SPRO vs TBPH vs INVA vs ARWR

For growth investors, Arrowhead Pharmaceuticals, Inc.

(ARWR) is the stronger pick with 232. 6% revenue growth year-over-year, versus -53. 8% for Spero Therapeutics, Inc. (SPRO). Innoviva, Inc. (INVA) offers the better valuation at 6. 9x trailing P/E (11. 9x forward), making it the more compelling value choice. Analysts rate Spero Therapeutics, Inc. (SPRO) a "Buy" — based on 13 analyst ratings — the highest consensus in this comparison. The "better buy" depends entirely on your goals: growth investors should weight revenue trajectory, value investors should weight P/E and PEG, and income investors should weight dividend yield and streak.

On forward P/E, Spero Therapeutics, Inc.

is actually cheaper at 3. 7x — notably different from the trailing picture, reflecting expected earnings growth.

Over the past 5 years, Innoviva, Inc.

(INVA) delivered a total return of +94. 4%, compared to -81. 3% for Spero Therapeutics, Inc. (SPRO). Over 10 years, the gap is even starker: ARWR returned +1253% versus SPRO's -78. 2%. Past returns do not guarantee future results, and the stock with the higher historical return may already have its best growth priced in.

By beta (market sensitivity over 5 years), Innoviva, Inc.

(INVA) is the lower-risk stock at 0. 13β versus Arrowhead Pharmaceuticals, Inc. 's 1. 81β — meaning ARWR is approximately 1337% more volatile than INVA relative to the S&P 500. On balance sheet safety, Spero Therapeutics, Inc. (SPRO) carries a lower debt/equity ratio of 9% versus 73% for Arrowhead Pharmaceuticals, Inc. — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), Arrowhead Pharmaceuticals, Inc.

(ARWR) is pulling ahead at 232. 6% versus -53. 8% for Spero Therapeutics, Inc. (SPRO). On earnings-per-share growth, the picture is similar: Innoviva, Inc. grew EPS 816. 7% year-over-year, compared to -395. 3% for Spero Therapeutics, Inc.. Over a 3-year CAGR, SPRO leads at 150. 0% annualised revenue growth. Higher growth typically commands a higher valuation multiple — check whether the premium P/E or P/S is justified by the growth rate using the PEG ratio.

Innoviva, Inc.

(INVA) is the more profitable company, earning 63. 8% net margin versus -142. 9% for Spero Therapeutics, Inc. — meaning it keeps 63. 8% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: INVA leads at 38. 5% versus -152. 9% for SPRO. At the gross margin level — before operating expenses — TBPH leads at 100. 0%, reflecting greater pricing power or product mix advantage. Stronger margins indicate durable pricing power, lower cost of revenue, or higher mix of software/services. They are one of the clearest signs of business quality.

On forward earnings alone, Spero Therapeutics, Inc.

(SPRO) trades at 3. 7x forward P/E versus 11. 9x for Innoviva, Inc. — 8. 2x cheaper on a one-year earnings basis. Analyst consensus price targets imply the most upside for INVA: 65. 2% to $37. 67.

None of the stocks in this comparison currently pay a material dividend.

All are effectively zero-yield and should be held for capital appreciation rather than income.

For long-horizon retirement investors, Innoviva, Inc.

(INVA) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0. 13)). Both have compounded well over 10 years (INVA: +94. 9%, SPRO: -78. 2%), confirming both are viable long-term holds — but the lower-volatility option typically results in less emotional selling during corrections. Retirement portfolios generally favour predictability over maximum returns. Consult a financial advisor before making allocation decisions.

Both stocks operate in the Healthcare sector, making this a peer-level intra-sector comparison — the same macro tailwinds and headwinds will affect both.

In terms of investment character: SPRO is a small-cap quality compounder stock; TBPH is a small-cap quality compounder stock; INVA is a small-cap high-growth stock; ARWR is a mid-cap high-growth stock. These fundamental differences mean investors should not choose between them on a single metric — the "better stock" depends entirely on which of these characteristics aligns with your investment strategy.