Vu Nguyen

Therapeutic Drug Monitoring and Clinical Outcomes in Immune Mediated Diseases: The Missing Link.

Abstract:As the incidence of inflammatory bowel diseases and the number of patients treated with anti-TNF agents keep on increasing so are the phenomena of primary non response (PNR) and secondary loss of response (SLR) to these medications. Traditionally PNR and SLR have been managed empirically—that is, switching medications for PNR and increasing the anti-TNF dose for SNR. More recently an approach based on testing drug levels and antibodies to the drug (therapeutic drug monitoring) has gained increasing popularity in the management of inflammatory bowel diseases. However, while this strategy might offer an insight into the mechanisms leading to PNR/SLR it often falls short of providing a simple, reproducible method to manage these issues in clinical practice. Here, we will review the currently recommended therapeutic strategies when using therapeutic drug monitoring; the evidence for and against such approach and the current standard strategies in Rheumatology (the specialty with the largest and longest experience with anti-TNF agents). We will then discuss the possible reasons of the shortcomings of therapeutic drug monitoring and the rationale and need to move the therapeutic target to the disease burden in inflammatory bowel diseases—along with the supporting preliminary evidence. Finally, we will focus on future crucial studies that need to be done to make approaches to PNR/SLR more rigorous and at the same time user-friendly for the practicing gastroenterologist.

Management of post-operative Crohn’s disease in 2017: where do we go from here?

ABSTRACT Introduction: Postoperative recurrence (POR) of Crohn’s disease is common after surgical resection. How to best manage POR remains uncertain. Areas covered: In this review, we will first describe the natural course and the best modalities to diagnose this surgical sequela. We will then focus on the potential risk factors for relapse and highlight the main shortcomings in the current study designs and endoscopic and clinical scoring systems, which may partly explain the unexpected outcomes of recent clinical trials. Finally, we will propose a strategy to address the management of POR. Expert commentary: Anti-tumor necrosis factor (Anti-TNF) agents are the most effective therapy to prevent POR in Crohn’s disease. Patient risk stratification and active monitoring with scheduled ileocolonoscopy are cornerstones of optimal POR management. Further studies are needed to address areas of uncertainty including timing and duration of therapy and the role of therapeutic drug monitoring in this setting.

Transmembrane TNF-α Density, but not Soluble TNF-α Level, is Associated with Primary Response to Infliximab in Inflammatory Bowel Disease

Objectives:Anti-tumor necrosis factor (TNF)-α agents like Infliximab (IFX) are effective in the treatment of inflammatory bowel diseases (IBDs) and are widely used. However, a considerable number of patients do not respond or lose response to this therapy. Preliminary evidence suggests that transmembrane TNF-α (tmTNF-α) might be linked to response to IFX by promoting reverse signaling-induced apoptosis in inflammatory cells. The main aim of this study was the evaluation of this hypothesis in primary IFX non-responders.Methods:A total of 47 IFX naive IBD patients were included in the study. Blood samples were taken before the start of IFX therapy (at week 0) and after induction therapy (at week 14). Endoscopic disease activity and markers of inflammation at baseline and at week 14 were used to evaluate response. Baseline soluble TNF-α (sTNF-α), percentage of circulating TNF-α positive cells, mean fluorescence intensity (MFI) of tmTNF-α, and apoptosis rate at week 14 in the peripheral blood mononuclear cells (PBMCs) were evaluated in IFX responders and non-responders.Results:Mean sTNF-α was not significantly different in responders compared to non-responders (P=0.13). Mean percentage of tmTNF-α bearing lymphocytes and monocytes was higher in the PBMCs of responders (P=0.05 and P=0.014, respectively). Mean MFI of tmTNF-α in circulating lymphocytes and monocytes was greater in responders (P=0.002 and P<0.001, respectively). Moreover, the mean percentage of apoptosis in PBMCs was significantly greater in responders compared to non-responders (P=0.002).Conclusions:The percentage of tmTNF-α bearing lymphocytes and monocytes and the intensity of tmTNF-α in the circulating leukocyte population of IBD patients was directly related to primary response to IFX. This was likely due—as assessed by the apoptosis rate—to promotion of inflammatory cell death. Thus, our data suggest that peripheral leukocytes could in principle be used for predicting primary response to IFX in IBD patients.

