Ladies and gentlemen, thank you for standing by, and welcome to the Seres Therapeutics Investor call. I would now like to turn the call over to Eric Shaff, Seres Therapeutics' CEO. Please go ahead.
Thank you operator. Good morning, everyone. I will begin on slide 2 of our posted presentation. I'd like to remind you that we'll be making forward-looking statements today. Please refer to our SEC filings for additional information. Moving to slide 3. I'm excited to be joined by a number of my colleagues here today, as well as a leading academic and practicing gastroenterologist, Professor Carl Crawford. Dr. Crawford is an Assistant Professor of Clinical Medicine with Weill Cornell Medicine, and has many years of experience managing patients with recurrent CDI. Dr. Crawford will provide an overview of the disease from a practicing clinician's perspective and his view of the specific need for new therapies. Following Dr. Crawford, Dr. Lisa von Moltke, Seres' Chief Medical Officer, will review the SER-109 phase III program, study results, and discuss the status of our BLA filing.
Terri Young, our Chief Commercial and Strategy Officer, will provide our perspective on the commercial opportunity for our investigational oral microbiome therapeutic, SER-109, which we believe is significant. Terri will discuss the status of our commercial preparations, our view of the opportunity for SER-109, and our plans to maximize this opportunity. Seres has had a long-term collaboration with Nestlé Health Science, including an agreement related to the co-commercialization of SER-109 in the U.S. We are very pleased to have Greg Behar join us today. Greg is CEO of Nestlé Health Science. He will be discussing the capabilities which the companies will leverage to support a successful launch of SER-109, and how our companies are working together to prepare for a successful launch.
Following the presentations, we will be sure to save time for a Q&A session that will include all of our speakers, as well as David Arkowitz, Seres' Chief Financial Officer. Moving to slide 4. I'd like to highlight several key points that we would like to emphasize. First, recurrent CDI is a debilitating disease causing over 20,000 deaths per year in the U.S. alone. This is a disease that results in a particularly high burden to the healthcare system. Not only is CDI devastating from a patient perspective, this is also a very costly disease to treat. Second, we will discuss why we believe SER-109 could provide an innovative new oral solution that addresses the underlying cause of the disease, delivers highly compelling efficacy, and that could fundamentally transform how this disease is managed.
Third, we expect that SER-109 will soon be available to patients and healthcare providers pending FDA approval. Based on our strong phase III study data, we have filed a BLA, and last month, the FDA provided us with a PDUFA action date of April 26, 2023. Fourth, Seres and Nestlé Health Science are well underway in preparing for launch. Terri and Greg will discuss these activities in more detail, and how the two companies are working together to drive towards a coordinated commercialization effort. Fifth, assuming approval, we anticipate a meaningful commercial opportunity for SER-109. With this product, we believe that over time, we are positioned to achieve significant penetration into the entire recurrent CDI population. Turning to slide 5. Before we get into the specific SER-109 content, I'd like to briefly cover Seres' broader mission.
We seek to use our pioneering microbiome therapeutics approach to transform patients' lives. Our drug candidates contain consortia of commensal bacteria, and these are designed to target multiple mechanisms related to the desired clinical activity. In the case of C. diff infection, our approach is designed to suppress C. difficile growth, as well as the pathology caused by this infection. The SER-109 data clearly indicate the potential for our microbiome therapeutics, and we believe that our approach could similarly prevent other life-threatening infections, including those that impact numerous medically vulnerable patient populations. Our longer term vision is to create a franchise of products that protect patients against these deadly infections and thereby also help to blunt the growth of antibiotic resistance, which has become a major public health threat. We look forward to providing updates on our other R&D efforts in the near future.
Moving to slide 6. We've completed a robust phase III development program that includes two well-designed studies. The results of these studies reveal that SER-109 may meaningfully reduce the incidence of CDI recurrence. This benefit is seen early after treatment and remains durable over an extended period of time. These SER-109 data have been published in The New England Journal of Medicine and JAMA, both highly prestigious journals, a further testament to the significance of the results. The clinical data generated provides support of the potential for SER-109 to truly change patient outcomes for those facing recurrent CDI. Turning to slide 7. Based on our phase III data, we have filed a BLA in the U.S. The review of this application is ongoing with the FDA.
SER-109 has obtained an accelerated review based on its Breakthrough Therapy designation, and the FDA has provided us with a PDUFA action date of April 26, 2023. Over the next hour, you will hear much more about everything that we're doing alongside our Nestlé Health Science collaborators to prepare for a successful product launch, presuming a favorable FDA decision. Moving to slide 8. Based on the substantial opportunity we see for our approach in infection protection, we envision a breadth of opportunities for our microbiome therapeutics. Over the coming years, we believe we have the potential to create a steady stream of pipeline growth with new therapeutics and with a focus on infections. At the foundation of this effort is SER-109, our flagship program. Beyond SER-109, we believe there are multiple additional opportunities to protect medically compromised patient groups from life-threatening infections.
This includes individuals with cirrhosis, solid organ transplants, and neutropenia. Our SER-155 program is currently in a phase I-B study in patients receiving allogeneic stem cell transplants, a highly medically vulnerable patient population and at very high infection risk. We look forward to providing further updates of this program early in the new year, as well as on our pipeline more generally. It is now my honor to introduce Dr. Crawford.
Thank you so much. I'd like to talk about the current standard of care in the treatment of recurrent C. difficile infection. I'll start on slide 10. C. difficile infections are caused by a spore-forming toxin, producing gram-positive anaerobic bacteria. The symptoms that C. difficile infection can manifest in are simple diarrheal illnesses, but can be as severe as colitis that can cause hospitalizations in many individuals. This is one of the few infections that's also associated with a high degree of morbidity and mortality. We heard before that there can be up to 30,000 deaths per year. If we put that into perspective, that's about 80 people dying every single day from a C. difficile infection. Now, one of the easy things about my job is that I can prescribe antibiotics and make individuals get better.
However, this is one of the few infections that has a built-in relapse rate. I have to tell my patients that there's about a 25% chance that they can get this infection again after I successfully treat it the first time. If they get it a second time, I have to tell my patient that they have about a 45% chance they can get it again. If that individual comes back to me with another recurrence, I have to tell them that they have about a 65% chance or greater than a flip of a coin that this infection will come back. The bane of my existence is treating individuals that have recurrent C. difficile infections. If we move on to slide 11, we can see that in addition to the physical illness that people will experience with a C.
difficile infection, there is also a number of lasting quality of life issues that these individuals will experience. Here on the right, we can see a short form, a health domain survey, and these are individuals that have self-reported having had an infection with C. difficile. We can see a number of these domains that include vitality, general health, physical functioning, mental health, bodily pain, physical functioning, as well as emotional issues as well. The bars in blue represent the average individual. That's you and me feeling how well we do every single day. We can see individuals that have a current C. difficile infection represented by the red bars do much less than us sitting in these rooms right now. However, one of the interesting things to notice is that in the green bars, these are the individuals that actually recovered from a C.
