Ionis Pharmaceuticals (IONS) has been in focus after a busy stretch that included US FDA Priority Review and Breakthrough Therapy designations for partner drug bepirovirsen, additional positive zilganersen data in Alexander disease, and a first quarter earnings update.

The recent FDA designations for bepirovirsen, encouraging zilganersen data and raised 2026 revenue guidance help explain why Ionis Pharmaceuticals has a 1-year total shareholder return of 123.75% even as the 90-day share price return is 11.01% lower, suggesting strong long term momentum with some recent cooling.

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With Ionis shares pulling back 11.01% over 90 days yet still showing a 1-year total return of 123.75%, and trading below the average analyst price target, is there still a buying window here, or is the market already pricing in future growth?

Most Popular Narrative: 22.2% Undervalued

Compared to the last close at $75.28, the most followed narrative places Ionis Pharmaceuticals' fair value at $96.73, framing the recent pullback as only part of a bigger earnings story.

The rapid revenue growth and positive launch trajectory for Tryngolza in familial chylomicronemia syndrome (FCS), along with the imminent launch of Donidalorsen for HAE and multiple late-stage pipeline assets reading out or launching by 2027, are set to drive sustained, stepwise increases in top-line revenue and operating leverage as Ionis transitions from R&D-heavy to commercial-stage. Expanding addressable patient populations, from rare diseases to larger segments like severe hypertriglyceridemia (sHTG), combined with favorable physician feedback and significant unmet need, position Ionis to capture substantial market share and revenue growth from trends tied to the rise in chronic disease and an aging population.

Want to understand why this fair value sits well above today's price? The narrative leans on rapid double digit revenue growth, a sharp swing toward profitability, and a future earnings multiple more often associated with mature, high confidence franchises. Curious which assumptions about margins, patient volumes, and earnings paths are doing the heavy lifting in that model? The full narrative lays those forecasts out step by step.

Result: Fair Value of $96.73 (UNDERVALUED)

However, there is still meaningful execution risk, as heavier reliance on a few late stage drugs and potential pricing pressure in broader indications could quickly challenge that upbeat narrative.

Another View: Price-To-Sales Sends A Different Signal

The narrative fair value and SWS DCF output point to Ionis as deeply undervalued, yet the current P/S of 11.8x is far higher than the peer average of 4.1x and also above the SWS fair ratio of 4.8x. That gap suggests valuation risk if sentiment or revenue expectations soften.

Next Steps

After all this optimism and caution, the real question is what it means for you right now. Move quickly, review the numbers, weigh the upside yourself, and then take a closer look at the 2 key rewards.

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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.