Tavapadon Improves Parkinson Disease Motor Fluctuations in Phase 3 Trial
Key Clinical Summary
- Tavapadon, a selective D1/D5 agonist, significantly increased daily on-time without troublesome dyskinesia (“good-on-time”) by 1.10 hours versus placebo in patients with Parkinson disease (PD) on levodopa.
- Daily off-time decreased by 0.94 hours compared with placebo, indicating improved motor symptom control.
- Most adverse events were mild to moderate, with nausea (14.3%), dyskinesia (10.0%), and dizziness (7.6%) most commonly reported.
A phase 3 randomized clinical trial published in JAMA Neurology found that tavapadon, an investigational oral D1/D5 dopamine agonist, was effective as an adjunctive therapy to levodopa in Parkinson disease (PD). The study examined whether selective receptor targeting could improve motor fluctuations while minimizing adverse events associated with traditional D2/D3 agonists.
Study Findings
The double-blind, placebo-controlled TEMPO-3 trial enrolled 507 adults with Parkinson disease experiencing motor fluctuations despite stable oral levodopa (≥400 mg/day). Participants were recruited from 148 sites across 14 countries between September 2020 and February 2024.
Patients were randomized 1:1 to receive flexible-dose tavapadon (5–15 mg once daily) or placebo for 27 weeks. The primary endpoint was change in daily “good-on-time” (time with improved mobility without troublesome dyskinesia) at week 26. Safety was also assessed in a 4-week follow-up.
Tavapadon significantly increased good-on-time by 1.10 hours compared with placebo (1.70 vs 0.60 hours; 95% CI, 0.60–1.70; P < .001). The key secondary endpoint, daily off-time, was also significantly reduced (−1.88 vs −0.93 hours; difference −0.94 hours; 95% CI, −1.48 to −0.41; P < .001).
While adverse events were more frequent with tavapadon than placebo (71.7% vs 55.1%), 93.2% were nonserious and largely mild to moderate. The most common events included nausea (14.3%), dyskinesia (10.0%), and dizziness (7.6%).
Clinical Implications
Motor fluctuations remain a major challenge in Parkinson disease management, particularly in patients on long-term levodopa therapy. Current adjunctive dopamine agonists improve symptom control but often increase adverse effects through D2/D3 receptor activation.
Tavapadon’s selective D1/D5 receptor activity represents a mechanistically distinct approach. The observed increase in good-on-time and reduction in off-time suggest clinically meaningful improvement in daily functioning. The safety profile also indicates that most adverse events were manageable and nonserious.
If approved, tavapadon could expand therapeutic strategies for patients with persistent motor fluctuations despite optimized levodopa regimens.
Expert Commentary
“These findings highlight the clinical utility of adjunctive tavapadon for the treatment of PD with off fluctuations,” wrote Hubert H. Fernandez, MD, Center for Neurological Restoration, Cleveland Clinic, Cleveland, Ohio, and study coauthors, who emphasized that increases in good-on-time “are associated with better clinical outcomes, improved quality of life, and reduced economic burden.”
However, because the study’s treatment duration was limited to 27 weeks, the authors underscored the need for further research to support longer-term efficacy and safety. They also noted that the study sample was predominantly White (96.8%), warranting further study of the drug across more diverse populations.
