UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                  SCHEDULE 13D
                    Under the Securities Exchange Act of 1934



                             AMARIN CORPORATION PLC
--------------------------------------------------------------------------------
                                (Name of Issuer)


                  Ordinary Shares, 50 pence par value per share
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                    02311107
--------------------------------------------------------------------------------
                                 (CUSIP Number)


                                   John Heard
                                 Abingworth LLP
                                  Princes House
                                38 Jermyn Street
                                 London SW1Y 6DN
                                +44 20 7534 1500
--------------------------------------------------------------------------------
                  (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications)


                                October 16, 2009
--------------------------------------------------------------------------------
             (Date of Event which Requires Filing of this Statement)


If the filing person has previously  filed a statement on Schedule l3G to report
the  acquisition  that is the subject of this  Schedule  13D, and is filing this
schedule because of Sections 240.13d-1(e),  240.13d-1(f) or 240.13d-1(g),  check
the following box. [ ]

Note:  Schedules  filed in paper format shall include a signed original and five
copies of the schedule,  including all exhibits. See Section 240.13d-7 for other
parties to whom copies are to be sent.

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for  any  subsequent   amendment   containing   information  which  would  alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).





Cusip No.  02311107
--------------------------------------------------------------------------------
1.   Names of Reporting Persons.  I.R.S. Identification Nos. of above persons
     (entities only):

             Abingworth LLP
             98-051-8585
--------------------------------------------------------------------------------
2.   Check the Appropriate Box if a Member of a Group (See Instructions):

         (a) [ ]
         (b) [X]
--------------------------------------------------------------------------------
3.   SEC Use Only

--------------------------------------------------------------------------------

4.   Source of Funds (See Instructions):  WC (See Item 3)
--------------------------------------------------------------------------------
5.   Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d)
     or 2(e): [ ]

--------------------------------------------------------------------------------
6.   Citizenship or Place of Organization:    England
--------------------------------------------------------------------------------

   Number of                          7. Sole Voting Power:                   0
                                         ---------------------------------------
   Shares Beneficially                8. Shared Voting Power:        17,000,000
                                         ---------------------------------------
   Owned by Each Reporting            9. Sole Dispositive Power:              0
                                         ---------------------------------------
   Person With                       10. Shared Dispositive Power:   17,000,000
                                         ---------------------------------------
--------------------------------------------------------------------------------

11   Aggregate Amount Beneficially Owned by Each Reporting Person:   17,000,000
--------------------------------------------------------------------------------

12.  Check if the Aggregate Amount in Row (11) Excludes Certain Shares
     (See Instructions):   [ ]
--------------------------------------------------------------------------------

13.  Percent of Class Represented by Amount in Row (11):   17.33%
--------------------------------------------------------------------------------

14.  Type of Reporting Person (See Instructions):  PN
--------------------------------------------------------------------------------







Cusip No.  02311107
--------------------------------------------------------------------------------
1.   Names of Reporting Persons.  I.R.S. Identification Nos. of above persons
     (entities only):

             Abingworth Bioventures V Co-Invest Growth Equity Fund LP
             98-057-9772
--------------------------------------------------------------------------------
2.   Check the Appropriate Box if a Member of a Group (See Instructions):

         (a) [ ]
         (b) [X]
--------------------------------------------------------------------------------
3.   SEC Use Only

--------------------------------------------------------------------------------

4.   Source of Funds (See Instructions):  WC (See Item 3)
--------------------------------------------------------------------------------
5.   Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d)
     or 2(e): [ ]

--------------------------------------------------------------------------------
6.   Citizenship or Place of Organization:    England
--------------------------------------------------------------------------------

   Number of                          7. Sole Voting Power:                   0
                                         ---------------------------------------
   Shares Beneficially                8. Shared Voting Power:         7,500,000
                                         ---------------------------------------
   Owned by Each Reporting            9. Sole Dispositive Power:              0
                                         ---------------------------------------
   Person With                       10. Shared Dispositive Power:    7,500,000
                                         ---------------------------------------
--------------------------------------------------------------------------------

11   Aggregate Amount Beneficially Owned by Each Reporting Person:    7,500,000
--------------------------------------------------------------------------------

12.  Check if the Aggregate Amount in Row (11) Excludes Certain Shares
     (See Instructions):   [ ]
--------------------------------------------------------------------------------

13.  Percent of Class Represented by Amount in Row (11):    7.65%
--------------------------------------------------------------------------------

