Substituted 11-phenyl-dibenzazepine compounds useful for the treatment or prevention of diseases characterized by abnormal cell proliferation

#The present invention relates to aromatic organic compounds which are specific, potent and safe inhibitors of the Ca2+-activated potassium channel (Gardos channel) of erythrocytes and/or of mammalian cell proliferation. More particularly, the invention relates to substituted 11-phenyl dibenzazepine compounds capable of inhibiting the Gardos channel of sickle erythrocytes and/or mitogen-induced mammalian cell proliferation. The compounds can be used to reduce sickle erythrocyte dehydration and/or delay the occurrence of erythrocyte sickling or deformation in situ as a therapeutic approach towards the treatment or prevention of sickle cell disease. The compounds can also be used to inhibit mammalian cell proliferation in situ as a therapeutic approach towards the treatment or prevention of diseases characterized by abnormal cell proliferations.

#Sickle cell disease has been recognized within West Africa for several centuries. Sickle cell anemia and the existence of sickle hemoglobin (Hb S) was the first genetic disease to be understood at the molecular level. It is recognized today as the morphological and clinical result of a glycine to valine substitution at the No. 6 position of the beta globin chain (Ingram, 1956, Nature 178:792-794). The origin of the amino acid change and of the disease state is the consequence of-a single nucleotide substitution (Marotta et al., 1977, J. Biol. Chem. 252:5040-5053).

#The major source of morbidity and mortality of patients suffering from sickle cell disease is vascular occlusion caused by sickled erythrocytes, which causes repeated episodes of pain in both acute and chronic form and also causes ongoing organ damage with the passage of time. It has long been recognized and accepted that the deformation and distortion of sickle cell erythrocytes upon complete deoxygenation is caused by polymerization and intracellular gelation of sickle hemoglobin, hemoglobin S (Hb S). The phenomenon is well reviewed and discussed by Eaton and Hofrichter, 1987, Blood 70:1245. The intracellular gelation and polymerization of Hb S can occur at any time during erythrocyte's journey through the vasculature. Thus, erythrocytes in patients with sickle cell disease containing no polymerized hemoglobin S may pass through the microcirculation and return to the lungs without sickling, may sickle in the veins or may sickle in the capillaries.

#FIG. 1 provides a reaction scheme for synthesizing 11-aryl-5,6-dihydro-11H-dibenz[b,e]azepine compounds according to the invention; and

#FIG. 2 provides a reaction scheme for synthesizing 11-aryl-11-substituted-5,6-dihydro-dibenz[b,e]azepine compounds according to the invention.

#As discussed in the Background section, blockade of sickle dehydration via inhibition of the Gardos channel is a powerful therapeutic approach towards the treatment and/or prevention of sickle cell disease. Studies have shown that antimycotic agents such as Clotrimazole block Ca2+-activated K+ transport and reduce cell dehydration in sickle erythrocytes in vitro (Brugnara et al., 1993, J. Clin. Invest. 92:520-526), and also inhibit the Gardos channel of erythrocytes, increase red cell K+ content, decrease the mean cell hemoglobin concentration (MCHC) and decrease red cell density in vivo in a transgenic mouse model for sickle cell disease (SAD mouse, Trudel et al., 1991, EMBO J. 11:3157-3165; De Franceschi et al., 1994, J. Clin. Invest. 93:1670-1676). Moreover, therapy with oral Clotrimazole induces inhibition of the Gardos channel and reduces erythrocyte dehydration in human patients with sickle cell disease (Brugnara et al., 1996, J. Clin. Invest. 97:1227-1234). Other antimycotic agents which inhibit the Gardos channel in vitro include miconazole, econazole, butoconazole, oxiconazole and sulconazole (U.S. Pat. No. 5,273,992 to Brugnara et al.). All of these compounds contain an imidazole-like ring, i.e., a heteroaryl ring containing two or more nitrogens.

#Also as discussed in the Background section, the modulation of early ionic mitogenic signals and inhibition of cell proliferation are powerful therapeutic approaches towards the treatment and/or prevention of disorders characterized by abnormal cell proliferation. It has been shown that Clotrimazole, in addition to inhibiting the Gardos channel of erythrocytes, also modulates ionic mitogenic signals and inhibits cell proliferation both in vitro and in vivo.

#For example, Clotrimazole inhibits the rate of cell proliferation of normal and cancer cell lines in a reversible and dose-dependent manner in vitro (Benzaquen et al., 1995 Nature Medicine 1:534-540). Clotrimazole also depletes the intracellular Ca2+ stores and prevents the rise in cystolic Ca2+ that normally follows mitogenic stimulation. Moreover, in mice with severe combined immunodeficiency disease (SCID) and inoculated with MM-RU human melanoma cells, daily administration of Clotrimazole resulted in a significant reduction in the number of lung metastases observed (Benzaquen et al., supra).