We aimed to describe and compare treatment modalities in a large cohort of patients with hereditary transthyretin amyloidosis (hATTR) seen at the University of Pennsylvania Amyloidosis Center.

Treatments for hATTR amyloidosis fall into 2 major categories: transthyretin (TTR) stabilizers (tafamidis and diflunisal) and TTR gene silencers(patisiran and inotersen). Most patients are on one or the other. However, some patients are on both classes of treatment (combination therapy) and there is lack of data to determine whether combination therapy is superior to monotherapy.

We performed a retrospective chart review of hATTR patients seen at the University of Pennsylvania between 2018 and 2022. Patient characteristics, treatment, and outcomes were collected and a comparison will be made between the different groups of patients based on treatment modalities.

164 patients with hATTR were identified. The most common gene mutations were V122I (87 patients, 53%) and T60A (32 patients, 20%) and V30M (17 patients, 10%). 122 (74%) patients were symptomatic. 47 symptomatic patients (39%) had only cardiac symptoms, 15 patients (12%) had only neurological symptoms, and 60 patients (49%) had a mixed phenotype. 104 (85%) of the symptomatic received treatment, of which 36 (35%) patients received combination therapy with both a gene silencer and protein stabilizer, and 68 (65%) patients received treatment with only one of these medication classes. Statistical analysis comparing cardiac biomarkers and Neuropathy Impairment Scores  between patients receiving combination versus monotherapy based on will be performed and presented during the AAN 2023 meeting.

A significant number of hATTR patients are on both gene silencing and protein stabilizing therapy. There is a lack of data regarding whether patients on combination therapy differ in disease severity compared to those on monotherapy. This study will help bridge this knowledge gap by comparing disease severity and progression between the two groups.