First quarter earnings shift draws fresh attention to Protagonist Therapeutics

Protagonist Therapeutics (PTGX) has moved from a loss to a profit in the first quarter of 2026, reporting net income of US$3.78 million after a net loss of US$11.66 million a year earlier.

The earnings swing to profit comes after a strong run for investors, with the share price delivering a 25.39% return over the past 90 days and a very large 292.25% total shareholder return over three years. However, the 1-day share price return declined 3.19% and the 30-day share price return fell 3.09%. This may hint that some investors are reassessing short term expectations around the current US$102.18 level.

If this kind of earnings shift has your attention, it could be a good moment to see what else is moving in healthcare, starting with 32 healthcare AI stocks

With Protagonist now reporting quarterly profit and the stock up sharply over three years, yet trading below the average analyst price target, investors have to ask: is there still upside here, or is the market already pricing in future growth?

Price to book of 10x, is it justified?

On the latest numbers, Protagonist Therapeutics trades on a P/B of 10x based on the $102.18 share price, which screens as expensive versus the broader US biotech industry but cheaper than a group of closer peers.

The P/B ratio compares the company’s market value to its net assets on the balance sheet, which can be a useful yardstick for early stage or loss making biotechs where earnings are not yet a steady guide. At 10x book value, investors are effectively paying a high premium to the current equity base, which suggests the share price already reflects meaningful expectations for future progress in the pipeline.

Against the wider US biotechs industry average P/B of 2.4x, Protagonist looks heavily priced, pointing to higher expectations than the sector overall. However, when stacked up against a narrower peer set on an average of 43.6x, its 10x P/B looks far more restrained, which implies the stock is not at the top end of optimism within its specialist group despite the strong premium to industry. See what the numbers say about this price — find out in our valuation breakdown.

Result: Price to book of 10x (ABOUT RIGHT)

However, there are clear pressure points here, including ongoing net losses of US$114.711 million and reliance on successful clinical outcomes across multiple early stage drug programs.

Another view: DCF points in a very different direction

While the 10x P/B ratio makes Protagonist Therapeutics look expensive against the broader biotech industry, the SWS DCF model presents a different perspective, with an estimated fair value of $379.87 per share compared with the current $102.18. That gap raises a simple question: is the market being overly cautious about the pipeline and future cash flows?

Simply Wall St performs a discounted cash flow (DCF) on every stock in the world every day (check out Protagonist Therapeutics for example). We show the entire calculation in full. You can track the result in your watchlist or portfolio and be alerted when this changes, or use our stock screener to discover 50 high quality undervalued stocks. If you save a screener we even alert you when new companies match - so you never miss a potential opportunity.

Next Steps

If this mix of optimism and caution has you thinking, take a moment to review the numbers yourself and weigh the trade offs. To see what investors are currently optimistic about, check the 2 key rewards.

Looking for more investment ideas?

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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.