Repligen Corporation plans to conduct a clinical trial to evaluate RG1068, synthetic human secretin, in patients with schizophrenia. The objective of the trial is to determine if the improvements in social interaction found in a Phase 2 study of secretin in autism can be replicated in patients with schizophrenia who have significant social deficits.

The trial is designed to replicate clinical results from investigators at the University of North Carolina at Chapel Hill who conducted a double-blind, placebo-controlled study of a single dose of secretin in 22 patients with schizophrenia results. Patients in this study had been ill for an average of 20 years and had severe symptoms despite at least three trials of antipsychotic drugs. The secretin-treated group showed a significant improvement in the Clinical Global Impression of Improvement scale (CGI-I) at day two (p=0.03), week one (p=0.009) and week three (p=0.002). Three of eleven patients who received secretin showed transient but marked improvements in their social or communicative symptoms following a single infusion of secretin. Differences between the groups on the Positive and Negative Symptoms Scales for Schizophrenia were not significant.

Pending approval by the FDA, the Phase 2 trial will evaluate the potential of multiple doses of RG1068 to treat the "negative" symptoms of schizophrenia including social interaction and communication deficits, which are often resistant to treatment with existing antipsychotic therapy. Patients will be evaluated with standardized instruments for the assessment of the symptoms of schizophrenia, the Clinical Global Impression of Improvement scale and other clinical instruments focused on social interaction symptoms. The trial will be conducted at multiple centers in the United States.

"The observation that secretin improved the social deficits of several patients with schizophrenia reinforces the observation of improved social interaction we observed in our Phase 2 study of secretin in autism," said Walter Herlihy, President and CEO of Repligen. "We previously demonstrated that secretin activates a brain region called the amygdala in both animals and humans and this brain region has been implicated in both autism and schizophrenia."