Phase III trial of Linzess (linaclotide) for IBS-C meets all endpoints- Actavis/Ironwood Pharma

Actavis and Ironwood Pharmaceuticals announced that top-line data demonstrate linaclotide (Linzess) met all primary and secondary endpoints, covering multiple abdominal and constipation symptoms, in a Phase III clinical trial of adults with irritable bowel syndrome with constipation (IBS-C). The trial was conducted primarily in China and the companies intend to file in early 2016 for China Food and Drug Administration (CFDA) approval to market linaclotide.

Top-line data indicate linaclotide-treated patients showed statistically significant improvement compared to placebo-treated patients for both co-primary endpoints. 60.0% of linaclotide-treated patients were Abdominal Pain/Discomfort Responders, compared to 48.8% of placebo-treated patients (p=0.001). 31.7% of linaclotide-treated patients were IBS Degree of Relief Responders, compared to 15.4% of placebo-treated patients (p<0.0001). Linaclotide-treated patients reported greater improvements in abdominal pain than placebo-treated patients: these effects were evident in the first week of treatment and continued to improve throughout the treatment period, with the greatest decreases in abdominal pain seen at week 12 of treatment (44% decrease for linaclotide compared to 34% decrease for placebo). The most common adverse event reported in linaclotide-treated patients was diarrhea (9.4% for linaclotide vs. 1.2% for placebo).

Comment: Linaclotide is currently approved in the United States (as Linzess) for the treatment of adults with IBS-C or chronic idiopathic constipation (CIC), and in a number of other countries for adults with IBS-C – in the EU it is marketed as Constella.