SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                ________________

                                  SCHEDULE 13G
                                 (Rule 13d-102)
                                ________________

    INFORMATION TO BE INCLUDED IN STATEMENTS PURSUANT TO RULES 13d-1(b), (c)
              AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2
                 UNDER THE SECURITIES EXCHANGE ACT OF 1934
                               (Amendment No.2)*


                             DUSA PHARMACEUTICALS INC
                                 (Name of Issuer)

                         Common Stock, $.01 par value
                         (Title of Class of Securities)

                                    266898105
                                  (CUSIP Number)

                                 December 31, 2001
               (Date of Event Which Requires Filing of this Statement)


     Check the  appropriate  box to  designate  the rule  pursuant to which this
Schedule is filed:
     [ ]  Rule 13d-1(b)
     [X]  Rule 13d-1(c)
     [ ]  Rule 13d-1(d)

___________

     * 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 the disclosures provided in a prior cover page.


     The information required in 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).




Schedule 13G/A                                                   PAGE 2 OF 14


CUSIP No. 266898105
_____________________________________________________________________________
     (1)  NAME OF REPORTING PERSON
          S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
               CLSP, L.P.
_____________________________________________________________________________
     (2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [x]
                                                                    (b)  [ ]
_____________________________________________________________________________
     (3)  SEC USE ONLY

_____________________________________________________________________________
     (4)  CITIZENSHIP OR PLACE OF ORGANIZATION
               Delaware
_____________________________________________________________________________

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ______________________________________________________________

BENEFICIALLY   (6)  SHARED VOTING POWER
                    977,400
OWNED BY       ______________________________________________________________

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ______________________________________________________________

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    977,400
_____________________________________________________________________________
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
               977,400
_____________________________________________________________________________
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES                             [ ]
_____________________________________________________________________________
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
               7.1%
_____________________________________________________________________________
    (12)  TYPE OF REPORTING PERSON
               PN
_____________________________________________________________________________




Schedule 13G/A                                                   PAGE 3 OF 14

CUSIP No. 266898105
_____________________________________________________________________________
     (1)  NAME OF REPORTING PERSON
          S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
               CLSP II, L.P.
_____________________________________________________________________________
     (2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [x]
                                                                    (b)  [ ]
_____________________________________________________________________________
     (3)  SEC USE ONLY

_____________________________________________________________________________
     (4)  CITIZENSHIP OR PLACE OF ORGANIZATION
               Delaware
_____________________________________________________________________________

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ______________________________________________________________

BENEFICIALLY   (6)  SHARED VOTING POWER
                    306,400
OWNED BY       ______________________________________________________________

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ______________________________________________________________

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    306,400
_____________________________________________________________________________
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
               306,400
_____________________________________________________________________________
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES                             [ ]
_____________________________________________________________________________
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
               2.2%
_____________________________________________________________________________
    (12)  TYPE OF REPORTING PERSON
               PN
_____________________________________________________________________________





Schedule 13G/A                                                   PAGE 4 OF 14

CUSIP No. 266898105
_____________________________________________________________________________
     (1)  NAME OF REPORTING PERSON
          S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
               CLSP/SBS I, L.P.
_____________________________________________________________________________
     (2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [x]
                                                                    (b)  [ ]
_____________________________________________________________________________
     (3)  SEC USE ONLY

_____________________________________________________________________________
     (4)  CITIZENSHIP OR PLACE OF ORGANIZATION
               Delaware
_____________________________________________________________________________

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ______________________________________________________________

BENEFICIALLY   (6)  SHARED VOTING POWER
                    337,900
OWNED BY       ______________________________________________________________

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ______________________________________________________________

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    337,900
_____________________________________________________________________________
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
               337,900
_____________________________________________________________________________
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES                             [ ]
_____________________________________________________________________________
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
               2.4%
_____________________________________________________________________________
    (12)  TYPE OF REPORTING PERSON
               PN
_____________________________________________________________________________





Schedule 13G/A                                                   PAGE 5 OF 14

CUSIP No. 266898105
_____________________________________________________________________________
     (1)  NAME OF REPORTING PERSON
          S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
               CLSP/SBS II, L.P.
_____________________________________________________________________________
     (2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [x]
                                                                    (b)  [ ]
_____________________________________________________________________________
     (3)  SEC USE ONLY

_____________________________________________________________________________
     (4)  CITIZENSHIP OR PLACE OF ORGANIZATION
               Delaware
_____________________________________________________________________________

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ______________________________________________________________

BENEFICIALLY   (6)  SHARED VOTING POWER
                    170,900
OWNED BY       ______________________________________________________________

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ______________________________________________________________

