Seres Therapeutics (MCRB) investor relations material

Executive summary

• Focused on developing novel live biotherapeutic products for medically vulnerable populations, with a pipeline including SER-155, SER-603, SER-428, and SER-147.

• Approaching a key clinical milestone with imminent data from the SER-155 study in immune checkpoint inhibitor-related enterocolitis (irEC).

• Successfully developed and sold VOWST, the first FDA-approved oral microbiome therapeutic, to Nestlé Health Science in September 2024.

• Operational focus on advancing live biotherapeutic programs in inflammatory and immune diseases, including SER-155 and SER-603.

• Implemented cost reduction actions, including a 30% workforce reduction in February 2026, to extend cash runway.

Financial highlights

• Net loss of $19.9 million for Q1 2026, compared to net income of $32.7 million in Q1 2025, primarily due to the absence of one-time gains from the VOWST sale.

• Total revenue was $0.4 million, derived from CARB-X grant reimbursement.

• Research and development expenses increased to $13.2 million, while general and administrative expenses decreased to $8.1 million year-over-year.

• Cash and cash equivalents totaled $29.8 million as of March 31, 2026, with a runway expected through Q3 2026.

• Operating expenses were approximately $6 million lower year-over-year.

Outlook and guidance

• Additional funding required following Q3 2026 to support ongoing operations and advance clinical programs.

• Clinical data from the SER-155 irEC study expected in the coming weeks, potentially informing further development.

• Actively seeking business development transactions or partnerships to support SER-155 and pipeline advancement.

• IND-enabling activities for SER-603 ongoing, with efforts to secure collaborators.

• Expenses expected to increase if clinical development resumes; cost containment measures in place.