SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* ORBIMED ADVISORS LLC (Last) (First) (Middle) 601 LEXINGTON AVENUE, 54TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 04/30/2012	3. Issuer Name and Ticker or Trading Symbol SUPERNUS PHARMACEUTICALS INC [ SUPN ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series A Convertible Preferred Stock	(1)	(1)	Common Stock	1,668,472	(1)	I	See Footnotes(2)(3)(6)
Series A Convertible Preferred Stock	(1)	(1)	Common Stock	624,710	(1)	I	See Footnotes(2)(4)(6)
Series A Convertible Preferred Stock	(1)	(1)	Common Stock	206,816	(1)	I	See Footnotes(2)(5)(6)

1. Name and Address of Reporting Person* ORBIMED ADVISORS LLC (Last) (First) (Middle) 601 LEXINGTON AVENUE, 54TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip)

1. Name and Address of Reporting Person* ISALY SAMUEL D (Last) (First) (Middle) 601 LEXINGTON AVENUE, 54TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip)

1. Name and Address of Reporting Person* ORBIMED CAPITAL GP II LLC (Last) (First) (Middle) 601 LEXINGTON AVENUE, 54TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip)

Explanation of Responses:

1. The Issuer's Series A Convertible Preferred Stock ("Preferred Stock") will convert automatically, without the payment of additional consideration, upon the closing of the Issuer's initial public offering into the number of shares of Common Stock set forth above, reflecting a conversion ratio of one share of Common Stock for every four shares of Preferred Stock. Shares of Preferred Stock do not have an expiration date.

2. The shares of Preferred Stock ("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 3 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, 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 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.

	/s/ Samuel D. Isaly	04/30/2012
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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