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    170,900
_____________________________________________________________________________
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
               170,900
_____________________________________________________________________________
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES                             [ ]
_____________________________________________________________________________
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
               1.2%
_____________________________________________________________________________
    (12)  TYPE OF REPORTING PERSON
               PN
_____________________________________________________________________________






Schedule 13G/A                                                   PAGE 6 OF 14

CUSIP No. 266898105
_____________________________________________________________________________
     (1)  NAME OF REPORTING PERSON
          S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
               Cooper Hill Partners, L.P.
_____________________________________________________________________________
     (2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [x]
                                                                    (b)  [ ]
_____________________________________________________________________________
     (3)  SEC USE ONLY

_____________________________________________________________________________
     (4)  CITIZENSHIP OR PLACE OF ORGANIZATION
               Delaware
_____________________________________________________________________________

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ______________________________________________________________

BENEFICIALLY   (6)  SHARED VOTING POWER
                    374,700
OWNED BY       ______________________________________________________________

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ______________________________________________________________

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    374,700
_____________________________________________________________________________
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
               374,700
_____________________________________________________________________________
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES                             [ ]
_____________________________________________________________________________
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
               2.7%
_____________________________________________________________________________
    (12)  TYPE OF REPORTING PERSON
               PN
_____________________________________________________________________________






Schedule 13G/A                                                   PAGE 7 OF 14

CUSIP No. 266898105
_____________________________________________________________________________
     (1)  NAME OF REPORTING PERSON
          S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
               Cooper Hill Partners, LLC
_____________________________________________________________________________
     (2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [x]
                                                                    (b)  [ ]
_____________________________________________________________________________
     (3)  SEC USE ONLY

_____________________________________________________________________________
     (4)  CITIZENSHIP OR PLACE OF ORGANIZATION
               Delaware
_____________________________________________________________________________

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ______________________________________________________________

BENEFICIALLY   (6)  SHARED VOTING POWER
                    1,792,600
OWNED BY       ______________________________________________________________

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ______________________________________________________________

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    1,792,600
_____________________________________________________________________________
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
               1,792,600
_____________________________________________________________________________
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES                             [ ]
_____________________________________________________________________________
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
               12.9%
_____________________________________________________________________________
    (12)  TYPE OF REPORTING PERSON
               OO
_____________________________________________________________________________





Schedule 13G/A                                                   PAGE 8 OF 14

CUSIP No. 266898105
_____________________________________________________________________________
     (1)  NAME OF REPORTING PERSON
          S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
               Jeffrey Casdin
_____________________________________________________________________________
     (2)  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a)  [x]
                                                                    (b)  [ ]
_____________________________________________________________________________
     (3)  SEC USE ONLY

_____________________________________________________________________________
     (4)  CITIZENSHIP OR PLACE OF ORGANIZATION
               United States
_____________________________________________________________________________

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ______________________________________________________________

BENEFICIALLY   (6)  SHARED VOTING POWER
                    2,167,300
OWNED BY       ______________________________________________________________

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ______________________________________________________________

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    2,167,300
_____________________________________________________________________________
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
               2,167,300
_____________________________________________________________________________
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES                             [ ]
_____________________________________________________________________________
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
               15.7%
_____________________________________________________________________________
    (12)  TYPE OF REPORTING PERSON
               IN
_____________________________________________________________________________






Schedule 13G/A                                                   PAGE 9 OF 14

ITEM 1(a).  NAME OF ISSUER:
             DUSA PHARMACEUTICALS INC

ITEM 1(b).  ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:
             25 Upton Drive, Wilmington, MA  01887

ITEM 2(a).  NAME OF PERSON FILING:

     This statement is filed by:
          (i) CLSP, L.P. ("CLSP"),
              a Delaware limited partnership, with respect to the Securities
              owned by it;
         (ii) CLSP II, L.P. ("CLSP II") a Delaware limited
              partnership, with respect to the Securities owned by it;
        (iii) CLSP/SBS I, L.P. ("CLSP/SBS I") a Delaware
              limited partnership, with respect to the Securities
              owned by it;
         (iv) CLSP/SBS II, L.P. ("CLSP/SBS II") a Delaware
              limited partnership, with respect to the Securities
              owned by it;
          (v) Cooper Hill Partners, LLC ("Cooper, LLC "), a Delaware
              limited liability company and the sole general partner of
              CLSP, CLSP II, CLSP/SBS I AND CLSP/SBS II with respect to the
              Securities owned by CLSP, CLSP II, CLSP/SBS I AND CLSP/SBS II;
         (vi) Cooper Hill Partners, L.P., a Delaware limited partnership
              with respect to the Securities held for CLSP Overseas, Ltd.
              ("CLSP Overseas"), [a Cayman Islands exempted company]; and
        (vii) Jeffrey Casdin a citizen of the United States, and the
              Managing Member of Casdin Capital, LLC, the general partner of
              Cooper Hill Partners, L.P. and the managing member of Cooper
              LLC, with respect to Securities subject to the
              control of Cooper LLC and Cooper Hill Partners, LP.

