Enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of Vedolizumab (Entyvio®) in human serum and plasma. This Assay Genie kit has been especially developed for the quantitative analysis of Vedolizumab in serum and plasma samples and is for research use only.

Solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle. Standards and samples (serum or plasma) are incubated in the microtitre plate coated with the reactant for vedolizumab (Entyvio®). After incubation, the wells are washed. A horse radish peroxidase (HRP) conjugated probe is added and binds to vedolizumab captured by the reactant on the surface of the wells. Following incubation wells are washed and the bound enzymatic activity is detected by addition of chromogen-substrate. The colour developed is proportional to the amount of vedolizumab in the sample or standard. Results of samples can be determined directly using the standard curve.

Vedolizumab is a recombinant humanized IgG1 monoclonal antibody directed against the human lymphocyte α4β7 integrin, a key mediator of gastrointestinal inflammation. Vedolizumab binds specifically to α4β7 integrin but does not bind to, or inhibit function of, α4β1 or αEβ7 integrins. Inhibition of the α4β7 integrin is a shared mechanism with natalizumab, however vedolizumab binds solely to the α4β7but not the α4β1 integrin, unlike natalizumab which binds to both.

As a result, natalizumab modulates the systemic immune system and is associated with other side effects such as progressive multifocal leukoencephalopathy (PML). Non-clinical studies have shown that the pharmacodynamic effects of vedolizumab are reversible upon removal of the antibody: pharmacologic activity of cells inhibited by vedolizumab could be partially restored within 24 hours after removal, with near complete restoration within 4 days. There are no known drug interactions as vedolizumab is a humanized antibody and does not modulate production of cytokines, which is known to affect drug metabolism.

It is used in the treatment of moderate to severe active ulcerative colitis and Crohn's disease for patients who have had an inadequate response with, lost response to, or were intolerant to inhibitors of tumor necrosis factor alpha (TNF alpha) or other conventional therapies. By blocking its primary target, α4β7 integrin, vedolizumab reduces inflammation in the gut. Vedolizumab binds to α4β7 integrin, a key mediator of gastrointestinal inflammation expressed on the surfaces of T and B lymphocytes. By selectively inhibiting the α4β7 integrin, vedolizumab inhibits adhesion of lymphocytes to its natural ligand, mucosal addressin cell adhesion molecule-1 (MAdCAM-1), thereby preventing lymphocytic cells from entering the gut lamina propria and gut-associated lymphoid tissue (GALT). Specifically inhibiting this pathway alleviates GI inflammation without impairing systemic immune responses.

Vedolizumab is indicated for adult patients with moderately to severely active ulcerative colitis or Crohn's disease who have had an inadequate response with, lost response to, or were intolerant to a tumor necrosis factor (TNF) blocker or immunomodulator; or had an inadequate response with, were intolerant to, or demonstrated dependence on corticosteroids.

Entyvio® is a trademark of Millennium Pharmaceuticals, Inc.