FDA Schedules Advisory Meeting for Microbiota-based C. Diff Therapy

The FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) will hold a meeting on Sept. 22, 2022, to review data supporting Ferring Pharmaceutical’s biologics license application (BLA) to reduce recurrent C. difficile infection (CDI) after antibiotic treatment. RBX2660 is microbiota-based live biotherapeutic that contains live microorganisms (diverse spore-forming and non-spore forming bacteria) that are used as active substances.

Elizabeth Garner, M.D.

“The gut microbiome is a highly diverse community of microbes that plays an essential role in human health. Emerging research has shown the promise of leveraging the microbiome to address a range of conditions, including serious diseases such as recurrent C. difficile infection,” Elizabeth Garner, M.D., chief scientific officer, Ferring Pharmaceuticals, U.S., said in a press release.

The human microbiome is a complex community of microorganisms in and on the body. In the gut, if a microbial imbalance occurs, this can lead to C. diff, irritable bowel syndrome or even diabetes. C. diff is a serious disease that causes severe diarrhea, fever, stomach tenderness or pain, loss of appetite, nausea, and colitis. It has been estimated that up to 35% of cases recur after initial diagnosis and people who have had a recurrence are at significantly higher risk of further infection.

Data from the PUNCH program studying RBX2660 were released in May 2022. A subgroup analysis of integrated data from randomized participants who received one dose of blinded treatment of RBX2660 or placebo in the PUNCH CD2 and PUNCH CD3 trials. In the analysis, participants who received RBX2660 demonstrated greater treatment success compared with placebo. Treatment success was defined as remaining recurrence-free for eight weeks after treatment.

Another analysis looked at participants in the modified intent-to-treat study population of the PUNCH CD3 trial who were stratified by underlying comorbidities based on Charlson Comorbidity Index (CCI) scores, which provides an estimate for risk of long-term mortality. Across all CCI subgroups, participants who received RBX2660 showed greater and consistent treatment success compared with placebo.

Most treatment-emergent side effects were mild or moderate regardless. Serious adverse events were infrequent and reported in a similar percentage of participants regardless of treatment or underlying comorbidities. One participant with a severe CCI score who received RBX2660 experienced an adverse event leading to death but no deaths or serious AEs were considered related to RBX2660 or its administration.

The FDA has granted RBX2660 fast track, orphan, and breakthrough therapy designations. RBX2660 was developed by Rebiotix, a Ferring company.