Arrowhead’s siRNA shows strong tau reduction in early human study, outpacing other BBB platforms

Arrowhead Pharmaceuticals reported that its investigational siRNA candidate ARO-MAPT produced notable reductions in cerebrospinal fluid tau in a Phase 1/2a trial of healthy volunteers.

Doses of 2.1 mg/kg, 6.4 mg/kg and 12.8 mg/kg were administered on days 1, 8 and 15 (or days 1 and 15 for the highest dose). Average tau reductions at day 105 were 40%, 69% and 73% respectively, with a peak reduction of 85% observed in the high‑dose cohort.

Stifel analysts noted that the magnitude of tau lowering appears to surpass results from other blood‑brain barrier delivery platforms, offering early clinical validation for Arrowhead’s subcutaneous approach to central nervous system targeting.

The trial continues to enroll up to 112 participants, including patients, and the data will guide further development of the platform for neurodegenerative disease programs.