Mechanism of action
- aClostridioides difficile (C. diff) infection.
- bThe mechanism of action of VOWST has not been established.6
- CDI, Clostridioides difficile infection; rCDI, recurrent Clostridioides difficile infection.
A bimodal approach may help address both the rCDI and dysbiosis of the microbiome, particularly during the weeks after finishing antibiotics, during the window of vulnerability1-4,7
- aStool specimens for whole metagenomic sequencing were obtained at baseline and at weeks 1, 2, and 8. Of the 182 participants, 29 were excluded from analyses because of missing specimens or protocol deviations. The number of specimens available for analysis depended on the availability of baseline and post-treatment samples.5
- bEngraftment was defined as the number of VOWST dose species detected after treatment that had not been present at baseline.5
Engraftment data
Bacterial engraftment data from exploratory analysis in ECOSPOR III5,a
VOWST dose species engraftment was observed as early as week 1 and remained through week 85,a,b
Limitations: engraftment data yield descriptive results, and the relationship between these data and efficacy or safety has not been established
- aStool specimens for whole metagenomic sequencing were obtained at baseline and at weeks 1, 2, and 8. Of the 182 participants, 29 were excluded from analyses because of missing specimens or protocol deviations. The number of specimens available for analysis depended on the availability of baseline and post-treatment samples.5
- bEngraftment was defined as the number of VOWST dose species detected after treatment that had not been present at baseline.5
Manufacturing
VOWST is a bacterial spore suspension sourced from qualified donors and is composed of Firmicutes spores.6
Step 1: Donor Screening
Medical screening tests are conducted to determine eligibility. Qualified donors are identified based on microbiome health and general health history, and undergo rigorous routine medical screening.
Step 2: Donation Testing
Donations must meet stringent internal standards. Donations from individuals are repeatedly screened using the highest standards for safety, quality, and consistency.
There are multiple steps in the donor screening process, including screening for more than 30 pathogens.
Step 3: Pathogen Inactivation
The solvent-based inactivation process kills live pathogenic bacteria, viruses, parasites, and fungi while preserving Firmicutes bacterial spores.
Step 4: Purification
Filtration and centrifugation steps help remove inactivated pathogens, additional viruses, and other debris to produce a highly refined spore fraction.
Bioburden testing: A sample is sent for bioburden testing to ensure the total absence of any multidrug-resistant organisms, including E. coli.
Step 5: Encapsulation
The final product is bacterial spore suspension capsule for oral administration containing the highly refined Firmicutes spore fraction.
Step 1: Donor Screening
Medical screening tests are conducted to determine eligibility. Qualified donors are identified based on microbiome health and general health history, and undergo rigorous routine medical screening.
Step 2: Donation Testing
Donations must meet stringent internal standards. Donations from individuals are repeatedly screened using the highest standards for safety, quality, and consistency.
There are multiple steps in the donor screening process, including screening for more than 30 pathogens.
Step 3: Pathogen Inactivation
The solvent-based inactivation process kills live pathogenic bacteria, viruses, parasites, and fungi while preserving Firmicutes bacterial spores.
Step 4: Purification
Filtration and centrifugation steps help remove inactivated pathogens, additional viruses, and other debris to produce a highly refined spore fraction.
Bioburden testing: A sample is sent for bioburden testing to ensure the total absence of any multidrug-resistant organisms, including E. coli.
Step 5: Encapsulation
The final product is bacterial spore suspension capsule for oral administration containing the highly refined Firmicutes spore fraction.
ABX, antibiotics.
References: 1. Vincent C, Miller MA, Edens TJ, Mehrotra S, Dewar K, Manges AR. Bloom and bust: intestinal microbiota dynamics in response to hospital exposures and Clostridium difficile colonization or infection. Microbiome. 2016;4:12. doi:10.1186/s40168-016-0156-3 2. Chilton CH, Pickering DS, Freeman J. Microbiologic factors affecting Clostridium difficile recurrence. Clin Microbiol Infect. 2018;24(5):476-482. doi:10.1016/j.cmi.2017.11.017 3. McGovern BH, Ford CB, Henn MR, et al. SER-109, an investigational microbiome drug to reduce recurrence after Clostridioides difficile infection: lessons learned from a phase 2 trial. Clin Infect Dis. 2021;72(12):2132-2140. doi:10.1093/cid/ciaa387 4. Khanna S, Sims M, Louie TJ, et al. SER-109: an oral investigational microbiome therapeutic for patients with recurrent Clostridioides difficile infection (rCDI). Antibiotics (Basel). 2022;11(9):1234. doi:10.3390/antibiotics11091234 5. Feuerstadt P, Louie TJ, Lashner B, et al. SER-109, an oral microbiome therapy for recurrent Clostridioides difficile infection. N Engl J Med. 2022;386(3):220-229. doi:10.1056/NEJMoa2106516 6. VOWST [Prescribing Information]. Bridgewater, NJ: Aimmune Therapeutics, Inc. 02/2025. 7. Normington C, Chilton CH, Buckley AM. Clostridioides difficile infections; new treatments and future perspectives. Curr Opin Gastroenterol. 2024;40(1):7-13. doi:10.1097/MOG.0000000000000989
