Spero Therapeutics (SPRO) soars 17.37% on positive trial results, partnerships

Spero Therapeutics (SPRO) shares soared 17.37% today, reaching their highest level since September 2022, with an intraday gain of 31.46%.

The strategy of buying SPRO shares after they reached a recent high and holding for 1 week yielded moderate returns over the past 5 years, with a 7.56% annualized return and a 37.12% overall return. However, the strategy underperformed the market, as evidenced by the 14.56% annualized return and 64.89% overall return of the SPY ETF over the same period. The results suggest that while the strategy captured some of the subsequent momentum, it did not keep pace with broader market performance.

Spero Therapeutics has seen significant stock price movements recently due to a series of positive developments. On May 28, 2025, the company's stock surged following the successful completion of a promising trial. This trial was part of a collaboration with GSK and involved an oral drug for treating complicated urinary tract infections (cUTI). The drug achieved its Phase III goal early, paving the way for an FDA filing and potential shifts in treatment options.

Additionally, on May 29, Spero Therapeutics announced partnerships with major pharmaceutical firms to leverage their antibiotic platforms. These strategic alliances have further intensified interest in the company’s growth potential, capturing investors’ imaginations and suggesting a promising trajectory for Spero’s future market presence.