Tomeglovir is a potent anti-CMV agent, inhibiting the processing of viral DNA-concatemers (IC50s: 0.34/0.039 μM for HCMV and MCMV).

HCMV:0.34 μM, MCMV:0.039 μM

Tomeglovir suppresses HELF and NIH 3T3 cells (CC50s: 85 μM/62.5 μM) [1]. Tomeglovir inhibits HCMV Davis and various monkey CMV strains with EC50s of 1.03 μM and < 1 μM [2].

Tomeglovir (3, 10, 30, 100 mg/kg, p.o.) dose-dependently reduces MCMV-DNA in livers, salivary glands and kidneys of MCMV-infected NOD-SCID mice, and prolongs the survival of the mice. Tomeglovir (10, 25 and 50 mg/kg) shows antiviral activity in the hollow fiber mouse model [1]. Tomeglovir shows antiviral activity in SCID mice with MCMV, and the LD50 is >2000 mg/kg in mice and rats [2].

In order to evaluate drug toxicity, 96-well microtitre plates are prepared with 100 μL of EMEM/10 per well. After addition of 2 μL of 50 mM Tomeglovir stock solutions in duplicate into 198 μL in row 2, serial two-fold dilutions are made with 100 μL up to row 12 and 100 μL of a HELF, NHDF or 3T3 cell suspension (5 × 10^3 cells/mL) are added per well. Row 1 serves as an untreated cell control. After incubation for 6 days at 37°C and 5% CO2, the cells are washed once with phosphate-buffered saline (PBS), and 200 μL of a 10 μg/mL fluorescent dye solution in PBS, pH 7.2 (fluorescein diacetate) are dispensed per well. After 45 min, the fluorescence signal is measured with a Fluorskan Ascent fluorimeter (excitation filter 485 ± 11 nm, emission filter 530 ± 15 nm). The relative fluorescence units (RFUs) of treated cells are expressed as percentages of untreated cell controls and CC50 values are determined graphically [2].

NOD/LtSz-scid/j mice, 20-30 g body weight, are anesthetized with 0.015-0.017 mL/g body weight Avertin 2.5% (Avertin 100% consists of 10 g tribromoethyl alcohol in 10 mL tertiary amyl alcohol). After shaving and cleaning the belly aseptically, the abdomens are opened and the fibers inserted intra-abdominally. The abdomens are closed with two suture layers. Only asymptomatic animals are included in the study. Starting 1 day after transplantation, the mice are treated with the Tomeglovir at indicated dosages twice daily for four consecutive days per os. In preliminary experiments, viral peak titers are observed on day 5 under these conditions [1].