Epithelial desquamation observed in a phase I study of an oral cathepsin C inhibitor (GSK2793660).

GSK2793660 inhibited CTSC activity but not the activity of downstream neutrophil serine proteases. The palmar-plantar epidermal desquamation suggests a previously unidentified role for CTSC or one of its target proteins in the maintenance and integrity of the epidermis at these sites, with some similarities to the phenotype of CTSC-deficient humans.