Pentasa is the least effective mesalamine for UC I believe. It releases too high and it's better for Crohns. Look it up. I would definitely consider Asacol/Apriso/Lialda/Delzicol/Colazal (If it's left sided).
I don't know about
the overall stats, but Pentasa for me was perfect and I had no inflammation in my small intestine. I think the majority of it releases in the large bowel so to say it releases too high sounds a bit dismissive to me.