Spero Therapeutics, Inc. 10-K — AI Bull & Bear Analysis

The 10-K filing reveals a company in a high-stakes transition. Spero has successfully cleaned up its balance sheet and clinical portfolio, moving from a speculative research shop to a focused regulatory play. The conclusion of the SEC investigation in January 2026 further removes a significant governance overhang, leaving the June 18, 2026 PDUFA date as the primary driver of value. Investors are essentially weighing a fortress-like runway against a binary regulatory event. While the financial flip to profitability is an encouraging signal of discipline, the lack of recurring revenue means Spero is still a 'lottery ticket' stock. The ultimate outcome depends on whether the FDA accepts the PIVOT-PO data and whether GSK can effectively penetrate the competitive cUTI market.