Simulations to guide drug design strategies for anti Bcl-2 therapy. A, Minimum amount of therapy required to induce tumor regression is observed to vary exponentially with the inhibition constant KDi of BL193 for Bcl-2. Reducing KDi from its baseline value by 25% decreases the least amount of therapy required from 27.26 mM to 0.52 mM. B, As the rate of diffusion Di of BL193 into the cell is increased, the least amount of efficacious therapy reduces by a maximum amount of 56%, after which no significant change is observed, when compared to baseline values for Di.