zibotentan and Neoplasms

Endothelins are a family of small peptides (ET-1, ET-2, and ET-3) that mediate various physiological processes of mitogenesis, repair, and tissue differentiation by binding to endothelin A (ETA) and endothelin B (ETB) cell surface receptors. Activation of the ETA receptor by ET-1 has emerged as an important factor promoting tumor cell proliferation, survival, angiogenesis, migration, invasion, and metastasis in several tumor types including prostate, ovary, colon, cervix, breast, and lung. As activation of the ETB receptor has an opposing effect, inducing cell death by apoptosis, a rationale exists for specific antagonism of the ETA receptor as a treatment strategy for cancer. ZD4054 is a specific ETA receptor antagonist currently being evaluated in hormone-resistant prostate cancer in phase III clinical trials. In vitro, ZD4054 reversed ET-1-mediated inhibition of apoptosis in serum-deprived rat A10 and human VLTR-16 cells in a concentration-dependent manner. ZD4054 inhibited ET-1-mediated survival signaling pathways and decreased proliferation in ovarian OVCA 433 and HEY cells and in prostate PPC-1 and LAPC-4 cells. In A673 rhabdomyosarcoma cells, ET-1-induced phosphorylation of FAK, FAK, and paxillin was reversed with ZD4054, inhibiting the invasive phenotype mediated by these adhesion factors. In vivo, ZD4054 led to a significant reduction in tumor growth in animals bearing ovarian tumor xenografts, and significantly inhibited tumor angiogenesis. Pretreatment with ZD4054 also significantly delayed the onset of metastatic events after intracardiac injection of bladder TSU-Pr1-B1 cells in mice. These preclinical data show the potential anticancer effects of the specific blockade of the ETA receptor with ZD4054, supporting a program of clinical investigation.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Proliferation; Drug Evaluation, Preclinical; Endothelin A Receptor Antagonists; Humans; Neoplasms; Neovascularization, Pathologic; Pyrrolidines

Endothelins are a family of peptide compounds which exert regulatory control over cellular processes important for growth, survival, invasion, and angiogenesis. In particular, endothelin-1, acting primarily through the endothelin-A receptor, is implicated in the neoplastic growth of multiple tumor types. In preclinical models, endothelin antagonism inhibits tumor cell proliferation, invasiveness, and new vessel formation, as well as attenuates osteoblastic and pain-related responses to tumor. Clinical testing of an orally bioavailable endothelin antagonist has demonstrated benefit in PSA progression, markers of bone turnover, and pain in men with prostate cancer, but has not demonstrated significant improvement in survival or time to cancer progression. Although this class of drugs is promising for targeted anti-cancer therapy, their role in treatment remains to be defined by completion of future clinical trials.

Topics: Atrasentan; Bosentan; Clinical Trials as Topic; Endothelin Receptor Antagonists; Endothelin-1; Female; Humans; Male; Neoplasms; Ovarian Neoplasms; Prostatic Neoplasms; Pyrimidines; Pyrrolidines; Receptors, Endothelin; Signal Transduction; Sulfonamides

The endothelin axis and the endothelin A (ET(A)) receptor have been implicated in tumor development and bone metastasis. This study aimed to investigate the pharmacokinetic (PK) and safety profiles of the specific ET(A) receptor antagonist, zibotentan, in elderly, male Chinese patients with advanced solid tumors. The PK data generated in these Chinese patients were further compared with those previously reported in Japanese and Caucasian patient populations.. In this Phase I, open-label study, patients received a single dose of zibotentan 10 mg on Day 1, followed by a 72-h washout period and 12 consecutive days of once-daily zibotentan 10 mg.. Fifteen patients received at least one dose of zibotentan 10 mg. Exposure was demonstrated in all patients and the PK profiles following single dosing and multiple dosing showed relatively rapid absorption, decline in a monophasic manner, a modest amount of accumulation, and relatively low apparent clearance and volume of distribution. Zibotentan was well tolerated with no new safety concerns. Adverse events reported in >1 patient were pyrexia (n = 4), constipation (n = 3), headache (n = 3) and peripheral edema (n = 2). Comparative analysis found no evidence of significant differences in zibotentan exposure between the Chinese patients in our study, and the previous Japanese and Caucasian studies.. The PK and safety profiles of zibotentan determined in this Chinese patient population are similar to those previously reported. Our findings suggest no clinically relevant inter-ethnic differences in zibotentan disposition between the patient populations analyzed.

Topics: Aged; Area Under Curve; Asian People; China; Constipation; Dose-Response Relationship, Drug; Drug Administration Schedule; Fever; Headache; Humans; Intestinal Absorption; Japan; Male; Metabolic Clearance Rate; Middle Aged; Neoplasms; Pyrrolidines; White People