14.  Type of Reporting Person (See Instructions):  PN
--------------------------------------------------------------------------------







Cusip No.  02311107
--------------------------------------------------------------------------------
1.   Names of Reporting Persons.  I.R.S. Identification Nos. of above persons
     (entities only):

             Abingworth Bioventures V L.P.
             98-051-8587
--------------------------------------------------------------------------------
2.   Check the Appropriate Box if a Member of a Group (See Instructions):

         (a) [ ]
         (b) [X]
--------------------------------------------------------------------------------
3.   SEC Use Only

--------------------------------------------------------------------------------

4.   Source of Funds (See Instructions):  WC (See Item 3)
--------------------------------------------------------------------------------
5.   Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d)
     or 2(e): [ ]

--------------------------------------------------------------------------------
6.   Citizenship or Place of Organization:    England
--------------------------------------------------------------------------------

   Number of                          7. Sole Voting Power:                   0
                                         ---------------------------------------
   Shares Beneficially                8. Shared Voting Power:         7,500,000
                                         ---------------------------------------
   Owned by Each Reporting            9. Sole Dispositive Power:              0
                                         ---------------------------------------
   Person With                       10. Shared Dispositive Power:    7,500,000
                                         ---------------------------------------
--------------------------------------------------------------------------------

11   Aggregate Amount Beneficially Owned by Each Reporting Person:    7,500,000
--------------------------------------------------------------------------------

12.  Check if the Aggregate Amount in Row (11) Excludes Certain Shares
     (See Instructions):   [ ]
--------------------------------------------------------------------------------

13.  Percent of Class Represented by Amount in Row (11):    7.65%
--------------------------------------------------------------------------------

14.  Type of Reporting Person (See Instructions):  PN
--------------------------------------------------------------------------------






Cusip No.  02311107
--------------------------------------------------------------------------------
1.   Names of Reporting Persons.  I.R.S. Identification Nos. of above persons
     (entities only):

             Abingworth Bioequities Master Fund Limited
             66-066-0960
--------------------------------------------------------------------------------
2.   Check the Appropriate Box if a Member of a Group (See Instructions):

         (a) [ ]
         (b) [X]
--------------------------------------------------------------------------------
3.   SEC Use Only

--------------------------------------------------------------------------------

4.   Source of Funds (See Instructions):  WC (See Item 3)
--------------------------------------------------------------------------------
5.   Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d)
     or 2(e): [ ]

--------------------------------------------------------------------------------
6.   Citizenship or Place of Organization:    Cayman Islands
--------------------------------------------------------------------------------

   Number of                          7. Sole Voting Power:                   0
                                         ---------------------------------------
   Shares Beneficially                8. Shared Voting Power:         2,000,000
                                         ---------------------------------------
   Owned by Each Reporting            9. Sole Dispositive Power:              0
                                         ---------------------------------------
   Person With                       10. Shared Dispositive Power:    2,000,000
                                         ---------------------------------------
--------------------------------------------------------------------------------

11   Aggregate Amount Beneficially Owned by Each Reporting Person:    2,000,000
--------------------------------------------------------------------------------

12.  Check if the Aggregate Amount in Row (11) Excludes Certain Shares
     (See Instructions):   [ ]
--------------------------------------------------------------------------------

13.  Percent of Class Represented by Amount in Row (11):    2.04%
--------------------------------------------------------------------------------

14.  Type of Reporting Person (See Instructions):  CO
--------------------------------------------------------------------------------






Item 1.   Security and Issuer
          -------------------

          This Schedule 13D relates to the ordinary  shares,  50 pence par value
per share (the "Ordinary  Shares"),  of Amarin  Corporation  plc (the "Issuer"),
each Ordinary Share represented by one American Depositary Share (each, an "ADS"
and,  collectively,  the  "ADSs").  The ADSs are  listed on the  Nasdaq  Capital
Market.  The Issuer's  principal executive office is located at 7 Curzon Street,
London W1J 5HG England.

Item 2.   Identity and Background
          -----------------------

          (a)   This statement is filed on behalf of: (i) Abingworth Bioventures
V L.P. ("ABV V"); (ii) Abingworth  Bioventures V Co-Invest Growth Equity Fund LP
("AGE");  (iii) Abingworth  Bioequities  Master Fund Limited ("ABE" and together
with  ABV  V  and  AGE,  the  "Abingworth   Funds");  and  (iv)  Abingworth  LLP
("Abingworth" and together with the Abingworth Funds, the "Reporting  Persons"),
the investment manager of the Abingworth Funds.

