Welcome to our dedicated page for Spero Therapeuti SEC filings (Ticker: SPRO), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Spero Therapeutics, Inc. filings document the regulatory record of a Nasdaq-listed clinical-stage biopharmaceutical company developing treatments for rare diseases and multi-drug resistant bacterial infections. Form 8-K reports cover operating results, Regulation FD investor presentations, tebipenem HBr business updates, compensatory arrangements, board changes, and other material events.
Proxy materials describe director elections, annual meeting votes, executive compensation, board committees, and stock incentive plan matters. The filing record also identifies the company’s common stock, par value and exchange listing, and records governance and regulatory matters including the reported conclusion of a previously disclosed SEC investigation without a recommended enforcement action.
Spero Therapeutics reported a smaller quarterly loss as it continued shifting its business toward the tebipenem HBr program partnered with GSK. For the three months ended March 31, 2026, total revenue was $0.3 million, down from $5.9 million a year earlier, mainly due to lower collaboration revenue from GSK as performance obligations were completed.
Research and development expense fell to $2.9 million from $13.6 million, and general and administrative expense declined to $4.9 million, reducing the net loss to $7.2 million, or $0.13 per share. Operating cash flow turned positive, providing $15.9 million, largely from collection of GSK collaboration receivables.
The company ended the quarter with $56.1 million in cash and cash equivalents and stockholders’ equity of $52.9 million. Management expects this cash to fund operations for at least 12 months from the financial statement issuance date but anticipates needing additional capital to develop any future product candidates. Spero’s prospects now largely depend on tebipenem HBr, where a Phase 3 trial met its primary endpoint and GSK’s resubmitted NDA has a PDUFA date of June 18, 2026.
Spero Therapeutics reported first quarter 2026 results and updated progress on its tebipenem HBr antibiotic program. Revenue was $258,000, down from $5.874 million a year earlier, reflecting lower grant and collaboration revenue. Operating expenses fell sharply to $7.796 million from $20.605 million, leading to a narrower net loss of $7.203 million versus $13.866 million in 2025. Cash and cash equivalents increased to $56.129 million at March 31, 2026, compared with $40.265 million at year-end 2025, and the company estimates this will fund operations into 2028. Management highlighted continued work with GSK on tebipenem HBr for complicated urinary tract infections and noted an FDA PDUFA decision date of June 18, 2026, which could determine whether tebipenem HBr becomes the first oral carbapenem antibiotic for U.S. cUTI patients.
Spero Therapeutics, Inc. officer Rajavelu Esther reported an automatic sale of common stock tied to tax withholding on vested restricted stock units. On May 4, 2026, 25,240 shares were sold at $2.51 per share to fund a “sell to cover” tax obligation rather than a discretionary trade. After this transaction, Esther directly owned 986,851 shares of Spero Therapeutics common stock.
Spero Therapeutics is asking stockholders to vote at its 2026 virtual annual meeting on June 23, 2026. The meeting will be held via live audio webcast, with holders of common stock as of April 24, 2026 entitled to vote.
Key items include electing two directors, ratifying PricewaterhouseCoopers LLP as auditor for 2026, an advisory vote on executive compensation, doubling authorized common stock from 120,000,000 to 240,000,000 shares, and approving the 2026 Stock Incentive Plan. As of the record date, 57,901,493 common shares were outstanding. The proxy also details board structure, committee responsibilities, insider ownership and comprehensive 2024–2025 compensation and severance arrangements for senior executives and directors.
Spero Therapeutics, Inc. is soliciting proxies for its 2026 annual meeting to be held virtually at 9:00 a.m. ET on June 23, 2026. The Board asks stockholders to elect two directors; ratify PwC as auditor; approve executive compensation (advisory); approve an amendment to increase authorized common stock from 120,000,000 to 240,000,000 shares; and adopt the 2026 Stock Incentive Plan.
Holders of record as of April 24, 2026 may vote. The proxy materials, including the 2025 Annual Report on Form 10-K, will be delivered under the SEC notice-and-access process.
Spero Therapeutics reported a strong turnaround for 2025, moving from a net loss in 2024 to net income. Total revenues rose to $66.8M for the year ended December 31, 2025, up from $48.0M, driven mainly by collaboration revenue, including from its tebipenem HBr partnership with GSK.
Full-year research and development expense fell to $38.5M from $96.8M, while general and administrative costs declined modestly to $21.2M. Net income attributable to common shareholders was $8.6M for 2025 versus a $68.6M loss in 2024, and fourth quarter diluted EPS reached $0.53.
Cash, cash equivalents and marketable securities were $40.3M as of December 31, 2025, and Spero estimates this will fund operations into 2028. Operationally, the company completed the global phase 3 trial of tebipenem HBr in cUTI, resubmitted its NDA, and highlighted an FDA PDUFA decision date of June 18, 2026.
Spero Therapeutics’ annual report centers on its pivot to a single lead asset, tebipenem HBr, for complicated urinary tract infections. Tebipenem is partnered with GSK, has completed a pivotal Phase 3 trial that met its primary endpoint, and is under FDA review with a PDUFA date of June 18, 2026.
The company has ceased development of SPR206 and SPR720 to focus resources on supporting GSK and exploring new clinical‑stage assets. The GSK license provides milestone potential exceeding $300.0 million plus tiered royalties, but Spero remains dependent on tebipenem’s regulatory and commercial success and has not generated product sales.
Spero Therapeutics officer Esther Rajavelu reported automatic sales of Spero Therapeutics common stock to cover taxes from restricted stock unit (RSU) vesting. On February 6, 2026, she sold 37,101 shares and 50,816 shares, each at $2.36 per share, in sell-to-cover transactions that were not discretionary trades. After these tax-related sales, she directly beneficially owned 1,012,091 Spero Therapeutics shares.
Spero Therapeutics Chief Operating Officer Timothy Keutzer reported an automatic sale of common stock tied to tax obligations. On 02/06/2026, 18,652 shares of common stock were sold at $2.36 per share to cover tax withholding arising from restricted stock unit (RSU) vesting.
After this transaction, Keutzer beneficially owned 742,506 shares of Spero Therapeutics common stock in direct form. The filing explains that the sale was a mandatory "sell to cover" transaction to fund taxes and was not a discretionary trade by the executive.