difficile infection, never get back to the same way that we feel in this room today. They're always left with something that's lingering. In addition, the most important 2 bars are the vitality and general health. Even after successful treatment, these individuals will never feel the same, and this goes beyond just not feeling well each day. These individuals say that their mental health is destroyed. They feel that they are at risk to their families and friends, and this also has a number of other issues with how they're gonna be able to function at work. If we move on to slide 12, we can realize that C. difficile is actually a disease that's very unique because it requires 2 factors in order to manifest the disease. The leading risk factor for a C.
difficile infection is exposure to antibiotics, this usually causes collateral damage to the beneficial bacteria that live inside of the gastrointestinal tract, namely the colon. An individual may have a urinary tract infection or a pneumonia, they may require specific antibiotics that are justified. However, this will cause damage to a lot of the bacteria that are capable of suppressing a C. difficile infection. Of course, if this microbiota is damaged and an individual carries a C. difficile organism inside of their gastrointestinal tract, this is the correct circumstances that will allow for C. difficile infection to produce a toxin that will cause colitis or diarrhea. If we look at slide 13, what we can see is something that's very interesting. If we look at individuals who have no C. difficile infection, and that's marked by the blue lines as C for control.
If we look at individuals that are experiencing their first incidence of a C. difficile infection, that's the CDI. If we look at individuals that have had recurrent C. difficile infections, we can notice one thing. These graphs are looking at the number of different kinds of bacteria or phylotypes. Controls have a number of different kinds of bacteria that are important in the biodiversity. In particular, they have two phyla, known as Firmicutes and Bacteroidetes, which are capable of preventing C. difficile infections. However, those individuals that have an incident C. difficile infection tend to lose those Firmicutes and Bacteroidetes bacteria, and those that have multiple recurrences have even less of those particular phyla, putting them at increased risk for having a C. difficile infection every time thereafter. Let's move to slide 14. Because of this two-phase life cycle of a C.
C. difficile organism, antibiotic therapy is necessary, but it will often be insufficient to prevent a recurrence. When the microbiome is disrupted by broad-spectrum antibiotics, C. difficile spores germinate into toxin-producing bacteria, and this is what leads to the onset of symptoms, whether it's diarrhea or colitis. We have to remember that it's the vegetative bacteria that are killed off by the antibiotics, and these bacteria are the ones that are freely moving and secreting a toxin. The spores are the bane of our existence. The spores are resistant to antibiotics. Antibiotics have no effect on them. The spores are actually present inside of the gastrointestinal tract for weeks on end, and they can actually exist in the environment for up to 6 months. These spores are very hardy. They're resistant to light, heat, alcohol, UV light, et cetera.
On slide 15, we can see that microbiome therapeutics may actually play an important role in restoring host defenses against potential pathogens and improve clinical outcomes. The GI tract is a reservoir for potential bacterial invaders. A diverse microbiome is essential to preventing colonization and infection from these potential invaders. This is known as colonization resistance. Antibiotics drive the loss of the beneficial bacteria that are responsible for preventing infections from C. difficile infection. One of the things that we're hopeful for is that SER-109, a donor-derived consortium of Firmicutes spores, is able to help those that have recurrent C. difficile infections. This is through repopulation of those particular bacteria that are important in colonization resistance.
On slide 16, we can see a nice infographic as to what is happening during this two-hit process and the reason why we require a two-pronged treatment approach. In a normal individual, we have a high diversity of microbiome or microbiota present inside of the gastrointestinal tract, and this is what provides host defenses against these potential pathogens. If we do require an antibiotic for a specific infection, this can disrupt the microbiome. This promotes C. difficile spores to germinate into living bacteria and allow those bacteria to multiply and produce a toxin that can lead to symptomatic disease of diarrhea. We do require antibiotics at this point to treat C. difficile infection. However, we do not treat the underlying dysbiosis. This is where the role of microbiome therapeutics comes in.
If we can actually restore the healthy microbiota as well as the biodiversity, we can actually inhibit spore germination and prevent recurrences of C. difficile infection. We move on to slide 17, FMT and investigational FMT drug products are vulnerable to emerging infections. Although replacing microbiota from donors is a great idea at preventing C. difficile recurrences, we do have to remember that there are potential risks to using whole stool or full-spectrum stool. Using complete communities of bacteria may be associated with risk when new infections are not detected. We never knew, for instance, that H. pylori could be associated with gastric cancer. We never knew that HPV could be associated with cervical cancer or rectal cancer or head and neck tumors. We're always playing a catch-up game with how we use this particular landscape.
In fact, the FDA set forth a number of warnings related to FMT use. In March 2020, the FDA set forth warnings about pathogenic bacteria, such as those that could be transmitted, you know, in particular studies. These included multi-drug-resistant bacteria as well as certain kinds of infections. As soon as 2020, the FDA issued warnings about the potential for transmission of SARS-CoV-2. As recently as this year, the FDA sent warnings out about the potential for mpox transmission. We're always playing a catch-up game. Prior therapies have not been sufficient to break the cycle of recurrence, and the standard of care therapeutics do not restore the gut microbiome. For instance, antibiotic therapies treat the active infection by targeting vegetative bacteria, but they also disrupt the microbiome, which is known as the collateral damage.
There are other therapies that we've tried, such as monoclonal antibody treatment, which targets anti-toxin D. However, there's always limits to what we can do. The recent FDA approval of fecal microbiota transplantation is actually very promising, and FMT products are vulnerable to emerging infections nonetheless. The goal of therapy is achieving both the initial and sustained clinical responses, but having a safety profile that is favorable to all. Patients facing recurrent C. difficile infections require microbiome repair. When I see my patients, I have to stare at them and look at a fork in the road. For about 75% of patients, I can cross my fingers and hope that they will do well, but for the remaining 25% of individuals, I don't know who they will be, but I have to let them know that they may be in a cycle of recurrence.
These are the individuals that I'll have to treat with antibiotics again, disrupt their microbiome, and cross my fingers and hope that they don't develop a recurrence. Unfortunately, I do take care of a number of patients who keep coming back to me until I'm able to break the cycle using a fecal microbiota transplant. SER-109 may fill an important unmet need, and that's the prevention of these recurrences. Early and urgent intervention in the cycle of recurrence can prevent further recurrences, and it's clear. SER-109 could have a unique place in the treatment algorithm, potentially transforming the standard of care in how we're treating this infection now. It can reduce the need for antibiotic taper regimens and other options that do not restore the microbiome and break that cycle.
Moving away from repeated short course regimens of antibiotics alone without subsequent microbiome restoration is probably not ideal. Now, SER-109 does offer some attractive value propositions. From a clinical perspective, I think that the most important things are to be able to deliver something to our patients that works, so having a demonstrated efficacy, something that is extremely safe for our patients, and something that our patients can actually do that's convenient. I'll end here.
