1 Supernus Pharmaceuticals SPN-812 Phase IIb Topline Data Investor Webcast – October 11, 2016

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Viloxazine hydrochloride Norepinephrine reuptake inhibitor Once-daily oral extended-release product New Chemical Entity (NCE) Five year market exclusivity Previously marketed outside the US as an antidepressant Building strong IP portfolio with expirations from 2029-2033 API, formulation, novel use Emerging clinical profile points to a well differentiated ADHD product A highly effective non-stimulant with a tolerable side effect profile SPN-812: Novel Non-Stimulant ADHD Product 3

SPN-812 Phase IIb Design Objectives: Assess effect of SPN-812 ER in reducing symptoms of ADHD in children aged 6-12 years Evaluate safety and tolerability of SPN-812 ER in children with ADHD Primary Endpoint: Change from baseline to End of Study in the ADHD-RS-IV total score Secondary Endpoints: Assess effect of SPN-812 ER on: Clinical Global Impression – Improvement Scale (CGI-I) and Clinical Global Impression – Severity Scale (CGI-S) 4

Design: Double-blind, placebo-controlled, multicenter Dose-ranging study; 5-arm, parallel-group Monotherapy Randomization: Randomized in a ratio of 1:2 of placebo to each of the active treatment arms (100/200/300/400 mg) 222 subjects randomized Study Duration: 3 weeks titration (100mg/week), 5 weeks treatment Rollover to Open-Label Extension Study SPN-812 Phase IIb Design 5

Three SPN-812 Doses Met Primary Endpoint Statistics 400 mg N=44 300 mg N=47 200 mg N=46 100 mg N=45 Placebo N=24 LS Mean -19.0 -18.6 -18.4 -16.7 -10.5 End of Study Effect Size 0.63 0.60 0.55 0.46 P-value 0.021* 0.027* 0.031* 0.089 * At end of study all SPN-812 doses except the 100 mg dose are statistically significant compared to placebo at = 0.05 level. Primary Analysis Change from baseline in ADHD-RS-IV Total Score (ITT Population with LOCF) ITT = Intent To Treat LOCF = Last Observation Carried Forward 6

LS Means of Change from Baseline in ADHD-RS-IV Score * * * *P-value <0.05 7 /

All SPN-812 Doses Met Primary Endpoint Statistics 400 mg N=32 300 mg N=34 200 mg N=29 100 mg N=35 Placebo N=19 LS Mean -23.3 -19.2 -20.7 -18.3 -9.4 End of Study P-value 0.001* 0.017* 0.008* 0.028* * At end of study, all SPN-812 doses are statistically significant compared to placebo at = 0.05 level. Sensitivity Analysis Change from baseline in ADHD-RS-IV Total Score (PP Population) PP = Per Protocol 8

Statistics 400 mg N=44 300 mg N=47 200 mg N=46 100 mg N=45 Placebo N=24 ITT = Intent To Treat LOCF = Last Observation Carried Forward CGI-I = Clinical Global Impression Improvement CGI-S = Clinical Global Impression Severity *Statistical significance at = 0.05 level. Change from baseline to End of Study in CGI-S LS Mean -1.7 -1.6 -1.5 -1.4 -0.8 P-value 0.014* 0.015* 0.031* 0.071 Analysis of Secondary Endpoints, CGl-I and CGI-S (ITT Population with LOCF) Three SPN-812 Doses Met CGI-S Secondary Endpoint Observed CGI-I at End of Study LS Mean 2.4 2.2 2.6 2.6 3.0 P-value 0.055 0.009* 0.138 0.131 9

Percentage of Patients with Related AEs, >5% SPN-812 ER Adverse Event (AE) Placebo N=24 100 mg N=48 200 mg N=48 300 mg N=48 400 mg N=49 Somnolence 0 14.6 20.8 20.8 24.5 Decreased appetite 8.3 10.4 12.5 8.3 16.3 Headache 0 4.2 10.4 6.3 12.2 Insomnia 0 6.3 4.2 6.3 6.3 Nausea 0 4.2 2.1 8.3 4.1 Fatigue 0 4.2 4.2 2.1 10.2 Irritability 0 2.1 8.3 4.2 2.0 Weight decreased 0 0 0 0 8.3 Discontinuations Due to AEs 0 8.3 6.3 2.1 10.2 SPN-812 Was Well Tolerated 10

Completed Phase IIa and Phase IIb studies in ADHD Demonstrated safety and efficacy in adults and children SPN-812: Novel Non-Stimulant ADHD Product 2017 Phase III studies Market Opportunity $2.5B Total ADHD Prescriptions ADHD Prescriptions per SHA TRx data, December 2014 ADHD Prevalence Centers for Disease Control “Trends in the Parent-Report of Health Care Provider-Diagnosed and Medicated ADHD: United States, 2003–2011; WebMD; Datamonitor 11 92% 8% Stimulant Non- Stimulant 0 2 4 6 8 Millions Age 6-17 Age 18+

12 Positioned For Continued Strong Growth Strong Portfolio in Neurology Potential Peak Sales for Oxtellar XR® and Trokendi XR® >$500M Innovative Late Stage Portfolio in Psychiatry SPN-812 : Highly Effective and Well Tolerated Non-Stimulant SPN-810 : The First Treatment for Impulsive Aggression 12