Arrowhead’s plozasiran shows favorable safety in severe hypertriglyceridemia late-stage trials

Arrowhead presented late-stage data for its RNA interference therapy plozasiran, marketed as Redemplo, in severe hypertriglyceridemia at the European Society of Cardiology 2026 meeting in Munich.

The studies indicated that overall treatment-emergent adverse events were comparable to placebo, and serious adverse events occurred in 8.3% of patients receiving plozasiran versus 10% on placebo, suggesting a safety profile similar to placebo.

Analysts are split on the implications. Stifel described the results as favorable and potentially best-in-class, while BMO Capital Markets continued to favor Ionis Pharmaceuticals' existing antisense therapy Tryngolza as the commercially available option.

Arrowhead may leverage the safety data to pursue a supplemental FDA submission to broaden Redemplo’s indication beyond familial chylomicronemia syndrome.