In short
Clinical trials investigating Levodopa are studying how it is used in Parkinson’s disease and other patient groups. These trials look at outcomes such as motor symptoms, “ON” time, safety, and patient-reported results. The studies include people with Parkinson’s disease, advanced disease with motor fluctuations, healthy adults, and a small rare-disease group.
Key points
- Clinical trials investigating Levodopa are mainly focused on Parkinson’s disease, especially motor symptoms, motor fluctuations, and daily “ON” time. The studies include Phase 1, Phase 2, Phase 3, and Phase 3b designs, so they range from early comparison studies to larger trials of effectiveness and safety. Most participants are people with Parkinson’s disease, but one study includes healthy adults and one small study includes a rare CTNNB1-related disorder. The main outcomes include movement scores, diary-based “ON” time, safety, tolerability, and bioavailability measures. Several trials are authorised, and one Phase 1 study has been completed. Some studies also compare Levodopa-related approaches with placebo or other treatments.
Clinical trials overview
These studies investigate Levodopa in different trial settings, mostly for Parkinson’s disease and related movement problems. The trial data includes studies that are authorised, one that is completed, and designs that range from early testing to larger comparative studies.
Some trials study Levodopa directly, while others study Levodopa-based treatment strategies, devices, or comparison regimens in people with Parkinson’s disease. The main goal across the studies is to understand effectiveness, safety, tolerability, and how treatment affects daily movement control.
Who is being studied
Most trials include people with Parkinson’s disease, including early to moderate disease, advanced disease, and motor fluctuations. Motor fluctuations means symptoms can change during the day, with “good” and “bad” movement periods.
One trial includes healthy adult volunteers, and its purpose is to compare inhaled Levodopa products in a non-patient setting. Another small Phase 2 study includes patients with a rare CTNNB1-related neurodevelopmental disorder, which means a developmental condition linked to a specific gene change.
Trial phases and study designs
The trial set includes Phase 1, Phase 2, Phase 3, and Phase 3b studies. Phase 1 in this group is a bioavailability study in healthy adults, while later phases focus more on symptom control, safety, and patient experience.
Most of the studies are interventional, which means the researchers assign a treatment and then measure the results. Some are randomized, placebo-controlled, or open-label, meaning either the treatment is compared fairly with another option or both the researchers and participants know what is given.
Main outcomes being measured
A common outcome is motor symptom change, often measured with MDS-UPDRS Part 3, a standard scale for movement problems in Parkinson’s disease. One Phase 2 study measures this at several follow-up visits and looks at change from baseline to month 18.
Several studies measure ON time, which is the time when movement symptoms are better controlled during the day. One Phase 3 study focuses on ON time without troublesome dyskinesia, while another compares good ON time at Week 12 between treatment groups.
Safety and tolerability are also important outcomes, especially in the long-term infusion study and in the Phase 1 bioavailability trial. The healthy adult study also measures pharmacokinetic endpoints, which are body-level measurements such as peak concentration and total exposure to the drug.
One small rare-disease study measures motor function with the GMFM-88, a 88-item test used to track gross motor skills before and after treatment. Another study uses a patient questionnaire to evaluate a new medicine dispenser and app for Flexilev minitablets.
Key trial examples
The MONTPARK trial is a Phase 2 randomized placebo-controlled study in mild to moderate Parkinson’s disease, and it measures motor symptoms with MDS-UPDRS Part 3 over time. Its main objective is to examine disease progression in early to moderate Parkinson’s disease.
The BouNDless study is a Phase 3 trial in Parkinson’s disease with motor fluctuations, and it compares continuous subcutaneous ND0612 with oral treatment using diary-based ON/OFF recordings. Its primary endpoint is daily ON time without troublesome dyskinesia, adjusted to waking hours.
The study titled “Management of Parkinson’s disease if levodopa is broken down prematurely” is a Phase 2 trial in Parkinson’s disease that looks at response rates and compares apomorphine versus Levodopa, and rifaximin versus placebo. It is aimed at people with increased activity of Levodopa-metabolizing enzymes or bacteria that produce related enzymes.
The CTNNB1 pilot study is a very small Phase 2 trial with only seven participants, and it measures motor score change from day 1 to 6 months using the GMFM-88. This makes it a focused exploratory study in a rare patient group.
The BeyoND study is a Phase 2 long-term safety trial of continuous subcutaneous ND0612 in advanced Parkinson’s disease, and its main goal is to assess systemic and local safety and tolerability over 12 months. This kind of study helps show how a treatment performs over a longer period.
The INITIATE-LECIG trial is a Phase 3 study in Parkinson’s disease that compares LECIG therapy with best medical treatment for hyperdopaminergic symptoms on the Ardouin Behavioural Scale. Hyperdopaminergic symptoms means symptoms linked to too much dopamine-related stimulation, as defined by the study scale.
The ADIP study is a Phase 3b open-label randomized trial in advanced Parkinson’s disease with motor fluctuations, and it compares IPX203 with immediate-release Levodopa and a decarboxylase inhibitor regimen. Its primary endpoint is the change in good ON time at Week 12.
The OraFID study is a Phase 3 patient evaluation of a new medicine dispenser and app for Flexilev minitablets, and the main outcome is a self-reported questionnaire about the device. This shows that some trials focus not only on medicine effects but also on how easy treatment is to use in daily life.
The completed Phase 1 Levodopa Cyclops™ study in healthy adults compared inhaled Levodopa Cyclops™ with INBRIJA® and measured pharmacokinetic endpoints such as Cmax, Tmax, AUC, and half-life. It was designed to find the dose at which comparative bioavailability would be reached.
What these studies may mean for patients
For patients, these trials show that Levodopa-related research is not limited to one question. The studies look at symptom control, daily function, long-term safety, treatment delivery, and whether new approaches can improve “good time” during the day.
Some studies are small and early, while others are larger and designed to compare treatments in a more practical way. Together, they help researchers understand where Levodopa-based treatment strategies may fit for different patient groups, especially people living with Parkinson’s disease.