Spero Therapeutics (SPRO) Earnings Turn Positive Challenging Bearish Profitability Narratives

Spero Therapeutics (SPRO) closed FY 2025 with fourth quarter revenue of US$41.3 million and basic EPS of US$0.56, alongside trailing twelve month revenue of US$66.8 million and EPS of roughly US$0.15 that mark a shift into profitability over the period. Over recent quarters, the company has seen revenue range from US$5.4 million to US$41.3 million with quarterly EPS moving from a loss of about US$0.25 per share at the start of FY 2025 to a profit in the latest quarter, providing a clearer picture of how the income statement has progressed through the year. Now that positive earnings are reflected in the trailing figures, the key question this quarter is how durable those margins prove to be as the business scales.

See our full analysis for Spero Therapeutics.

With the latest numbers on the table, the next step is to compare these results with the most widely held narratives about Spero Therapeutics and assess which storylines hold up and which may need a rethink.

See what the community is saying about Spero Therapeutics

Profitability holds in the trailing 12 months

• On a trailing 12 month basis to Q4 2025, Spero reported US$66.8 million in revenue and US$8.6 million in net income, which supports the move to basic EPS of about US$0.15 and is being described as high earnings quality.
• Consensus narrative highlights future revenue potential from Tebipenem HBr and partnership milestones. This trailing profitability provides a factual anchor:
  • Analysts talk about Tebipenem HBr and partner funding reducing fixed costs, while the last 12 months already show the income statement moving from a net loss of US$69.8 million in the prior trailing period to a net profit of US$8.6 million.
  • That shift lines up with the bullish idea that cost sharing and late stage progress can support margins, even though the narrative also flags heavy reliance on a single drug and partner as a key risk if those milestones or approvals do not play out as expected.

Bulls point to the swing to US$8.6 million in trailing net income and high earnings quality as early evidence that the Tebipenem HBr story can translate into real profits, while still needing milestones and approvals to keep that going long term. 🐂 Spero Therapeutics Bull Case

P/E of 15.3x versus market and biotech peers

• The trailing P/E of 15.3x sits below the US market average of 18.4x and slightly below the US biotechs industry average of 15.6x, so investors are paying a lower multiple than the wider market for a company that has just turned profitable.
• Critics in the bearish narrative focus on concentration risk and funding needs, and the current valuation multiples sit against those concerns:
  • Bears highlight dependence on Tebipenem HBr and a single commercialization partner, and point out that analyst assumptions require the company to trade on a P/E of 129.1x to support a US$4.00 price target, which is far above both the current 15.3x and the industry average of 15.5x referenced in the narrative.
  • They also underline that analysts see revenue falling by 33.4% per year over the next 3 years in their model, which contrasts with the trailing period where revenue is US$66.8 million and earnings are positive, making the current multiple look tied more to what has already been achieved than to those modeled future declines.

Skeptics argue that relying on one key asset and partner plus modeled revenue declines makes the 129.1x implied future P/E behind the US$4.00 price target hard to justify against today’s 15.3x trailing P/E and US$2.33 share price. 🐻 Spero Therapeutics Bear Case

Five year earnings growth of 30.5% a year

• Over the last five years Spero’s earnings are reported to have grown by 30.5% per year, culminating in the latest trailing 12 month net income of US$8.6 million and basic EPS of about US$0.15, after a period that previously included losses as large as US$69.8 million on a trailing basis.
• Consensus narrative connects that long run earnings improvement to pipeline and regulatory drivers, while the numbers show both support and pressure points:
  • The view that late stage results, partner backing and regulatory support can help margins is consistent with the company moving from a net loss of US$20.9 million in Q4 2024 to net income of US$31.5 million in Q4 2025 on revenue of US$41.3 million.
  • At the same time, the narrative flags that SPR720 missed its primary endpoint in Phase IIa with safety concerns and that the business relies heavily on Tebipenem HBr, which means this 30.5% annualized earnings growth rate has been achieved with a concentrated pipeline that could be sensitive to any setback in that lead asset.

Next Steps

To see how these results tie into long-term growth, risks, and valuation, check out the full range of community narratives for Spero Therapeutics on Simply Wall St. Add the company to your watchlist or portfolio so you'll be alerted when the story evolves.

With sentiment split between recent profitability and ongoing risks, now is a good time to look through the numbers yourself and test the narratives on both sides. To see how the potential upsides and concerns line up in one place, check out the 2 key rewards and 1 important warning sign.

See What Else Is Out There

Spero Therapeutics relies heavily on a single lead asset and partner, with analyst models pointing to steeply modeled revenue declines and a stretched target P/E.

If that concentration and earnings uncertainty feels uncomfortable, widen your options by checking companies in the 67 resilient stocks with low risk scores that prioritise resilience and more balanced risk profiles.

This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.

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