Highlight
Ecopipam, a selective dopamine D1 receptor antagonist, significantly lowered relapse risk versus placebo in pediatric Tourette syndrome after an initial open-label response phase.
The benefit was demonstrated in a randomized withdrawal design, with a pediatric hazard ratio for relapse of 0.47 (95% CI, 0.26-0.84; P = .008).
Across 24 weeks of treatment exposure, ecopipam did not show a clinically meaningful effect on weight, metabolic measures, or psychiatric scale outcomes, and drug-induced movement disorders were not observed.
Adverse events were mainly central nervous system-related, most commonly somnolence, anxiety, headache, insomnia, tic worsening, and fatigue.
Background and Unmet Clinical Need
Tourette syndrome (TS) is a neurodevelopmental disorder characterized by multiple motor tics and at least 1 vocal tic, with onset in childhood and a fluctuating clinical course. Although many patients experience attenuation of symptoms over time, a substantial subset continue to have functionally impairing tics into adolescence and adulthood. Beyond the tics themselves, comorbid attention-deficit/hyperactivity disorder, obsessive-compulsive symptoms, anxiety, depression, sleep disturbance, and psychosocial impairment often shape disease burden as much as tic severity.
Current pharmacologic management remains constrained by tolerability. Alpha-2 adrenergic agonists may be modestly effective, particularly when ADHD coexists, but can be limited by sedation and hypotension. Antipsychotics, including dopamine receptor antagonists and vesicular monoamine transporter 2 inhibitors in selected settings, can reduce tic severity but are often accompanied by weight gain, metabolic complications, prolactin changes, sedation, akathisia, parkinsonism, or tardive syndromes. These liabilities contribute to frequent treatment discontinuation and reinforce the need for better-tolerated options, especially for children and adolescents who may require extended treatment windows.
Ecopipam is mechanistically distinct from currently used dopamine D2 receptor-blocking strategies. As a selective dopamine D1 receptor antagonist, it offers a biologically plausible alternative approach to tic control that may avoid some of the extrapyramidal and metabolic consequences associated with many antipsychotics. Earlier development work suggested efficacy in reducing tics, but durable benefit and medium-term safety required confirmation in a larger phase 3 setting.
Study Design
Gilbert and colleagues conducted a phase 3, double-blind, placebo-controlled, randomized withdrawal trial between January 31, 2023, and February 4, 2025, at 77 sites across 12 countries. Eligible participants were 6 years and older with Tourette syndrome. The design included a 12-week open-label ecopipam period followed by a 12-week double-blind randomized withdrawal phase among responders.
Open-label lead-in
During the first 12 weeks, all enrolled participants received ecopipam, titrated over 3 to 4 weeks to a target dose of 1.8 mg/kg per day. This enrichment phase identified participants with a clinically meaningful initial response.
Randomized withdrawal phase
Responders were defined as participants with at least 25% improvement in Yale Global Tic Severity Scale Total Tic Score (YGTSS-TTS) at both week 8 and week 12 of the open-label period. These responders were then randomized either to continue ecopipam or to taper to placebo for another 12 weeks under double-blind conditions.
Primary endpoint
The primary endpoint was time to relapse among participants aged 6 to 18 years. Relapse was defined as at least 50% loss of the improvement achieved during the open-label period on the YGTSS-TTS. Adult outcomes were considered exploratory.
Population
The trial enrolled 216 participants into the open-label phase. Of these, 167 participants (77.3%) were pediatric. Overall, 146 participants (67.6%) were male and 70 (32.4%) were female. After the response-enrichment period, 43 pediatric participants and 8 adults were randomized to continue ecopipam, while 47 pediatric participants and 6 adults were randomized to placebo. Mean ages among randomized pediatric participants were 14.3 years in the ecopipam group and 14.0 years in the placebo group.
This trial structure is important for interpretation. A randomized withdrawal design is well suited to testing maintenance of effect and relapse prevention in a chronic fluctuating disorder, but it does not answer the same question as a conventional parallel-group efficacy trial starting at baseline. Specifically, it tells clinicians whether benefit is maintained among prior responders, not the overall probability that an unselected patient will respond.
Key Findings
Primary efficacy outcome: relapse prevention in pediatric participants
Among pediatric responders, continuing ecopipam significantly reduced the risk of relapse compared with switching to placebo. The hazard ratio was 0.47 (95% CI, 0.26-0.84; P = .008; n = 90). In practical terms, this indicates an approximately 53% relative reduction in relapse risk over the 12-week double-blind period among children and adolescents who had already demonstrated benefit during the open-label phase.