          (b)   The address of the  principal  business  office of the Reporting
Persons is Princes House, 38 Jermyn Street, London SW1Y 6DN.

          (c)   The principal business of the  Abingworth Funds is  to invest in
and  assist  growth-oriented  businesses  in the  life  science  and  biomedical
industries.  The principal  business of Abingworth is to serve as the investment
manager to certain investment funds, including the Abingworth Funds.

          (d)   Neither the Reporting Persons nor any of its  executive officers
has, during the last five years, been convicted in a criminal proceeding.

          (e)   Neither the Reporting Persons nor any of its executive  officers
has,  during  the  last  five  years,  been a party to a civil  proceeding  of a
judicial or  administrative  body of competent  jurisdiction  and as a result of
such proceeding was or is subject to a judgment, decree or final order enjoining
future violations of, or prohibiting or mandating activities subject to, federal
or state securities laws or finding any violation with respect to such laws.

          (f)   Each of AGE and ABV V is a  limited partnership organized  under
the laws of England. ABE is a corporation organized under the laws of the Cayman
Islands.  Abingworth is a limited liability partnership organized under the laws
of England.

Item 3.   Source and Amount of Funds or Other Consideration
          -------------------------------------------------

          Pursuant to a Securities Purchase  Agreement,  dated as of October 12,
2009  (the  "Securities  Purchase  Agreement"),  by and among  the  Issuer,  the
Abingworth Funds and the other purchasers named therein (the "Other  Purchasers"
and together with the Abingworth Funds, the "Purchasers"),  the Abingworth Funds
acquired,  at the closing of the  transactions  contemplated  by the  Securities
Purchase Agreement (the "Closing"),  17,000,000  Ordinary Shares,  each Ordinary
Share represented by one ADS, and warrants (the "Warrants") to purchase up to an
aggregate  of  8,500,000  Ordinary  Shares for an  aggregate  purchase  price of
$17,000,000.  Each  Abingworth  Fund is prohibited  from exercising the Warrants
purchased by it, to the extent that after giving effect to such  exercise,  such
Abingworth Fund (together with its affiliates) would  beneficially own in excess
of 9.99% of the Ordinary Shares  outstanding  immediately after giving effect to
such exercise;  provided that such Abingworth Fund may increase or decrease such
percentage to any other  percentage (or waive the  applicability of the blocker)
upon written notice to the Issuer; provided, further, that any such increase (or
waiver) will not be effective until the sixty-first (61st) day after such notice
is delivered to the Issuer.  The Abingworth  Funds purchased the Ordinary Shares
and Warrants with their investment capital. Abingworth does not directly own any





of  the  Ordinary  Shares  or  the  Warrants.  Abingworth  disclaims  beneficial
ownership  of the  securities  reported  herein,  except  to the  extent  of its
pecuniary interest.  Each of the Abingworth Funds disclaims beneficial ownership
of any of the securities  reported  herein,  except for the  securities  held of
record by such Abingworth Fund.

Item 4.   Purpose of Transaction
          ----------------------

          The Reporting  Persons  acquired the  securities  reported  herein for
investment in the ordinary  course of business  because of their belief that the
Issuer  represents  an  attractive  investment  based on the  Issuer's  business
prospects and strategy.  The Reporting Persons reserve the right to acquire,  or
cause to be acquired,  additional  securities  of the Issuer,  to dispose of, or
cause  to be  disposed,  such  securities  at any  time  or to  formulate  other
purposes,  plans or proposals regarding the Issuer or any of its securities,  to
the extent deemed advisable in light of general  investment and trading policies
of the Reporting  Persons,  market  conditions or other  factors.  Except as set
forth  herein,  the Report  Persons do not have any plan or proposal  that would
relate to, or result in, any of the  matters  set forth  under  subsections  (a)
through (j) of Item 4 of Schedule 13D.

