OBJECTIVES: Hereditary ATTR amyloidosis with polyneuropathy (hATTR-PN), also known as familial amyloidotic polyneuropathy (FAP), is an inherited, progressive disease leading to death within 5-15 years. hATTR-PN is due to a mutation in the transthyretin (TTR) gene. Patisiran is an investigational, RNA interference (RNAi) therapeutic targeting TTR. This abstract aims to further characterize hATTR-PN burden of illness. METHODS: The ongoing, patisiran Phase 3 APOLLO trial was utilized to collect patient-reported EQ-5D, Norfolk-DN, Rasch-built Overall Disability Scale (R-ODS), and healthcare resource utilization from hATTR-PN patients with symptomatic disease. RESULTS: APOLLO included 225 patients; median age of 62 years (range: 24-82), median neurological impairment score (NIS) of 6-141.6 and representative of the global patient population (19 countries) with a broad range of mutations and disease severities. At baseline, 57 patients had a Polyneuropathy Disability (PND) Score I and 168 patients had a PND Score ≥ II. By FAP Stage, 104 were FAP Stage 1 and 121 were FAP Stage 2. 41 patients (PND Score ≥ II) reported ≥1 hospitalization of ≥3 nights in duration due to hATTR-PN in the 12 months prior to enrollment. Mean EQ-5D scores were 0.76 (PND Score I) and 0.59 (PND Score ≥ II). Patients reported perceived health status on the EQ-VAS with mean scores of 66.9 (PND Score I) and 51.3 (PND Score ≥ II). Mean Norfolk-QoL-DN scores were 35.5 (PND Score I) and 66.0 (PND Score ≥ II). 145 patients (131 PND Score ≥ II) reported they cannot work because of hATTR-PN. Mean R-ODS scores were 40.9 and 25.9 for PND Score I and PND Score ≥ II, respectively. CONCLUSIONS: These data, from the largest controlled study of patients with hATTR-PN to date, further demonstrate that patients experience considerable burden of illness early in the course of disease and this burden increases with disease progression.