Actavis’ Viberzi (eluxadoline) has been approved by the FDA as a twice-daily, oral treatment for adults suffering from irritable bowel syndrome with diarrhea (IBS-D). Viberzi (eluxadoline) has mixed opioid receptor activity, it is a mu receptor agonist, a delta receptor antagonist and a kappa receptor agonist.

IBS-D is a multifactorial disorder marked by recurrent abdominal pain or discomfort and altered bowel function that affects as many as 15 million adult Americans, impacting about twice as many women as men. There are few treatment options available for IBS-D, particularly options that relieve both the diarrhea and abdominal pain associated with IBS-D.

"The unpredictable symptoms experienced by patients with IBS-D can have a significant impact on everyday life," said William D. Chey, M.D., Nostrant professor of gastroenterology at the University of Michigan Health System.

The FDA has recommended that Viberzi be classified as a controlled substance. This recommendation has been submitted to the DEA. Once Viberzi receives final scheduling designation, the updated label will be available. Pending final scheduling designation, product launch is anticipated in Q1 2016.

Efficacy was established in two phase III clinical studies, demonstrating significant superiority over placebo on the composite endpoint of simultaneous improvement in both abdominal pain and diarrhea at both 75mg and 100mg twice daily doses. The primary efficacy responder endpoint was evaluated over the duration of double-blind, placebo-controlled treatment.

Response rates were compared based on patients who met the daily composite response criteria (improvement in both abdominal pain and stool consistency on the same day) for at least 50% of the days from weeks one to 12 (FDA endpoint) and weeks one to 26 (EMA endpoint).

The most common adverse events in the two phase III clinical trials were constipation (7% and 8% for eluxadoline 75mg and 100mg; 2% for placebo) and nausea (8% and 7% for eluxadoline 75mg and 100mg; 5% for placebo). Rates of severe constipation were less than 1% in patients receiving 75mg and 100mg eluxadoline. Rates of discontinuation due to constipation were low for both eluxadoline and placebo (<=2%) and similar rates of constipation occurred between the active and placebo arms beyond 3 months of treatment. A total of 2,426 subjects were enrolled across the two studies.