SYT-510 for Generalized Anxiety Disorder: Phase 2 Trial Dosing Initiated

Synendos Therapeutics today announced it has started dosing in its phase 2 efficacy and safety clinical trial of SYT-510 in patients with the diagnosis of generalized anxiety disorder (GAD). The trial will investigate the efficacy, safety, tolerability and pharmacokinetics of a single dose of SYT-510 in participants meeting DSM-5 diagnostic criteria for GAD.¹

SYT-510 belongs to a novel class of endocannabinoid system (ECS) modulators called selective endocannabinoid reuptake inhibitors (SERIs), which represent first-in-class, new chemical entities that modulate the ECS through a self-limiting mode of action. This novel mode of action has the potential to combine treatment of a range of symptoms with sustained efficacy in large patient populations alongside the potential to address chronic tolerability. This represents an innovative and potentially safer therapeutic approach to multiple CNS disorders such as anxiety, mood, and stress-related conditions, and more. Furthermore, SERIs could allow more patients remain treatment adherent and achieve an improved quality of life.

This study marks the first time a SERI molecule will be dosed in a patient population.

“SERIs represent a new class of endocannabinoid system modulators designed to restore healthy brain signaling by gently enhancing endogenous cannabinoid activity to unleash its full therapeutic potential without overstimulation,” said Andrea Chicca, PhD, the chief executive officer and cofounder at Synendos. “Because the endocannabinoid system is often described as a ‘master regulator’ of brain activity, helping to keep key functions such as mood, stress, sleep and appetite in balance, this novel mechanism offers a fine-tuned, precise and powerful way to support brain homeostasis without the drawbacks seen with earlier cannabinoid‑based approaches.”

The study is taking place in collaboration with Allan Young, PhD, MPhil, FRCP, FRCPC, FRCPsych, and King’s College, London. Preliminary data is anticipated in early 2027.

Young, who is chair of academic psychiatry at Imperial College London, said, “At King’s, we are evaluating SYT‑510, the first‑in‑class SERI in anxiety disorders, using our established experimental medicine model, which quantifies the drug’s effects on the amygdala—a central hub of fear and anxiety processing that shows heightened activity in individuals with moderate to severe anxiety.”

The phase 2 study follows Synendos’ highly successful phase 1 clinical program in healthy volunteers from last year, which demonstrated safety, tolerability, and the penetration of the therapeutic into the central nervous system and preliminary evidence of a pharmacodynamic effect on the brain. The phase 1 clinical program included 60 healthy volunteer participants, who were dosed in the single and multiple ascending dose studies with no drug-related safety concerns. Key findings from this phase 1 program include (1) plasma and central nervous system exposure reached the anticipated pharmacological levels for activity, and (2) the effect of SYT-510 on electroencephalograms (EEG) showed an effect on the brain consistent with that seen with anxiolytic medicines used successfully to control anxiety symptoms.^2,3

“Our partnership with King’s College marks the start of a focused journey to evaluate this promising new approach to restoring balance in brain chemistry,” concluded George Garibaldi, MD, the chief medical officer at Synendos. “In addition to characterizing its effects on the amygdala, this study will address patient‑relevant outcomes, including the impact on social avoidance—a common, disabling feature of anxiety disorders that significantly impairs social relationships and work life.”

References

1. Synendos Therapeutics starts phase 2 trial in generalized anxiety disorder. News release. May 20, 2026. Accessed May 20, 2026. https://www.globenewswire.com/news-release/2026/05/20/3298159/0/en/synendos-therapeutics-starts-phase-2-trial-in-generalized-anxiety-disorder.html

2. Synendos Therapeutics reports positive and highly promising topline results from phase 1 trials, paving the way for phase 2 in mental health. News release. September 24, 2025. Accessed September 24, 2025. https://www.biospace.com/press-releases/synendos-therapeutics-reports-positive-and-highly-promising-topline-results-from-phase-1-trials-paving-the-way-for-phase-2-in-mental-health

3. Kuntz L. SYT-510: first-in-class inhibitor targets endocannabinoid system to improve mental health outcomes. Psychiatric Times. September 24, 2025. https://www.psychiatrictimes.com/view/syt-510-first-in-class-inhibitor-targets-endocannabinoid-system-to-improve-mental-health-outcomes