AVL-292

A new series of diphenylpyrimidine derivatives (SFA-DPPYs) were synthesized by introducing a functional sulfonamide into the C-2 aniline moiety of pyrimidine template, and then were biologically evaluated as potent Bruton's tyrosine kinase (BTK) inhibitors. Among these molecules, inhibitors 10c, 10i, 10j and 10k displayed high potency against the BTK enzyme, with IC;50; values of 1.18 nM, 0.92 nM, 0.42 nM and 1.05 nM, respectively. In particular, compound 10c could remarkably inhibit the proliferation of the B lymphoma cell lines at concentrations of 6.49 μM (Ramos cells) and 13.2 μM (Raji cells), and was stronger than the novel agent spebrutinib. In addition, the inhibitory potency toward the normal PBMC cells showed that inhibitor 10c possesses low cell cytotoxicity. All these explorations indicated that molecule 10c could serve as a valuable inhibitor for B-cell lymphoblastic leukemia treatment.

A new series of diphenylpyrimidine derivatives (DPPYs) bearing various aniline side chains at the C-2 position of pyrimidine core were synthesized as potent BTK inhibitors. Most of these inhibitors displayed improved activity against B leukemia cell lines compared with lead compound spebrutinib. Subsequent studies showed that the peculiar inhibitor 7j, with IC;50; values of 10.5 μM against Ramos cells and 19.1 μM against Raji cells, also displayed slightly higher inhibitory ability than the novel agent ibrutinib. Moreover, compound 7j is not sensitive to normal cells PBMC, indicating low cell cytotoxicity. In addition, flow cytometry analysis indicated that 7j significantly induced the apoptosis of Ramos cells, and arrested the cell cycle at the G0/G1 phase. These explorations provided new clues to discover pyrimidine scaffold as more effective BTK inhibitors.

BACKGROUND: ;Recent data suggest that Bruton's tyrosine kinase (BTK) is an emerging therapeutic target in IgE receptor (IgER)-cross-linked basophils.;METHODS: ;We examined the effects of four BTK inhibitors (ibrutinib, dasatinib, AVL-292, and CNX-774) on IgE-dependent activation and histamine release in blood basophils obtained from allergic patients (n=11) and nonallergic donors (n=5). In addition, we examined the effects of these drugs on the growth of the human basophil cell line KU812 and the human mast cell line HMC-1.;RESULTS: ;All four BTK blockers were found to inhibit anti-IgE-induced histamine release from basophils in nonallergic subjects and allergen-induced histamine liberation from basophils in allergic donors. Drug effects on allergen-induced histamine release were dose dependent, with IC;50; values ranging between 0.001 and 0.5 μmol/L, and the following rank order of potency: ibrutinib>AVL-292>dasatinib>CNX-774. The basophil-targeting effect of ibrutinib was confirmed by demonstrating that IgE-dependent histamine release in ex vivo blood basophils is largely suppressed in a leukemia patient treated with ibrutinib. Dasatinib and ibrutinib were also found to counteract anti-IgE-induced and allergen-induced upregulation of CD13, CD63, CD164, and CD203c on basophils, whereas AVL-292 and CNX-774 showed no significant effects.