Phosphodiesterase 10, or PDE10, is an enzyme that is expressed in areas of the brain strongly linked to diseases that affect cognition. Cognitive dysfunction occurs early in these diseases and is responsible for substantial disability. PDE10 inhibitors have been shown to be effective in multiple animal models of behavior and cognition, and there remain substantial unmet clinical needs with current treatments. Our proprietary compound OMS824, which inhibits PDE10, has received orphan drug designation for the treatment of Huntington's disease and fast track designation for the treatment of cognitive impairment in patients with Huntington's disease.
In our OMS824 program, we continue to advance our PDE10 inhibitors for treatment of neurological disorders. The FDA has approved our conducting clinical trials with our lead candidate subject to dosing limitations pending further discussions potentially to remove those limitations. Given the dosing limitations, we are currently focused on assessing the relative advantages of a number of our back-up compounds.
As of February 16, 2018, we owned 12 issued patents and six pending patent applications in the U.S., and 32 issued patents and 48 pending patent applications in foreign markets, that are directed to proprietary PDE10 inhibitors.