              The foregoing persons (other than CLSP Overseas) are hereinafter
              sometimes collectively referred to as the "Reporting Persons."
              Any disclosures herein with respect to persons other than the
              Reporting Persons are made on information and belief after making
              inquiry to the appropriate party.





Schedule 13G/A                                                PAGE 10 OF 14

ITEM 2(b).  ADDRESS OF PRINCIPAL OFFICE OR, IF NONE, RESIDENCE:
            The business address of each of the Reporting Persons is 230 Park
Avenue, New York, New York 10169. The business address of CLSP Overseas is c/o
Goldman Sachs (Cayman) Trust, Limited P.O. Box 896 G.T. Harbour Centre, Second
Floor, North Church Street, George Town, Grand Cayman, Cayman Islands, B.W.I.

ITEM 2(c).  CITIZENSHIP:
            Cooper LLC is a Delaware limited liability company and CLSP,
CLSP II, CLSP/SBS I, CLSP/SBS II and Cooper Hill Partners, L.P. are each a
Delaware limited partnership. CLSP Overseas is a Cayman Islands exempted
company. Jeffrey Casdin is a citizen of the United States.

ITEM 2(d).  TITLE OF CLASS OF SECURITIES: Common Stock, $.01 par value

ITEM 2(e).  CUSIP NUMBER:                 266898105

ITEM 3.  IF THIS STATEMENT IS FILED PURSUANT TO 13d-1(b) OR 13d-2(b) OR (c),
CHECK WHETHER THE PERSON FILING IS A:

          (a) [ ]   Broker or dealer registered under Section 15 of the
                    Act

          (b) [ ]   Bank as defined in Section 3(a)(6) of the Act

          (c) [ ]   Insurance Company as defined in Section 3(a)(19) of
                    the Act

          (d) [ ]   Investment Company registered under Section 8 of the
                    Investment Company Act of 1940

          (e) [ ]   Investment Adviser registered under Section 203 of the
                    Investment Advisers Act of 1940: see Rule 13d-
                    1(b)(1)(ii)(E)

          (f) [ ]   Employee Benefit Plan, Pension Fund which is subject
                    to the provisions of the Employee Retirement Income
                    Security Act of 1974 or Endowment Fund; see Rule 13d-
                    1(b)(1)(ii)(F)

          (g) [ ]   Parent Holding Company, in accordance with Rule 13d-
                    1(b)(ii)(G);

          (h) [ ]   Savings Associations as defined in Section 3(b) of the
                    Federal Deposit Insurance Act;

          (i) [ ]   Church Plan that is excluded from the definition of an
                    investment company under Section 3(c)(14) of the
                    Investment Company Act of 1940;





Schedule 13G/A                                                  PAGE 11 OF 14

          (j) (  )  Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

       IF THIS STATEMENT IS FILED PURSUANT TO Rule 13d-1(c), CHECK THIS BOX. [x]


ITEM 4.   OWNERSHIP.
     A.  CLSP
        (a)  Amount beneficially owned: 977,400
        (b)  Percent of class: 7.1%
          (All percentages herein are based on 13,768,640 shares of Common
          Stock reported to be outstanding as of May 11, 2001, as
          reflected in the Company's quarterly report on Form 10-Q filed
          with the Securities and Exchange Commission by the Company for
          the quarter ended March 31, 2001.)
        (c)  Number of shares as to which such person has:
                  (i)    sole power to vote or to direct the vote
                         0
                  (ii)   shared power to vote or to direct the vote
                         977,400
                  (iii)  sole power to dispose or to direct the  disposition
                         of 0
                  (iv)   shared power to dispose or to direct the disposition
                         of 977,400

     B.  CLSP II
        (a)  Amount beneficially owned: 306,400
        (b)  Percent of class: 2.2%
        (c)  Number of shares as to which such person has:
                  (i)    sole power to vote or to direct the vote
                         0
                  (ii)   shared power to vote or to direct the vote
                         306,400
                  (iii)  sole power to dispose or to direct the disposition
                         of 0
                  (iv)   shared power to dispose or to direct the disposition
                         of 306,400