Okay. Thank you, Dr. Crawford. Good morning, everyone. Moving to slide 22, SER-109 is an investigational oral microbiome therapeutic designed to break the cycle of recurrent CDI. The product candidate is an ecology of Firmicutes spores, which Dr. Crawford mentioned. These germinate into bacteria that are known to have a dominant role in gastrointestinal health, more specifically, have been observed to prevent the germination and growth of C. difficile spores. The SER-109 bacterial spores are resistant to gastric acid, allowing formulation into oral capsules. Our manufacturing process is designed to ensure product consistency while also mitigating the risk of transmission of pathogens, including those that cause bacterial and viral infections. Slide 23 shows an outline of our phase III study, ECOSPOR III, which enrolled 182 patients with multiply recurrent disease.
Our study subjects have been treated with either vancomycin or fidaxomicin for 10-21 days as per investigator discretion. Subjects were randomly assigned 1 to 1 to either SER-109 or matching placebo, administered orally for three days. Subjects were stratified by age 18-64 years old or 65 and over, and by the antibiotic they received for rCDI. The primary endpoint was the proportion of subjects who had CDI recurrence by eight weeks after dosing. CDI recurrence was determined by the return of diarrhea, the need to reinitiate CDI antibiotics, and the confirmation of the clinical diagnosis with a positive toxin test. This phase III study clearly met the primary endpoint with a highly statistically significant reduction in the relative risk of C. diff recurrence with a P value of less than 0.001.
The results indicated that approximately 88% of patients experienced a sustained clinical response. Slide 24 provides an overview of the safety information from the phase III ECOSPOR III study. SER-109 was well tolerated and patients administered SER-109 had no Serious Treatment-Emergent Adverse Events or deaths that were attributed to study drug. The most commonly observed TEAEs were GI disorders, the majority of which were mild to moderate in nature and included flatulence, abdominal distension, and abdominal pain. These AEs were observed in a similar proportion of patients in the placebo arm. Returning to the efficacy results on slide 25, we also evaluated SER-109 efficacy over time. The data provided 2 important results. First, we noted that efficacy was observed as early as 2 weeks following drug administration.
A second important finding was that SER-109 efficacy was found to be highly durable, and we continued to observe significant levels of efficacy out to 24 weeks. Next slide. Following receipt of the positive ECOSPOR III data, we had further discussions with the FDA regarding the requirements for a BLA filing. At that time, the FDA indicated that they would require a total safety database that included at least 300 patients followed for 6 months. Based on that guidance, we subsequently enrolled a study, ECOSPOR IV, which was an open-label study that included over 260 additional individuals. These safety results are shown on slide 26. The study reaffirmed and extended the SER-109 ECOSPOR III results. Overall, the safety profile in ECOSPOR IV through 24 weeks of follow-up indicated that SER-109 was well tolerated.
This was consistent with the safety profile observed in the placebo-controlled ECOSPOR III study. In ECOSPOR IV, the most common Treatment-Emergent Adverse Events were diarrhea, flatulence, nausea, abdominal pain, abdominal distension, urinary tract infection, and fatigue. These are all issues common to the CDI population. Approximately 12.5% of patients in ECOSPOR IV experienced a severe adverse event. However, none of these events, including any of the eight observed deaths, were deemed related or possibly related to the study drug by the study investigator. On slide 27, we show an overview of the CDI recurrence rates in ECOSPOR IV. Overall, we observed a sustained clinical response at up to eight weeks in approximately 91% of subjects, which was remarkably similar to the 88% rate observed in ECOSPOR III.
We also examined clinical response rates based on the number of prior CDI episodes. We were very pleased to see a similar recurrence rate across the entire study population, regardless of the number of prior episodes. This study included a meaningful proportion of first recurrence patients, where we observed that only 6.5% of patients experienced a recurrence for a sustained clinical response of 94.5% in this group. Our clinical results in this first recurrence population are consistent with our understanding of the underlying pathophysiology of the disease, which is believed to be similar across rCDI patients, regardless of the number of prior episodes. Moving to slide 28. As Eric mentioned, we are very pleased that the FDA has accepted our SER-109 BLA filing for review and provided us with a PDUFA target action date of April 26.
We had previously obtained Breakthrough Therapy designation for SER-109, and the PDUFA date we obtained reflects an expedited priority review period. We continue to constructively engage with the FDA as they review the submission and look forward to continued dialogue with the agency. Transitioning to our medical affairs activities on slide 29. We have built strong medical affairs capabilities across both Seres and Nestlé Health Science. The team has been functioning as a single integrated entity and is busy educating key external stakeholders about the role of microbiome in this disease and the benefits that a microbiome therapeutic might provide. The Nestlé Health Science team has existing operational core functions to support its currently marketed products, and we are further scaling and leveraging these capabilities. These operational functions are increasingly supporting SER-109 as we get closer to anticipated approval and launch.
As shown on slide 30, an important goal of our medical affairs activities is to further educate the medical community on recurrent CDI and the potential role of microbiome therapeutics. SER-109 represents a potential paradigm shift in the treatment of rCDI, with the opportunity to address the underlying disease pathophysiology of microbiome disruption. Our medical affairs teams are engaging with treating physicians and advanced practice providers, including those involved in formulating practice guidelines. They are also communicating with medical societies and patient advocacy groups, ensuring that there is broad awareness of the SER-109 data and potential benefit to patients. As indicated on slide 31, we have been highly active at target conferences and have frequently presented clinical data. Additionally, data has been published in a number of high impact journals.
This has raised the visibility of SER-109 and also enabled our team to have a meaningful dialogue with physicians and other healthcare professionals who are involved in treating recurrent CDI patients. I would like to conclude on slide 32 by sharing some of the quotes we have heard from clinicians related to SER-109 from medical conferences and other interactions. On this slide, we have included specific comments we have heard related to SER-109 and where clinicians might plan to use this therapeutic pending approval. The enthusiasm for an oral microbiome therapy with the durable efficacy results and safety profile seen with SER-109 remains high, and we look forward to getting this therapy to patients. With that, I will turn the presentation over to Terri.
Thank you, Lisa. I'll start on slide 34 with an update on what we believe is the appropriate population for SER-109. As you may know, the CDC conducts active disease surveillance for C. difficile infection or CDI, providing regular updates of both hospital and community acquired infection rates. These reports from the Emerging Infections Program, along with a historically rich publication stream on the topic, have enabled us to estimate the potential addressable patient pool for SER-109. Recently, there have been updates from the CDC and others that we have incorporated into our view of the market and represent here on this slide. CDC has reported that healthcare acquired CDI experienced an approximately 6% decline between 2014 and 2019. Just last month, the CDC updated this figure and reported a 3% decline between 2020 and 2021.
This declining decline was no surprise to us, given that the likely main driver of the decline, implementation of the CDC 7 Core Elements of Antibiotic Stewardship, has recently reached a likely peak level of 95% adoption across U.S. hospitals. We believe this declining decline trend will continue, reaching an overall steady state of flat or zero growth by 2025 for the healthcare-acquired infections segment. In contrast, community-acquired CDI has shown modest, steady growth of 2.3% for some time now. Combining the two segments and factoring in an overall U.S. population growth rate, we estimate a composite market growth rate of 2% from 2025 forward. Applying these growth rates to historic estimates of annual cases brings us to 156,000 cases of rCDI in 2023, which of course is our anticipated launch year for SER-109.
