UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
ALEXION PHARMACEUTICALS, INC.
(Name of Issuer)
Common Stock
(Title of Class of Securities)
0015351109
(CUSIP Number)
January 29, 1999
(Date of Event which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to whichthis
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 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. 0015351109
(1) Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
OrbiMed Advisers Inc.
----------------------------------------------------------------------
(2) Check the Appropriate Box if a Member of Group (See Instructions)
[ ] (a)
[ ] (b)
----------------------------------------------------------------------
(3) SEC Use Only
----------------------------------------------------------------------
(4) Citizenship or Place of Organization British Virgin Islands
----------------------------------------------------------------------
Number of (5) Sole Voting Power 0
Shares
Beneficially -------------------------------------------------------------
Owned by (6) Shared Voting Power 750,500
Each -
Reporting -------------------------------------------------------------
Person (7) Sole Dispositive Power 0
With
-------------------------------------------------------------
(8) Shared Dispositive Power 750,500
----------------------------------------------------------------------
(9) Aggregate Amount Beneficially Owned by Each Reporting Person
750,500
----------------------------------------------------------------------
(10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions)
----------------------------------------------------------------------
(11) Percent of Class Represented by Amount in Row (9)
6.7%
----------------------------------------------------------------------
(12) Type of Reporting Person (See Instructions) IA
--------------------------
CUSIP No. 0015351109
(1) Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
Worldwide Health Sciences Portfolio
----------------------------------------------------------------------
(2) Check the Appropriate Box if a Member of Group (See Instructions)
[ ] (a)
[ ] (b)
----------------------------------------------------------------------
(3) SEC Use Only
----------------------------------------------------------------------
(4) Citizenship or Place of Organization New York
----------------------------------------------------------------------
Number of (5) Sole Voting Power 0
Shares
Beneficially -------------------------------------------------------------
Owned by (6) Shared Voting Power 750,500
Each -
Reporting -------------------------------------------------------------
Person (7) Sole Dispositive Power 0
With
-------------------------------------------------------------
(8) Shared Dispositive Power 750,500
----------------------------------------------------------------------
(9) Aggregate Amount Beneficially Owned by Each Reporting Person
750,500
----------------------------------------------------------------------
(10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions)
----------------------------------------------------------------------
(11) Percent of Class Represented by Amount in Row (9)
6.7%
----------------------------------------------------------------------
(12) Type of Reporting Person (See Instructions) IV
--------------------------
CUSIP No. 0015351109
(1) Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
OrbiMed Advisors LLC
----------------------------------------------------------------------
(2) Check the Appropriate Box if a Member of Group (See Instructions)
[ ] (a)
[ ] (b)
----------------------------------------------------------------------
(3) SEC Use Only
----------------------------------------------------------------------
(4) Citizenship or Place of Organization Delaware
----------------------------------------------------------------------
Number of (5) Sole Voting Power 0
Shares
Beneficially -------------------------------------------------------------
Owned by (6) Shared Voting Power 750,500
Each -
Reporting -------------------------------------------------------------
Person (7) Sole Dispositive Power 0
With
-------------------------------------------------------------
(8) Shared Dispositive Power 750,500
----------------------------------------------------------------------
(9) Aggregate Amount Beneficially Owned by Each Reporting Person
750,500
----------------------------------------------------------------------
(10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions)
----------------------------------------------------------------------
(11) Percent of Class Represented by Amount in Row (9)
6.7%
----------------------------------------------------------------------
(12) Type of Reporting Person (See Instructions) CO
--------------------------
CUSIP No. 0015351109
(1) Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
Caduceus Capital Trust
----------------------------------------------------------------------
(2) Check the Appropriate Box if a Member of Group (See Instructions)
[ ] (a)
[ ] (b)
----------------------------------------------------------------------
(3) SEC Use Only
----------------------------------------------------------------------
