NEW YORK, July 22, 2026, 14:08 EDT — U.S. regular session underway.
- The stock rose 23.4% to $91.96, while the SPDR S&P Biotech ETF (NYSEARCA:XBI) slipped 1.0%.
- Plozasiran lowered median triglyceride levels by 79%-81% and decreased pancreatitis events by 78% in total.
- Initial calculations show the share increase boosted market value by approximately $2.48 billion.
Arrowhead’s stock jumped as the SHASTA-3 and SHASTA-4 studies achieved all their prespecified endpoints. The latest quoted price was recorded at 13:52 EDT.
Plozasiran reduced median triglyceride levels by 79% and 81% at 12 months, while those given placebo saw reductions of approximately 27%.
The decision was limited to the company. XBI fell, and Ionis Pharmaceuticals NASDAQ:IONS traded mostly unchanged.
An initial intraday estimate shows Arrowhead’s market value increasing by approximately $2.48 billion. Its market capitalisation rose to around $13.09 billion.
The increase amounts to 1.4 times Arrowhead’s cash holdings as of March. Arrowhead’s market value advantage over Ionis has grown to about $4.30 billion. Both firms have wider pipelines, making the difference not solely about their drugs.
Dosing could be a key commercial factor. Plozasiran requires four injections per year, compared to about 12 for Tryngolza. This amounts to approximately 67% fewer injections.
The key programmes are now contrasted as below:
| Measure | Arrowhead plozasiran | Ionis Tryngolza |
|---|---|---|
| U.S. severe-hypertriglyceridemia status | Supplemental submission expected before end-2026 | FDA cleared June 24, 2026 |
| Pivotal enrolment | Roughly 750 participants in two trials | 1,063 participants in two trials |
| Dosing | Administered once per three months | Administered monthly |
| Reported triglyceride result | 79%-81% median decrease from baseline at 12 months; placebo decrease was about 27% | 49%-72% reduction against placebo after six months; reduction maintained through 12 months |
| Pooled pancreatitis-event reduction | 78% | 85% |
Results are as reported by the companies. The trials were conducted separately and relied on varying statistical analyses.
Arrowhead reported a 78% reduction in pooled pancreatitis cases across both trials in the overall population. The highest-risk treated subgroup experienced zero events.
The company observed no notable mean liver fat change in the MRI subgroup and detected no clinically relevant alterations in liver enzymes. There were no new safety concerns.
Chief Executive Christopher Anzalone emphasized “dosing only four times per year.” Arrowhead intends to submit a supplemental filing in the U.S. by year-end. Arrowhead Pharmaceuticals, Inc.
Ionis benefits from first-mover status. The FDA broadened the label for Tryngolza on June 24. Ionis announced the drug will be available in the U.S. beginning in July.
RBC Capital Markets analyst Luca Issi described the data as “a best-case scenario for ARWR.” Investor’s Business Daily
Arrowhead stated it held $1.78 billion in cash resources as of March 31. The company posted a net loss of $132.7 million for its fiscal second quarter.
Risks are still significant. Complete datasets have not been released. Comparing results across trials can be misleading, and regulators have not verified the broader assertion. Ionis currently markets products in this space.
Comprehensive SHASTA results are set for release on August 30 during the ESC Congress. This session will further assess both subgroup detail and safety.
