Sibrafiban (G-7453) is the orally administered, nonpeptide, double-prodrug of Ro 44-3888 which is a selective glycoprotein IIb/IIIa receptor antagonist. Sibrafiban is a double prodrug that undergoes bioconversion to the inactive prodrug Ro 48-3656 and to the active IIb/IIIa antagonist, Ro 44-3888, after oral administration. Sibrafiban was undergoing clinical trials for secondary prevention of cardiac events in patients stabilised after acute coronary syndromes. Sibrafiban has been shown to have comparable efficacy to aspirin in preventing recurrent ischemic events in patients suffering from acute coronary syndromes. Sibrafiban was under development by Genentech and Hoffmann-La Roche, and in phase III trials as an antithrombotic. The development of sibrafiban was discontinued in 1999 following unfavorable Phase III efficacy data.

Ezatiostat (TLK199) [γ-glutamyl-S-(benzyl)cysteinyl-R-phenyl glycine diethyl ester] is an inhibitor of Glutathione S-transferase P1–1 (GSTπ). The drug is a peptidomimetic of GSH (glutathione), esterified to enhance cellular uptake and designed to bind to the “G-site” of GSTP1–1. Independent of catalysis inhibition, TLK199 also disrupts the protein:protein interaction site(s) between GSTP1–1 and JNK1. Telik Inc was developing TLK-199 for the potential prevention of myelosuppression in blood diseases, namely myelodysplastic syndrome.

Dalcetrapib (JTT-705) is a modulator than an inhibitor of cholesteryl ester transfer protein (CETP) activity and it may interact with and decrease CETP activity by a unique mechanism without an off-target effect. Dalcetrapib increased high-density lipoprotein (HDL) cholesterol levels but did not reduce the risk of cardiovascular events. It is in phase III of clinical trials for the treatment of acute coronary syndrome.