Page 1

Arrowhead Pharmaceuticals Announces ARO - MAPT Interim Phase 1 / 2a Clinical Data Demonstrating Deep and Durable Tau Reductions in Healthy Volunteers Share in . . . • • • Arrowhead's TRiM ™ platform achieves clinical validation for delivery of siRNA that crosses the blood - brain barrier after subcutaneous injection ARO - MAPT demonstrates mean cerebrospinal fluid total tau reduction of 73 % on Day 105 , with a maximum individual reduction of 85 % , supporting the potential for quarterly dosing Arrowhead will host a webinar today , October 14 , at 2:30 PM ET / 11 : 30 am PT to review additional interim results PASADENA , Calif .-- ( BUSINESS WIRE ) -- Arrowhead Pharmaceuticals , Inc. ( NASDAQ : ARWR ) today announced interim results from an ongoing Phase 1 / 2a study of ARO - MAPT , the company's investigational RNA interference ( RNAi ) therapeutic being developed as a potential treatment for Alzheimer's disease and other tauopathies . These results represent the first successful clinical validation of a platform to deliver siRNA across the blood - brain barrier and achieve substantial target gene knockdown in the brain . In healthy volunteers , subcutaneous administration of ARO - MAPT achieved deep and durable reductions in cerebrospinal fluid ( CSF ) total tau , with a mean reduction of up to 73 % at Day 105 and a maximum reduction of 85 % . Arrowhead will review additional results during its webinar today at 2:30 pm ET / 11 : 30 a.m. PT , featuring presentations from Arrowhead management and Adam Boxer , M.D. , Ph.D. , Endowed Professor in Memory and Aging in the Department of Neurology at the University of California , San Francisco . A live webcast with Q & A and replay will be available on the Events and Presentations page under the Investors section of the Arrowhead website . " These early clinical data are exciting because they demonstrate that ARO - MAPT can achieve deep and durable reductions of tau expression in the brain following a simple subcutaneous administration , representing an important step toward developing a potential treatment for Alzheimer's disease and other primary tauopathies , ” said Christopher Anzalone , Ph.D. , President and Chief Executive Officer of Arrowhead . " Abnormal tau accumulation is a key feature of multiple devastating diseases , and we believe reducing tau production has the potential to offer a meaningful new approach for patients . Equally important , these results provide clinical validation of our proprietary Targeted RNAi Molecule ( TRIMT ) delivery platform to potentially address multiple diseases in the central nervous system ( CNS ) . This major scientific breakthrough further solidifies Arrowhead's position as the leading innovator in siRNA therapies . " ARO - MAPT is designed to silence expression of the microtubule - associated protein tau ( MAPT ) gene in the central nervous system , reducing production of all six isoforms of the tau protein . Pathological aggregation of tau is implicated in a group of neurodegenerative diseases called tauopathies , which include Alzheimer's disease , MAPT - related frontotemporal dementia , and Progressive Supranuclear Palsy . Interim Healthy Volunteer Results • • CSF total tau : ARO - MAPT administered at 2.1 mg / kg and 6.4 mg / kg on Days 1 , 8 , and 15 achieved mean reductions of 40 % and 69 % , respectively , at Day 105. ARO - MAPT administered at 12.8 mg / kg on Days 1 and 15 achieved a mean reduction of 73 % at Day 105 with a maximum reduction of 85 % . Durability : Day 105 represents 90 days following the final dose , with the sustained reduction in CSF total tau supporting the potential for dosing once every three months or less frequently . The reported biomarker results are from healthy volunteers . Effects on tau protein tangles in the brain , cognition , function , and disease progression must be investigated in patients with Alzheimer's disease and other tauopathies . These patients are being studied in Part 2 of the current Phase 1 / 2a study and in additional planned studies .