Seres Therapeutics Overview - Seres' VOWST, the first-ever oral live microbiome therapeutic, received FDA approval in April 2023 for preventing C difficile infection recurrence, demonstrating approximately 88% sustained clinical response rate[6,9] - The sale of the VOWST asset, completed in September 2024, provided Seres with capital to support pipeline advancement and streamline the organization[9,10] - As of June 30, 2025, Seres had approximately $45.4 million in cash and cash equivalents, projecting a cash runway into Q1 2026[92] SER-155 Clinical Development - SER-155 Phase 1b data in allo-HSCT showed a 77% relative risk reduction in bacterial bloodstream infections (BSIs) compared to placebo[6,45,92] - SER-155 Phase 1b data also showed significantly lower mean cumulative exposure to systemic antibacterials/antimycotics compared to placebo (9.2 days vs 21.1 days)[45,50] - SER-155 Phase 1b data also showed a lower incidence rate of febrile neutropenia in SER-155-treated subjects vs placebo[46] - A Phase 2 study protocol for SER-155 in allo-HSCT was submitted to the FDA in May 2025, with study commencement dependent on funding and aiming to enroll 248 patients[6,31,78] Pipeline and Future Opportunities - Seres is developing SER-147 to prevent infections in chronic liver disease patients, with preclinical data showing a 1-3 log reduction of E coli in in vitro models[6,80] - Seres is also developing SER-603 to target inflammatory drivers of Inflammatory Bowel Disease (IBD)[83] - Seres is engaging with multiple parties regarding various deal structures to secure capital for the clinical advancement of SER-155 and other live biotherapeutic product candidates[6,78,92]

SER-155 Clinical Data and Development - SER-155 Phase 1b study showed a 77% relative risk reduction in bacterial bloodstream infections (BSIs) compared to placebo[6,44,83] - SER-155 treatment was associated with significantly lower mean cumulative exposure to systemic antibacterials/antimycotics compared to placebo[44,49] - The company plans to submit a Phase 2 protocol to the FDA in Q2 2025, incorporating FDA feedback[6,31,73,83] - The FDA granted SER-155 Breakthrough Therapy designation in December 2024[6,73,82] Financial Position and Strategy - The VOWST asset sale to Nestlé closed in September 2024, providing capital to support SER-155 advancement[6,9,10,12,83] - The VOWST asset sale included a $100 million upfront payment, less ~$20 million in net obligations, a $15 million equity investment, and a $60 million prepaid sales-based milestone at closing[10] - As of March 31, 2025, the company had approximately $588 million in cash/cash equivalents, projecting a cash runway into Q1 2026[83] - The company is pursuing a strategic partnership for SER-155 to accelerate the next study in allo-HSCT and expand to multiple target populations[6,73,83] Pipeline and Platform - VOWST was FDA approved in April 2023 to prevent the recurrence of C difficile infection in adults, demonstrating an approximately 88% sustained clinical response rate[6,9] - SER-155 is being developed initially in allo-HSCT, with potential to expand to autologous-HSCT, blood cancers, and CAR-T recipients[6,30] - SER-147 is designed to prevent infections in chronic liver disease, with IND-enabling activities underway[6,30,74,82]

Financial Data and Key Metrics Changes - Seres reported a net loss from continuing operations of $15.7 million for Q4 2024, compared to a net loss of $34.7 million for the same period in 2023, indicating a significant improvement [49] - For the full year 2024, the net loss from continuing operations was $125.8 million, down from $190.1 million in 2023, primarily due to lower operating expenses of approximately $74 million [49] - Research and development (R&D) expenses for Q4 2024 were $12.8 million, down from $23 million in Q4 2023, reflecting a focus on the lead program SER-155 [51] - General and administrative (G&A) expenses for Q4 2024 were $12.5 million, compared to $14 million in Q4 2023, also showing cost management efforts [52] Business Line Data and Key Metrics Changes - The company has made substantial progress with SER-155, a biotherapeutic aimed at preventing bloodstream infections in allo-HSCT patients, showing a 77% relative risk reduction in bloodstream infection rates in a Phase 1b study [10][23] - Manufacturing services expenses were introduced as a new category in 2024, amounting to $3.5 million for Q4 2024, related to services under the transition agreement with Nestle [53] Market Data and Key Metrics Changes - The commercial opportunity in allo-HSCT alone is considered sizable, with approximately 9,300 procedures conducted annually in the US and around 20,000 in Europe [43] - Market research indicates a high unmet need for preventing bacterial bloodstream infections, with healthcare professionals and payers expressing a desire for better prophylactic options [40][41] Company Strategy and Development Direction - The company is focused on advancing SER-155 and exploring partnerships to maximize its potential, with plans to submit a draft study protocol to the FDA in Q2 2025 [21][56] - SER-155 is positioned to address not only allo-HSCT but also other medically vulnerable patient populations, including those with inflammatory bowel disease [35][61] Management's Comments on Operating Environment and Future Outlook - Management expressed optimism about the progress made with SER-155, highlighting the breakthrough therapy designation received from the FDA and the constructive feedback from the agency [58] - The company aims to operationally prepare for the next study of SER-155 while seeking additional guidance from the FDA [15][19] Other Important Information - The VOWST sale transaction closed in September 2024, providing Seres with $155 million, which has allowed the company to retire its debt and simplify operations [46][48] - The company expects to fund operations into Q1 2026 based on its current cash position and anticipated payments from the VOWST transaction [55] Q&A Session Summary Question: Feedback from the FDA regarding manufacturing and patient enrollment - Management indicated that the FDA's feedback was comprehensive and that they are confident in their manufacturing plans moving forward [67][75] Question: Recent FDA feedback relative to expectations and Phase 2/3 study differences - Management found the FDA's feedback constructive and noted that a Phase 2/3 study would require more pre-specification and discussions with the agency [80][83] Question: Safety database considerations based on VOWST experience - Management acknowledged the importance of the safety database and indicated that discussions with the FDA would evolve as more data is generated [88][92] Question: Potential size of the next study and additional efficacy endpoints - Management suggested that a standalone Phase 2 study could provide meaningful data quickly, with additional endpoints including febrile neutropenia and antibiotic use being considered [100][102]