Zogenix, Inc. announced positive single-dose pharmacokinetic (PK) results from the Phase 1 clinical trial of Relday(TM), an investigational candidate of a proprietary, once-monthly subcutaneous formulation of risperidone for the treatment of schizophrenia. Adverse events in the Phase 1 trial in patients diagnosed with schizophrenia were generally mild to moderate and consistent with other risperidone products. Based on the favorable safety and PK profile demonstrated with the 25 mg and 50 mg once-monthly doses tested in the Phase 1 trial, Zogenix has extended the current study to include a 100 mg dose of the same formulation.

The addition of this dose arm to the study will enable evaluation of dose proportionality across the full dose range that would be anticipated to be used in clinical practice. Positive results from this study extension would better position Zogenix to begin a multi-dose clinical trial, which would provide the required steady-state PK and safety data prior to initiating Phase 3 development studies. Zogenix expects to complete the extension of the Phase 1 clinical trial during the second quarter of 2013.

Because this approach involves selecting the dose by administering different volumes of the same formulation by a healthcare professional, the development of Relday will first focus on delivery by conventional needle and syringe while accelerating the overall program timeline. The introduction of the DosePro needle-free technology can occur later in development or as part of life cycle management after further work involving formulation development, technology enhancements, and applicable regulatory approvals. If approved, Relday will be the first subcutaneous antipsychotic product that allows for once-monthly dosing.

Zogenix believes that Relday will offer an improved PK profile, significant reduction in injection volume and a simplified dosing regimen due to DURECT's SABER(R) controlled-release depot technology. The Phase 1 clinical trial for Relday was conducted as a single-center, open-label, safety and PK trial of 30 patients with chronic, stable schizophrenia or schizoaffective disorder. The study will be extended to include an additional cohort of 10 patients at a 100 mg dose.