Seres Therapeutics, Inc. SEC Filings

Seres Therapeutics, Inc. reported that officer Thomas DesRosier received a grant of stock options covering 7,500 shares of common stock at an exercise price of $9.13 per share. The options expire on March 3, 2036. According to the vesting schedule, 25% of the shares vest on March 2, 2027, with the remaining shares vesting in 12 equal quarterly installments thereafter.

Seres Therapeutics, Inc. reported results of its 2026 Annual Meeting of Stockholders, where all proposals were approved after the meeting was reconvened due to an earlier lack of quorum. Stockholders approved an amendment and restatement of the 2025 Incentive Award Plan, increasing the shares of common stock available for issuance under the plan by 900,000 shares, enabling continued use of equity-based compensation.

A total of 4,985,176 shares, representing approximately 51.75% of shares outstanding as of the April 13, 2026 record date, were represented in person or by proxy. Three Class II directors were elected to serve until the 2029 Annual Meeting, the appointment of PricewaterhouseCoopers LLP as independent auditor for 2026 was ratified, executive compensation was approved on an advisory basis, and an adjournment proposal was approved but ultimately not needed.

Seres Therapeutics reported early clinical data showing promising activity for its live biotherapeutic SER-155 in immune checkpoint inhibitor-related enterocolitis (irEC). In an investigator-sponsored trial at Memorial Sloan Kettering, 80% of 15 patients achieved an immunosuppressive-free clinical response of diarrhea by Day 15, and 33% reached complete remission, with SER-155 generally well tolerated and no drug-related serious adverse events.

The company also highlighted prior Phase 1b allo-HCT results where SER-155 was associated with a 77% relative risk reduction in bacterial bloodstream infections (10% vs 43% on placebo) and significant reductions in systemic antibiotic use. Seres is positioning SER-155 for both irEC and allo-HCT, advancing SER-603 for inflammatory bowel disease and preclinical candidate SER-147 for cirrhosis-related infections. The company reported approximately $29 million in cash and cash equivalents as of March 31, 2026, expects its cash runway to extend into Q1 2027, and has agreed to receive $25 million from Nestlé Health Science in 2026 to buy out future VOWST sales-based milestones, while actively seeking additional partnerships and financing.

Seres Therapeutics director Stephen Berenson received a new stock option grant covering 7,508 shares of common stock. The option has an exercise price of $7.94 per share and was awarded as a compensation-related grant, not an open-market purchase or sale.

The option vests in four equal quarterly installments on October 1, 2026, January 1, 2027, April 1, 2027, and July 1, 2027, with the final vesting date moving to the day before the 2027 annual stockholder meeting if that meeting occurs before July 1, 2027. Vesting is conditioned on Berenson continuing to serve as a non-employee director through each vesting date.

Seres Therapeutics director grants stock options

Seres Therapeutics, Inc. director Robert L. Rosiello received a grant of stock options covering 7,508 shares of common stock at an exercise price of $7.94 per share. These options were awarded as compensation rather than purchased on the open market.

The options vest in four equal quarterly installments on October 1, 2026, January 1, 2027, April 1, 2027, and July 1, 2027, with the final installment vesting earlier if the 2027 annual stockholder meeting occurs before July 1, 2027, subject to his continued service on the board as a non-employee director.

Seres Therapeutics director Dennis A. Ausiello received a grant of stock options covering 7,508 shares of common stock. The options have an exercise price of $7.94 per share and expire on July 1, 2036. The award vests in four equal quarterly installments on October 1, 2026, January 1, 2027, April 1, 2027, and July 1, 2027, with the final installment vesting earlier if the 2027 annual stockholder meeting occurs before July 1, 2027. Vesting requires his continued service on the board as a non-employee director through each vesting date.

Seres Therapeutics entered two agreements aimed at improving its finances and extending its operating cash runway well into the first quarter of 2027.

An amendment with Nestlé Health Science replaces potential future VOWST™ sales milestones with a one-time $25 million payment to Seres in two $12.5 million installments in July and October 2026. Separately, a lease amendment for its Cambridge facility surrenders space, lowers rent and building cost share, and is expected to reduce long-term lease obligations, partly offset by termination fees and use of an existing letter of credit.

Seres reported $29.8 million in cash and cash equivalents as of March 31, 2026 and, reflecting these actions and current plans, now expects to fund operations well into the first quarter of 2027 while advancing programs such as SER-155.

Seres Therapeutics, Inc. reported a governance change with the resignation of board member Hans-Juergen Woerle, M.D., Ph.D. On May 30, 2026, he notified the company that he would step down from the board and its committees, effective May 31, 2026. The company states that his departure is not due to any disagreement regarding operations, policies, or practices.

MCRB filing an SEC Form 144 reporting proposed and recent sales of common stock by Teresa L. Young. The notice lists $474.39 for 05/18/2026 (63 shares) and $77,966.58 for 03/17/2026 (8,553 shares). It also lists restricted stock dated 05/15/2026 described as issued by the issuer.