Onapgo exclusivity runs through 2032 as supply constraints persist
Key Facts
Exclusivity for Supernus Pharmaceuticals' Onapgo expires on February 3, 2032, according to the U.S. Food and Drug Administration's orphan drug database, setting the regulatory protection horizon for the treatment for advanced Parkinson's disease. The drug received its original marketing approval on February 3, 2025, according to the same database. The approval covers the treatment of motor fluctuations in adults with advanced disease. Orphan drug exclusivity prevents the FDA from approving the same drug for the same indication during the 7-year protection period, according to the agency's Office of Orphan Products Development. The exclusivity expiry is therefore tied to the original approval, and the announcement of protection in October does not start a new period.
On the commercial front, Supernus said net sales of Onapgo reached $13.5 million in the second quarter of 2026, compared with about $1.6 million in the second quarter of 2025. The company's financial results table reported year-on-year growth of 745%, against a limited sales base in the corresponding period a year earlier. The comparison period falls in the year the drug received its original marketing approval. In an indication of growing treatment enrollment requests, the company said it had received about 2,600 forms through the end of July 2026. Those forms were submitted by about 720 prescribers, according to its second-quarter earnings disclosure. The total represents treatment enrollment forms submitted, rather than a count of patients who had actually started receiving treatment.
Onapgo uses a wearable pump that delivers treatment continuously under the skin during waking hours, according to the statement Supernus issued upon the original approval. The substance infused this way is apomorphine, according to clinical investigator Stuart Isaacson's explanation in the statement. Isaacson said continuous infusion directly stimulates postsynaptic dopamine receptors. He added that this mechanism works without requiring metabolic conversion of the substance before stimulating those receptors. Describing the treatment's mechanism, he said: "With Onapgo, continuous infusion of apomorphine directly stimulates postsynaptic dopamine receptors, without the need for metabolic conversion." The treatment targets motor fluctuations in adults with advanced Parkinson's disease, the population specified in the U.S. approval.
In the clinical trial cited by Supernus in its approval statement, daily time during which treatment did not control symptoms fell by 2.6 hours among Onapgo recipients. Placebo recipients recorded a reduction of 0.9 hours a day, according to the comparison announced by the company. Alongside the treatment results, the FDA-approved prescribing information lists common side effects including infusion-site nodules and redness. The list also includes nausea, somnolence and dyskinesia. The prescribing information also identifies headache and insomnia as common side effects of the drug.
But meeting demand for Onapgo faced operational hurdles, as Supernus said in its annual report filed with the U.S. Securities and Exchange Commission that demand was stronger than expected. It said supplier constraints affected its ability to meet that demand in full. In its second-quarter earnings disclosure, the company outlined plans to seek approval for an additional supplier, identifying mid-2027 as a potential date for FDA approval. Efforts to add the supplier come amid supply difficulties accompanying demand for the drug. Before then, Supernus will announce its third-quarter 2026 results after the market closes on October 29, 2026, according to its SEC disclosure.