Olorinab for Abdominal Pain Associated with Crohn's Disease

In a recent, open-label study, investigators found use of olorinab could result in an improvement in average abdominal pain score (AAPS) without psychotropic effects in subjects with Crohn’s disease (CD) experiencing abdominal pain.

The study, which was presented at Digestive Disease Week 2019 in San Diego, CA, evaluated the effects of olorinab in CD patients with minimal inflammation experiencing abdominal pain. After examining 14 patients over the course of 8 weeks and found that olorinab lowered AAPS without psychotropic effects in patients, which is a common issue in other drugs used to treat abdominal pain in UC patients.

Preston Klassen, MD, MHS, head of research and development at Arena Pharmaceuticals, sat down with MD Magazine® at DDW 2019 to discuss the findings of the study and plans for future research into olorinab.

MD Mag: What were the results of your study examining the efficacy and safety of olorinab in patients with Crohn’s disease?

Klassen: We studied 14 patients, across 2 doses of olorinab 25mg and 100mg, and again this was open-label and we did not have a placebo control over 8 weeks of dosing. It's a relatively short period of time relatively small sample size but what we saw was pretty significant. 100% of patients — every patient— at week 8 was a clinical responder in terms of a reduction in their abdominal pain score. This is measured using the average abdominal pain scale or AAPS and the definition of a clinical responder uses the FDA accepted definition of at least a 30% reduction in pain score from baseline at the end of 8 weeks. So, 100% of patients that made it to week 8 were clinical responders by this definition.

In addition, the overall magnitude the AAPS score is a 10-point scale and the overall magnitude of reduction was an average of 4.6 across the patients and that seems to be very important in terms of the amount of reduction in abdominal pain when compared to other agents particularly in IBS space that do purport to have some reduction in pain. This is a very large magnitude of response and so while the study is limited by its small sample size and lack of a placebo control, there's also very interesting and certainly warrant for the investigation with a larger placebo controlled trial which we are gearing up to conduct later this year — a phase 2b study looking specifically at irritable bowel syndrome or IBS in patients with the ability of olorinab reduce their abdominal pain.