definiens: , and shall mean a human clinical trial for which the primary endpoints include a preliminary determinati on of efficacy and safety in patients being studied as required in 21 C.F.R. § 312.21(b ), or similar clinical study in a country other than the United S tates . shall mean a Phase II Clinical Trial whose primar y objective is to explore safety and tolerability, pharmacokinetic an d pharmacodynamic effects in human patients in a study [ * ] . shall mean a clinical trial that is initiated after the release of data concerning a completed Phase I Clinical Trial and which has the primary ob jective to collect data on dosages and additional data on safety, and make an initial demonstration of clinical efficacy in a target population for a spec ific disease or condition under study . In a Phase IIb Clinical Trial, the trial res ults are to be assessed for statistically significant differences between group s for clinical endpoints considered as a basis for registration, which may i nclude generally accepted surrogate pharmacodynamic endpoints