How many mg/kg are you given and how often are your infusion? The max you can do is 10mg/kg at every 4 weeks. If you are there already, and your drug levels are this low, your body metabolizes the drug too fast and you need to move on.
I started on Humira but developed antibodies + my body was metabolizing it too fast, so once a week wasn't even working, so I switched to Inflectra (Remi biosimilar) along with Imuran. The imuran is to prevent antibodies. I've been mostly symptom free for a little over a year (randomly, a few days before I get my period, I have 1-2 days of bleeding, and I am not sure if it is because I have always gotten D with my period since I was a teen and it's irritating things, or if the hormone changes impact the UC). So you can definitely switch between the two and see one work and not the other.
5 mg every 8 weeks. I've only had 4 infusions. I was also not being given enough the first 3 times based on my weight. They upped it to 4 vials this last infusion.
Thanks for sharing your experience about
switching! I'm glad it is working for you!