Ionis Pharmaceuticals Stock Drops to $50.00 Low Amid Pelacarsen Trial Setback

Ionis Pharmaceuticals Inc. reached a five-year low of $50.02 on September 15, 2026, as disappointing results from its Phase 3 HORIZON trial for the drug pelacarsen prompted a wave of analyst downgrades. The company’s market capitalization stands at $8.45 billion, reflecting a 35% decline in 2026 alone and an 18.06% drop over the past year. Analysts have revised their price targets downward, signaling growing skepticism about the drug’s potential to meet its cardiovascular risk-reduction objectives despite its ability to lower lipoprotein(a) levels significantly.