- Even though RedHill Biopharma Ltd. had just announced positive results from a mid-stage study evaluating one of its gastrointestinal drugs, the company's stock was down by double-digits on Tuesday morning — suggesting there could be some weariness about how the drug might compete in an already crowded market.
- Bekinda, also known as RHB-102, met the study's primary endpoint, improving stool consistency response without increasing pain for patients who have irritable bowel syndrome with diarrhea (IBS-D). In fact, 54.7% of participants receiving a 12 mg regimen of Bekinda were responders compared to 35.3% of participants on placebo.
- While a positive readout doesn't normally come with a stock slide, shareholders may have found concern with the primary endpoint's 0.5 p-value, which indicates the result was right on the cusp of being statistically insignificant. The company also noted that its study wasn't "powered for statistical significance of the secondary efficacy endpoints," in an Oct. 3 statement.
RedHill's bread and butter are gastrointestinal and inflammation drugs, yet many indications within those broader markets are already fairly fleshed out.
Take IBS, for example. There are already several big-name contenders that have secured U.S. approval, including Allergan plc's Viberzi (eluxadoline) and Valeant Pharmaceuticals International's Xifaxan (rifaximin).
As with any increasingly crowded therapeutic area, IBS drugmakers have had to demonstrate their products are differentiated from competitors' in order to carve out some sort of market share. RedHill, for instance, touted that the absolute difference stool consistency response for patients on 12 mg Bekinda versus placebo was 19.4%, whereas Xifaxan 550 mg had an average absolute difference of 10.5% across two Phase 3 trials and Viberzi 100 mg had an average absolute difference of 13.5% across two Phase III trials.
Clinical trials, however, are notoriously difficult to compare unless rival therapies are assessed head to head in a single investigation. And in that light, Bekinda's performance on secondary outcome measures loses weight. RedHill noted how overall response rate (ORR) seen in the Phase 2 study was 15.8% in favor of the Bekinda arm, while the ORR from those respective late-stage studies of Xifaxan and Viberzi were 9.5% and 10.5%.
"The theoretical comparison between the Bekinda 12 mg Phase II study results and published data from studies of IBS-D-approved therapies Xifaxan and Viberzi serves as a general benchmark for the effect size observed with Bekinda 12 mg and should not be construed as a direct and/or equal comparison given that the studies were not identical in design, patient population and treatment duration and were not conducted head-to head in the same patient population," RedHill said in the Oct. 3 statement.
The results will surely be more fleshed out as late-stage testing takes place. RedHill currently plans to conduct at least two Phase 3 studies of its drug and meet with the FDA no later than early 2018 to parse out a path to market.
"If both the safety and efficacy results are reproduced in the planned pivotal studies, possibly powered to win on pain as well, Bekinda 12 mg has the potential, if approved, to become an important new therapy and standard-of-care for IBS-D," June Almenoff, a member of RedHill's Advisory Board, said.