- A total of 21 evaluable patients will be enrolled in either cohort 1 or 2 as appropriate, in order to have 80% power to detect a response rate consistent with 30% and ruling out 10%, with a one-sided significance level of 0.10 for the cohort. As an early stopping rule for safety, if 2/3 or greater patients at any given dose level experiences a dose limiting toxicity requiring dose reduction or discontinuation, that dose will not be subsequently used and no further dose escalation will take place.