Ionis Pharmaceuticals' Sell-Off Was Overdone Despite Clinical Setbacks
On July 9, 2026, Ionis Pharmaceuticals (IONS) experienced a steep sell-off after two of its experimental therapies missed key clinical endpoints. Eplontersen failed in Phase 3 trials for transthyretin amyloid cardiomyopathy and tominersen also underperformed in Huntington's disease studies. These setbacks initially caused the stock to drop more than 20%, with a partial rebound since, but it remains about 30% below its July peak. Despite these challenges, analysts argue that the sell-off was overdone due to Ionis' strong fundamentals and successful proprietary therapies. Sales of Dawnzera for hereditary angioedema rose sharply in Q2 2026 by 63%, while Tryngolza received FDA approval for a new indication and is projected to reach peak sales exceeding $3 billion. Additionally, the company awaits an FDA decision on zilganersen for Alexander disease. The stock's forward earnings multiple remains high at nearly 91x, but its long-term growth potential may justify this valuation given Ionis' promising pipeline of fully owned therapies and expanding global reach.
