A 12-week double-blind, placebo-controlled, randomized, multicenter trial of Xermelo was conducted in adult patients with a well-differentiated metastatic neuroendocrine tumor and carcinoid syndrome diarrhea who were having between 4 to 12 daily bowel movements despite the use of SSA therapy at a stable dose for at least 3 months. Patients were randomized to placebo or treatment with Xermelo 250 mg three times daily. 

Study medication was administered within 15 minutes before or within 1 hour after a meal or snack [see Dosage and Administration (2)]. All patients were required to stay on their baseline SSA regimen and were allowed to use rescue medication (short-acting octreotide) and antidiarrheals (e.g., loperamide) for symptomatic relief. A total of 90 patients were evaluated for efficacy. The mean age of the population was 63 years of age (range 37 to 83 years), 50% were male, and 90% were White. 

The primary efficacy endpoint was the change from baseline in the number of daily bowel movements averaged over the 12-week treatment period. The analysis results can be found in Table 2 below. The average was based on the number of days with valid, non-missing data. When a patient had more than 6 weeks of missing data, the change from baseline was considered equal to zero. A week of missing data was defined as a patient missing at least 4 days of diary data in that week. 

In the 12-week study, a difference in average weekly reductions in bowel movement frequency between Xermelo and placebo was observed as early as 1 to 3 weeks, and persisted for the remaining 9 weeks of the study. 

To aid in the interpretation of the bowel movement reduction results, the proportion of patients reporting any particular level of reduction in overall average bowel movement frequency is depicted in Figure 1 below. For example, 33% of patients randomized to Xermelo and 4% of patients randomized to placebo experienced a reduction in overall average bowel movements from baseline of at least 2 bowel movements per day. 

Figure 1: Cumulative Proportion of Patients with Carcinoid Syndrome Diarrhea Reporting Change in Overall Average Bowel Movement Frequency

Other symptoms of carcinoid syndrome (abdominal pain or flushing) did not show improvement in the comparison of Xermelo to placebo. 

The average number of daily short-acting octreotide injections used for rescue therapy over the 12-week double-blind treatment period was 0.3 and 0.7 in the Xermelo and placebo groups, respectively. In the subgroup of patients who received short-acting octreotide injections, observed reductions in the number of bowel movements per day and treatment differences were generally consistent with the reductions and differences observed in patients who did not receive rescue therapy, and were similar to the overall data presented in Table 2 above [see Dosage and Administration (2), Drug Interactions (7.2)]. 

A third randomized treatment arm of Xermelo 500 mg three times daily did not demonstrate additional treatment benefit on the primary endpoint and had a greater incidence of adverse reactions than Xermelo 250 mg three times daily. Therefore, Xermelo 500 mg three times daily is not recommended [see Dosage and Administration (2)].