Ionis hammered after GSK opts against TTR study

Ionis Pharmaceuticals Inc. (NASDAQ:IONS) plummeted $13.90 (39%) to $21.36 on Thursday, shedding nearly $1.7 billion in market cap, after it said partner GlaxoSmithKline plc (LSE:GSK; NYSE:GSK) will not start the Phase III CARDIO-TTR study of IONIS-TTRRx ( GSK2998728) to treat transthyretin (TTR)-related amyloid cardiomyopathy.

On a conference call Thursday, CEO Stanley Crooke said "less than a handful" of patients receiving IONIS-TTRRx in the separate Phase III NEURO-TTR trial to treat familial amyloid polyneuropathy (FAP) experienced a "serious" decline in platelet counts. Crooke also said an undisclosed number of patients receiving the company's volanesorsen ( ISIS 304801) in a Phase III study to treat familial chylomicronemia syndrome experienced "severe" platelet declines after "relatively short dosing." ...