Final answer:
Patients selected for phase I studies are chosen to investigate the safety and tolerability of the drug, while patients selected for phase II studies are chosen to assess the efficacy and dose-response.
Step-by-step explanation:
Patients selected for phase I studies are different from patients generally chosen for phase II studies because of the different goals and criteria of each phase. In phase I clinical trials, the main goal is to investigate the safety and tolerability of the drug in humans. Pharmacokinetic properties, such as absorption and elimination, are also evaluated. Phase I studies usually start with sub-therapeutic dose studies and escalate gradually to determine the safe dosing range. Patients in phase II studies, on the other hand, are chosen to assess the efficacy and dose-response of the drug. These studies involve a larger number of patients and may include special sub-populations like pediatric and elderly populations.