          Pursuant to the Securities Purchase  Agreement,  (i) the Issuer issued
and sold to the Abingworth  Funds,  and the Abingworth  Funds purchased from the
Issuer,  at  the  Closing,  17,000,000  Ordinary  Shares,  each  Ordinary  Share
represented by one ADS, and Warrants to purchase up to an aggregate of 8,500,000
Ordinary Shares and (ii) the Issuer issued and sold to the Other Purchasers, and
the Other  Purchasers  purchased  from the Issuer,  at the  Closing,  53,399,996
Ordinary  Shares,  each Ordinary  Share  represented by one ADS, and warrants to
purchase up to an  aggregate of  26,699,996  Ordinary  Shares (the  transactions
specified in clauses (i) and (ii) above are referred to herein  collectively  as
the "Private Placement"). Each Abingworth Fund is prohibited from exercising the
Warrants  purchased  by it,  to the  extent  that  after  giving  effect to such
exercise, such Abingworth Fund (together with its affiliates) would beneficially
own in excess of 9.99% of the  Ordinary  Shares  outstanding  immediately  after
giving effect to such exercise;  provided that such Abingworth Fund may increase
or decrease such percentage to any other percentage (or waive the  applicability
of the blocker) upon written notice to the Issuer;  provided,  further, that any
such increase (or waiver) will not be effective until the sixty-first (61st) day
after such notice is delivered to the Issuer.

          The Securities Purchase Agreement contains a right of first refusal in
favor of each Purchaser to purchase up to such  Purchaser's  Pro Rata Percentage
(as defined in the  Securities  Purchase  Agreement) of any offering (an "Equity
Offering") by the Issuer of Ordinary  Shares or any other class or series of its
capital  stock,  or any other  securities  convertible  or  exercisable  into or
exchangeable  for Ordinary Shares or any other class or series of capital stock,
subject to certain exceptions as set forth in the Securities Purchase Agreement.
To the extent any Other  Purchaser  elects  not to  exercise  its right of first
refusal to purchase its full Pro Rata  Percentage  of any Equity  Offering,  the
Abingworth  Funds  shall have the first  right of refusal to  subscribe  for and
purchase any  securities not  subscribed  for by any such Other  Purchaser.  The
right of first refusal  shall  terminate  with respect to a Purchaser  (counting
such  Purchaser  and  its  affiliates   purchasing  Ordinary  Shares  under  the
Securities  Purchase  Agreement as one Purchaser) at such time as such Purchaser
(together with its affiliates) ceases to collectively own at least fifty percent
(50%) of the Ordinary  Shares  purchased by such Purchaser and its affiliates at
the Closing.

          Under the terms of the Securities Purchase  Agreement,  the Issuer has
agreed to (i) prepare  and file (as soon as  reasonably  practicable,  but in no
event later than sixty (60) days after the Closing (the "Filing Deadline Date"))
with the Securities and Exchange Commission (the "SEC") a registration statement
to register the resale of the Ordinary  Shares  issued in the Private  Placement
(including the Ordinary  Shares issuable upon exercise of the warrants issued in
the Private Placement) and (ii) use its commercially reasonable efforts to cause
the Registration  Statement to be declared effective by the SEC no later than 90
days (120 days in the event the  registration  statement is reviewed by the SEC)
after the earlier of (i) the initial  filing of the  registration  statement  or
(ii) the Filing  Deadline Date. The Issuer will be liable for certain  penalties





set forth in the  Purchase  Agreement  for the  failure to meet such  filing and
effective date  deadlines.  The Purchasers  also received  certain  "piggy-back"
registration rights covering the Ordinary Shares issued in the Private Placement
(including  the Ordinary  Shares  issuable upon exercise of the warrants sold in
the Private Placement).

          In connection  with the  transactions  contemplated  by the Securities
Purchase  Agreement,  the  Abingworth  Funds  entered into a  Management  Rights
Agreement with the Issuer and certain of the Other  Purchasers,  whereby (i) the
Abingworth  Funds will have the right to nominate  one  designee for election to
the Issuer's  Board of Directors for so long as the Abingworth  Funds  (together
with their respective affiliates) beneficially own at least five percent (5%) of
the  issued  and  outstanding  Ordinary  Shares  of the  Issuer,  (ii) each Lead
Investor (as defined in the Management  Rights Agreement) will individually have
the right to  nominate  one  designee  for  election  to the  Issuer's  Board of
Directors so long as such Lead Investor beneficially owns the number of Ordinary
Shares equal to at least fifty percent (50%) of the number of Ordinary Shares it
purchased in the Private Placement, (iii) the Lead Investors will have the right
to  collectively  nominate two (2) other  individuals  to the Issuer's  Board of
Directors so long as the Lead Investors,  collectively as a group,  beneficially
own in the  aggregate  at least  twenty-five  percent  (25%) of the  issued  and
outstanding Ordinary Shares of the Issuer and (iv) the parties to the Management
Rights  Agreement  agreed to vote their Ordinary Shares in favor of the director
designees specified in the foregoing clauses (i), (ii) and (iii).

