<qa>  What is the maximum safe dose of each drug?During the alternate weeks Days 8-14 and 22-28, participants will take R115777 tablets by mouth in the morning and evening with food. At the beginning of the study, groups of 3 participants each will take increasing doses of both R115777 and temozolomide until the highest safe dose of each drug, when given in combination, is found. Participants entering the study after the highest safe dose is found will receive that dosage. 