BOSTON — Seaport Therapeutics said new research suggests that how often clinicians assess patients during generalized anxiety disorder clinical trials may significantly influence placebo response, underscoring ongoing challenges in neuropsychiatric drug development.
The findings come from a new meta-analysis presented at the International Society for CNS Clinical Trials and Methodology Conference, held Feb. 18–20 in Washington, D.C. The analysis examined the relationship between key clinical trial design factors and the magnitude of placebo response in generalized anxiety disorder, or GAD, trials.
According to the company, the analysis found a strong association between the frequency of clinician-administered assessments and increased placebo response. Other factors evaluated, including baseline Hamilton Anxiety Rating Scale scores, number of trial sites, and total patient enrollment, did not show a strong correlation with placebo effects.
The results build on Seaport’s earlier research in major depressive disorder trials, which also found that more frequent clinician-administered assessments were linked to higher placebo responses.
“This robust analysis highlights the persistent challenges in CNS drug development, where in order to demonstrate efficacy, a sponsor must carefully manage the potential for high placebo response,” said Tony Loebel, M.D., chief medical officer and president of clinical development at Seaport. He said the company is applying these insights to improve trial design and execution with the goal of advancing new treatments for patients with anxiety, depression, and other neuropsychiatric disorders.
Despite substantial unmet need, more than 90 percent of neuropsychiatric drug candidates fail in development, according to industry data. Seaport said suboptimal clinical trial design remains a major contributor to these failures, with placebo response presenting a particularly difficult obstacle.
The meta-analysis reviewed 22 industry-sponsored Phase 2 through Phase 4 randomized, placebo-controlled GAD trials conducted over the past two decades. All studies met strict inclusion criteria, including use of the Hamilton Anxiety Rating Scale as the primary endpoint, enrollment of at least 100 total participants, and a minimum of 25 patients in the placebo arm.
Seaport said the findings sharpen understanding of factors driving placebo response in anxiety trials and reinforce the importance of continued optimization of clinical trial design in central nervous system research.
