X0305 4 2012-05-04 0 0001356576 SUPERNUS PHARMACEUTICALS INC SUPN 0001283887 SHEFFERY MICHAEL B C/O ORBIMED ADVISORS LLC, 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 1 0 0 0 Common Stock 2012-05-04 4 C 0 1668472 A 1668472 I By OrbiMed Private Investments II, LP Common Stock 2012-05-04 4 C 0 624710 A 624710 I By OrbiMed Private Investments II (QP), LP Common Stock 2012-05-04 4 C 0 206816 A 206816 I By UBS Juniper Crossover Fund, L.L.C. Common Stock 2012-05-04 4 P 0 734128 5.00 A 2402600 I by OrbiMed Private Investments II LP Common Stock 2012-05-04 4 P 0 274873 5.00 A 899583 I By OrbiMed Private Investments II (QP), LP Common Stock 2012-05-04 4 P 0 90999 5.00 A 297815 I By UBS Juniper Crossover Fund, L.L.C Series A Preferred Stock 2012-05-04 4 C 0 6673891 0 D 2005-12-22 Common Stock 1668472 0 I By OrbiMed Private Investments II, LP Series A Preferred Stock 2012-05-04 4 C 0 2498842 0 D 2005-12-22 Common Stock 624710 0 I By OrbiMed Private Investments II (QP), LP Series A Preferred Stock 2012-05-04 4 C 0 827627 0 D 2005-12-22 Common Stock 206816 0 I By UBS Juniper Crossover Fund, L.L.C. Each share of Series A Preferred Stock automatically converted into 0.25 shares of Common Stock (together the shares of Series A Preferred Stock and the shares of Common Stock, the "Shares") without payment of consideration upon the closing of the Issuer's initial public offering. Any fractional shares upon the conversion were paid out in cash. The shares of Series A Preferred Stock do not have an expiration date. Mr. Sheffery is a member of OrbiMed Advisors LLC, the managing member of OrbiMed Capital GP II LLC, which is the general partner of OrbiMed Private Investments II, LP and OrbiMed Private Investments II (QP), LP. Investment professionals employed by OrbiMed Advisors LLC manage UBS Juniper Crossover Fund, L.L.C.'s investment portfolio on behalf of UBS Juniper Management, L.L.C. Mr. Sheffery disclaims beneficial ownership of the Shares and this report shall not be deemed an admission that such reporting person is the beneficial owner of such Shares, except to the extent of his pecuniary interest, if any, in the Shares by virtue of his interest in OrbiMed Advisors LLC. /s/ Gregory S. Patrick, as attorney-in-fact 2012-05-07