Serum Transaminase Levels Should Be Measured Immediately Prior to Dosing in Early Phase I Clinical Trials

Observations of predose spikes in transaminases from a phase I study prompted our review of other clinical trials, including 250 healthy participants from 4 studies at 3 sites. Six of these participants (2.4%) displayed elevated alanine aminotransferase/aspartate aminotransferase (ALT/AST) levels immediately predose despite normal values <48 hours previously, including one with ALT/AST = 237/175 IU/L (previously 41/29 IU/L). Testing immediately prior to dosing can exonerate a study drug and avoid unnecessary, expensive delays in early clinical trials.