Comparison of Vedolizumab Treatment to Adalimumab Dose Intensification in Crohn's Disease Patients With Loss of Response or Biomarker Activity to Adalimumab on First Line With Therapeutic Drug Concentration.

This study is for people with Crohn's disease — a chronic inflammatory bowel condition — who were doing well on a biologic drug called adalimumab but have started to lose its effectiveness, even though blood tests show they still have enough of the drug in their system. The study compares two strategies: switching to a different biologic (vedolizumab) versus increasing the adalimumab dose. **You may be eligible if...** - You have Crohn's disease and initially responded well to adalimumab - You are now experiencing a return of symptoms despite adequate adalimumab levels in your blood (above 7.5 mcg/mL) - You are 18 or older and have provided informed consent - You have active disease signs confirmed by biomarkers (e.g., elevated CRP or fecal calprotectin) **You may NOT be eligible if...** - You never responded to adalimumab in the first place - Your adalimumab blood levels are too low (subtherapeutic) - You have already tried vedolizumab - You have serious infections or other conditions that prevent biologic therapy Talk to your doctor to see if this trial is right for you.