We congratulate Kelly et al. on an excellent review of advances in microbiome therapeutic development [1]. The article states that FDA has approved the first two live biotherapeutic products (LBPs) for prevention of recurrent Clostridioides difficile infection and outlines important considerations in the future development of LBPs. We would like to draw attention to an important update on FDA terminology for further discussion.

We note that FDA did not use the term LBP to refer to the two referenced approvals. FDA instead uses the term “Fecal Microbiota Products” on the agency’s website [2] and the generic naming convention “fecal microbiota” [3] and “fecal microbiota spores” [4] in the corresponding Approval Letters to refer to the drugs’ active ingredients. We also note that Fecal Microbiota Products (FMPs) have variable strain composition and thus do not conform to the description and characterization of a drug substance described in the FDA’s chemistry, manufacturing, and control guidance for industry involving early clinical trials with LBPs [5].

We acknowledge that our publication in Journal of Infectious Diseases’s 2021 Supplement on “The State of Microbiome Science at the Intersection of Infectious Diseases and Antimicrobial Resistance” similarly used the term LBP in a manner inconsistent with FDA’s current terminology to refer to the products now termed Fecal Microbiota Products [6]. With the benefit of hindsight of FDA’s recent communications, it appears the agency intends to use the term LBP for products of defined composition and that many publications in the microbiome field are using the term inconsistently. We hope that aligning the terminology in academic and industry publications with FDA will advance the field and help advance FDA’s mission.