Ionis Pharmaceuticals, Inc. (IONS) Faces Investor Scrutiny After Surprise Trial Failure Drives Stock Down 23% – HBSS

Ionis Pharmaceuticals' stock plunged 23% on July 9, 2026, after its Phase 3 CARDIO-TTRansform trial for eplontersen failed to meet its primary efficacy endpoint. The unexpected failure wiped out $3.3 billion in market capitalization. Hagens Berman has launched an investigation into whether the company was sufficiently transparent about the trial's data and design, potentially violating federal securities laws.