(4) Citizenship or Place of Organization Bermuda
----------------------------------------------------------------------
Number of (5) Sole Voting Power 0
Shares
Beneficially -------------------------------------------------------------
Owned by (6) Shared Voting Power 750,500
Each -
Reporting -------------------------------------------------------------
Person (7) Sole Dispositive Power 0
With
-------------------------------------------------------------
(8) Shared Dispositive Power 750,500
----------------------------------------------------------------------
(9) Aggregate Amount Beneficially Owned by Each Reporting Person
750,500
----------------------------------------------------------------------
(10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions)
----------------------------------------------------------------------
(11) Percent of Class Represented by Amount in Row (9)
6.7%
----------------------------------------------------------------------
(12) Type of Reporting Person (See Instructions) OO
--------------------------
CUSIP No. 0015351109
(1) Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
Finsbury Worldwide Pharmaceutical Trust
----------------------------------------------------------------------
(2) Check the Appropriate Box if a Member of Group (See Instructions)
[ ] (a)
[ ] (b)
----------------------------------------------------------------------
(3) SEC Use Only
----------------------------------------------------------------------
(4) Citizenship or Place of Organization United Kingdom
----------------------------------------------------------------------
Number of (5) Sole Voting Power 0
Shares
Beneficially -------------------------------------------------------------
Owned by (6) Shared Voting Power 750,500
Each -
Reporting -------------------------------------------------------------
Person (7) Sole Dispositive Power 0
With
-------------------------------------------------------------
(8) Shared Dispositive Power 750,500
----------------------------------------------------------------------
(9) Aggregate Amount Beneficially Owned by Each Reporting Person
750,500
----------------------------------------------------------------------
(10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions)
----------------------------------------------------------------------
(11) Percent of Class Represented by Amount in Row (9)
6.7%
----------------------------------------------------------------------
(12) Type of Reporting Person (See Instructions) OO
--------------------------
CUSIP No. 0015351109
(1) Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
PHARMA/wHEALTH
----------------------------------------------------------------------
(2) Check the Appropriate Box if a Member of Group (See Instructions)
[ ] (a)
[ ] (b)
----------------------------------------------------------------------
(3) SEC Use Only
----------------------------------------------------------------------
(4) Citizenship or Place of Organization Luxembourg
----------------------------------------------------------------------
Number of (5) Sole Voting Power 0
Shares
Beneficially -------------------------------------------------------------
Owned by (6) Shared Voting Power 750,500
Each -
Reporting -------------------------------------------------------------
Person (7) Sole Dispositive Power 0
With
-------------------------------------------------------------
(8) Shared Dispositive Power 750,500
----------------------------------------------------------------------
(9) Aggregate Amount Beneficially Owned by Each Reporting Person
750,500
----------------------------------------------------------------------
(10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions)
----------------------------------------------------------------------
(11) Percent of Class Represented by Amount in Row (9)
6.7%
----------------------------------------------------------------------
(12) Type of Reporting Person (See Instructions) OO
--------------------------
Item 1. Issuer
(a) Alexion Pharmaceuticals, Inc.
(b) 25 Science Park
New Haven, CT 06511
Item 2. Persons Filing
(a) Name of Persons Filing:
OrbiMed Advisers Inc.
OrbiMed Advisors LLC
Worldwide Health Sciences Portfolio
Finsbury Worldwide Pharmaceutical Trust
Caduceus Trust
PHARMA/wHEALTH
(b) Address of Principal Offices:
c/o OrbiMed Advisors Inc.
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: 0015351109
Item 3. Not Applicable
Item 4. Ownership
Please see Items 5, 6, 7, 8, 9, and 11 for each
cover sheet for each filing entity.
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
Not applicable.
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 12, 1999
ORBIMED ADVISERS 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
WORLDWIDE HEALTH SERVICES
PORTFOLIO
By: /s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Title: Director
CADUCEUS CAPITAL TRUST
By: /s/ Deborah O'Donnel
----------------------------
Name: Deborah O'Donnel
Title: Secretary
FINSBURY WORLDWIDE
PHARMACEUTICAL TRUST
By: /s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Title: Director
PHARMA/wHEALTH
By:/s/ Samuel D. Isaly
----------------------------
Name: Samuel D. Isaly
Title: Director