Objectives: Ustekinumab induction therapy was studied in a placebo-controlled trial of patients with Crohn's disease (CD; n=104). In patients receiving ustekinumab, 49% achieved clinical response at week 8 vs. 40% for placebo (P=0.34). In a subgroup of patients previously treated with infliximab (n=49), 59% receiving ustekinumab responded vs. 26% receiving placebo (P=0.02).
Methods: C-reactive protein (CRP) concentrations were analyzed from serum collected at baseline and at week 8. Change from baseline CRP concentration after treatment, the relationship between baseline CRP concentration and clinical response, and the relationship between baseline CRP concentration and disease location were investigated.
Results: Mean changes from baseline CRP at week 8 in the primary group were -0.3 and -3.1 mg/l after treatments with placebo (n=43) and ustekinumab (n=46), respectively (P=0.074). In the infliximab-experienced subgroup, the mean changes were +2.0 (placebo, n=23) and -2.6 mg/l (ustekinumab, n=20) (P=0.004). Patients with baseline CRP >or=10 mg/l tended to have lower placebo and a higher ustekinumab response. In addition, more extensive diseases associated with CD in the colon and ileum were reflected by higher CRP concentrations.
Conclusions: The potential benefit of ustekinumab in CD is supported by serum CRP reductions. Evidence suggests that increased systemic inflammation as manifested by higher baseline CRP values leads to larger treatment effects with ustekinumab, especially in infliximab-experienced patients.