Cumulative fractional responses (CFRs) targeting different PK/PD indices for the standard (50 mg) and alternatives doses of caspofungin. The in vitro EI99, EI99.9, and EI99.99 values correlated with overall success, favorable (complete plus partial), and complete response, respectively, observed in a prospective phase II clinical trial where 50 mg of caspofungin was used as primary therapy for pulmonary invasive aspergillosis (IA) (15).