Once-daily therapy eases early Parkinson’s symptoms in Phase 3 trial
Study found benefits with tavapadon after 26 weeks of treatment
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- Tavapadon significantly eased motor symptoms and daily-function problems in people with early Parkinson’s.
- Benefits compared with a placebo were seen by week 5 and continued through the end of treatment.
- Side effects were mostly mild to moderate, and an FDA decision on tavapadon is expected later this year.
Once-daily treatment with tavapadon, an experimental oral small molecule being developed by Abbvie, outperformed a placebo at easing motor symptoms and problems with daily functioning in people with early Parkinson’s disease, while somnolence, or excessive sleepiness, and impulse control disorders occurred infrequently.
These are six-month data from TEMPO-2 (NCT04223193), a Phase 3 clinical trial that tested the safety and efficacy of tavapadon in adults with early Parkinson’s who had received little or no previous treatment for their symptoms.
“The short observation period limits conclusions about long-term tolerability,” researchers wrote. However, data from the long-term open-label extension study TEMPO-4 (NCT04760769) supported tavapadon’s longer-term safety and effectiveness in easing Parkinson’s symptoms. Most participants did not need to begin levodopa or increase their existing levodopa dose during the study.
FDA decision expected later this year
Abbvie has submitted an application to the U.S. Food and Drug Administration (FDA) seeking approval of tavapadon, with a decision expected later this year.
The data, “Safety, tolerability, and efficacy of flexible-dose tavapadon for Parkinson’s disease (TEMPO-2): a phase 3, randomised, placebo-controlled, double-blind trial,” were published in The Lancet Neurology. The study was funded by Abbvie.
Parkinson’s symptoms develop when nerve cells that produce dopamine — a brain chemical that helps control movement — gradually die. A standard treatment is oral levodopa, which the body converts into dopamine. However, its effects may become less consistent over time, and it can cause involuntary movements known as dyskinesia.
Tavapadon is a dopamine agonist designed to selectively and partially activate two dopamine receptor proteins, called D1 and D5, to mimic some of dopamine’s effects. This is expected to strengthen dopamine signaling without directly increasing dopamine levels, as levodopa does. Tavapadon may therefore ease motor symptoms with a lower risk of certain side effects associated with other dopamine agonists. As a once-daily medication, it also may make treatment schedules easier to manage.
The TEMPO-2 clinical trial involved 304 adults who had been diagnosed with Parkinson’s disease within the previous three years. About two-thirds (66%) had been diagnosed less than a year earlier. They were randomly assigned to receive tavapadon or a placebo once daily for 27 weeks, or just over six months. Tavapadon was gradually increased to a dose of 5 mg and could then be adjusted up to 15 mg daily, based on tolerability. More than half of the participants (56%) were men.
The trial’s main goal was to compare changes in the combined Movement Disorder Society–Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Parts II and III score after six months of treatment with tavapadon or a placebo. Part II measures how Parkinson’s affects daily activities, while Part III assesses motor symptoms during a clinical examination. Lower scores indicate fewer or less severe problems.
Tavapadon outperforms placebo on motor and daily-function scores
At the start of the study, the average combined MDS-UPDRS score was 30.5 points. The score decreased by an average of 10.3 points with tavapadon, compared with 1.2 points with the placebo, indicating greater improvements in motor symptoms and daily functioning. Improvements compared with the placebo were seen by week 5 and continued through the end of treatment. “Tavapadon resulted in significant and meaningful improvements,” the researchers wrote.
The Patient Global Impression of Change (PGIC), which measures how patients feel their condition has changed, also favored tavapadon. After six months, a higher proportion of participants taking tavapadon rated their condition as “much improved” or “very much improved” than those taking the placebo (46% vs. 19%). At least minimal improvement was also reported more frequently with tavapadon (78% vs. 40%).
Most side effects were not serious and were mild to moderate, but they were more common with tavapadon than with the placebo (76% vs. 55%). The most frequent side effects were nausea, headache, and dizziness, and side effects overall occurred most often during dose titration. More participants stopped treatment because of side effects with tavapadon than with the placebo (24% vs. 4%).
While these data “support the clinical potential of tavapadon as a new option for the treatment of Parkinson’s disease,” the researchers pointed to the open-label extension study TEMPO-4 as a source of longer-term safety and efficacy data. “Ongoing data from the TEMPO-4 open-label extension will further characterise the long-term clinical profile of tavapadon,” they concluded.
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