Repeated Administration of Newly Synthesized Aceclofenac Sustained Release Form Causes Agranulocytosis: Case Report of an Unforeseen Adverse Event during the Phase 1 Trial

Aceclofenac is a non-steroidal anti-inflammatory drug (NSAIDs) for inflammatory diseases. In this report, we report a serious adverse event (AE) occurred during the phase I clinical trial for a new sustained-release (SR) formulation of aceclofenac. There was a serious adverse event (AE), agranulocytosis, induced by aceclofenac SR form. An open-labeled, repeated-doses, randomized, crossover study was conducted at Kyung Hee University Hospital and 26 Korean healthy male volunteers were enrolled. All subjects received both aceclofenac SR 200 mg once daily and aceclofenac IR 100 mg twice daily for 4 days with 11 days washout period. After 11 days washout period, one subject showed a serious decrease in the segment neutrophil (267/mm3) on a laboratory test prior to the reference drug administration in period 2. We first report a case of agranulocytosis, during a phase I clinical trial.