Sarswat, N.

Importance Transthyretin amyloid cardiomyopathy (ATTR-CM), a progressive disease caused by misfolded transthyretin (TTR), occurs as wild-type (ATTRwt-CM) or variant (ATTRv-CM) forms. p.Val142Ile is the most common variant in the US, linked to rapid progression and increased mortality. Acoramidis achieves near-complete (≥90%) TTR stabilization and showed clinical benefit in the 30-month ATTRibute-CM trial and through month 42 in the ongoing open-label extension (OLE). Objective To evaluate the efficacy of acoramidis in ATTRwt-CM, ATTRv-CM, and variant subgroups (p.Val142Ile and non-p.Val142Ile). Design, Setting, and Participants This international, multicenter, phase 3, randomized placebo-controlled study took place from April 2019 to May 2023 with ongoing OLE (month 42). ATTRibute-CM enrolled 632 participants with ATTR-CM; 611 of 632 were included in the modified intention-to-treat (mITT) population. There were 380 participants who continued into the OLE. These data were analyzed from January 2025 to July 2025. Interventions Oral acoramidis, 712 mg, or placebo twice daily for 30 months, followed by 12 months of open-label treatment. Main Outcomes and Measures All-cause mortality (ACM), cardiovascular-related hospitalizations (CVH), serum TTR, 6-minute walk distance, Kansas City Cardiomyopathy Questionnaire Overall Summary score, and N-terminal pro B-type natriuretic peptide in participants with ATTRwt-CM and ATTRv-CM. Post-hoc analyses were conducted in variant subgroups, including p.Val142Ile. Results Overall, 552 participants with wild-type ATTR-CM (mean [SD] age, 78 [6.3] years; 92.0% male and 8.0% female) and 59 participants with variant ATTR-CM (mean [SD] age, 73 [7.7] years; 77.3% male and 22.7% female) were randomized (mITT population), including 35 with p.Val142Ile. Consistent efficacy was observed in wild-type and variant subgroups for ACM/CVH through month 30 and ACM through month 42. At month 30, acoramidis reduced the risk of ACM/first CVH vs placebo by 31% in ATTRwt-CM (hazard ratio [HR], 0.69; 95% CI, 0.52-0.90; P = .007) and by 59% in ATTRv-CM (HR, 0.41; 95% CI, 0.21-0.81; P = .01). ACM was reduced through month 42 with HRs of 0.70 (95% CI, 0.50-0.98; P = .04) and 0.41 (95% CI, 0.19-0.93; P = .03) in the ATTRwt-CM and ATTRv-CM groups, respectively. Consistent treatment benefit was observed in participants with ATTRwt-CM and ATTRv-CM for secondary end points. Within variant subgroups (p.Val142Ile vs non-p.Val142Ile), consistent treatment benefits were observed for ACM/CVH through month 30 and ACM through month 42. Conclusions and Relevance The beneficial effect of acoramidis was observed consistently in ATTRwt-CM and ATTRv-CM groups. These hypothesis-generating results indicate that further studies are warranted to better characterize the therapeutic benefit of acoramidis in variant subgroups. Trial Registration ClinicalTrials.gov Identifiers: NCT03860935 ; NCT04988386

