Pharmacological characterization of PF‐00547659, an anti‐human MAdCAM monoclonal antibody

Abstract

Background and purpose:The adhesion molecule mucosal addressin cell adhesion molecule (MAdCAM) plays an essential role in the recruitment of lymphocytes to specialized high endothelial venules of the gastrointestinal tract and in their excessive tissue extravasation observed in inflammatory conditions, such as Crohn's disease. We have characterized the in vitro pharmacological properties of two monoclonal antibodies blocking MAdCAM, MECA-367 and PF-00547659, and determined their pharmacokinetic/pharmacodynamic profiles in vivo. Experimental approach: Functional adhesion assays and surface plasmon resonance were used to characterize, in vitro, the pharmacological properties of MECA-367 and PF-00547659. The in vivo effects of MECA-367 and PF-00547659 on restriction of b7 + memory T lymphocytes were determined in mice and macaques, respectively, over the pharmacological dose range to confirm pharmacokinetic/pharmacodynamic relationships. Key results: MECA-367 and PF-00547659 bound with high affinity to mouse and human MAdCAM with Kd values of 5.1 and 16.1 pmol·L -1 respectively and blocked the adhesion of a4b7 + leukocytes to MAdCAM with similar potency. MECA-367 and PF-00547659 induced a similar, dose-dependent two-to threefold increase in circulating populations of b7 + memory T-cells in the mouse and macaque; without affecting the b7 -populations. Conclusions and implications: PF-00547659 has potential utility in the treatment of inflammatory conditions by blocking tissue homing of activated a4b7 + leukocytes. The characterization of a rodent cross-reacting antibody as a surrogate for PF-00547659 in the search for potential pharmacological biomarkers and the determination of efficacious doses was effective in addressing the restricted orthologous cross-reactivity of PF-00547659 and the challenges this poses with respect to efficacy and safety testing.

CNS Elevation of Vascular and Not Mucosal Addressin Cell Adhesion Molecules in Patients with Multiple Sclerosis

“…Consistent with previously reported data, 10,11 PF-00547659 produced marked to very marked membranous and cytoplasmic MAdCAM labeling of the vascular endothelium, perivascular tissue, and aggregates of leukocytes in the mucosa, submucosa, and Peyer's patches. In contrast, PF-00547659 did not bind to the gut epithelium, and the isotype and method controls were negative.…”

“…10 An anti-human mouse monoclonal IgG1 VCAM antibody as well as mouse IgG1 control monoclonal antibody were purchased from Abcam (ab58838, ab27479 respectively). Frozen control (n ϭ 4, 2 blocks per donor) and MS brain tissue (n ϭ 10, 4 blocks per donor) were kindly provided by the UK MS Society Tissue Bank (http://www.ukmstissuebank.org.uk/).…”

“…The expression of MAdCAM was assessed using a direct immunoperoxidase procedure (Vector Laboratories) as previously described. 10 VCAM expression was detected using an indirect immunoperoxidase method with a biotinylated horse anti-mouse secondary antibody 1:200 for 1 hour at room temperature before diaminobenzidine detection. Both methods included hydrogen peroxide, serum, and avidin/biotin blocking steps.…”

“…10 Several studies have concluded that MAdCAM expression appears to be restricted to the endothelium of the gastrointestinal tract; 10,11 however, the observed expression in brain tissue under certain circumstances, the cloning of the receptor from CNS tissue, [12][13][14] as well as the observed effects of blocking anti-␤ 7 integrin or anti-MAdCAM antibodies in models of experimental autoimmune encephalomyelitis have suggested that MAdCAM may have an additional role in CNS immune surveillance in normal, as well as inflamed conditions. [15][16][17] In the context of these observations, the purpose of this study was to characterize and compare the pattern as well as intensity of CNS MAdCAM expression with VCAM in control and MS brain tissue.…”

Novel Drug Therapies for the Treatment of Crohn's Disease

“…It inhibits the function of the β7+ memory T-cells and its affinity to mouse and human MAdCAM was proven [36]. Eighty moderately-severely active UC patients have been involved into a multicentre RCT study to evaluate the efficacy of PF00547659 [37].…”