NITD008 (7-Deaza-2'-C-acetylene-adenosine) is a potent and selective adenosine nucleoside inhibitor.NITD008 is an adenosine nucleoside analog with broad-spectrum antiviral activity that inhibits dengue, animal cupripoxvirus, and Zika virus.

NITD008 exhibits potent inhibition against various viruses, including Dengue virus (DENV), West Nile virus, yellow fever virus, and Poissan virus. In the case of DENV-2, NITD008 inhibits the virus in a dose-responsive manner, with an EC50 value of 0.64 μM. Treatment with 9 μM of the compound results in a reduction in viral titer by >104-fold[1].Furthermore, NITD008 also demonstrates inhibitory activity against a luciferase-reporting replicon of hepatitis C virus (HCV, genotype 1b), a member of the genus Hepacivirus, with an EC50 value of 0.11 μM[1].

NITD008, with good pharmacokinetic properties, is orally bioavailable. The formulation using 6 N HCl (1.5 equimolar amount), 1 N NaOH (pH adjusted to 3.5), and 100 mM citrate buffer (pH 3.5) yields the best pharmacokinetic parameters. Following intravenous (i.v.) injection, NITD008 demonstrates a high volume of distribution (3.71 L/kg) and low systemic clearance (31.11 mL/min per kg), resulting in a long elimination half-life (t1/2=4.99 h).
After oral dosing, NITD008 is rapidly absorbed (time of peak plasma concentration=0.5 h), reaching a maximal plasma concentration of 3 μM, with a bioavailability of 48%. When administered immediately after viral infection, a dose of 1 mg/kg of NITD008 does not reduce mortality, but treatment with 3 mg/kg provides partial protection, and doses of ≥10 mg/kg completely protect infected mice from death. NITD008 effectively suppresses peak viremia, reduces cytokine elevation, and prevents mortality in the infected mice[1].