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)
_____ 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)
12/17/2012
(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 12/17/2012   S   197,815 D $ 6.8479 (1) 100,000 I See Footnotes (3) (6)
Common Stock 12/18/2012   S   100,000 D $ 7.0767 (2) 0 I See Footnotes (3) (6)
Common Stock (7)               2,402,600 I See Footnotes (4) (6)
Common Stock (7)               899,583 I See Footnotes (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

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    
ISALY SAMUEL D
601 LEXINGTON AVENUE
54TH FLOOR
NEW YORK, NY 10022		     X    
ORBIMED CAPITAL GP II LLC
601 LEXINGTON AVENUE
54TH FLOOR
NEW YORK, NY 10022		     X    

Signatures

 /s/ Samuel D. Isaly   12/19/2012
**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) This price reported in Column 4 is a weighted average price. The reported shares were sold in multiple transactions at prices ranging from $6.79 to $7.32, inclusive. Upon request, the Reporting Persons undertake to provide the Issuer, any security holder of the Issuer, or the Securities and Exchange Commission, full information regarding the shares sold at each separate price within the ranges set forth in footnote (1) of this Form 4.
(2) This price reported in Column 4 is a weighted average price. The reported shares were sold in multiple transactions at prices ranging from $6.83 to $7.51, inclusive. Upon request, the Reporting Persons undertake to provide the Issuer, any security holder of the Issuer, or the Securities and Exchange Commission, full information regarding the shares sold at each separate price within the ranges set forth in footnote (2) of this Form 4.
(3) The Shares reported herein are directly owned by UBS Juniper Crossover Fund, L.L.C. ("Juniper"). OrbiMed Advisors LLC ("Advisors"), a registered adviser under the Investment Advisers Act of 1940, as amended, manages the portfolio of Juniper and may be deemed to have beneficial ownership of Shares held by Juniper by virtue of that relationship. Mr. Samuel D. Isaly ("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 OrbiMed Private Investments II, LP ("OP II"). OrbiMed Capital GP II LLC ("GP II") is the general partner of OPI II. 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 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 OrbiMed Private Investments II (QP), LP ("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 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, Isaly and GP II 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.
(7) No transaction has been made with respect to the Shares listed in this row.

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