Since we know that the entirety of this population is both diagnosed and treated with medication today, all 156,000 cases could potentially be appropriate for SER-109 once approved. I'll move to slide 35. Our market research and every conversation we have with HCPs confirms the high current unmet need of preventing recurrence. In fact, HCPs, including Dr. Crawford here today, have referred to recurrent CDI as the bane of their existence because it keeps coming back and they don't have good options today with current standard of care. As a reminder, current standard of care is represented by the placebo arm in our ECOSPOR III trial. During our most recent interactions with HCPs at the IDWeek and ACG congresses in October, they reaffirmed the need for a better option and conveyed palpable excitement for the potential approval of SER-109.
On slide 36, you'll see our expectations on HCP adoption. It's no surprise, given the unmet need in the category and the robust profile of SER-109, that HCPs have patients in mind for initial trial of SER-109 once approved. This is very typical with a new therapy, where an HCP will choose a patient that he or she believes is most in need of something new for their initial trial. You can see the thought process represented in the quote on the left side of this slide. These same HCPs tell us that after this trial period where they can observe clinical success in their own practices, they fully expect to expand use to the broader population of recurrent CDI patients within the labeled indication. The next slide depicts a view of current patient share by treatment.
We are excited about the ability to fundamentally change this landscape. Based on HCP feedback regarding how they'd like to use SER-109 once available, we fully expect a significant paradigm shift away from antibiotic use alone and significant penetration of antibiotic share as utilization of a multi-step regimen takes hold. For those physicians who are using FMT today, we'd expect the various FMT approaches to fall even further back in the treatment algorithm, given the robust profile of SER-109, inclusive of high efficacy rates in oral administration and its attractive value proposition for patients. On slide 38, we describe our broad disease education efforts, which supplement those that Lisa described earlier from our medical affairs team. We developed and launched the campaign Endless Sequels in 2021 and have increased its reach as we move through the pre-launch period.
This campaign was awarded the coveted Manny Award earlier this year for best professional web campaign. We at Seres, our collaborators at Nestlé Health Science, and our agency partner, AbelsonTaylor, were quite proud of this accomplishment, given that it was our first foray into anything resembling broad, proactive rCDI disease education and advertising. This accomplishment speaks to the experienced commercial talent that we have across our organizations working to bring SER-109 to patients. The campaign is designed to educate in three areas, and Dr. Crawford previously spoke to the relevance of all of these. First, recurrence means you're a marked man, needing urgent protection from further recurrences. Number two, microbiome restoration is foundational to achieve a sustained clinical response. Number three, antibiotics and microbiome therapeutics each play a unique role, and both are necessary to keep rCDI at bay.
Moving to the next slide, we have mapped our potential rCDI patient population across sites of care in the U.S. You can see the results here. Approximately 70% of patients complete treatment for rCDI in the outpatient setting. We are prioritizing these patients at launch because they are concentrated in areas that we believe we can effectively and efficiently reach and most easily get product to patient. This is because these patients would be completing their antibiotic regimen, and therefore receiving SER-109, in the outpatient setting and via the outpatient pharmacy benefit. It's not that we won't tackle the other sites of care over time, they are a longer play for us and we are not focused there initially. In a like manner, you'll see in slide 40 that we have mapped the patient population across HCP specialties.
Data reveal a significant concentration of patients in a segment of HCPs and hospitals. This is where we will focus most of our resources at launch, with a plan to blanket the treating specialties of gastroenterology and infectious disease, with additional efforts directed towards other high-volume treaters. We will be bringing on the current ZENPEP selling team at Nestlé Health Science post-approval to cover the vast majority of the high-volume outpatient business. Greg will speak more about this team, but suffice to say that we have 150 representatives with deep penetration into gastroenterology offices today. The teams are working to further segment this outpatient audience to identify those who may adopt SER-109 the quickest, and as we move towards launch, we will finalize our call plans for this priority audience.
We will be standing up a supplemental sales team at Nestlé Health Science to cover top volume hospitals in addition to infectious disease specialists who tend to spend much of their time in hospitals. We are hiring a team of 20 this quarter and plan to deploy them in Q1 of next year. They will profile the top institutions and build a roadmap pre-launch that spells out exactly what needs to be done by whom at each institution to make SER-109 readily available to patients at discharge. Our early work indicates a high level of variability amongst these institutions in terms of how rCDI is treated and who is involved. There is no one solution, and it will take time to get the protocols in place to make the patient road to SER-109 a smooth one in each institution.
At least having a roadmap that is developed in Q1 gets us to the starting line with a plan. Finally, we will be leveraging the experience and understanding that the Nestlé Health Science commercial team has built via their currently marketed products on how to reach HCPs when the sales representative is not in the office using other channels. This capability is key to help quickly educate the educate the HCPs we're calling on, but also to ensure that we can get to the ones we are not reaching with a sales representative to create awareness before patients present to them asking about SER-109. I'll shift gears to the payer audience on slide 41.
We deployed the Nestlé Health Science payer field team last spring to begin our pre-approval information exchange with these important stakeholders. We are working with the team at Nestlé to refine our mitigation plans against typical payer management tools that can be employed for specialty medicines. This is important for any specialty medicine, but with the narrow window a patient has to obtain a prescription for, fill, and take SER-109, it's even more critical that we carefully address any onerous management tactics. I'll go further into this topic in a few slides. We expect SER-109 to be subject to the typical review and approval processes that each payer employs for new medicines.
Our experienced payer field team knows how it works at each one and is prepared to get SER-109 into the workflow as soon as it's practical upon approval. The evaluation process will take time. As a result, we estimate that many patients receiving SER-109 early on will need to go through a medical exception process that is part of navigating the new to market blocks that the vast majority of payers use for new products today. Of course, the three largest PBMs control the majority of patient lives for SER-109, as is the case for many outpatient orally administered products. Our ability to ensure broad and easy access with these important stakeholders will smooth the way for SER-109 to many of our patients. On slide 42, you can see our estimated payer channel mix for our CDI patients.
Most patients have commercial coverage, which is why I referenced the importance of the PBMs just now. We have a sprinkling of Medicaid and other government, VA and DOD, and an estimated 37% of patients are Medicare. Within Medicare, you have some who will be covered as low-income subsidy patients. These patients have Medicaid-like cost-sharing requirements. Most of the Medicare patients will be subject to the high cost-sharing requirements that are typical with the benefit design today. We estimate that these patients will experience significant affordability issues with SER-109. Unlike commercial patients, we are not permitted to help them by providing co-pay assistance. Based on what we understand about the Inflation Reduction Act, however, these patients could experience significant relief beginning in 2025, potentially allowing for further penetration of the total Medicare patient pool.
Since we all know that payer decisions and patient affordability can significantly temper HCP and patient demand, we are very focused on establishing an environment that permits broad patient access. In particular, we want to prevent any potential onerous utilization management that causes us to lose a patient during the treatment window and are committed to providing patient financial assistance to commercial patients. On the next slide, you'll see our current thinking on price articulated. As we've covered, SER-109, if approved, would bring significant value to patients in the healthcare system, delivering approximately 90% efficacy in a well-tolerated oral regimen and meeting the largest, most pressing unmet need in the market uniquely well. Lisa described the composition of SER-109 and how it is designed to address the biology of recurrent C. diff infection.
