It was developed as a potential treatment for severe sepsis, an excessive inflammatory response to an infection.

It failed a five year Phase III clinical trial, the results of which were published in 2013,[1][2] and as of 2014 was no longer being developed.

[3] It was being developed by the Japanese pharmaceutical company Eisai Co. and was administered intravenously as the sodium salt eritoran tetrasodium.

[4] TLR4 is part of the innate immune system and plays an important role in triggering defense against pathogens.

Eritoran is similar in structure to the lipopolysaccharide lipid A - a part of bacteria that binds to TLR4 and activates TLR4, triggering a defense.