Efficacy and Safety of Two Doses of SPD476 (Mesalazine) 2.4g and 4.8g Once Daily, With Reference to Asacol 0.8g Three Times Daily in Subjects With Acute, Mild to Moderate Ulcerative Colitis

Inclusion Criteria: * newly diagnosed or relapsing mild to moderate UC (score of 4-10 (inclusive) on the UC-DAI scale, with a sigmoidoscopy score of =\> 1 and a PGA \<=2) with compatible histology * females eligible if post--menopausal, surgically sterile or if they had a negative urine pregnancy test at screening and were on adequate contraception Exclusion Criteria: * subjects with relapsing UC who were in relapse for \> 6 weeks prior to baseline * subjects who relapsed on maintenace therapy with doses of mesalazine =\> 2g/day * subjects who had unsuccessfully treated their current relapse with steroids or a mesalazine dose of \> 2g/day * subjects with Crohn's disease, proctitis, bleeding disorders, active peptic ulcer disease, previous colonic surgery, or those at an immediate risk of toxic megacolon or a stool culture positive for enteric pathogens * subjects who had used systemic or rectal steroids within the last 4 weeks, immunosuppressants wihtin the last 6 weeks or anti-inflammatory drugs on a repeat basis within 7 days prior to the baseline visit * subjects with hypersensitivity to salicylates and subjects with moderate/severe renal impairment