Growth inhibition of mouse autochthonous skin cancer by oral administration of new serine protease inhibitor ONO-3403.

The orally active serine protease inhibitor ONO-3403 is an analog of FOY-3403 that has more potent protease-inhibitory activity. In the present study, oral administration of ONO-3403 was used to challenge 3-methylcholanthrene-induced carcinoma. This drug was administered 3 times daily for 9 weeks via a stomach tube at a dose of 10 mg/kg in a 1-ml volume in 6 mice harboring solid tumors. This protease inhibitor significantly inhibited tumor growth (p<0.001) and prolonged survival-time (p<0.01). These results indicated that oral administration of the potent serine protease inhibitor ONO-3403 has an antitumor effect on malignant tumors.