Background: In 2 preceding studies, delayed release phosphatidylcholine (rPC) was found to (a) improve disease activity and (b) withdraw steroids in patients with chronic-active ulcerative colitis.

Objective: Objective of the study was to determine the most effective rPC dose with least adverse events.

Methods: A randomized, dose-controlled, double-blinded study. Four groups of 10 patients each with nonsteroid-treated, chronic-active ulcerative pancolitis with a clinical activity index (CAI) and endoscopic activity index (EAI) >or=7. Patients were treated with oral rPC at doses of 0.5, 1, 3, and 4 g daily over 12 weeks.

Results: The CAI changes from baseline to the end of the study were 2.5 (0.5 g), 7.0 (1 g), 5.5 (3 g), and 6.0 (4 g dose arm). Significant improvement of the CAI was registered between the lowest rPC dose of 0.5 g (control group) and all higher doses of 1.0, 3.0, and 4.0-g rPC (Por=50% CAI improvement) were 70% in all of the effective dose groups (1 to 4 g, P=0.003). This was paralleled by the EAI improvement and by the rates of mucosal healing. Median time to clinical response was 5 (IQR 2 to 8) weeks. Bloating was registered in 40% of the patients irrespective of the treatment dose. Three of the 10 patients in the 4 g dose group reported nausea.

Conclusions: We found a saturable dose response of rPC in the treatment of chronic-active ulcerative colitis with effective doses >or=1 g per day; doses of 3 and 4 g seem to be superior in achieving remission.