          By  virtue  of the  terms  of the  Management  Rights  Agreement,  the
Reporting  Persons  and the  Other  Purchasers  party to the  Management  Rights
Agreement  may be deemed to  constitute a "group"  within the meaning of Section
13(d)(3) of the  Securities  Exchange  Act of 1934,  as amended.  The  Reporting
Persons and the Other  Purchasers  party to the Management  Rights Agreement are
not acting as a "group", and the Reporting Persons disclaim beneficial ownership
of, and any pecuniary interest in, all of the Ordinary Shares beneficially owned
by the Other Purchasers party to the Management Rights Agreement.

          The foregoing descriptions of the Purchase Agreement, the Warrants and
the Management  Rights Agreement do not purport to be complete and are qualified
in their entirety by the terms of such document which are incorporated herein by
reference in response to this Item 4 and which,  (i) in the case of the Purchase
Agreement  and the Form of Warrant,  have been filed as exhibits to the Issuer's
Annual  Report on Form 20-F for the fiscal year ended  December 31, 2008,  filed
with the SEC on October 22, 2009 and (ii) in the case of the  Management  Rights
Agreement, has been filed as an exhibit to this Schedule 13D.

Item 5.   Interest in Securities of the Issuer
          ------------------------------------

          (a)   ABV V is the owner of  record of 7,500,000  Ordinary Shares  and
Warrants to purchase an  aggregate of 3,750,000  Ordinary  Shares.  ABV V may be
deemed  to  beneficially  own,  in  the  aggregate,  7,500,000  Ordinary  Shares
(excluding  the  Warrants  held by ABV V due to the 9.99%  beneficial  ownership
blocker provision  contained therein),  representing  approximately 7.65% of the
Issuer's  outstanding Ordinary Shares (based upon the 98,081,974 Ordinary Shares
outstanding immediately after the consummation of the Private Placement).

          AGE is the owner of record of 7,500,000  Ordinary  Shares and Warrants
to purchase an  aggregate  of 3,750,000  Ordinary  Shares.  AGE may be deemed to
beneficially  own, in the aggregate,  7,500,000  Ordinary Shares  (excluding the
Warrants held by AGE due to the 9.99%  beneficial  ownership  blocker  provision
contained therein), representing approximately 7.65% of the Issuer's outstanding
Ordinary  Shares  (based  upon  the  98,081,974   Ordinary  Shares   outstanding
immediately after the consummation of the Private Placement).

          ABE is the owner of record of 2,000,000  Ordinary  Shares and Warrants
to purchase an  aggregate  of 1,000,000  Ordinary  Shares.  ABE may be deemed to
beneficially  own, in the aggregate,  2,000,000  Ordinary Shares  (excluding the





Warrants held by ABE due to the 9.99%  beneficial  ownership  blocker  provision
contained therein), representing approximately 2.04% of the Issuer's outstanding
Ordinary  Shares  (based  upon  the  98,081,974   Ordinary  Shares   outstanding
immediately after the consummation of the Private Placement).

          Abingworth  is not the  owner of  record  of any  Ordinary  Shares  or
Warrants to purchase  Ordinary Shares.  Abingworth may be deemed to beneficially
own, in the aggregate,  17,000,000  Ordinary Shares (excluding any Warrants held
by the Abingworth Funds due to the 9.99% beneficial ownership blocker provisions
contained   therein),   representing   approximately   17.33%  of  the  Issuer's
outstanding   Ordinary  Shares  (based  upon  the  98,081,974   Ordinary  Shares
outstanding immediately after the consummation of the Private Placement).

          (b)   As set forth in the cover sheets to this Schedule 13D, (i) ABV V
has shared voting and dispositive  power with respect to the 7,500,000  Ordinary
Shares held by ABV V and has sole voting and dispositive  power over none of the
securities  reported  herein;  (ii) AGE has shared voting and dispositive  power
with respect to the  7,500,000  Ordinary  Shares held by AGE and has sole voting
and dispositive power over none of the securities reported herein; (iii) ABE has
shared  voting and  dispositive  power with  respect to the  2,000,000  Ordinary
Shares  held by ABE and has sole voting and  dispositive  power over none of the
securities   reported  herein;   and  (iv)  Abingworth  has  shared  voting  and
dispositive  power with respect to the  17,000,000  Ordinary  Shares held by the
Abingworth  Funds and has sole  voting  and  dispositive  power over none of the
securities reported herein.

