Almost to the finish line, Arrowhead Pharmaceuticals stock jumps on Phase 3 trial results

Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) shares rose 18% Wednesday following the announcement of topline results from its Phase 3 SHASTA-3 and SHASTA-4 studies of plozasiran in patients with severe hypertriglyceridemia.

The studies met their primary endpoint of triglyceride reduction versus placebo and all prespecified secondary endpoints. Plozasiran, administered as a 25 mg subcutaneous injection once every three months, led to median triglyceride reductions of 79% and 81% at month 12 in SHASTA-3 and SHASTA-4, respectively, compared to approximately 27% reduction with placebo.

A pre-planned pooled analysis of acute pancreatitis events across both studies showed a statistically significant reduction in event rates compared to placebo. The drug demonstrated a favorable safety and tolerability profile with no new safety signals and no clinically meaningful differences in routine clinical laboratory measurements.

Plozasiran has received regulatory approval as REDEMPLO in the United States, European Union, China, Australia, and Canada for treating adults with familial chylomicronemia syndrome. The company plans to file a supplemental new drug application with the U.S. FDA before the end of 2026 to expand the drug’s indication to severe hypertriglyceridemia.