Clinical study of the radioprotective effects of Amifostine (YM-08310, WR-2721) on chronic radiation injury.

We have previously reported that Amifostine, a radioprotective agent, was effective in treating acute radiation mucositis in the head and neck region. We found that when a considerable amount of Amifostine accumulates in the salivary glands, it may be useful in preventing chronic disturbances of salivary secretion. We have observed an increase in the uptake of Ga-67-citrate to the salivary glands when they were irradiated. In this paper, the radioprotective effects of Amifostine, in treating chronic radiation injury of the salivary glands, were studied, using the cessation of an increase in uptake of Ga-67-citrate after radiotherapy as the criterion. The subjects were 105 patients, (280 salivary glands in Ga-scintigrams) with malignancy of the head and neck region treated by irradiation from 1978 to 1984. Ga-negative glands were recognized in 97%, that is, 36 out of 37 glands, before irradiation, and the figure decreased to 19%, seven out of 37, within 1 to 2 weeks (10Gy less than or equal to) after the start of radiotherapy. In patients who were irradiated with more than 30 Gy and in whom scintigraphy was performed at 6 months or more after radiotherapy, Ga-negative glands were recognized in 18 out of 41 glands, 44%, with Amifostine, compared with 13%, four out of 32 glands, without Amifostine. A difference was recognized between these two groups in the negative change in Ga-67 uptake after radiotherapy (p less than 0.05). These facts suggest that Amifostine may have a radioprotective effect on chronic radiation injury.