X0508 4 2025-12-19 0 0001356576 SUPERNUS PHARMACEUTICALS, INC. SUPN 0001804567 Mottola Frank C/O SUPERNUS PHARMACEUTICALS, INC., 9715 KEY WEST AVENUE ROCKVILLE MD 20850 0 1 0 0 SVP, Chief Tech. Ops. Officer 1 Common Stock 2025-12-19 4 M 0 5000 39.40 A 20496 D Common Stock 2025-12-19 4 S 0 5000 50.22 D 15496 D Common Stock 2025-12-19 4 M 0 15000 25.30 A 30496 D Common Stock 2025-12-19 4 S 0 15000 50.47 D 15496 D Employee Stock Option (Right to Buy) 39.40 2025-12-19 4 M 0 5000 0 D 2028-02-14 Common Stock 5000 0 D Employee Stock Option (Right to Buy) 25.30 2025-12-19 4 M 0 15000 0 D 2027-02-24 Common Stock 15000 0 D Transaction made pursuant to a 10b5-1 trading plan adopted September 15, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.00 to $50.39. The Reporting Person undertakes to provide to Supernus Pharmaceuticals, Inc. ("Supernus"), any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.00 to $50.69. The Reporting Person undertakes to provide to Supernus Pharmaceuticals, Inc. ("Supernus"), any security holder of Supernus, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to this Form 4. The option vests in four equal annual installments beginning on February 14, 2019 . The option vests in four equal annual installments beginning on February 24, 2018. /s/ Timothy C. Dec, as attorney-in-fact 2025-12-22