This is a clinically meaningful finding. In Tourette syndrome, symptom fluctuation can be substantial even without treatment changes, and relapse after withdrawing effective medication is a major management challenge. A hazard ratio below 0.5 in a responder-enriched maintenance study suggests that the therapeutic signal is not merely transient or driven only by nonspecific open-label effects.
Adult findings
In adults, the estimated effect was directionally similar, with a hazard ratio of 0.51, but the confidence interval was wide (95% CI, 0.11-2.30) and the result was not statistically significant (P = .37; n = 14). The most likely explanation is inadequate power rather than clear absence of effect. The adult randomized sample was very small, and no firm efficacy conclusion for adults should be drawn from this trial alone.
Clinical interpretation of the efficacy result
The pediatric efficacy result is particularly relevant because Tourette syndrome treatment decisions are most often made in childhood and adolescence. The study shows that in pediatric patients who achieve an initial response to ecopipam, continued therapy is more effective than withdrawal in sustaining tic improvement. That is a useful and clinically actionable message for maintenance treatment planning.
However, the enriched design also narrows the inference. The trial does not directly quantify how ecopipam compares with placebo from treatment initiation in the full Tourette syndrome population, nor does it establish superiority against active comparators such as aripiprazole, risperidone, or clonidine. It instead supports durability of benefit among responders.
Safety and Tolerability
Safety is where ecopipam may have its greatest clinical appeal if replicated in longer-term experience. Across the open-label and double-blind periods, the most frequently reported adverse events were somnolence in 24 participants (11.1%), anxiety in 21 (9.7%), headache in 21 (9.7%), insomnia in 19 (8.8%), tic in 17 (7.9%), and fatigue in 14 (6.5%). These events were largely central nervous system-related, which is not surprising for a centrally active dopaminergic agent.
Several negative findings are especially notable. Ecopipam did not have a clinically meaningful impact on weight, metabolic parameters, or psychiatric scale measures. Drug-induced movement disorders were not observed. For clinicians accustomed to balancing tic reduction against risks such as extrapyramidal symptoms, akathisia, dystonia, parkinsonism, hyperprolactinemia, and weight gain with D2-blocking agents, this safety profile is potentially important.
The absence of a metabolic signal is particularly relevant in pediatric practice, where long-term consequences of antipsychotic-associated weight gain can be substantial. Likewise, the absence of observed drug-induced movement disorders fits the mechanistic expectation that D1-selective antagonism may behave differently from traditional D2 receptor antagonism. That said, the treatment duration was limited to 24 weeks, and rare or delayed adverse effects cannot be excluded.
Clinicians should still note the burden of somnolence, fatigue, insomnia, and anxiety. Although these events may be manageable, they matter in school-aged children and adolescents, in whom alertness, sleep quality, and emotional regulation have clear functional implications. As with many neuropsychiatric medications, the practical question is not whether adverse events occur, but whether they are milder and more acceptable than those associated with available alternatives.
Mechanistic and Therapeutic Context
The dominant pharmacologic tradition in tic treatment has centered on D2 receptor antagonism or modulation. Ecopipam represents a different strategy, targeting the dopamine D1 receptor. From a circuit perspective, Tourette syndrome is linked to dysfunction in cortico-striato-thalamo-cortical networks, with dopaminergic signaling long implicated in tic generation and expression. A D1-based approach raises the possibility of modulating these pathways while potentially sidestepping some liabilities associated with D2 blockade.
This trial does not prove mechanistic superiority, but it strengthens the translational rationale for D1-targeted therapy in TS. It also expands the therapeutic conversation beyond a simple choice between alpha-2 agonists and antipsychotics. If eventually incorporated into clinical practice, ecopipam could occupy an intermediate position: a targeted antidopaminergic option with a potentially more favorable metabolic and extrapyramidal profile.
Strengths of the Trial
The study has several notable strengths. It was international and multicenter, improving procedural robustness and reducing dependence on a single-center effect. The double-blind randomized withdrawal phase is a strong design for testing maintenance of benefit. The endpoint was clinically meaningful and anchored to the widely used YGTSS-TTS. The pediatric sample was reasonably sized for the randomized comparison, and the safety assessment directly addressed concerns that often limit use of existing Tourette syndrome medications.
Equally important, the trial evaluated up to 24 weeks of exposure, which is more informative than short acute studies for a disorder often requiring sustained treatment. The emphasis on relapse prevention rather than only short-term symptom change reflects real-world treatment goals.
Limitations and Remaining Questions
Several limitations should temper interpretation. First, the randomized comparison was restricted to responders during the open-label phase, which enriches the sample for treatment sensitivity and may overestimate benefit relative to an unselected population. Second, adults were underrepresented, making adult efficacy essentially unresolved. Third, the study duration, though longer than many acute trials, remains insufficient to define longer-term outcomes on growth, mood, cognition, sleep architecture, or rare adverse effects.
