, addressed to the party to be notified at its address shown above, or at
such other address as may be furnished in writing to the notifying party.

10. Waiver: Modification. No change or modification of this Agreement shall be
valid or binding on the parties hereto, nor shall any waiver of any term or
condition be deemed a waiver of any such term or condition in the future, unless
such change or modification or waiver shall be in writing and signed by the
parties hereto.

11. Severability. In the event any provision or portion of this Agreement shall
be declared invalid by any court of competent jurisdiction, said declaration
shall have no effect upon the remaining provisions of this Agreement, all of
which shall remain in full force and effect and shall constitute the complete
understanding of the parties.

12. Limitation of Liability. In no event shall either party be liable to the
other party under this Agreement for any consequential, incidental, punitive or
other indirect damages except as set forth in Section 10 of the Supply
Agreement.

13. Conflicts. In the event of a conflict between the terms of this Agreement
and the Supply Agreement, the terms of the Supply Agreement shall govern.

14. Applicable Law. The validity and effect of this Agreement shall be governed
by and construed and enforced in accordance with the laws of the State of
Delaware.


NxStage Medical, Inc.

By: /s/ Jeffrey H. Burbank
    ------------------------------

Name:  Jeffrey H. Burbank
       ---------------------------

Title: President & CEO
       ---------------------------


Membrana GmbH

By: /s/ Ulf Seidel                           /s/ Stefan Breiter
    ------------------------------           ------------------------------

Name:  Dr. Ulf Seidel                        Dr. Stefan Breiter

Title: VP Sales and Marketing                Scientific Marketing Manager
       Medical Separations                   Medical Separations



                                      -32-
<PAGE>




APPENDIX 1.: Typeset of Licensed Trademark



The licensed Trademark "PUREMA" must appear as shown below and appear in the
typical PUREMA-red. The logo must not appear in running texts. In running text,
the Trademark is written in upper case in the same font as the text.



PUREMA(R)

colour:

CMYK:    100m 56y 18k

Pantone: 1945

HKS:     17

RAL:     3027

rgb:     175r 17g 54b










                                      -33-


<PAGE>


                                    EXHIBIT A

                          SAMPLE PROMOTIONAL MATERIALS




















                                      -34-