GC376 sodium exhibits favorable bioavailability and safety in cats. GC376 sodium is rapidly absorbed after s.c. administration and the peak plasma level is reached within 2 hr after injection. The mean plasma drug concentrations remains above the 50% effective concentration (EC50) value of the aldehyde form of GC376 (8 ng/mL) for 18 hrs post injection. Virus infected cats shows improvement in attitude and resolution of fever. The profound absolute lymphopenia observed in all cats prior to antiviral treatment also returns to normal before the next blood testing one week later[3]. Nineteen of 20 cats treated with GC376 sodium regain outward health within 2 weeks of initial treatment. However, disease signs recur 1-7 weeks after primary treatment and relapses and new cases are ultimately treated for a minimum of 12 weeks[4].