Improvement of the antitumor activity of intraperitoneally and orally administered 5,6-dimethylxanthenone-4-acetic acid by optimal scheduling.

The antitumor action of DMXAA is schedule dependent, and the achievement of an adequate tumor tissue DMXAA concentration above a threshold value appears to be critical for activity. The use of a pharmacokinetically guided schedule provides excellent oral activity against Colon 38 tumors and provides a basis for developing more effective administration schedules in clinical trials.