# Arrowhead Pharmaceuticals Reports Phase 1/2a Data for Alzheimer's Candidate

- URL: https://stocks.freetheai.org/news/arrowhead-pharmaceuticals-reports-phase-1-2a-data-for-alzheimer-s-candidate-1931e1
- Published: 2026-10-14T11:30:00Z
- Category: company_news; sentiment: mixed; impact: high
- Symbols: [NASDAQ:ARWR](https://stocks.freetheai.org/symbols/NASDAQ-ARWR)
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Arrowhead Pharmaceuticals, Inc. (NASDAQ:ARWR) announced interim Phase 1/2a trial results for ARO-MAPT, an experimental RNA interference drug being developed for Alzheimer's disease and other tauopathies. In healthy volunteers, subcutaneous administration of ARO-MAPT achieved a mean reduction of 73% in cerebrospinal fluid total tau at Day 105, with peak reductions reaching 85%.

The findings demonstrate clinical delivery of RNA interference therapy across the blood-brain barrier to reduce target gene activity in the central nervous system. Tau protein accumulation is a primary feature in several neurodegenerative conditions. The candidate was generally well tolerated, with mostly mild side effects reported, including injection-site reactions, headache, upper respiratory infection, and back pain, with no serious treatment-related adverse events.

Arrowhead Pharmaceuticals, Inc. (NASDAQ:ARWR) has fully enrolled healthy volunteer cohorts and is advancing patient enrollment in early-stage Alzheimer's disease cohorts, with data updates planned for 2027. The company is also initiating regulatory discussions for trials in other neurodegenerative diseases.

## Key points

- ARO-MAPT achieved a mean tau protein reduction of up to 73% at Day 105 in healthy volunteers, with maximum reductions reaching 85%.
- The trial provided clinical validation for delivering RNA interference molecules across the blood-brain barrier to target brain genes.
- The drug candidate was generally well tolerated with mostly mild side effects and no serious treatment-emergent adverse events reported.
- Patient enrollment is continuing in early Alzheimer's disease cohorts, with additional data updates expected in 2027.

## Questions and answers

### What did Arrowhead's ARO-MAPT trial demonstrate?

Subcutaneous administration of ARO-MAPT achieved a mean reduction of up to 73% in cerebrospinal fluid total tau at Day 105, with a peak reduction of 85% in healthy volunteers.

### What were the common side effects of ARO-MAPT?

Side effects were mostly mild and included injection-site reactions, vessel puncture bruising, upper respiratory tract infections, back pain, and headache. No serious adverse events were reported.

### When will Arrowhead release more ARO-MAPT clinical data?

Arrowhead is enrolling patients with early Alzheimer's disease and expects to share data updates in 2027.