Adults

Two placebo-controlled studies (Studies 1 and 2) have demonstrated the efficacy of mesalamine delayed-release tablets in patients with mildly to moderately active ulcerative colitis. 

In one randomized, double-blind, multi-center, placebo-controlled clinical trial of 6 weeks’ duration in 158 patients (Study 1), patients received mesalamine delayed release dosages of 1.6 grams per day (800 mg twice a day; n=53) and 2.4 grams per day (800 mg three times a day; n=53), compared to placebo (n=52). The scoring system for determination of treatment efficacy included assessment of stool frequency, rectal bleeding, sigmoidoscopic findings, patient’s functional assessment, and physician global assessment. At the dosage of 2.4 grams per day, 21 of 43 (49%) patients using mesalamine delayed release tablets showed an improvement in sigmoidoscopic appearance of the bowel compared to 12 of 44 (27%) patients using placebo (p = 0.048). In addition, significantly more patients in the mesalamine delayed release tablets 2.4 grams per day group showed improvement in rectal bleeding and stool frequency. The 1.6 grams per day dosage regimen is not recommended because it did not produce consistent evidence of effectiveness [see Dosage and Administration (2.2)]. 

In a second randomized, double-blind, placebo-controlled clinical trial of 6 weeks’ duration in 87 patients (Study 2), patients received mesalamine delayed release tablets of 1.6 grams per day (400 mg four times a day; n=11) and 4.8 grams per day (1.2 grams four times a day; n=38), compared to placebo four times a day (n=38). Mesalamine delayed release tablets 4.8 grams per day for 6 weeks resulted in sigmoidoscopic improvement in 28 of 38 (74%) patients compared to 10 of 38 (26%) placebo patients (p less than 0.001). Also, more patients in the mesalamine delayed release tablets 4.8 grams per day group than the placebo group showed improvement in overall symptoms. The 4.8 grams per day dosage regimen is not recommended because greater efficacy was not demonstrated with this dosage compared to the 2.4 grams per day dosage [see Dosage and Administration (2.2)].

Pediatrics

The safety and effectiveness of mesalamine delayed release in pediatric patients 5 to 17 years of age for treatment of mildly to moderately active ulcerative colitis are supported by evidence from adequate and well controlled studies of mesalamine delayed release in adults and a single study in pediatric patients.

A randomized, double-blind, 6-week study of two dosage levels of mesalamine delayed release tablets (Study 3) was conducted in 82 pediatric patients 5 to 17 years of age with mildly or moderately active ulcerative colitis defined as a score of 10 to 55 on the Pediatric Ulcerative Colitis Activity Index (PUCAI) (which includes assessment of abdominal pain, rectal bleeding, stool consistency, number of stools per 24 hours, presence of nocturnal bowel movement and activity level, and has a total maximum score of 85; each of the subscales are scored from 0 to 10 except rectal bleeding which is scored from 0 to 30, and number of stools per 24 hours which is scored from 0 to 15) and rectal bleeding and stool frequency Mayo subscale scores of ≥1 (each of these subscales are scored from zero (normal) to three (most severe).

All patients were divided by weight category (17 to less than 33 kg, 33 to less than 54 kg, and 54 to 90 kg) and randomly assigned to receive a low dosage (1.2, 2, and 2.4 grams per day for the respective weight category) or a high dosage (2, 3.6, and 4.8 grams per day). Doses were administered every 12 hours. 

The proportion of patients who achieved success based on the Truncated Mayo Score (TM-Mayo) (based on the stool frequency and rectal bleeding subscores of the Mayo Score) and based on the PUCAI was measured after 6 weeks of treatment. Success based on TM-Mayo was defined as either partial response (improvement from baseline in stool frequency or rectal bleeding subscores with no worsening in the other) or complete response (both stool frequency and rectal bleeding subscores equal 0). Success based on PUCAI was defined as either partial response (PUCAI reduction of greater than or equal to 20 points from Baseline to Week 6 with Week 6 score greater than or equal to 10) or complete response (PUCAI less than 10 at Week 6). 

There were 41 patients in the low dosage group and 41 patients in the high dosage group who received at least one dose of mesalamine delayed-release 400 mg tablets; 36 patients in each dosage group completed the study. Patients were considered treatment failures if they did not achieve success or dropped out due to adverse reaction or lack of efficacy. 

At Week 6, 73% of the patients in the low dosage group, and 70% of the patients in the high dosage group achieved success based on the TM-Mayo; 34% of the patients in the low dosage group and 43% of the patients in the high dosage group achieved complete response. At Week 6, 56% of the patients in the low dosage group, and 55% of the patients in the high dosage group achieved success based on the PUCAI; 46% of the patients in the low dosage group and 43% of the patients in the high dosage group achieved complete response. 

The high dosage regimen is not recommended because it was not more effective than the low dosage regimen [see Dosage and Administration (2.2)].