          (c)   Except as  described in Item 3 and Item 4 of this  Schedule 13D,
during the past 60 days, there were no purchases or sales of Ordinary Shares, or
securities  convertible  into  or  exchangeable  for  Ordinary  Shares,  by  the
Reporting  Persons  or any  person or entity  for  which the  Reporting  Persons
possess voting control over the securities thereof.

          (d)   Each Abingworth Fund has the right to receive dividends from, or
proceeds  from the sale of, the  Ordinary  Shares and  Warrants  (including  the
Ordinary Shares issuable upon exercise  thereof)  purchased by it in the Private
Placement. The limited partners or shareholders of each Abingworth Fund have the
right to  participate  indirectly in the receipt of dividends  from, or proceeds
from the sale of, the  Ordinary  Shares and  Warrants  (including  the  Ordinary
Shares issuable upon exercise thereof)  purchased by such Abingworth Fund in the
Private  Placement in accordance with their  respective  ownership  interests in
such Abingworth Fund.

Item 6.   Contracts, Arrangements, Understandings or Relationships with  Respect
          to Securities of the Issuer
          ----------------------------------------------------------------------

          As described in Items 3 and 4 above,  the Abingworth  Funds  purchased
the Ordinary Shares and Warrants pursuant to the Securities  Purchase Agreement.
In connection  with the  transactions  contemplated  by the Securities  Purchase
Agreement,  the Abingworth Funds entered into a Management Rights Agreement with
the Issuer and certain of the Other Purchasers.

Item 7.   Material to be Filed as Exhibits
          --------------------------------

          The following exhibits are incorporated into this Schedule 13D:

          Exhibit 1     Securities Purchase  Agreement,  dated as of October 12,
                        2009, by and among the Issuer,  the Abingworth Funds and
                        the  Other  Purchasers  (incorporated  by  reference  to
                        Exhibit 4.94 to the Issuer's  Annual Report on Form 20-F
                        for the fiscal year ended  December 31,  2008,  as filed
                        with the SEC on October 22, 2009).





          Exhibit 2     The Form of  Warrant,  dated  as of  October  16,  2009,
                        issued  by the  Issuer  to each  purchaser  party to the
                        Securities Purchase Agreement (incorporated by reference
                        to Exhibit  4.96 to the Issuer's  Annual  Report on Form
                        20-F for the fiscal year ended  December  31,  2008,  as
                        filed with the SEC on October 22, 2009).

          Exhibit 3     Management  Rights  Agreement,  dated as of October  16,
                        2009, by and among the Issuer,  the Abingworth Funds and
                        certain of the Other Purchasers.

          Exhibit 4     Joint Filing  Agreement,  dated October 23, 2009, signed
                        by each of the  Reporting  Persons  in order to  confirm
                        that this  statement is being filed on behalf of each of
                        the Reporting Persons.







                                    Signature
                                    ---------

          Signature After reasonable inquiry and to the best of my knowledge and
belief,  I certify  that the  information  set forth in this  statement is true,
complete and correct.

Dated:  October 26, 2009

                                      ABINGWORTH BIOVENTURES V L.P.

                                      By: Abingworth LLP, its Manager


                                      By:   /s/ Timothy J. Haines
                                         ---------------------------------------
                                         Name:  Timothy J. Haines
                                         Title: Partner


                                      ABINGWORTH BIOVENTURES V CO-INVEST GROWTH
                                      EQUITY FUND LP

                                      By: Abingworth LLP, its Manager


                                      By:   /s/ Timothy J. Haines
                                         ---------------------------------------
                                         Name:  Timothy J. Haines
                                         Title: Partner


                                      ABINGWORTH BIOEQUITIES MASTER FUND LIMITED


                                      By:   /s/ John G. Heard
                                         ---------------------------------------
                                         Name:  John G. Heard
                                        Title:  Authorized Signatory


                                      ABINGWORTH LLP


                                      By:   /s/ Timothy J. Haines
                                         ---------------------------------------
                                         Name:  Timothy J. Haines
                                         Title: Partner




      Attention: Intentional misstatements or omissions of fact constitute
                Federal criminal violations (See 18 U.S.C. 1001).