The primary difference between Tysabri (natalizumab) and Entyvio (vedolizumab) is that vedo is a site specific medication that targets gut tissue. Tysabri, on the other hand, is systematic which is why it can hit brain tissue.
Both medications work by using anti-adhesion. Lymphocytes (white blood cells) are elevated in patients with uc. Lymphocytes reside in the circulatory system, and must transition from our circulatory system to our gut tissue inorder to attack and cause inflammation. In order to exit the circulatory system, they must adhere and transfer between cells in our smallest blood vessles near the targeted tissue (in this case gut tissue). Vedo interferes with that process, preventing inflammation from occurring in gut tissue.
Refer to the discussion section of:http://jpet.aspetjournals.org/content/330/3/864.long
The pdf of this has a color illustration that helps explain it a bit as well (both links pulled from google scholar). http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3002582/
So PML shouldn't happen with vedo, well according to theory at least. It hasn't been studied in large groups though.
Rx: Remicade 5mg per kg, every 8 weeks
Daily 75mg 6MP + 5g Lialda + Rowasa
Diet: Diet mods and supplements haven't done a thing for me
Post Edited (iPoop) : 3/17/2014 6:53:31 AM (GMT-6)