We believe the strength of the unmet need, the profile of SER-109, and the level of innovation we are bringing to the market affords us pricing flexibility. We will continue to work with our colleagues at Nestlé Health Science to define the exact price point as we approach launch and plan to announce the SER-109 price soon after approval. On slide 44, you'll see a view of the prescription to patient portion of the patient journey. This journey is not unique to SER-109. I show it here to illustrate the importance of the treatment window for SER-109 patients. If any one of these steps is delayed or derailed, a patient who desperately needs SER-109 could miss the window after antibiotic completion, leaving them on a rapid path to their next recurrence. As Dr.
Crawford described earlier, once a patient's antibiotic regimen is completed and without urgent microbiome restoration, the C. diff spores quickly begin to germinate and an active infection ensues once again. We are committed to providing the right support to ensure that patients receive SER-109 within the treatment window, thereby creating an overall exceptional user experience. To maximize control of the patient experience, we plan to distribute SER-109 through specialty pharmacies. By selecting the best external partners, we can help address the tight timeline for shipping product and documenting any payer prior authorization requirements. On the next slide, I'll shift gears once again to our primary stakeholder, the patient. One aspect of this market that has really struck me is how involved our CDI patients are in managing their care. Dr.
Crawford described the profoundly negative effect of our CDI on patient quality of life. We definitely hear from patients that they are isolated and miserable when suffering with our CDI. The effects last far beyond the current episode. They state that they prioritize addressing our CDI above any comorbidity that they may have, including cancer. This creates a responsibility for us as a company to engage these patients once SER-109 is approved to help them understand what SER-109 could do for them so that they can discuss the option with their treating HCP. The more you've had our CDI, the more motivated you are not to get it again.
We plan to focus our patient activation efforts on these highly motivated, multiply recurrent patients at launch, broadening our efforts to all as HCPs prescribing evolves. On slide 46, you'll see the 1-page view of our high-level patient journey. Today, you've heard in more detail than previously provided about our plans to bring SER-109 to patients and prepare for commercialization. These include the following key areas: increasing the urgency to restore the microbiome in patients with rCDI, creating broad awareness of a better option with SER-109, smoothing the path of product to patients to create a positive user experience and with optimal access. Each aspect of our launch has been well thought through with our teammates at Nestlé Health Science, and we will take a very deliberate stepwise approach to gaining our foothold and broadening over time.
Here on slide 46, you can see the activities that we will be focused on during our launch period and after. We are well aware that we have an innovative medicine that could fundamentally transform care over time for a patient population in dire need of a better option. We will start with the areas that are primed for early use, where we can have the best initial patient experience, establish our foothold, and grow from there. The team and I can't wait. Now I'll pass the mic to my colleague, Greg Behar, CEO of Nestlé Health Science, who will provide additional background on his organization and how they are seeing the opportunity with SER-109. Over to you, Greg.
Thank you, Terri. Hi, everybody. I'm Greg Behar, CEO of Nestlé Health Science, and we'll begin on slide 48. I'm delighted to share a little about who we are, our long-standing relationship with Seres, and how we expect SER-109 will be an important and exciting part of our growing portfolio of solutions for patients and their families. Moving to 49, for those of you that may not be familiar with Nestlé Health Science, we are a division within Nestlé dedicated to transforming the lives of patients and their families by providing therapies and solutions to gastrointestinal and nutritional-related diseases and conditions. We have capabilities and infrastructure across all area of the pharmaceutical value chain, including R&D, manufacturing and regulatory. The majority of our employees work within the commercial part of our business. This is something that I will be discussing in more detail on a later slide.
Moving to slide 50. Within Nestlé Health Science, Aimmune Therapeutics is a biopharma organization housed within the medical nutrition side of our, of our business. With a portfolio focused on pediatric care and food allergy, adult medical care, and acute care, Nestlé Health Sciences medical nutrition products and services are recommended by healthcare professional for patients with very specific dietary needs related to illness, disease states, or special challenges at different life stages. This medical nutrition pillar complements the one of consumer care, which combines science-based innovation and global reach to address individuals' unmet and emerging needs. These products are found in pharmacies, retail shops, and online, and are focused on the fast-developing area of healthy aging, healthy growth, gut, metabolic health, and obesity. Turning to slide 51.
Aimmune was originally founded in 2011 out of a meeting with patient advocates, the FDA, NIH, academic leaders, and industry representatives with a specific focus on the development of treatments for food allergies. Nestlé Health Science first became an investor in Aimmune in 2016, then fully acquired the company in 2020. Also that year, Nestlé acquired the rights to ZENPEP, a pancreatic enzyme replacement therapy, which was made available by the acquisition of Allergan by AbbVie. The experienced ZENPEP commercial team, including their sales organization, joined Nestlé Health Science as part of the transaction and were welcomed into the Aimmune organization to form a singular pharmaceutical entity within the company. This also evolved the focus and mission of Aimmune to better align with that of Nestlé Health Science. Today, our broader focus is on advancing and commercializing treatments for both GI and nutrition-related diseases.
part of our strategy to deliver our mission is to partner with the world's leading biotech companies in the food, GI, and metabolic-related disease arenas to expand our portfolio of groundbreaking treatments. Our collaboration with Seres is, of course, a key component of that strategy. Moving to slide 52. This collaboration with Seres has its roots back in 2015 when Seres and Nestlé Health Science entered into their first agreement for the development and commercialization outside of the United States and Canada of a number of product candidates, including one for C. diff and SER-109. Since then, the initial agreement has been expanded to include North America, and now that Aimmune is part of Nestlé Health Science, we're collaborating with Seres to utilize our commercial network and GI know-how to bring this extremely exciting and potentially transformative drug to market. Moving to slide 53.
As you can see from this chart, we have deep expertise and a track record to drive a successful launch for this product. Since ZENPEP came under our wing, it's gone from strength to strength. Despite the product being in the market for more than 10 years, we've been steadily growing its share of new prescriptions since the acquisition. We're singularly committed to continuing to gain share for this growing PERT market. We're leveraging our existing ZENPEP GI pharma, commercial, and medical infrastructure, including a high experience and tenured sales force, to set SER-109 up for successful launch. Our more than 150 sales reps, covering more than 85% of GI practices, have an average of 10 years tenure in the pharmaceutical industry, with more than 5 of these in the GI space. Now to 54.
Beyond our sales force, we of course, have seasoned employees across the functions typical of biopharma companies with the competencies and capabilities to drive launch readiness. For example, in market access, we have seven director of strategic accounts who cover 60, 76 payer accounts, representing more than 90% of commercial and Medicare Part D lives. That team has more than 20 years of experience on average at both large manufacturers, pharma manufacturers, as well as payers, as well as recent experience launching a first-in-class therapeutic. Of course, the team has extensive experience managing complex products through specialty pharmacies to streamline HCP and patient experience and has recently led the selection of a limited distribution network with high touch capabilities for the SER-109 launch.
