Supernus Pharmaceuticals (NASDAQ: SUPN) entered 2025 as a neurology-focused specialty pharma company with a single breakout product and two aging legacy drugs in structural decline. It ended the year as a substantially larger operation, having acquired Sage Therapeutics, launched a Parkinson’s disease device, and reported a trailing twelve-month revenue of $719 million. Armistice Capital held Supernus as one of its five largest disclosed equity positions throughout, according to 13F filings compiled by GuruFocus and WhaleWisdom.
A Commercial Foundation Built on Qelbree
Qelbree (viloxazine extended-release) is the commercial engine driving Supernus’s growth. The drug carries FDA approval for ADHD in adults and children six and older and carries no controlled substance scheduling, differentiating it from the stimulant medications that dominate the ADHD market. That distinction became commercially relevant as stimulant supply disruptions and telemedicine policy changes created friction in accessing Schedule II medications through 2024 and into 2025.
Prescription volumes for Qelbree climbed through every quarter of 2025. Total IQVIA prescriptions reached 214,908 in Q1, 225,254 in Q2, and 238,770 in Q3, representing year-over-year gains of 22%, 23%, and 23%, respectively. Net sales of Qelbree rose 44% year-over-year in Q1 to $64.7 million, then 31% in Q2 to $77.6 million, and 23% in Q3 to $81.4 million. The active prescriber base expanded from approximately 27,902 in Q1 2024 to 34,416 in Q1 2025 and approximately 36,000 by Q2 2025.
Supernus CEO Jack Khattar described the first-half performance in the company’s Q2 2025 earnings release: “Our strong operating performance in the first half of the year was driven by continued strong sales growth of Qelbree and GOCOVRI, which combined accounted for 72% of total net sales in the second quarter of 2025.”
The Sage Acquisition and ONAPGO Launch
Two events materially changed Supernus’s scale and scope in 2025. The first was the April 2025 launch of ONAPGO, the first and only subcutaneous apomorphine infusion device approved for motor fluctuations in adults with advanced Parkinson’s disease. More than 750 patient enrollment forms were submitted by over 300 prescribers through the end of Q2 2025. By Q3, that figure had grown to more than 1,300 enrollment forms from over 450 prescribers. Demand outpaced supply, with Supernus disclosing in its Q3 earnings release that supplier constraints were limiting its ability to fully meet early physician interest.
The second was the completed acquisition of Sage Therapeutics on July 31, 2025, which added ZURZUVAE (zuranolone), approved for postpartum depression, and a CNS discovery platform to Supernus’s commercial portfolio. Following the acquisition, Supernus raised its full-year 2025 revenue guidance to $685 million to $705 million, up from the previous $600 million to $630 million. The company reported trailing twelve-month revenue of $719 million as of December 31, 2025. Paragraph IV notice letters regarding proposed generic versions of Qelbree arrived in May 2025, with Supernus disclosing that its Orange Book-listed patents expire between 2029 and 2035.
Armistice Capital’s Position in Context
Armistice Capital maintained Supernus as approximately 2.55% of reported long equity exposure as of March 31, 2025, per WhaleWisdom’s compilation of the firm’s Schedule 13F. The fund held 4,836,000 shares of Supernus valued at approximately $174.9 million as of Q4 2024. By Q4 2025, Supernus remained in Armistice Capital’s top five disclosed equity holdings, accounting for approximately 1.63% of the portfolio weight, with the position valued at approximately $136 million after a 41% share reduction during the year.
Millennium Management raised its stake in Supernus by 370.5% during Q1 2025, reaching 143,356 shares. Nuveen LLC acquired a new stake in the first quarter valued at approximately $4.4 million. Qube Research and Technologies raised its position by 134.2% during Q2 2025, reaching 229,710 shares. Jane Street Group initiated a new position in Q1. Wellington Management Group reported 22,224 shares as of May 2025. Public Sector Pension Investment Board grew its stake by 59.7% in Q1, reaching 219,731 shares. Millennium and Jane Street tend toward quantitative and event-driven approaches, while Armistice’s concentrated healthcare allocation points to a longer-horizon view on the underlying commercial trajectory.
The CNS Market as an Investment Category
Supernus occupies a narrow but growing slice of the central nervous system therapeutics market, with approved products across ADHD, Parkinson’s disease, postpartum depression, epilepsy, migraine, cervical dystonia, and chronic sialorrhea. The ADHD market is large and competitive, dominated by stimulant medications from major pharmaceutical companies with significantly larger commercial infrastructure. Qelbree competes within the non-stimulant segment, which has historically held a smaller share of total ADHD prescriptions but has gained ground as stimulant supply and scheduling constraints have shifted some prescriber behavior.
Supernus disclosed that Qelbree prescriptions grew 23% in Q2 2025, outpacing the ADHD market’s 9% growth and the non-stimulant segment’s 11% growth over the same period. Adult prescriptions grew 29%, compared to 20% in pediatrics. The company has also initiated a Phase 2b study of SPN-820, a novel molecule targeting treatment-resistant focal seizures, and plans to initiate a Phase 1 study of SPN-443, a novel ADHD stimulant candidate, in 2026.
Supernus presents a profile that differs from the pre-revenue rare disease bets that typically generate more coverage in hedge fund disclosures. Approved, revenue-generating products, a newly expanded portfolio following the Sage acquisition, and several pipeline candidates at varying stages draw capital from a wider range of fund types than clinical-stage biotechs typically attract. Armistice Capital’s sustained presence across multiple quarters of a transition year, alongside institutional peers with different time horizons and strategies, reflects that dynamic directly.