**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Yousuf Razvi
University College London
London, UK

**Main Body of the Abstract**
Background: Acoramidis (A) is a second-generation, oral, near-complete transthyretin (TTR) stabilizer with efficacy demonstrated in a randomized (2:1), double-blind, placebo (P)-controlled, phase 3 study (ATTRibute-CM) in patients with ATTR amyloid cardiomyopathy (ATTR-CM). We report data from a CMR substudy.
Methods: 52 subjects were enrolled (41 A, 11 P) from 2 UK sites. CMR was performed and read centrally, in a blinded fashion, at the National Amyloidosis Centre (London). 31 subjects (26 A, 5 P) had CMR at month 30.
Results: Median age was 76 years (min-max 55-86); 8 subjects (15.4%) had variant ATTR-CM, of whom 6 received A. Median LVEF at entry was 52% (A), 50% (P), min-max 18%-74%. From initial CMR to month 30, treatment with A, compared to P, demonstrated consistent improvement (Figure) in LV mass index [−2.0 A, +5.6 P g/m2], LV stroke volume index [+4.9 A, 0.0 P mL/m2], LVEF [+4.6 A, −8.2 P %] and LV global longitudinal strain [+0.1 A, +2.2 P %]. An ECV reduction of ≥5%, indicating cardiac amyloid regression and shown to be clinically meaningful, occurred in 3/24 (12.5%) receiving A, and none receiving P.
Conclusions: In this exploratory CMR substudy in ATTR-CM, with a small placebo control group, 30-month treatment with acoramidis was associated with a trend toward cardiac functional improvement and, in a proportion of subjects, cardiac amyloid regression. These data may mechanistically inform the observations of broad clinical benefit of acoramidis in ATTRibute-CM.



**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Yousuf Razvi
University College London
London, UK

**Main Body of the Abstract**
**Background:** Acoramidis (A) is a second-generation, oral, near-complete transthyretin (TTR) stabilizer with efficacy demonstrated in a randomized (2:1), double-blind, placebo (P)-controlled, phase 3 study (ATTRibute-CM) in patients with ATTR amyloid cardiomyopathy (ATTR-CM). We report data from a CMR substudy.
**Methods:** 52 subjects were enrolled (41 A, 11 P) from 2 UK sites. CMR was performed and read centrally, in a blinded fashion, at the National Amyloidosis Centre (London). 31 subjects (26 A, 5 P) had CMR at month 30.
**Results:** Median age was 76 years (min-max 55-86); 8 subjects (15.4%) had variant ATTR-CM, of whom 6 received A. Median LVEF at entry was 52% (A), 50% (P), min-max 18%-74%. From initial CMR to month 30, treatment with A, compared to P, demonstrated consistent improvement (Figure) in LV mass index [−2.0 A, +5.6 P g/m2], LV stroke volume index [+4.9 A, 0.0 P mL/m2], LVEF [+4.6 A, −8.2 P %] and LV global longitudinal strain [+0.1 A, +2.2 P %]. An ECV reduction of ≥5%, indicating cardiac amyloid regression and shown to be clinically meaningful, occurred in 3/24 (12.5%) receiving A, and none receiving P.
**Conclusions:** In this exploratory CMR substudy in ATTR-CM, with a small placebo control group, 30-month treatment with acoramidis was associated with a trend toward cardiac functional improvement and, in a proportion of subjects, cardiac amyloid regression. These data may mechanistically inform the observations of broad clinical benefit of acoramidis in ATTRibute-CM.



Acoramidis May Improve Cardiac Function and Promote Regression in ATTR-CM: Data From the ATTRibute-CM Cardiac Magnetic Resonance (CMR) Substudy PC128 (#315)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.