In summary, SER-109 will add an important asset to our commercial GI portfolio, and we are working tirelessly to utilize our extensive resources and infrastructure to bring it to market. This includes our ability to understand and navigate market access and reimbursement dynamics, our expertise in specialty care, our experience in designing and establishing gold standard patient support services, and leveraging our relationship with key opinion leaders, HCPs, and other decision-makers in the GI space. We're extremely excited about the potential for SER-109 and what it offers to revolutionize the management of recurrent C. diff. The role Nestlé is playing in collaboration with the Seres team in bringing this potentially transformative product to patients in need. I will now pass the call back to Eric.
Thanks very much, Greg. I'd like to thank all of our speakers for their insightful presentations. As you have heard today, we are incredibly excited by the opportunity ahead with SER-109. We believe the clinical data generated to date is compelling and that pending approval, this product could transform how patients with recurrent CDI are managed. We also realize that there's a lot of work to do and it will take time and effort to build this market. The Seres and Nestlé Health Science teams are collaborating closely. We intend to continue to work with diligence and urgency as we bring SER-109 forward to patients. Our ultimate goal is for SER-109 to have a positive impact on the lives of individuals living with recurrent CDI, and that we are able to truly make a difference in these patients' lives.
We certainly believe that this is possible, and we also expect that SER-109 will represent an important commercial opportunity. While today's event was focused on SER-109, we're also advancing additional microbiome therapeutics that also address challenging diseases that are not well addressed today. With that, we look forward to your questions, and I'll pass the call back over to the operator to manage the Q&A.
The floor is now open for your questions. To ask a question at this time, please press star 1 on your telephone keypad. If at any point you'd like to withdraw from the queue, please press star 1 again. You will be provided the opportunity to ask 1 question and 1 further follow-up question. I will take a moment to render our roster. Our first question comes from Joseph Thome from Cowen. Please proceed.
Hi there. Good morning. Thank you for the presentation, thank you for taking my questions. Maybe the first one, just for Dr. Crawford. How early in the refractory treatment paradigm would you like to use SER-109? Obviously, if payer considerations weren't an issue, would you wanna use this at a first recurrence, or would it be second and third? Maybe the second one just for Greg, more the commercialization side. I know the company did mention looking at strategic options for Palforzia, can you just give us a little bit of an idea if that decision has changed how you're thinking about SER-109, or if the company maybe is just looking to consolidate more into a GI focus and away from allergy? That would be great. Thank you.
Thanks for the question, Thome. Maybe Dr. Crawford can go first.
Sure, Mr. Thome, thank you for your question. I would probably aim to use this, you know, as early as the first recurrence if it's allowed. That's because I know that once an individual has demonstrated that they're capable of a recurrence, they're down this pathway where they're more likely to have this again and again. In a perfect world, just knowing the pathophysiology of how C. difficile infections, you know, occur, if an individual is able to get the first occurrence, the first time ever episode of C. difficile infection, there's something that's unique about them that is gonna predispose them to getting an infection again.
Once again, if cost was not an issue, if there were no other regulatory issues in my practice, I would also look at those individuals that I would be worried about even after their first infection having the potential to get this again. For instance, if I have an individual that's immunosuppressed that has colitis.
That gets a C. difficile infection the first time, they may end up in the hospital. Anyone having a first infection where I think that they're gonna have a high degree of morbidity and mortality again, I would wanna use this therapy as soon as that first occurrence. Now, once again, you know, we're talking about recurrences. I would say for a first recurrence, that's where I would try to position this as quickly as possible. For individuals at high risk for death, I would probably aim to position this, you know, as quickly as possible. That's what we do even, you know, in our hospital with standard FMT, the way we see it.
If I have an individual that is in an ICU and they are not responding to therapy, there are recommendations by our governing societies like the ACG, where we can use FMT for someone that's refractory to therapy, but also to prevent a recurrence that could be catastrophic if they get it again. I hope that answers your question.
I think the second question, Joe, was to Greg and the Palforzia announcement last week and potential implications.
Yes. Thanks, Eric Shaff, and thanks for the question, Joe . Regarding Palforzia, as you mentioned, we announced that we've put Palforzia up for strategic review. It is a product that basically has performed lower than we expected. It's a smaller size opportunity, and it's a single product within allergy and hence our decision. Now, of course, GI is very different. We're very committed to gastrointestinal opportunity, and we have a very strong footprint already with an existing product that's performing well, as I mentioned. The team is very excited to bring SER-109 to market. We see significant synergies to drive the performance. We're very excited to be part of the microbiome innovation and therapeutics.
We believe also that nutrition has an important component to play, hence our big involvement. We really are looking forward to keep learning about microbiome science.
Perfect. Thank you both. Very helpful.
Thanks for the question, Joe.
Our next question comes from the line of Ted Tenthoff from Piper Sandler. Please proceed.
Great. Good morning. Thanks very much. I enjoyed the presentation. Very thorough, as always. My question's for Dr. Crawford. I really appreciated your answer to the last question with respect to kinda where you would use this. You mentioned in your comments that you don't really know which patients are likely to recur. Is there any work that you're looking at or seeing or anything that the company is doing to potentially generate biomarkers that may start to give us a clue of who's at higher risk to recur? Thank you very much.
Mr. Tenthoff, thank you for that question again. There are some clinical predictors of who we think are at risk for recurrences. The biggest group are those individuals that are over the age of 65, and with each decade of life over that, they're at a higher risk for having recurrences. Individuals that are gonna require multiple doses of antibiotics with time are at higher risk. Individuals that are immunosuppressed, whether it's pharmacologically or natively immunosuppressed, will be at increased risk for having these recurrences. You can look at an individual's medical history and determine, you know, who's at risk for a recurrence. The harder thing to predict is that initial first case of C. difficile infection.
Not everyone who gets exposure to antibiotics will develop an infection, and I think that's where we have the harder, you know, the harder, you know, game to play. We do know that if you look at all of the individuals that are exposed to antibiotics, many of them will just develop diarrhea, but it's only about 20% of those individuals that get the diarrhea from antibiotics that will get a C. difficile infection. I would say any individual that's over 65 immunosuppressed are probably gonna be at a higher risk for a C. difficile infection. I'd be looking at them.
There are some biomarkers that we could take a look at, such as the microbiome after antibiotic exposure and see which individuals are depleted from Firmicutes or Bacteroidetes, but we don't have those tests yet, mainly because the population of those that get antibiotics are so large. To be able to screen every single person that gets an antibiotic is sometimes not feasible. It's just too large of a number with the amount of prescriptions that we send out.
Fair enough. Excellent. This, again, really helpful. Great event today. This is gonna be an important therapy launch next year. Thanks for the time.
Thank you for the question, Ted.
Our next question comes from the line of Mark Breidenbach from Oppenheimer. Please proceed.
