Clinical experience with a protease inhibitor [N,N-dimethylcarbamoylmethyl 4-(4-guanidinobenzoyloxy)-phenylacetate] methanesulfate for prevention of recurrence of carcinoma of the mouth and in treatment of terminal carcinoma.

A protease inhibitor, (N,N-dimethylcarbamoylmethyl 4-(4-guanidinobenzoyloxy)-phenylacetate) methanesulfate was administered orally 3 times daily to 9 patients with squamous cell carcinoma of the oral cavity, at doses ranging from 0.6 g. to 7.2 g. Seven of 9 patients who had undergone all kinds of therapies were observed to see whether recurrence was prevented and in no case did the tumour recur. Also, in 2 terminal secondary cases tumour remission resulted. Histologically, after this therapy, carcinomatous lesions showed marked hyperkeratosis in 2 cases and the survival time in 1 case was markedly prolonged. Haematological and gastrointestinal toxicity was almost never observed at these doses.