Ferring Pharmaceuticals' RBX2660, a gut microbiome-based therapy, has received Breakthrough Therapy Designation from the FDA for the treatment of recurrent Clostridioides difficile infection (rCDI). This designation aims to expedite the development and review of drugs intended to treat a serious condition where preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over available therapies. RBX2660, developed by Rebiotix (acquired by Ferring in 2018), represents a novel approach to combating rCDI by restoring the balance of microorganisms in the gut.
The Challenge of Recurrent C. diff Infection
Clostridioides difficile infection is a severe gastrointestinal infection characterized by diarrhea, fever, and loss of appetite. In the US alone, C. diff is responsible for approximately 30,000 deaths annually. A significant challenge in managing C. diff is its recurrence, with 20-30% of patients experiencing multiple episodes. Current treatments primarily involve antibiotics, which, while effective in the short term, can disrupt the gut's natural microbiome, paradoxically increasing the risk of recurrence. There are currently no FDA-approved drugs specifically indicated for patients with two or more recurrences of C. diff.
RBX2660: A Microbiota Restoration Approach
RBX2660 is designed to address rCDI by employing Microbiota Restoration Therapy. This involves transplanting live, human-derived microbes from healthy donors into the patient's intestinal tract. The drug, administered via enema, aims to repopulate the GI tract with beneficial bacteria, outcompeting C. diff and restoring microbial balance. This approach builds upon the established concept of fecal microbiota transplantation (FMT), but utilizes a stabilized, quality-controlled product.
Clinical Evidence and Regulatory Pathway
RBX2660 has demonstrated "preliminary positive efficacy" in the ongoing PUNCH CD 3 phase 3 trial, according to Ferring. The primary outcome measure of the study is the proportion of patients with recurrent C. diff infection within eight weeks of treatment with RBX2660 versus placebo. Patients are being followed for several months to assess long-term safety. Detailed data from the PUNCH CD 3 study will be presented later this year, and Ferring plans to initiate discussions with the FDA regarding a regulatory filing. In addition to Breakthrough Therapy Designation, RBX2660 has been granted orphan drug and fast-track status by the FDA.
Implications for Antimicrobial Resistance
If approved, RBX2660 could play a role in combating antimicrobial resistance. C. diff is frequently treated with antibiotics, which can contribute to the development of resistance. By offering a non-antibiotic alternative, RBX2660 could help reduce the reliance on antibiotics in rCDI management.
The Competitive Landscape
Ferring and Rebiotix are among the frontrunners in the development of live microbiota-based therapies. Other companies in the field include Microbiota (partnered with Roche), Vedanta (partnered with Johnson & Johnson), Seres Therapeutics, Evelo, Finch Therapeutics, and uBiome, each pursuing various targets within and beyond gastrointestinal disorders.
