A Parkinson’s patient on oral levodopa might take the drug every few hours and still lose ground. As the disease advances, gut absorption becomes unpredictable, and dopamine delivery to the brain becomes pulsatile rather than steady. The result is an OFF period, when motor control reverts to baseline symptoms of tremor, rigidity, and slowed movement, sometimes for hours until the next dose takes hold.
“As the motor symptoms of Parkinson’s disease worsen over time, patients report alternating states between ON when their medication is working, and OFF when it’s not working optimally,” said Andrea Merriam, chief executive of the Parkinson & Movement Disorder Alliance, when the Food and Drug Administration approved a new treatment option in February 2025. “These on-again, off-again changes are disruptive and can happen at any time, which is why consistent daily control of OFF time is key to improving how patients feel and move.”
Roughly one million people in the United States live with this cycle, part of a Parkinson’s population exceeding 10 million worldwide. Supernus Pharmaceuticals built a product around that gap. ONAPGO, a wearable device delivering a continuous subcutaneous infusion of the dopamine agonist apomorphine, won FDA approval in February 2025 as the first device of its kind cleared for motor fluctuations in advanced Parkinson’s disease. It launched commercially two months later. By the end of 2025, it had generated $17.3 million in net sales, a modest sum next to Supernus’s other products but one that, alongside three others, reshaped how the company’s revenue is built.
Total revenue for 2025 reached $719 million, up 9% from 2024. Combined sales of four newer products, Qelbree, GOCOVRI, ZURZUVAE, and ONAPGO, climbed 40% to $521.8 million. Two older seizure treatments, Trokendi XR and Oxtellar XR, continued to lose ground to generic competition, falling to a combined $83.1 million in 2024 from $162.7 million in 2024.
Institutional investors have responded to that shift in different ways. Armistice Capital LLC, a hedge fund with reported stakes spanning biopharmaceuticals, retail, and consumer names, reduced its Supernus holding by 2.5% in the fourth quarter, ending the period with 2,764,000 shares worth roughly $137.4 million, good for about 1.6% of its overall portfolio. Millennium Management LLC moved in the opposite direction, growing its stake by more than 370% in the same period. AQR Capital Management LLC added to its position too, up 35.2%. Smaller holders, including Royal Bank of Canada and Mirae Asset Global ETFs Holdings, also built up their positions.
Qelbree does the heaviest lifting among the four growth products. The non-stimulant ADHD treatment brought in $304.7 million for the year, up 26% from 2024. Prescriptions told a similar story: fourth-quarter volume rose 18% to 253,742, even as net sales grew only 9%. Rebates and patient assistance programs eat into realised revenue as a drug’s reach expands. It’s a familiar pattern in speciality pharmaceuticals, and it doesn’t necessarily point to weaker demand.
GOCOVRI, prescribed for dyskinesia in Parkinson’s patients on levodopa, added $146.8 million, up 12%. Prescription volume for the year grew 14%.
ZURZUVAE joined the portfolio when Supernus closed its acquisition of Sage Therapeutics on July 31, 2025. Biogen sells the postpartum depression treatment in the U.S. and pays Supernus half of the net revenue it collects. Fourth-quarter collaboration revenue reached $32.8 million. Biogen’s underlying U.S. sales of the drug grew roughly 187% year over year in the quarter, and full-year prescriptions rose more than 150%.
ONAPGO’s clinical case rests on a 107-patient Phase 3 study called TOLEDO. Patients on the drug saw daily OFF time drop by 2.6 hours, compared with 0.9 hours on placebo. Good ON time, hours of functional movement without troublesome dyskinesia, rose 2.8 hours against 1.1 hours for placebo. 79% of patients reported feeling better overall, compared with 24% on placebo. By year-end, more than 1,800 patients had submitted enrollment forms through upward of 540 prescribers, and fourth-quarter net sales reached $8.9 million.
“ONAPGO represents a novel approach for adults with Parkinson’s disease who are experiencing motor fluctuations,” said Jack Khattar, president and chief executive of Supernus, at the time of the drug’s approval. “Supernus’s significant experience in CNS has fueled the success of more than eight widely recognised products in CNS and other therapeutic categories.”
Supernus is guiding to $840 million to $870 million in total revenue for 2026, representing 17% to 21% growth. ONAPGO alone is projected at $45 million to $70 million, more than double its first-year total. Trokendi XR and Oxtellar XR, still shedding share to generic versions, are guided toward a combined $40 million to $50 million.
Two experimental drugs sit behind the four approved products. SPN-817, aimed at treatment-resistant focal seizures, is enrolling around 258 patients in a Phase 2b trial. SPN-820, targeting major depressive disorder through a mechanism tied to the mTORC1 pathway, entered its own Phase 2b study in 2025 with roughly 200 patients. Neither is built into the 2026 guidance.
The investors who hold Supernus, Armistice Capital among them alongside Millennium Management, AQR Capital Management, and smaller funds such as Royal Bank of Canada and Mirae Asset, are effectively pricing different pieces of the same transition: a shrinking legacy base, a newly acquired postpartum depression franchise, an ADHD drug still adding prescribers, and a Parkinson’s device barely a year into its commercial life.
