Ionis Pharmaceuticals (NASDAQ:IONS) Stock Plunges on Disappointing Clinical Trial Results

Font: Financial Modeling Prep  • Jul 09, 2026

• Ionis Pharmaceuticals (NASDAQ:IONS) experienced a significant stock decline following the failure of its drug Wainua in a late-stage clinical trial.
• Analyst firm Needham reiterated a Buy rating but lowered its price target for Ionis from $105.00 to $86.00.
• The market reaction saw Ionis shares fall by 23.94%, while competitor Alnylam Pharmaceuticals (NASDAQ:ALNY) saw its stock price increase.

Ionis is a leading biotechnology company specializing in the discovery and development of RNA-targeted therapeutics. It aims to treat a wide variety of diseases. The company, with a market capitalization of approximately $10.62 billion, faces competition from firms like Alnylam, which also works in the gene silencing space.

Analyst firm Needham reiterates its Buy rating for Ionis, indicating a continued positive outlook on the stock's potential. However, the firm lowered its price target to $86.00 from a previous $105.00. A price target represents an analyst's projection of a stock's future value. The stock was priced at $64.25 when the rating was released.

This adjustment follows disappointing clinical trial results. As highlighted by Reuters, Ionis and its partner AstraZeneca (NASDAQ:AZN) announced that their drug Wainua (eplontersen) failed to meet the main goal in a late-stage study. The trial did not show a significant reduction in cardiovascular deaths or recurring heart problems for patients with a specific heart disease.

The market reacted strongly to this news. Shares of Ionis fell by 23.94%, a drop of $20.22, to trade at $64.24. The stock saw a very high trading volume of 13.34 million shares, which shows a large number of investors were selling their shares following the announcement from the company.

The trial's outcome also affected competitors. As highlighted by Barron's, while shares of Ionis and AstraZeneca declined, the stock price for competitor Alnylam increased. This demonstrates how clinical trial results for one company can directly influence investor sentiment and stock prices for its rivals in the same sector.