A Safety and Efficacy Comparison of a New Sulfate-Based Tablet Bowel Preparation Versus a PEG and Ascorbate Comparator in Adult Subjects Undergoing Colonoscopy

INTRODUCTION: A new tablet-based bowel prep for colonoscopy has been developed containing poorly absorbed sulfate salts which act to retain water within the intestinal lumen resulting in a copious diarrhea, thereby cleansing the bowel. This study evaluated the safety and efficacy of these oral sulfate tablets (OST) compared with a US FDA-approved bowel prep solution containing PEG3350, electrolytes, and ascorbate (polyethylene glycol and ascorbate [PEG-EA]). METHODS: Five hundred fifteen adult patients (mean 57y) were enrolled in this single-blind, multicenter, noninferiority study. Subjects were assigned either PEG-EA or OST to be administered in a split-dose regimen starting the evening before colonoscopy. PEG-EA was taken according to its approved labeling (1 L of prep solution with 16 oz. of additional water) in the evening and again in the morning. OST patients took a total of 24 tablets. OST patients were administered 12 tablets in the evening, and the following morning. Patients consumed 16 ounces of water with each dose of 12 tablets and drank an additional 32 oz. of water with each dose. Colonoscopies were performed by blinded investigators. Cleansing efficacy was evaluated globally and segmentally using a 4-point scale (Excellent-no more than small bits of feces/fluid which can be suctioned easily; achieves clear visualization of the entire colonic mucosa. Good-feces and fluid requiring washing and suctioning, but still achieves clear visualization of the entire colonic mucosa. Fair-enough feces even after washing and suctioning to prevent clear visualization of the entire colonic mucosa. Poor-large amounts of fecal residue and additional bowel preparation required). Scores of Good or Excellent were considered to be a success. Safety was assessed by spontaneously reported adverse events, solicited ratings of expected prep symptoms, and laboratory testing. RESULTS: A high rate of cleansing success was seen with OST (92%), which was noninferior to PEG-EA (89%). Only a small proportion of subjects rated their expected gastrointestinal symptoms as severe (<5% for both preps). No clinically significant differences were seen between preps for chemistry and hematology parameters. No serious adverse experiences were reported with OST. DISCUSSION: Sulfate tablets achieved a high level of cleansing in the study, comparable with US FDA-approved preps. OST was noninferior to PEG-EA in this study and achieved significantly more Excellent preps overall and in the proximal colon. The OST prep was well-tolerated, with a similar rate of spontaneously reported adverse experiences to PEG-EA and a low rate of severe expected gastrointestinal symptoms.