P-069 Can PET CT Scans Be Used as a Predictor of Response to Treatment With Anti-TNF Agents in Patients With Crohn’s Disease?

Abstract

Up to a third of patients with Crohn’s disease treated with Anti-TNF therapies are primary non-responders. Primary nonresponse may, in part, be due to stricturing disease with scarring rather than inflammation as the underlying pathology. Currently, the only way to identify primary nonresponders is to observe a lack of clinical and endoscopic response after repeated exposure to the medication. FDG-PET CT scans are a reliable tool to detect inflammation in the small bowel and may identify patients who are more likely to obtain benefit with Anti-TNF therapy. Our AIM was to determine whether low dose FDG-PET CT scan performed prior to first Anti-TNF exposure could identify patients likely to be responders at 12 weeks after Anti-TNF administration. Consecutive patients with small bowel Crohn’s disease who require therapy with Anti-TNF agents were recruited for the study. Information on disease information and disease activity were collected at the screening visit. An FDG-PET was performed and the maximum standardized uptake value (SUVmax) was calculated for each patient. The treating physician was blinded to the results. Patients were initiated on Anti-TNF therapy and re-evaluated for clinical response at week 12. Five consecutive patients with known small bowel Crohn’s disease with a clinical indication for treatment with anti-TNF therapy were recruited for the study (Table 1). All patients underwent FDG-PET CT scan and were exposed to infliximab. Three of 5 patients completed infliximab loading (1 lost to follow up, 1 required surgery). Two of 5 patients were identified as primary nonresponders at 12 weeks, but they were not associated with low SUVmax (Table 2). The SUVmax ranged from 5.2 to 13.4 (Table 1–2). There was not a statistically significant association between response to AntiTNF and treatment on SUVmax pretreatment. In this pilot study of patients with small bowel Crohn’s disease, FDG- PET CT scans did identify variable degrees of inflammation in the small bowel. Alternatives to SUVmax may be necessary to identify patients with small bowel inflammation that may be responsive to Anti-TNF therapy.