ZM 39923 HCl is an JAK1/3 inhibitor with pIC50 of 4.4/7.1 and almost no activity to JAK2 and modestly potent to EGFR. ZM39923 breaks down to form the JAK3 inhibitor ZM449829 which exhibit similar IC50 values. ZM39923 decomposes in neutral buffer to afford potent inhibition of the Janus kinase 3, and could be used as a standard Jak3 inhibitor in assays where breakdown could occur. ZM39923 is reduced by 300-fold in the presence of DTT (10 mM) in inhibiting TGM2. ZM39923 is reversible inhibitors when TGM2 is incubated with inhibitors in the absence of Ca2+. ZM39923 shows significant inhibition of crosslinking activity with IC50 of 25 nM in the absence of DTT and IC50 of 10 μM in the presence of DTT. ZM39923 prevents early death in a Drosophila Melanogaster model of a polyQ repeat disorder called Machado-Joseph Disease. M39923 inhibits the generation of AICD-FLAG and both Aβ40 and Aβ42 by purified γ-secretase in a concentration-dependent fashion with an approximate IC50 of 20 μM. ZM39923 decreases photoaffinity-labeled PS1-CTF in the presense of γ-secretase.

AZ-960 is a novel inhibitor of janus-associated kinases (JAKs) that exhibits a potent inhibition against janus kinase 2 (JAK2) with the value of inhibition constant of Ki of 0.45 nmol/L. It also exhibits a lesser inhibitory effects against other JAKs family members, including JAK1, JAK3 and TYK2 as well as other kinases, including TrkA, Aurora A and FAK, with 50% inhibition concentration IC50 of around 0.1 umol/L. In recent studies, AZ-960 demonstrates potential anti-cancer activity against adult T-cell leukemia (ATL), an aggressive malignancy of CD4+ T lymphocytes, by effectively inducing growth arrest and apoptosis in human T-cell lumphotropic virus type 1 (HTLV-1) infected T cells. AZ-960 potently inhibited the clonogenic growth and induced apoptosis of freshly isolated AML cells from patients in association with cleavage of caspase 3 and downregulation of anti-apoptotic Bcl-xL proteins.

R406 (TAMATINIB) is an ATP-competitive inhibitor of spleen tyrosine kinase (Syk), which plays a key role in the signaling of activating Fc receptors and the B-cell receptor (BCR). R406 blocked Syk-dependent FcR-mediated activation of monocytes/macrophages and neutrophils and BCR-mediated activation of B lymphocytes. R406 was selective as assessed using a large panel of Syk-independent cell-based assays representing both specific and general signaling pathways. Consistent with Syk inhibition, oral administration of R406 to mice reduced immune complex-mediated inflammation in a reverse-passive Arthus reaction and two antibody-induced arthritis models. R406 is the active compound of pro-drug Fostamatinib (R-788). Fostamatinib is being developed by Rigel Pharmaceuticals for the treatment of immune thrombocytopenic purpura (ITP) and IgA nephropathy.