Novartis shares plunge over 10% after del‑desiran trial failure rattles biotech sector

On September 8, Novartis (NVS) experienced its worst single‑session performance in over two decades as its experimental drug del‑desiran failed to meet the primary endpoint in a Phase 3 trial for myotonic dystrophy, sending the stock down more than 12% in a single day . The failure represents the third major pipeline setback for the Swiss pharma giant in a week, following Friday's failure of pelacarsen, its Lp(a)‑lowering heart drug licensed from Ionis Pharmaceuticals .

The market reaction was swift and broad. Novartis shares fell between 12% and 14%, erasing about CHF 24 billion in market value, according to Reuters . The news also dragged down peers; Amgen (AMGN) dropped 10% as investors reassessed exposure to the Lp(a) drug class, while muscle‑disease developers Dyne (DYN) and Sarepta (SRPT) saw their stocks tumble on sympathy . The broader market felt the impact, with the Dow and sector ETFs slipping as biopharma risk was repriced sector‑wide.

Analysts highlighted the systemic implications. Citi warned that the underlying Lp(a) hypothesis may be flawed, putting pressure on Amgen's olpasiran program, which remains in Phase 3 . The cascading sell‑off underscores how a single high‑profile trial failure can reverberate through the biotech ecosystem, affecting not only the company at the center but also competitors and investors with related exposures.

Going forward, investors will monitor Novartis's pipeline remediation strategy, including any potential pivot away from the del‑desiran program and how the company addresses the broader cholesterol‑lowering platform. Market participants are also watching for further guidance on upcoming trial readouts from Amgen and other firms tied to the Lp(a) space, as the sector's risk premium may remain elevated in the near term.

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