Clarification on FDA Terminology for Microbiome-Based Therapies

Overview

This letter to the editor highlights an important update regarding the FDA's terminology for microbiome-based therapies, specifically live biotherapeutic products (LBPs) and fecal microbiota products. The authors emphasize the need for consistent use of terminology aligned with FDA definitions to support regulatory clarity and scientific advancement.

Background

Microbiome-based therapies, including live biotherapeutic products, are emerging as important interventions for conditions such as recurrent Clostridioides difficile infection. The FDA has approved products in this category but uses specific terminology to describe these therapies. Accurate and consistent terminology is crucial for regulatory guidance, clinical development, and scientific communication within the microbiome field.

Data Highlights

The FDA refers to the approved products as "fecal microbiota products" rather than live biotherapeutic products (LBPs). The agency uses generic naming conventions such as "fecal microbiota" and "fecal microbiota spores" in approval letters. Fecal microbiota products have variable strain composition and do not meet the FDA's drug substance characterization criteria for LBPs as outlined in their guidance.

Key Findings

• The FDA does not classify the first two approved microbiome therapies as LBPs but as fecal microbiota products.
• FDA approval letters use the terms "fecal microbiota" and "fecal microbiota spores" to describe active ingredients.
• Fecal microbiota products have variable strain compositions, differing from defined LBPs.
• Previous publications, including the authors' own, have used the term LBP inconsistently with FDA terminology.
• The FDA appears to reserve the term LBP for products with defined composition.
• Aligning academic and industry terminology with FDA definitions is important to advance the field and regulatory mission.

Clinical Implications

Clinicians and researchers should be aware of the FDA's specific terminology when discussing microbiome-based therapies to ensure clarity in communication and regulatory compliance. Understanding that fecal microbiota products differ from defined LBPs may influence interpretation of clinical data and therapeutic development strategies.

Conclusion

Consistent use of FDA-aligned terminology for microbiome-based therapies will facilitate clearer scientific discourse and support regulatory processes, ultimately advancing the development and clinical application of these treatments.

References

1. Kelly et al 2023 -- Escape Velocity—The Emergence of Microbiome-Based Therapies
2. FDA Website -- Terminology for Microbiome Therapeutics
3. FDA Approval Letter -- Fecal Microbiota
4. FDA Approval Letter -- Fecal Microbiota Spores
5. FDA Guidance for Industry -- Chemistry, Manufacturing, and Control for LBPs
6. Journal of Infectious Diseases 2021 -- The State of Microbiome Science