Why Arrowhead Pharmaceuticals Stock Just Skyrocketed

Shares of Arrowhead Pharmaceuticals (NASDAQ: ARWR) skyrocketed on Wednesday, July 22, 2026, surging as much as 24% intraday, after the biotech unveiled blockbuster topline data from two pivotal Phase 3 trials.

The Pasadena, California-based RNA interference company reported that its investigational drug plozasiran hit the “best-case scenario” in the SHASTA-3 and SHASTA-4 studies, which evaluated the treatment in patients with severe hypertriglyceridemia — a condition marked by dangerously high triglyceride levels that raises the risk of acute pancreatitis and cardiovascular disease.

According to the results, plozasiran delivered deep, durable, and highly consistent median triglyceride reductions of 79% and 81% from baseline in SHASTA-3 and SHASTA-4, respectively, exceeding many analysts’ expectations and reinforcing the drug’s potential as a best-in-class therapy in a market with limited treatment options.

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The news comes as a sharp reversal for the stock, which had actually fallen recently amid broader biotech volatility and investor caution ahead of the data readout.

Wednesday’s rally has pushed shares to a fresh 52-week intraday high.

The strong dataset also drew comparisons to rival RNA-focused developer Ionis Pharmaceuticals, whose competing cardiometabolic pipeline assets faced renewed scrutiny following Arrowhead’s results.

Analysts now expect the plozasiran data to bolster Arrowhead’s regulatory and commercial prospects, positioning the company as a frontrunner in treating severe hypertriglyceridemia as it moves toward potential regulatory filings.