NEW YORK – RedHill Biopharma this week said it plans to launch a Phase II trial evaluating an investigational Crohn's disease drug in a biomarker-defined population, pending discussions with the US Food and Drug Administration regarding a possible path to approval.
The drug, RHB-204, is a next-generation formulation of a separate candidate from RedHill, RHB-104. In a randomized, controlled Phase III trial, the RHB-104 formulation in combination with standard care was 64 percent more effective than standard care alone in treating Crohn's disease.
RHB-204 is an oral capsule that contains a combination of clarithromycin, rifabutin, and clofazimine, three antimicrobial agents with anti-mycobacterial and anti-inflammatory properties. The improved formulation is designed to reduce pill burden and improve tolerability, safety, and adherence, RedHill said.
In the new Phase II trial, investigators plan to test RHB-204 in patients with moderate-to-severe Crohn's disease who are Mycobacterium avium subspecies paratuberculosis-positive (MAP+), representing a first-of-its-kind study, according to RedHill. MAP has been associated with Crohn's disease for years, but it's unclear whether it's the cause of the disease.
RedHill, which expects to observe more consistent benefit in the biomarker-defined study population, said study results also will help to better understand the role of MAP in Crohn's disease (CD).
"The study is designed to include only MAP+ CD patients and is expected to increase the study's power, potentially allowing to demonstrate the benefits of RHB-204 anti-MAP therapy in a relatively small sample size, over and above the promising efficacy observed in the positive Phase III study results of RHB-104's in all-comer CD patients," Gilead Raday, RedHill's COO and head of R&D, said in a statement.
Tel Aviv, Israel-based RedHill expects to evaluate mucosal healing, MAP status, and clinical remission as primary endpoints in the Phase II trial.
The company said anticipated program costs are low, given the small and defined patient population, precise endpoints, and expedited timeframe with early efficacy indications expected at 16 weeks.
RedHill expects to have type C discussions and receive guidance from the FDA on its development plans for RHB-204 in the second quarter of 2025. The company also said it is pursuing partnerships and collaborations for the program, including ongoing discussions with non-dilutive external funding sources.