Hey. Good morning, and thanks for this presentation and thanks for taking our questions. Just a couple that are probably both aimed at Dr. Crawford. I'm wondering how the recent FDA-issued warnings on FMT have impacted how you're treating patients. I guess, or is FMT still being performed at your clinic? Are you seeing any potential advantages that FMT or FMT-like products like REBYOTA might hold over a product like SER-109? The second question is really what fraction of your patients would you say have severe enough symptoms to justify prescribing SER-109 under medical exception? Thanks for taking the questions.
Thank you, Mr. Breidenbach. I'll ask you about that second question, probably again, I'll answer the first one. Currently, we still are performing FMTs, and we are doing this through OpenBiome, which is a bank here in Boston. We don't use directed donors. The reason is that we do have a large population that has, you know, multiple recurrences of C. difficile infection. Now, there's a difference between this product and REBYOTA. REBYOTA was FDA approved, you know, not too long ago, like within the last week or so, probably last week. They use what I would refer to as full-spectrum stool or whole stool, and that has the entire complement of all the microorganisms that are inside of your gastrointestinal tract, for instance. It has all the viruses, bacteria, fungi, yeast, protozoa, everything.
It is a shotgun approach to approaching this disease because it gives you everything and more in order to prevent a C. difficile infection. Seres is unique because they were able to take the phyla or one particular niche of bacteria and find that it's capable alone by itself of preventing recurrences of C. difficile infection. I'm just gonna use a poor man's, you know, thought approach to this. If you took stool and you dipped it in acid, you dipped it in alcohol, you wiped out everything else, and all you had were just specific spores, that's what you're giving back. A lot of the other potential pathogens have been killed off.
When I have to, you know, think about the landscape of what do I wanna give my patient that's the safest thing, I do have worries about using full spectrum or whole stool. I would prefer to treat a specific disease that has a specific pathophysiology which works the best for that thing. We get into precision treatment or precision medicine when we move to the Seres product, when we wanna treat an individual that has a C. difficile infection. Now, of course, you know, no therapy is 100% effective, and it may be the case if I had a patient that was treated with a Seres product and they failed, I may then move over to the next thing, which would be a REBYOTA. I don't think that a landscape needs to have one particular therapy.
I think there are gonna be individuals that need to have access to multiple different forms of a therapy for whatever reason. To be able to have these options as a clinician is something that's great. I'm glad that the FDA was able to approve a product that has everything in it because now it makes it easier, in my opinion, to pick out the specific thing that you really need. You just are giving an individual the minimum amount that they need with the least amount of risk, and it has a high degree of efficacy. The second question I said I was gonna get back to you, so you could repeat that one for me.
Yeah. It's just really, a question about, you know, if there's extra paperwork involved in terms of prescribing SER-109 under medical exception. You know, would that kind of limit the fraction of your patients that you'd wanna give this drug to or would you still kind of aim for even patients in first recurrence?
No. I think, you know, the way we're able to use FMTs is that we are using the FDA's enforcement discretion, so we are trying to, you know, adhere as much as possible to what they mandate. We do look for those individuals that have had a second recurrence currently. It would be ideal if we could move the way we use FMT to the first recurrence. However, there are some stipulations through, you know, the American College of Gastroenterology, where it is recommended that someone that's failing therapy or someone that has severe disease can have access to this. From my opinion, knowing what the pathophysiology of this disease is and working at an academic center, I force myself to do what's the best thing for the patient, which is trying to push for it.
Using my hospital resources, you know, my nurses, my staff, to really push for getting my patients the best treatment that there is. With time, as long as institutions like, you know, mine as well as others, you know, up here in Boston or wherever are pushing for this, it's gonna become the mainstay of treatment. We as early adopters, you know, will be pushing for this kind of therapy for our patients because it is the correct thing to do for them. In the past, we were using multiple rounds of antibiotics and patients kept coming back. There's that phrase, and I forget who coined it. It comes from like a dystopian novel, but doing the same thing over and over again and expecting a different result is the definition of madness.
That's what we've been doing for the last 20 years when this particular scourge of C. difficile, you know, came to North America. You know, at this point, we know what the right thing to do to break recurrences. We just have to do it. It's only the right thing to do for our patients.
All right. Thank you.
Sure.
Our next question comes from the line of Chris Howerton from Jefferies. Please proceed.
Hey there. Thank you so much for taking the questions. I think, mine are for Terri, if I may. On slide 39, I guess, you know, very helpful to segment out the patient population by their disposition. I guess I'm wondering if you have any insights yet, Terri, of what the payer coverage might look like for these different patient populations. The other one is just more of like a curiosity, you know, on your discussion around the epidemiology and the trends that you did on slide 34. Just wondering how you accounted for the impact of the pandemic on kind of your longer term projections. Thank you.
Sure.
Sure, Chris.
Your first question was around payer coverage of the population that we're focusing on at launch. Honestly, I think you can just apply the payer mix that we have in a subsequent slide to that population. There may be a bit more kind of leaning toward commercial. There may be a bit more commercial there, right, because this is the outpatient population. Knowing what we know about this disease and what Dr. Crawford shared, you know, it's no great stretch to imagine that a lot of the older patients are more brittle. They probably are in this inpatient to inpatient segment, the 25%. That's probably over-indexing to Medicare and the two segments we're focusing on, the complete treatment in the outpatient setting, you could imagine they're more over-indexed to commercial.
That, that's sort of how I see the channel mix. In terms of coverage, I referenced the PBMs in our, in my prepared remarks. You know, those basically control about 80%. There are three of them, three big ones that control 80% of commercial lives. Our goal is to get broad coverage with these payers. I think I've mentioned on previous calls that we deployed the Nestlé payer field team, in the spring of this year, and they have been educating payers not only on the role of the microbiome, but on the profile of SER-109. Those discussions have been very well received. Payers recognize the challenges that with current standard of care in this disease and the ultimate burden to the healthcare system that causes.
We have currently, using that payer field team, spoken with over 75% of commercial lives. Payers, the payer groups and the health plans representing 75% of commercial and Medicare lives to date this year. I feel like we've made really good progress in our engagement there. You know, we're marching toward launch. Once we're approved, we will deploy our payer field team at that point to make sure that SER-109 is in the workflow with the various payers and getting reviewed as quickly as possible. Your second question was around the impact of COVID on the patient population. You know, I would say that initially when we spoke to physicians, and it might actually be useful to have Dr.
Crawford see, you know, share what he saw in his practice, but, you know, you would think that you would have seen a dip and maybe further decreases, right, in these infection rates. We, you know, we are seeing that, right, in the rates that the CDC reported, the dip to 3%. We think that is more largely driven by the antibiotic stewardship initiatives that are taking hold. As I mentioned, 95% of hospitals have adopted the CDC's recommendations. Dr. Crawford, it'd be useful to have a real world perspective on the, on the impact of COVID. You know, I think all of us can see in the real world that impact is kind of in the rearview mirror with healthcare utilization these days.
