Actually, the scientists who studied the drug will tell you it has a higher chance of working if it's taken alongside an immunosuppressant drug. Barnsbury, the only user here who participated in the trial, had to take imuran for it to "work".
The same people behind the tysabri and vedolizumab trials said in 2011 that combo therapy is, and I quote:
Combination therapy with immunosuppressives and tumour necrosis factor antagonists is likely the best strategy for achieving optimal outcomes in patients at high risk of disease progression.
I don't want to burst anyone's bubble, but that's just the nature of biologics.
Though I agree with the premise, that quote is specific for TNF-alpha anatogonists, which Vedo is not.
@Gary - Personally, Im willing to take the small risk of the side effects with Imuran if it means a decrease in the chances of antibodies, because if you do develop antibodies, it doesnt matter at all how safe vedo is