Background:

TOK-8801 is a synthesized dihydroimidazothiazole carboxamide and is under development as an immunomodulator.

TOK-8801 is a synthesized dihydroimidazothiazole carboxamide and is under development as an immunomodulator. TOK-8801 augments the in vitro anti-SRBC PFC response of murine splenocytes in a bell-shaped manner. The stimulatory effect of TOK-8801 is observed at concentrations of 2.5×10-7 to 2.5×10-5 M and is diminished at 10-4 M. The cell-viability is not altered during the culture with TOK-8801 at any doses used in this experiment (10-7 to 10-4 M). TOK-8801 enhances the 3H-TdR uptake of these responses in a bell-shaped manner, and effective concentrations of TOK-8801 are 10-7 to 10-5 M[1].

The anti-SRBC PFC response per spleen, which is prominently lowered by restraint-stress (P<0.05), is significantly restored by the administration of TOK-8801 (0.5 mg/kg, P<0.05). The number of total splenic lymphocytes in restraint-stress is decreased, but there are no significant changes in the number of total splenic lymphocytes by the treatment with TOK-8801[1]. When TOK-8801 is administered orally at doses of 0.1 to 10 mg/kg, the number of plaque forming cell (PFC) significantly decreases or tends to decrease. Treatment of TOK-8801 at doses of 0.1 to 1 mg/kg causes significant suppression in the delayed-type hypersensitivity (DTH) reaction induced in high responder[2].

[1]. Fujiwara M, et al. Immunomodulatory activity of the newly synthesized compound TOK-8801 (N-(2-phenylethyl)-3,6,6-trimethyl-5,6-dihydroimidazo[2,1-b]thiazole-2- carboxamide). Jpn J Pharmacol. 1989 Dec;51(4):549-54. [2]. Shibata K, et al. Immunomodulatory effect of a newly synthesized compound, TOK-8801 (N-(2-phenylethyl)-3,6,6-trimethyl-5,6-dihydroimidazo [2,1-b]thiazole-2-carboxamide) on antibody production in vivo and delayed-type hypersensitivity in mice. Int J Immunopharmacol. 1990;12(5):497-502.