UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G/A
Under the Securities Exchange Act of 1934
Enzon Inc.
(Name of Issuer)
Common Stock
(Title of Class of Securities)
293904108
(CUSIP Number)
January 27, 2003
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:
[x] Rule 13d-1(b)
[ ] 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).
CUSIP No. 293904108
1. Names of Reporting Persons.
I.R.S. Identification Nos. of above persons (entities only).
OrbiMed Advisors Inc.
2. Check the Appropriate Box if a Member Of a Group (See Instructions)
[ ] (a)
[ ] (b)
3. SEC Use Only
4. Citizenship or Place of Organization
Delaware
5. Sole Voting Power 0
Number of
Shares 6. Shared Voting Power 4,317,600
Beneficially
Owned by 7. Sole Dispositive Power 0
Each Reporting
Person With 8. Shared Dispositive Power 4,317,600
9. Aggregate Amount Beneficially Owned by Each Reporting Person
4,317,600
10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares
(See Instructions)
11. Percent of Class Represented by Amount in Row (9) 10.04%
12. Type of Reporting Person (See Instructions) IA
CUSIP No. 293904108
1. Names of Reporting Persons.
I.R.S. Identification Nos. of above persons (entities only).
OrbiMed Advisors LLC
2. Check the Appropriate Box if a Member of a Group (See Instructions)
[ ] (a)
[ ] (b)
3. SEC Use Only
4. Citizenship or Place of Organization
Delaware
5. Sole Voting Power 0
Number of
Shares 6. Shared Voting Power 4,317,600
Beneficially
Owned by 7. Sole Dispositive Power 0
Each Reporting
Person With 8. Shared Dispositive Power 4,317,600
9. Aggregate Amount Beneficially Owned by Each Reporting Person
10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares
(See Instructions)
11. Percent of Class Represented by Amount in Row (9) 10.04%
12. Type of Reporting Person (See Instructions) IA
CUSIP No. 293904108
1. Names of Reporting Persons.
I.R.S. Identification Nos. of above persons (entities only).
Samuel D. Isaly
2. Check the Appropriate Box if a Member of a Group (See Instructions)
[ ] (a)
[ ] (b)
3. SEC Use Only
4. Citizenship or Place of Organization
United States
5. Sole Voting Power 0
Number of
Shares 6. Shared Voting Power 4,317,600
Beneficially
Owned by 7. Sole Dispositive Power 0
Each Reporting
Person With 8. Shared Dispositive Power 4,317,600
9. Aggregate Amount Beneficially Owned by Each Reporting Person
293904108
10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares
(See Instructions)
11. Percent of Class Represented by Amount in Row (9) 10.04%
12. Type of Reporting Person (See Instructions) HC
Item 1. (a) Issuer: Enzon Inc.
(b) Address: 685 Route 202/206
Bridgewater, New Jersey 08807
Item 2. (a) Name of Person Filing:
OrbiMed Advisors Inc.
OrbiMed Advisors LLC
Samuel D. Isaly
(b) Address of Principal Business Offices:
767 Third Avenue, 6th Floor
New York, New York 10010
(c) Citizenship:
Please refer to Item 4 on each cover sheet for each filing person
(d) Title of Class of Securities
Common stock
(e) CUSIP Number: 293904108
Item 3. OrbiMed Advisors Inc. and OrbiMed Advisors LLC are investment
advisors in accordance with ss.240.13d-1(b)(1)(ii)(E). Samuel D.
Isaly is a control person in accordance
with ss.240.13d-1(b)(1)(ii)(G).
Item 4. Ownership
Please see Items 5 - 9 and 11 for each cover sheet for each filing
separately
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.
Reporting persons are holding 10.04% of the securities on behalf of
other persons who have the right to receive or the power to direct
the receipt of dividends from, or the proceeds from the sale of,
such securities.
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
Not Applicable
Item 9. Notice of Dissolution of Group
Not Applicable
Item 10. Certification
By signing below I certify that, to the best of my 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 are not held in connection with or as a
participant in any transaction having that purpose or effect.
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.
Date: February 10, 2003
OrbiMed Advisors Inc.
By: /s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Title: President
By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired and held in
the ordinary course of business and 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 are not held in connection with or as a
participant in any transaction having that purpose or effect.
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.
Date: February 10, 2003
OrbiMed Advisors LLC
By:/s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Title: Managing Member
Samuel D. Isaly
By:/s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Exhibit 1.1
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JOINT FILING AGREEMENT
The undersigned hereby agree that the Statement on Schedule 13G/A, dated
February 10, 2003 (the "Schedule 13G/A"), with respect to the Common Stock,
$.001 par value, of Enzon Inc. is, and any amendments thereto executed by each
of us shall be, filed on behalf of each of us pursuant to and in accordance with
the provisions of Rule 13d-1(k) under the Securities and Exchange Act of 1934,
as amended, and that this Agreement shall be included as an Exhibit to the
Schedule 13G/A and each such amendment. Each of the undersigned agrees to be
responsible for the timely filing of the Schedule 13G/A and any amendments
thereto, and for the completeness and accuracy of the information concerning
itself contained therein. This Agreement may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
instrument.
IN WITNESS WHEREOF, the undersigned have executed this Agreement as of
the 10th day of February, 2003.
OrbiMed Advisors Inc.
By: /s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Title: President
OrbiMed Advisors LLC
By: /s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Title: Managing Member
By: /s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Exhibit 2.1
-----------
Statement of Control Person
The Statement on Schedule 13G/A dated February 10, 2003 with respect to the
common stock, $.001 par value, of Enzon Inc. is filed by Samuel D. Isaly in
accordance with the provisions of Rule 13d-1(b) and Rule 13d-1(k) respectively
as a control person (HC) of OrbiMed Advisors LLC and OrbiMed Advisors Inc.
OrbiMed Advisors Inc. and OrbiMed Advisors LLC file this statement on Schedule
13G/A in accordance with the provisions of Rule 13d-1(b) and Rule 13d-1(k),
respectively, as investment advisors (IA).