Release Date: March 13, 2025
For the complete transcript of the earnings call, please refer to the full earnings call transcript.
Positive Points
- Seres Therapeutics Inc (MCRB, Financial) reported a 77% relative risk reduction in bloodstream infection rates in their Phase 1b study for SER-155, indicating strong efficacy.
- The FDA granted Breakthrough Therapy designation to SER-155, highlighting the potential of the therapy and the unmet need it addresses.
- The company has received constructive feedback from the FDA, supporting the design of a Phase 2 study with a primary endpoint of reducing bloodstream infections.
- Seres Therapeutics Inc (MCRB) has secured a $155 million payment from the VOWST sale transaction, improving their financial position and allowing them to retire debt.
- The company has reduced its net loss from continuing operations significantly from the previous year, indicating improved financial management.
Negative Points
- The company is still in the process of refining the clinical study protocol for the next phase of SER-155, with no specific timeline for study initiation.
- Seres Therapeutics Inc (MCRB) continues to face uncertainties regarding the manufacturing and control processes for the next phase of SER-155 development.
- The company is seeking a partner to support the development of SER-155, indicating a need for additional resources and capabilities.
- Despite progress, the company has not yet provided specific guidance on the size or timing of the next clinical study for SER-155.
- The company reported a net loss from continuing operations of $125.8 million for the full year 2024, indicating ongoing financial challenges.
Q & A Highlights
Q: Hi there, good morning. Thank you for taking my question and best wishes to Lisa on her next step. Maybe just in terms of the feedback that you received from the FDA, it sounds like you got some feedback related to manufacturing and controls. I guess, is there anything that you'll need to implicate or do in terms of changing manufacturing between the Phase 1 and the potential Phase 2, Phase 2/3? And then second, when you think about the types of patients that would be enrolled in the next study, would you consider making any changes versus what you saw in the Phase 1?
A: Hey Joe, good morning and thanks for the question. We received comprehensive feedback from the FDA, including their suggestion that we consider the next study of SER-155 to be a Phase 2. We have not heard answers to our clarifying questions yet, but our expectation is to submit the clinical protocol as the next major step. We are considering both a standalone Phase 2 and an adaptive 2/3. We are moving forward with key critical path items to enable the next study. Regarding the patient population, we think we have the right population and will ensure we can handle variability. (Eric Shaff, President, CEO, Director; Lisa von Moltke, EVP, CMO; Chris McChalicher, SVP for Manufacturing, Quality, and Process Development)
Q: How has the recent FDA feedback and insight you have received thus far fallen relative to your expectations going into these interactions? And how would a Phase 2/3 differ from just the Phase 2 study?
A: We received Breakthrough Therapy designation at the end of last year, which suggests the FDA recognizes the unmet need and finds the initial data interesting. The feedback was constructive and comprehensive. A Phase 2/3 seamless design requires prespecifying and locking things in upfront, which can take more time and discussion with the agency. The FDA is asking for more data, which would be helpful for designing the next study. (Eric Shaff, President, CEO, Director; Lisa von Moltke, EVP, CMO)
Q: My question really has to do with the safety database. I know that, that was part of the consideration with VOWST approval. And I was wondering whether you guys have started to discuss the size of the potential safety database based on the prior experience with VOWST.
A: We are careful not to speak for the FDA, but based on our experience with VOWST, the FDA was looking for at least 300 patients in terms of exposure. The discussion on the safety database evolves as the safety profile evolves. The FDA has a minimum threshold of 300, but it varies with the population. We are pleased with what we've seen so far and expect it to continue. (Eric Shaff, President, CEO, Director; Lisa von Moltke, EVP, CMO)
Q: I wondered if you could give us any sense on the potential size of the next study for 155. Let's just assume at this point, maybe you run a Phase 2. And also, in addition to the 30-day bloodstream infection endpoint, what might be some of the other potential efficacy endpoints that you could look at?
A: If we're looking at a standalone Phase 2, we think there's an opportunity to get real data back reasonably quickly. We haven't guided on numbers, but we think we could potentially hit an interim read within 12 months of starting the study. In addition to BSIs, we'll be looking at fever during neutropenia, antibiotic use, hospitalization, ICU utilization, and GvHD rates as part of our safety assessment. (Eric Shaff, President, CEO, Director; Lisa von Moltke, EVP, CMO)
Q: How relevant is the prior experience with VOWST to the FDA's comfort with microbiome therapeutics?
A: The FDA's comfort with microbiome therapeutics is evolving. With VOWST, the FDA required exposure data for at least 300 patients. The relevance of this experience to SER-155 will depend on ongoing discussions with the FDA as we generate more data. (Eric Shaff, President, CEO, Director; Lisa von Moltke, EVP, CMO)
For the complete transcript of the earnings call, please refer to the full earnings call transcript.
