For me, it was within the first infusion or two. However, I was doing pretty well on chronic antibiotic therapy, but my GI did not want me on antibiotics indefinitely. Plus, I had a lot of deep ulcers and inflammatory polyps, even though I did not have a lot of symptoms. I had been on a number of biologics for my arthritis. Our strategy was to maintain the antibiotics for a few weeks after starting Remicade. This was in 2016. My remission continued after I stopped antibiotics. However, my arthritis symptoms worsened. This was addressed by increasing infusions from every 8 weeks to every 6 weeks and adding low dose azathioprine (50mg). Since then I was switched to Inflectra a few years ago, which is a Remicade biosimilar (for reduced cost).
I just had a scope a few months ago and everything looked pretty good.
Jan