Method of dynamic retardation of cell cycle kinetics to potentiate cell damage

A method of potentiating cell damage, comprising:

• a. administering a restraining agent to a target cell population to be damaged at a concentration and under conditions sufficient to dynamically retard but not arrest the progress of the target cell population through a reference point within a phase of the cell cycle, wherein the concentration of the restraining agent is less than 40% of its inhibitory concentration (IC40), as measured at a cell population doubling time or at a time interval which is less than the cell population doubling time, and is at least 50% of the cell population doubling time;
• and
• b. administering a targeted cytotoxic insult concomitant with or subsequent to the administration of the restraining agent, wherein the targeted cytotoxic insult inflicts biologically significant damage to the target cell population at a point in the cell cycle that is downstream of the reference point of the restraining agent, and wherein the targeted cytotoxic insult is administered at an effective concentration that minimizes the toxic effect on non-target cells;
• and
• wherein said restraining agent is a ribonucleotide reductase inhibitor.