Isolated Bilateral Gastrocnemius Myositis in Crohn Disease Successfully Treated with Adalimumab

Extraintestinal manifestations are common in inflammatory bowel disease; however, muscular involvement in Crohn disease is rarely reported. We present a case of a 26-year-old male with ileocolonic Crohn disease who developed sudden tenderness in both calves. Doppler ultrasound was negative for deep vein thrombosis. Magnetic resonance imaging of the gastrocnemius muscle showed high intensity signal in the muscle fibers, and muscle biopsy demonstrated nonspecific lymphocytic myositis. Other relevant laboratory results included normal antineutrophil cytoplasmic antibodies and creatine kinase as well as elevated C-reactive protein, erythrocyte sedimentation rate, and anti-Saccharomyces cerevisiae IgG titer. The patient was in clinical remission, being treated with azathioprine 2.5 mg/kg. Prednisone 60 mg/day was initiated with rapid resolution of calf tenderness; however, tenderness soon returned when the dose was tapered to 10 mg/day. Subsequently, prednisone and azathioprine were discontinued, and adalimumab was started at standard induction and maintenance doses. The patient’s symptoms resolved shortly after the first induction dose. A repeat magnetic resonance imaging of the calves – 3 months after starting adalimumab – showed complete resolution of muscle inflammation. To our knowledge, this is the first case of gastrocnemius myositis – a rare extraintestinal manifestation of Crohn disease – successfully treated with anti-tumor necrosis factor agents.

Knowledge Gaps in the Management of Postoperative Crohn’s Disease: A US National Survey

BackgroundPostoperative recurrence (POR) of Crohn’s disease (CD) is common. Guidelines on POR management have recently been issued, but clinical practice may vary.AimsTo examine the current clinical practice of POR management in the USAMethodsA web-based survey was sent to all members of the American Gastroenterological Association and the American College of Gastroenterology. The survey consisted of multiple-choice questions with clinical scenarios to assess how participants manage POR.ResultsA total of 189 responses were received from practices in 34 states. 44% of participants were from academic settings. The median number of CD patients seen each month was 20–30 patients per participant. The majority of participants considered smoking, prior intestinal surgery, penetrating disease, perianal fistula, early disease onset, and long extent of disease as high-risk factors for POR. To diagnose and grade endoscopic recurrence, 57% of participants used an endoscopic scoring system; 86% defined clinical recurrence using a combination of symptoms and endoscopic findings; and 79% of participants routinely performed colonoscopy after surgery. In high-risk patients, 65% offered medical prophylaxis—most often biologics and/or immunomodulators—immediately after surgery, while 34% offered medical prophylaxis regardless of the patient’s risk of POR. 64% of participants never stopped medical prophylaxis once initiated.ConclusionsMost gastroenterologists routinely perform colonoscopy to guide POR management. The majority of these providers continue medical prophylaxis indefinitely regardless of subsequent endoscopic findings. Further research is needed to determine the risks and benefits of continuing versus deescalating therapy in patients with potentially surgically induced remission.

A Rare Cause of Colonic Stricture

68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 Question: A 57-year-old man presented to our hospital with a week of generalized weakness and abdominal pain. Relevant medications included diclofenac 75 mg twice daily, aspirin 81 mg, and clopidogrel 75 mg/d. Vital signs were normal. Physical examination showed mild diffuse abdominal tenderness. Admission blood work revealed a hemoglobin of 8.8 g/dL, decreased from a baseline hemoglobin of 12 g/dL. The patient did not have overt gastrointestinal bleeding, but tested positive for fecal occult blood. A computed tomography scan demonstrated luminal narrowing at the hepatic flexure without bowel wall thickening or obstruction (Figure A). Esophagogastroduodenoscopy was normal. Colonoscopy revealed a circumferential stricture in the right colon with an estimated diameter of 8 mm (Figure B). Biopsies of the stricture showed significant lamina propria fibrosis, eosinophilic infiltration, and mild crypt distortion (Figure C). What was the diagnosis? Look on page 000 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. 95 96 97 98 99 100 Conflicts of interest The authors disclose no conflicts.