<qa>  How many patients are treated at the MTD?Cohorts of 3-6 patients per group receive escalating doses of 17-AAG until the maximum tolerated dose MTD is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. Up to 20 additional patients 10 per group are treated at the MTD. 