Spero Therapeutics, Inc. 8-K

What Happened

• Spero Therapeutics, Inc. (SPRO) filed an 8-K noting two items: on January 20, 2026 the company received a letter from the U.S. Securities and Exchange Commission stating the SEC has concluded its investigation and does not intend to recommend enforcement action at this time; and on January 30, 2026 Dr. Ankit Mahadevia notified the Board of his resignation from the Board and its Development Committee, effective January 30, 2026.

Key Details

• SEC letter dated January 20, 2026 advised no enforcement recommendation based on information as of the letter; provided under guidelines of Securities Act Release No. 5310.
• Director resignation effective January 30, 2026: Dr. Ankit Mahadevia stepped down from the Board, the Development Committee, and all officer/director roles in subsidiaries.
• Resignation attributed to other professional commitments; company says it was not due to any dispute or disagreement with management or the Board.
• Company and Dr. Mahadevia intend to enter a consulting agreement to provide management support going forward.

Why It Matters

• The SEC’s decision not to recommend enforcement reduces a regulatory overhang for Spero and may remove a material source of uncertainty for investors.
• The departure of a founding board member is notable, but the planned consulting arrangement and the company’s statement of no dispute suggest continuity of institutional knowledge and limited immediate operational disruption.
• Investors should watch for any follow-up disclosures about board composition, replacement directors, or terms of the consulting agreement that could affect governance or costs.