Novel 4-Anilinoquinazolines with C-7 Basic Side Chains:  Design and Structure Activity Relationship of a Series of Potent, Orally Active, VEGF Receptor Tyrosine Kinase Inhibitors

Abstract

We have previously shown that 4-anilinoquinazolines can be potent inhibitors of vascular endothelial growth factor (VEGF) receptor (Flt-1 and KDR) tyrosine kinase activity. A novel subseries of 4-anilinoquinazolines that possess basic side chains at the C-7 position of the quinazoline nucleus have been synthesized. This subseries contains potent, nanomolar inhibitors of KDR (median IC(50) 0.02 microM, range 0.001-0.04 microM), which are comparatively less potent vs Flt-1 tyrosine kinase (median IC(50) 0.55 microM, range 0.02-1.6 microM). The compounds also retain some inhibitory activity against the tyrosine kinase associated to the endothelial growth factor receptor (EGFR) (median IC(50) 0.2 microM, range 0.075-0.8 microM) but demonstrate selectivity vs that associated to the FGF receptor 1 (median IC(50) 2.5 microM, range 0.9-19 microM). This selectivity profile is also evident in a growth factor-stimulated human endothelial cell (HUVEC) proliferation assay (i.e., inhibition of VEGF > EGF > FGF), with inhibition of VEGF-induced proliferation being achieved at nanomolar concentrations (median IC(50) 0.06 microM). Further examination of compound 2 (ZD6474) in recombinant enzyme assays revealed excellent selectivity for the inhibition of KDR tyrosine kinase (IC(50) 0.04 microM) vs the kinase activity of erbB2, MEK, CDK-2, Tie-2, IGFR-1R, PDK, PDGFRbeta, and AKT (IC(50) range: 1.1 to >100 microM). Anilinoquinazolines possessing basic C-7 side chains exhibited markedly improved aqueous solubility over previously described anilinoquinazolines possessing neutral C-7 side chains (up to 500-fold improvement at pH 7.4). In addition, aqueous solubility of the neutral fraction present at pH 7.4 of the basic subseries of anilinoquinazoline proved to be higher than that of the neutral analogue 1 (ZD4190). Oral administration of representative compounds to mice (50 mg/kg) produced plasma levels between 0.2 and 3 microM at 24 h after dosing. Our development candidate 2 demonstrated a very attractive in vitro profile combined with excellent solubility (330 microM at pH 7.4) and good oral bioavailability in rat and dog (> 80 and > 50%, respectively). This compound demonstrated highly significant, dose-dependent, antitumor activity in athymic mice. Once daily oral administration of 100 mg/kg of compound 2 for 21 days inhibited the growth of established Calu-6 lung carcinoma xenografts by 79% (P < 0.001, Mann Whitney rank sum test), and substantial inhibition (36%, P < 0.02) was evident with 12.5 mg/kg/day.

Pharmacokinetic Drug Interactions with Vandetanib during Coadministration with Rifampicin or Itraconazole

“…[1][2][3] VEGFR-2, EGFR, and RET are involved in signaling pathways promoting angiogenesis and tumor growth. [4][5][6] Vandetanib is in development as an anti-tumor drug in several tumor types, including medullary thyroid cancer.…”

Targeted therapy of orthotopic human lung cancer by combined vascular endothelial growth factor and epidermal growth factor receptor signaling blockade

“…A single solid lung tumor progressed to a widespread and fatal thoracic process characterized by dissemination of lung cancer in the pleura and metastasis to intrathoracic and extrathoracic lymph nodes. The purpose of the present study was to evaluate and characterize the effects of inhibition of VEGFR2 and EGFR signaling by ZD6474, an orally available small-molecule receptor tyrosine kinase inhibitor (17,18), on tumor growth, progression, angiogenesis, and vascularization of human lung cancer in the lungs of nude mice.…”

A Phase I Dose-Escalation Study of ZD6474 in Japanese Patients with Solid, Malignant Tumors

“…[17][18][19][20] As such, ZD6474 has the potential to inhibit two key pathways in tumor growth: VEGF-dependent tumor angiogenesis, and EGFR-and RET-dependent tumor cell proliferation and survival. Indeed, preclinical evaluation of ZD6474 has demonstrated potent inhibition of VEGF-dependent signaling and angiogenesis in vivo, as well as dose-dependent inhibition of tumor growth, including profound regression in established PC-3 prostate tumors.…”