Efficacy of 1 L Polyethylene Glycol Plus Ascorbic Acid With Linaclotide Versus Senna for Bowel Preparation: A Multicenter, Endoscopist-Blinded, Randomized Controlled Trial (Apple Trial)

Abstract

Introduction: No bowel preparation (BP) for colonoscopy achieves optimal efficacy and tolerability. Combining polyethylene glycol plus ascorbic acid (PEG-Asc) with adjuvants has been explored to enhance cleansing efficacy and reduce the required volume. The aim of this study was to evaluate whether adding 0.5 mg linaclotide to 1 L PEG-Asc (1 L-PEG/AL) improves superior cleansing compared with adding 24 mg senna (1 L-PEG/AS), which we previously reported to be noninferior to the standard regimen of 2 L PEG-Asc.

Methods: A multicenter, endoscopist-blinded, randomized controlled trial was conducted at 5 centers in Japan with outpatients scheduled for colonoscopy. The primary outcome was adequate BP, evaluated using the Boston Bowel Preparation Scale. Analyses were stratified based on low-risk and high-risk groups for inadequate BP.

Results: Between April 2022 and April 2023, 1,464 patients were randomized to the 1L-PEG/AL (n = 731) or 1L-PEG/AS (n = 733). The 1L-PEG/AL demonstrated higher adequate BP rates (92% vs 86%, P = 0.001) compared with 1L-PEG/AS. Both groups experienced similar adverse events and expressed high willingness for repeat BP (83% vs 81%, P = 0.49). In high-risk patients (n = 892), 1L-PEG/AL had significantly higher adequate BP rates (94% vs 86%, P < 0.001), whereas rates were comparably high in low-risk patients (n = 539) (94% vs 94%, P = 0.66).

Discussion: The linaclotide regimen was superior to the senna regimen reagrding BP efficacy without reducing tolerability. It can be a promising new option for BP, especially in patients at a high risk of inadequate BP.

Keywords: Boston Bowel Preparation Scale; bowel preparation; linaclotide; polyethylene glycol plus ascorbic acid; senna.