The U.S. Food and Drug Administration (FDA) on February 4, 2025, approved Onapgo (apomorphine hydrochloride), a new Parkinson’s therapy for people with progressing Parkinson’s disease who experience significant “off” time (when symptoms are not controlled) or motor fluctuations, which are ups and downs in symptom control throughout the day. Onapgo uses a continuous, under-the-skin infusion to deliver apomorphine, a drug that helps control motor symptoms such as tremor. It is the first infusion-based apomorphine therapy approved in the U.S. for Parkinson’s disease. 

Onapgo, produced by Supernus Pharmaceuticals, is the second under-the-skin infusion-based therapy approved by the FDA within the last four months. The first, Vyalev, delivers a continuous infusion of levodopa and carbidopa. (It, too, is approved to treat motor fluctuations in progressing Parkinson’s so which drug to consider is based on individual symptoms and potential side effects.) Onapgo operates similarly to Vyalev, except it provides a constant supply of apomorphine. Consistent dosing aims to provide more consistent control of motor symptoms like tremor, slowness and stiffness, particularly in people with progressing Parkinson’s who may not achieve adequate symptom control with pills or who experience motor fluctuations.  

“This approval represents another step forward in the treatment of people with Parkinson’s who experience motor fluctuations,” says Rachel Dolhun, MD, DipABLM, principal medical advisor at The Michael J. Fox Foundation. “The more options we have for easing motor fluctuations, the better our chances of improving the daily lives of all people and families with Parkinson’s.”  

Apomorphine for Parkinson’s Symptoms 

Apomorphine is a type of drug known as a dopamine agonist. It looks and acts like dopamine, the brain chemical that affects movement and decreases in people with Parkinson’s. Despite the name, it does not contain morphine. Because the medication is delivered continuously through an under-the-skin infusion, Onapgo bypasses the gastrointestinal (GI) tract and enters the brain to stimulate dopamine receptors. For many people with PD, problems in the GI tract — such as irregular stomach emptying or constipation — can impact medication absorption and benefit. The under-the-skin infusion might therefore lead to better benefit and more predictable symptom control.  

Onapgo may be an option for people who experience motor fluctuations or significant amounts of “off” time, which are not adequately managed with existing medications for motor symptoms.  

Infused apomorphine is already available in several other countries. Apomorphine also is available, in the U.S. and elsewhere, as an under-the-skin, self-administered injection (Apokyn), which can be used as needed for sudden, unexpected “off” times, in addition to a person’s daily regimen of PD medications.  

FDA Approval for Onapgo 

FDA approval is based on the results of the Phase III, randomized, placebo-controlled TOLEDO clinical trial of 107 people with Parkinson’s disease. Study participants had Parkinson’s for at least three years, experienced levodopa-related motor fluctuations that were not well-controlled, and had an average of three hours or more “off” time (when symptoms are not controlled) per day.  

During the study, participants received either Onapgo or a look-alike placebo medication for 12 weeks. At the end of the study, those who received Onapgo experienced nearly two hours less “off” time and nearly three hours more “on” time per day, compared to participants who received placebo.   

Common medication side effects, which were experienced by people in the clinical trials, include headache, nausea, daytime sleepiness, insomnia, dyskinesia (extra, involuntary movement), and bruising, redness, or nodules at the needle infusion site. 

Researchers continue to study the long-term safety of Onapgo in an ongoing clinical trial (INFUS-ON).  

The FDA has reviewed the safety and effectiveness of Onapgo multiple times since Supernus first submitted a New Drug Application in September 2020. Updated applications were submitted to the FDA in December 2021 and October 2023. In April 2024, the FDA issued a complete response letter to Supernus requesting more data on product quality and other proprietary information. Through this lengthy review process, the FDA concluded that the drug is both safe and effective.  

Onapgo is the latest in more than 20 treatments approved since 2015 and the third in the last year alone. Onapgo will require a prescription; availability is expected in the second quarter of 2025. As with all medications, insurance coverage will vary and details, particularly for Medicare and Medicaid, generally take time to be determined. Talk with your personal Parkinson’s physician about all available treatment options and which is right for you.