We are investigating Spero Therapeutics, Inc. (SPRO) (“Spero” or the “Company”) for potential violations of the federal securities laws. In November 2017, Spero conducted its initial public offering (“IPO”), selling 5,500,000 shares of common stock priced at $14.00 per share. Then, on May 8, 2020, Spero issued a press release announcing the Company’s financial and operating results for the first quarter of 2020. Among other results, Spero reported $1.7 million in total revenue for the quarter, compared with revenues of $7.7 million for the same period in the prior year, and $20.4 million in research and development (“R&D”) expenses, compared with $9.5 million in R&D expenses for the same period in the prior year. Spero attributed the revenue decrease “to lower funding for tebipenem HBr received under Spero’s BARDA contract due to the timing of qualified tebipenem HBr expenses incurred in the quarter, and lower collaboration revenue as the first quarter of 2019 included a $3 million upfront fee associated with Spero’s License Agreement with Everest Medicines entered into during January 2019.” With respect to the increase in R&D expenses, Spero cited “greater spending on the tebipenem HBr program”. On this news, Spero’s stock price fell $0.40 per share, or 3.28%, to close at $11.78 per share on May 8, 2020.