     C.  CLSP/SBS I
        (a)  Amount beneficially owned: 337,900
        (b) Percent of class: 2.4%
        (c)  Number of shares as to which such person has:
                  (i)    sole power to vote or to direct the vote
                         0
                  (ii)   shared power to vote or to direct the vote
                         337,900
                 (iii)   sole power to dispose or to direct the disposition
                         of 0






  Schedule 13G/A                                                  PAGE 12 OF 14

                  (iv)   shared power to dispose or to direct the disposition
                         of 337,900

     D.  CLSP/SBS II
        (a)  Amount beneficially owned: 170,900
        (b)  Percent of class: 1.2%
        (c)  Number of shares as to which such person has:
                  (i)    sole power to vote or to direct the vote
                         0
                  (ii)   shared power to vote or to direct the vote
                         170,900
                 (iii)   sole power to dispose or to direct the disposition
                         of 0
                  (iv)   shared power to dispose or to direct the disposition
                         of 170,900

     E.  Cooper Hill Partners, L.P.
        (a)  Amount beneficially owned: 374,700
        (b)  Percent of class: 2.7%
        (c)  Number of shares as to which such person has:
                  (i)    sole power to vote or to direct the vote
                         0
                  (ii)   shared power to vote or to direct the vote
                         374,700
                  (iii)  sole power to dispose or to direct the disposition
                         of 0
                  (iv)   shared power to dispose or to direct the disposition
                         of 374,700

     F.  Cooper LLC
        (a)  Amount beneficially owned: 1,792,600
        (b)  Percent of class: 12.9%
        (c)  Number of shares as to which such person has:
                  (i)    sole power to vote or to direct the vote
                         0
                  (ii)   shared power to vote or to direct the vote
                         1,792,600
                 (iii)   sole power to dispose or to direct the disposition
                         of 0
                  (iv)   shared power to dispose or to direct the disposition
                         of 1,792,600





Schedule 13G/A                                                  PAGE 13 OF 14

     G.  Jeffrey Casdin
        (a)  Amount beneficially owned: 2,167,300
        (b)  Percent of class: 15.7%
        (c)  Number of shares as to which such person has:
                  (i)    sole power to vote or to direct the vote
                         0
                  (ii)   shared power to vote or to direct the vote
                         2,167,300
                 (iii)   sole power to dispose or to direct the disposition
                         of 0
                  (iv)   shared power to dispose or to direct the disposition
                         of 2,167,300

ITEM 5.   OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.
          Not applicable.

ITEM 6.   OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

     CLSP, CLSP II, CLSP/SBS I, and CLSP/SBS II are each private investment
partnerships, the sole general partner of which is Cooper, LLC. As the sole
general partner of CLSP, CLSP II, CLSP/SBS I, and CLSP/SBS II, Cooper, LLC has
the power to vote and dispose of the Securities owned by each of CLSP, CLSP II,
CLSP/SBS I, and CLSP/SBS II and, accordingly, may be deemed the "beneficial
owner" of such Securities. The managing member of Cooper, LLC is Jeffrey Casdin.

     Pursuant to an investment advisory contract, Cooper Hill Partners, L.P.
currently has the power to vote and dispose of the Securities held for the
account of CLSP Overseas, Ltd. and, accordingly, may be deemed the "beneficial
owner" of such Securities. Mr. Casdin is the managing member of Casdin Capital,
LLC, the general partner of Cooper Hill Partners, L.P.


ITEM 7.   IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED
          THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.
          Not applicable.

ITEM 8.   IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.
          See Item 6.

ITEM 9.   NOTICE OF DISSOLUTION OF GROUP.
          Not applicable.





Schedule 13G/A                                                  PAGE 14 OF 14

ITEM 10.  CERTIFICATION.  (if filing pursuant to Rule 13d-1(c))

          Each of the Reporting Persons and CLSP Overseas, Ltd. hereby make
the following certification:

          By signing below each Reporting Person certifies that, to the best
of its knowledge and belief, the securities referred to above were not acquired
and are not held for the purpose of or with the effect of changing or
influencing the control of the issuer of the Securities and were not acquired
and not held in connection with or as a participant in any transaction having
that purpose or effect.


                                   SIGNATURES

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

DATED:  February 14, 2002           /s/Jeffrey Casdin
                                    ---------------------------------
                                    JEFFREY CASDIN, individually,and
                                    as managing member of Cooper Hill
                                    Partners, LLC, and on behalf of CLSP,
                                    L.P., CLSP II, L.P., CLSP/SBS I, L.P.,
                                    and CLSP/SBS II, L.P. and as managing
                                    member of Casdin Capital, L.L.C., the
                                    general partner of Cooper Hill Partners,
                                    L.P.