I think we did see an initial dip in the amount of C. difficile infections in the hospital, you know, during COVID, but not on the outpatient, on the outpatient side. Mainly, you know, the reduction was probably because there wasn't a lot of individuals entering inside of the patient rooms. Antibiotic stewardship teams were on top of those patients. You had hand hygiene that was strictly adhered to. There was gowning and gloving out the wazoo. People were going into these rooms with hazmat suits on. The amount of infection control in the hospitals were at a all-time high, and they were extremely adherent. Over the next couple years, I can imagine that people will not be, you know, as, you know, adherent to all of these infection guidelines.
Then you will see a slight tick, you know, up in C. difficile infections again. We also have to remember that a number of these cases aren't happening inside of the hospitals. Like, we think of C. difficile infection as a hospital-borne disease. If you look at the growing epidemiology, a majority of individuals are in the outpatient setting and outside of hospitals, like skilled nursing facilities, nursing homes, et cetera. They're coming into the hospital with, you know, either having gotten symptomatic infection on the outpatient side, or they may be coming into the hospital that's colonizing, getting their infection there. That latter is not as large as we once traditionally thought.
Okay, that's really helpful. Thank you so much.
Thanks for the question, Chris.
Our final question comes from the line of Vernon Bernardino from H.C. Wainwright. Please proceed.
Hi, everyone. Thanks for taking my questions, and thanks for holding this event. This question perhaps is a follow-up for Dr. Crawford, and maybe some also insights from Lisa and Terri. Dr. Crawford, you mentioned the high probability of recurrence, greater than 20%. It's usually 1-2 weeks after completion of antibiotic therapy. Just wondering what you have seen as far as those recurrences when they have occurred. Usually 1-2 weeks is a rather I guess, a more general term. Just wondering what you've seen there or what you've seen in the literature as to when those recurrences occurred, whether it's the first or second, and you know, whether Lisa and Terri, you've seen that.
Also as a follow-up, you know, the goal is to have SER-109 be administered in a tight window, and that's 10-21 days after the antibiotic regimen has occurred. Dr. Crawford, just wondering what opinion you may have as far as the administration of SER-109 in that tight window and as it might relate to the fact that an antibiotic regimen might require 10-21 days. Thank you.
Sure. Bernardino, is that correct? Okay.
Yeah.
In terms of these recurrences, you know, most recurrences will happen within the first, you know, 30 days, you know, or so. If you think about, you know, why that typically happens is you can break down recurrences into two forms. One is a relapse, meaning that an individual has spores that are still inside of their intestinal tract, and they're just waiting to germinate again once the antibiotics have been stopped. Those relapses will happen, you know, in about 14 to 30 days because that's about how long it would take for those spores to wake up and become living organisms again that are capable of making a toxin. A majority will be these relapses.
There are some other individuals that can have a recurrence that happens, you know, 3 to 5 months, you know, after those antibiotics have been stopped, unless like amoxicillin because you had dental work or you had something, you know, for a urinary tract infection, and those we would call reinfections. An individual, after they've received an antibiotic, will treat the infection, but they also do that collateral damage to a lot of the good bacteria that's inside of the colon. Because C. difficile spores are ubiquitous and they're everywhere around us, they're like on the table surfaces, they're, you know, at the salad bars, they're in the meat that you eat at a steakhouse. You know, an individual who's susceptible that consumes these spores may end up developing a recurrence or a reinfection, you know, afterwards.
They may be cruising for a couple months and feeling fine, but they're still walking around with dysbiosis, and they're just waiting for the organism to get back into their system, and those are the delayed individuals. Knowing that there are, you know, some products that are available to break the cycle of recurrences, we or at least in my practice, I will, you know, give my patients antibiotics to bridge them until a definitive therapy, you know, can be given to them. I may extend the course of antibiotics sometimes for months until I can get an individual, you know, whether it's an antibody infusion or an FMT, we call it, like a fecal transplant, for instance. There's very few opportunities where I will say, "I know that you need a definitive therapy.
I have a date set for you, but I'm gonna stop the antibiotics short and, you know, risk a reinfection in that amount of time. I'll stop antibiotics if I think an individual will do well, but if I think that individual will not do well, I'm keeping them on that antibiotic, which is for the most part vancomycin because of its cost. Keeping an individual on vancomycin to give what's called quote, unquote, "suppressive therapy" has its risks as well because vancomycin has been associated with an antibiotic-resistant, you know, organism that we call VRE.
In those individuals, if they get an infection from that antibiotic-resistant bacteria, whether it's in the lungs or in the bloodstream or in the urine, their antibiotic choices after that are limited because those antibiotics have other kinds of side effects that can be, you know, harsh as well. Bone marrow toxicity in our individuals that have had stem cell transplants, for instance, are a group that I see, you know, this, you know, pretty much. An individual that had a renal transplant that tends to have recurrent urinary tract infections. You know, we start losing effective antibiotics for those infections if we create new ones by keeping people on antibiotics for too long.
Having a definitive therapy is great because we can get individuals off the antibiotics, we can stop doing the collateral damage and stop doing other kinds of damage that we don't know that we're doing as yet because this microbiome space is extremely interesting. There are a number of associated diseases with the microbiome. We never, you know, thought that your gut microbiome could be associated with neurologic diseases, metabolic diseases. We're doing a lot of tinkering with this collateral damage and at some point, we have to use, you know, what science is telling us on, you know, how we can treat a disease the correct way and spare us from developing other kinds of, you know, diseases in the future.
Thank you.
I hope.
Your insights are important and very, helpful. Thank you.
We do have a final question from the line of Joshua Chazaro from Canaccord Genuity. Please proceed.
Hi, good morning. This is Joshua on for John Newman. Thanks so much for taking my question. Thanks for the very informative presentation. Two quick questions. One on slide 39. This is for the Seres team. Could we confirm that the number of proportion, the proportion percentage that we're seeing are for recurrent C. diff as opposed to primary C. diff infections? Then a question for Dr. Crawford. In your experience, what do you think would be like a rough estimate of percentage of C. diff infections that are seen by gastroenterologists as opposed to hospitalists? Thank you.
Why don't we ask Terri to answer the first question, then we'll ask Dr. Crawford to answer the second.
Short answer, yes, it's recurrent C. diff. These are recurrent C. diff patients.
Very efficient. All right, Dr. Crawford.
Your question was the proportion of recurrent C. difficile patients that are seen by gastroenterologists versus hospitalists?
Correct.
I would say, you know, a large proportion of those individuals that are seeing C. diff, you know, will comprise gastroenterologists as well as internists and infectious disease specialists on the outpatient setting. I would say it's a smaller percentage, probably about 20%-30% that are seeing the C. difficile infections in the hospital. All of those individuals that are seen in the hospital are being treated to suppress their active disease, and they're gonna be discharged likely on antibiotic therapy to follow up with either the infectious disease provider, the internist or the gastroenterologist.
Great. Thank you.
I think we are at time. Before we conclude, I just wanna thank again Dr. Crawford for spending time with us and sharing his perspective as well as Greg for sharing his perspective. We look forward to keeping everyone updated on our progress. With that, we'll conclude the call. Thanks very much for the time this morning and hope everyone has a great week.
Thank you, ladies and gentlemen. This does conclude today's call. Thank you for your participation. You may now disconnect.