Another limitation is the lack of active comparator data. Clinicians deciding among ecopipam, aripiprazole, risperidone, or alpha-2 agonists need comparative effectiveness information, not just placebo-withdrawal evidence. In practice, treatment selection is influenced by comorbidity profile, urgency of tic suppression, prior medication history, and tolerance for adverse effects. Ecopipam’s relative place in therapy will remain uncertain until head-to-head or network-comparative data become available.
The relapse definition, based on loss of prior YGTSS-TTS improvement, is appropriate for a maintenance trial but may not fully capture broader patient-centered outcomes such as school participation, social functioning, distress, injury risk, or caregiver burden. Future work should integrate more functional endpoints and quality-of-life measures.
Implications for Practice
This phase 3 trial suggests that ecopipam could become a clinically relevant option for pediatric patients with Tourette syndrome who respond initially and require maintenance therapy. The most practice-changing aspect is not simply efficacy, but efficacy coupled with an apparently favorable profile regarding weight, metabolic complications, and drug-induced movement disorders.
At present, behavioral therapy, especially comprehensive behavioral intervention for tics when available, remains a key part of evidence-based care. Pharmacotherapy is generally reserved for functionally impairing tics or when behavioral therapy is insufficient, inaccessible, or not feasible. If approved and accessible, ecopipam may be particularly attractive for patients in whom antipsychotic-related metabolic or extrapyramidal risk is a major concern, or for families hesitant to use D2 receptor antagonists.
However, caution is warranted before extrapolating too broadly. The trial supports maintenance among pediatric responders; it does not yet define first-line positioning, superiority over established agents, or long-term pediatric safety beyond 24 weeks. Shared decision-making would still need to incorporate severity of tics, comorbid conditions, prior treatment responses, and family preferences.
Expert Commentary
The findings are broadly consistent with a longstanding therapeutic goal in Tourette syndrome: achieving meaningful tic control without creating a second clinical problem through treatment toxicity. Current American Academy of Neurology guidance emphasizes individualized treatment, balancing impairment reduction against adverse effects and comorbidity management. In that context, ecopipam is notable less as a replacement for all current therapies than as a potentially important addition to a limited pharmacologic armamentarium.
From a translational standpoint, this study also matters because it validates dopamine D1 antagonism as a viable pathway in TS. That may stimulate broader drug development focused on circuit-specific approaches rather than relying almost exclusively on D2 blockade.
Conclusion
In this phase 3 randomized withdrawal trial, ecopipam maintained tic improvement and significantly reduced relapse risk in pediatric Tourette syndrome over a 24-week treatment period. The safety profile was encouraging, with mostly central nervous system adverse events and no clinically meaningful signal for weight gain, metabolic disturbance, psychiatric worsening, or drug-induced movement disorders.
The study does not answer every clinically relevant question, particularly regarding adult efficacy, comparative effectiveness, and long-term safety. Even so, it represents a meaningful advance. For pediatric patients with TS who respond to ecopipam, continued treatment appears more effective than withdrawal, and the tolerability profile may offer an advantage over many currently used dopamine D2-blocking therapies.
If subsequent regulatory, comparative, and long-term data remain favorable, ecopipam may help shift Tourette syndrome pharmacotherapy toward a more targeted and potentially more tolerable model of care.
Funding and ClinicalTrials.gov
Trial registration: ClinicalTrials.gov Identifier: NCT05615220.
The abstract provided does not specify the funding source. Readers should consult the full JAMA Neurology publication for detailed funding, sponsor involvement, and conflict-of-interest disclosures.
Selected References
Gilbert DL, Atkinson SD, Kim DJB, Miller MM, Rice PM, Flatt JA, Karkanias GB, Munschauer FE, Bittman RM, Wanaski SP, Cunniff TM, Tomczak KK. Efficacy and Safety of Ecopipam for Tourette Syndrome: A Phase 3 Randomized Clinical Trial. JAMA Neurology. 2026-05-26. PMID: 42189524. Available at: https://pubmed.ncbi.nlm.nih.gov/42189524/
Pringsheim T, Holler-Managan Y, Okun MS, et al. Comprehensive systematic review summary: Treatment of tics in people with Tourette syndrome and chronic tic disorders. Neurology. 2019;92(19):907-915.
Pringsheim T, Okun MS, Müller-Vahl K, et al. Practice guideline recommendations summary: Treatment of tics in people with Tourette syndrome and chronic tic disorders. Neurology. 2019;92(19):896-906.
