Changes in the small bowel of symptomatic kidney transplant recipients converted from mycophenolate mofetil to enteric-coated mycophenolate sodium.

Background/aims: Gastrointestinal (GI) symptoms in renal transplant recipients may be caused due to mycophenolic acid (MPA) toxicity. Using small bowel capsule endoscopy (SBCE) we examined the impact of conversion from Mycophenolate Mofetil (MMF) to enteric-coated formulation of Mycophenolate Sodium (EC-MPS) given to treat GI mucosal lesions.

Methods: Adult kidney-only recipients at least 30 days after transplant, presenting with GI symptoms while receiving MMF completed a Gastrointestinal Symptom Rating Scale (GSRS) questionnaire, underwent SBCE, and had MMF substituted by EC-MPS. After 30 days, GSRS and SBCE were repeated and findings were compared to baseline values. Patients who were still on EC-MPS 6-24 months post-conversion were contacted for completing a follow-up GSRS questionnaire and SBCE.

Results: Eighteen out of 23 subjects completed the first part of the study. Subjects' median ages and post-transplant time were 47.5 years old and 4.5 months, respectively. Tacrolimus, MMF and prednisone was the main regimen (94%), with a median MMF dose of 750 mg BID. The average baseline GSRS was 2.99 ± 0.81; it significantly decreased to 2.19 ± 0.8 at 30 days post-conversion. At baseline, 50 had gastric and 89% had small bowel lesions. At 30 days, 29 and 62% of the SBCE were still showing gastric and small bowel lesions, respectively. Of 5 patients in the study extension, 4 had abnormal SBCE findings but have been reporting improvement in their symptoms.

Conclusion: Stomach and small bowel mucosal lesions are common in kidney recipients with GI symptoms when treated with MMF. Conversion to EC-MPS for 30 days significantly alleviated the GI symptoms; however, no evident correlation with SBCE findings was found.