Omeros provides update on OMS824 for treatment of schizophrenia, Huntington's disease

Omeros Corporation (NASDAQ: OMER) today provided an update on OMS824, the company's phosphodiesterase 10 (PDE10) inhibitor in development for the treatment of schizophrenia and Huntington's disease. OMS824 selectively inhibits PDE10, an enzyme expressed in areas of the brain linked to a wide range of diseases that affect cognition. Omeros has suspended its Huntington's clinical trial as it further evaluates an observation from a nonclinical study in rats. The observation occurred in several of the rats receiving the study's maximum dose of OMS824, a dose that resulted in OMS824 free-plasma concentrations multiply higher than those that have been measured in patients. Non-human primates exposed to plasma concentrations equal to those in the rat demonstrated no findings similar to the observation reported from the rat study. OMS824 has been well tolerated in all human clinical trials. 

Earlier this year, Omeros initiated a Phase 2 trial of OMS824 in patients with Huntington's disease. That trial is a sequential-cohort dose-escalation study that evaluates the safety and tolerability of OMS824 dosed for four weeks in patients with Huntington's disease. Concurrent with the clinical OMS824 program, Omeros is conducting nonclinical studies to allow clinical trials of longer duration. Following preliminary data collection from a 13‑week nonclinical study in rats, Omeros submitted a report on an observation in several of the rats receiving the maximum dose administered in the study to FDA's Division of Neurology Products and its Division of Psychiatry Products where Omeros has its Investigational New Drug applications for Huntington's disease and schizophrenia, respectively. The drug exposure at that maximum dose in the rat study is multiply above the drug exposure in humans at the doses used in the Huntington's disease trial, and the potential relevance of the nonclinical findings to humans, if any, is unknown. Based on follow-up communications with FDA, Omeros has suspended the ongoing Huntington's disease trial, the only OMS824 trial actively enrolling. FDA has requested that Omeros further evaluate the nonclinical data from the 13-week rat study as well as nonclinical studies that did not yield the observation in order to characterize it more fully prior to reinitiating the clinical trial.

In addition to the 13-week rat study, Omeros has conducted several nonclinical studies with OMS824 in rats and in primates, including a 13‑week nonclinical study in primates, at equally high drug exposures to those resulting from the maximal dose in the rat study, with no findings similar to the observation reported from the most recent study in rats. To date, over 120 people have received OMS824 for up to four weeks and the drug is well tolerated. Omeros plans to release available data from the Phase 2 Huntington's program later this year. In addition, other Omeros programs are on track for their near-term milestones.

"Omeros is further evaluating the data from the nonclinical animal studies of OMS824," stated Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. "Based on currently available data, we do not believe that the observation in the rats is caused by OMS824. We will work with the FDA and look forward to continuing the Phase 2 Huntington's trial."