Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
ORBIMED ADVISORS LLC
  2. Issuer Name and Ticker or Trading Symbol
SUPERNUS PHARMACEUTICALS INC [SUPN]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
601 LEXINGTON AVENUE, 54TH FLOOR
3. Date of Earliest Transaction (Month/Day/Year)
05/04/2012
(Street)

NEW YORK, NY 10022
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 05/04/2012   C   1,668,472 A (1) 1,668,472 I See Footnotes (2) (3) (6)
Common Stock 05/04/2012   C   624,710 A (1) 624,710 I See Footnotes (2) (4) (6)
Common Stock 05/04/2012   C   206,816 A (1) 206,816 I See Footnotes (2) (5) (6)
Common Stock 05/04/2012   P   734,128 A $ 5 2,402,600 I See Footnotes (2) (3) (6)
Common Stock 05/04/2012   P   274,873 A $ 5 899,583 I See Footnotes (2) (4) (6)
Common Stock 05/04/2012   P   90,999 A $ 5 297,815 I See Footnotes (2) (5) (6)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Series A Convertible Preferred Stock (1) 05/04/2012   C     6,673,891 12/22/2005   (1) Common Stock 1,668,472 $ 0 0 I See Footnotes (2) (3) (6)
Series A Convertible Preferred Stock (1) 05/04/2012   C     2,498,842 12/22/2005   (1) Common Stock 624,710 $ 0 0 I See Footnotes (2) (4) (6)
Series A Convertible Preferred Stock (1) 05/04/2012   C     827,627 12/22/2005   (1) Common Stock 206,816 $ 0 0 I See Footnotes (2) (5) (6)

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ORBIMED ADVISORS LLC
601 LEXINGTON AVENUE
54TH FLOOR
NEW YORK, NY 10022
  X   X    
ORBIMED CAPITAL GP II LLC
601 LEXINGTON AVENUE
54TH FLOOR
NEW YORK, NY 10022
  X   X    
ISALY SAMUEL D
601 LEXINGTON AVENUE
54TH FLOOR
NEW YORK, NY 10022
  X   X    

Signatures

 /s/ Samuel D. Isaly   05/08/2012
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Each share of Series A Convertible Preferred Stock automatically converted into 0.25 shares of Common Stock (together the shares of Series A Convertible Preferred Stock and the shares of Common Stock, the "Shares") without payment of consideration upon the closing of the Issuer's initial public offering. The shares of Series A Convertible Preferred Stock do not have an expiration date.
(2) The Shares reported herein as indirectly beneficially owned by OrbiMed Capital GP II LLC ("GP II"), OrbiMed Advisors LLC ("Advisors") and Samuel D. Isaly ("Isaly") are directly owned by OrbiMed Private Investments II, LP ("OPI II"), OrbiMed Private Investments II (QP), LP ("OPI II QP") and UBS Juniper Crossover Fund, L.L.C. ("Juniper"). Each of GP II, Advisors, and Isaly may be deemed to have a pecuniary interest in Shares beneficially owned by OPII and OPI II QP. This Form 4 is being jointly filed by GP II, Advisors and Isaly. The Reporting Persons have designated a representative, currently Michael B. Sheffery, to serve on the Issuer's board of directors.
(3) These Shares are beneficially owned by OPI II. GP II is the general partner of OPI II. Advisors, a registered adviser under the Investment Advisers Act of 1940, as amended, is the managing member of GP II. Advisors and GP II may be deemed to have beneficial ownership of Shares held by OPI II by virtue of such relationships. Isaly, a natural person, may be deemed to have beneficial ownership of such Shares in his capacity as the managing member of, and holder of a controlling interest, in Advisors.
(4) These Shares are beneficially owned by OPI II QP. GP II is the general partner of OPI II QP. Advisors is the managing member of GP II. Advisors and GP II may be deemed to have beneficial ownership of Shares held by OPI II QP by virtue of such relationships. Isaly, a natural person, may be deemed to have beneficial ownership of such Shares in his capacity as the managing member of, and holder of a controlling interest, in Advisors.
(5) These Shares are beneficially owned by Juniper. Advisors manages the portfolio of Juniper and may be deemed to have beneficial ownership of Shares held by Juniper by virtue of that relationship. Isaly, a natural person, may be deemed to have beneficial ownership of such Shares in his capacity as the managing member of, and holder of a controlling interest, in Advisors.
(6) Each of Advisors, GP II and Isaly disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that the Reporting Persons are beneficial owners for the purpose of Section 16 of the Exchange Act, or for any other purpose.

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