Aloxistatin (loxistatin, E-64d, EST) is a drug which acts as a cysteine protease inhibitor and has anticoagulant effects.

It is a synthetic analogue of E-64, a natural product derived from fungi.

[1][2][3] It was researched for the treatment of muscular dystrophy but was not successful in human clinical trials,[4] though it has continued to be investigated for treatment of spinal cord injury, stroke and Alzheimer's disease.

[10][11][12] Studies have shown it can inhibit cathepsin L, a protein believed to play a role in SARS-CoV-2 cellular entry.

In a laboratory study using SARS-CoV-2 pseudovirions, aloxistatin was able to reduce viral entry into cells by approximately 92%.