Introduction: Patients with variant transthyretin (TTR) amyloid cardiomyopathy (ATTRv-CM) experience early onset disease, rapid progression, and poor outcomes due to amyloid aggregated from destabilized tetrameric TTR. Acoramidis, a highly selective, oral TTR stabilizer, achieves ≥90% TTR stabilization and is approved in the USA, EU, Japan, and UK for adults with wild-type (ATTRwt-CM) or ATTRv-CM. In the phase 3 ATTRibute-CM study and its open-label extension (OLE), acoramidis reduced both the risk of all-cause mortality (ACM) or first cardiovascular-related hospitalization (CVH) through Month 30 and risk of ACM through Month 42 by 36%. Research Question: Is acoramidis efficacy in ATTRv-CM consistent with that observed in the overall ATTRibute-CM population? Methods: In ATTRibute-CM, participants with ATTR-CM were randomized 2:1 to acoramidis HCl 800 mg or PBO, twice daily (BID) for 30 months. After Month 30, all participants enrolled in the OLE received acoramidis HCl 800 mg BID. Genotype (ATTRwt-CM or ATTRv-CM) was captured at randomization; efficacy was analyzed separately in ATTRv-CM. Time-to-event analyses used a stratified Cox model with terms for treatment, baseline 6MWT, genotype, genotype×treatment interaction, stratified by randomization NT-proBNP and eGFR levels. ACM was analyzed at Month 42 (ATTRibute-CM 30 months + OLE 12 months). Results: The ATTRv-CM group comprised 59 patients (39 acoramidis, 20 PBO). Baseline characteristics were mostly similar in both groups ( Table ). The three most common variants reported were p.V142I (n=35), p.I88L (n=7), and p.T80A (n=5). Compared with PBO, acoramidis reduced the risk of ACM/first CVH through Month 30 by 59% (acoramidis, 46.2%; PBO, 75.0%; HR 0.41; 95% CI 0.21–0.81; P =0.011; Fig 1 ) and ACM through Month 42 by 59% (continuous acoramidis, 30.8%; PBO to acoramidis, 60.0%; HR 0.41; 95% CI 0.19–0.93; P =0.032; Fig 2 ) , with Kaplan–Meier curves separating at Months 5 and 10, respectively. Conclusions: In ATTRibute-CM, acoramidis use was associated with clinical benefit in the ATTRv-CM group as demonstrated by a 59% risk reduction in both ACM/first CVH at Month 30, and ACM at Month 42 compared to PBO. These previously unreported findings support the hypothesis that near complete TTR stabilization observed experimentally with acoramidis across multiple TTR mutations translates into improvement in long-term outcomes. Further validation by individual TTR variant is warranted.

Introduction: Patients with transthyretin amyloid cardiomyopathy (ATTR-CM) typically have low serum transthyretin (sTTR) levels, worsening heart failure, and increased mortality. A recent study has shown the association of sTTR levels ≥20mg/dL with reduced risk of all-cause mortality and cardiovascular mortality (CVM). It has also been shown that regardless of baseline sTTR level, greater increases in sTTR levels are associated with greater improvements in cardiovascular outcomes. Acoramidis, a near-complete (≥90%) TTR stabilizer, demonstrated a rapid and sustained increase from baseline in sTTR by Day 28 and reduced risk of cardiovascular outcomes in patients with ATTR-CM. Hypothesis: Acoramidis-mediated early increase in sTTR levels ≥20 mg/dL (lower limit of normal) at Day 28 reduces risks of CVM and cardiovascular-related hospitalizations (CVH) in patients with ATTR-CM. Methods: Analyses were conducted in the ATTRibute-CM modified intention-to-treat (mITT) population (acoramidis: 409; placebo: 202). The sTTR concentrations (normal range is 20-40 mg/dL) were assessed using an immunoturbidimetric method (Abbott ARCHITECT system) in a central laboratory. The proportion of participants with sTTR levels below normal at baseline and Day 28 were determined. The relationship between sTTR levels <20 or ≥20 mg/dL, at Day 28 across the pooled acoramidis and placebo treatment groups, and subsequent risk of CVM and of CVH over 30 months were analyzed using a stratified log-rank test. Results: At baseline about 25% of study participants had sTTR levels below normal in both treatment groups. At Day 28, less than 2% of participants had sTTR levels <20 mg/dL in the acoramidis arm compared with 26% in the placebo arm ( Table 1 ). When acoramidis and placebo treatment groups were pooled based on sTTR levels <20 or ≥20 mg/dL at Day 28, participants with sTTR ≥20 mg/dL were associated with a lower risk of the composite endpoint of CVM or first CVH at Month 30 in comparison with <20 mg/dL ( p <0.0001) ( Figure 1A ). Comparable findings were observed for the individual components (CVM, first CVH) ( Figure 1B and C ). Conclusion: Across treatment groups, sTTR levels above normal range (≥20 mg/dL) at Day 28 were associated with a lower risk of cardiovascular outcomes at Month 30, when compared with sTTR levels below normal range (<20 mg/dL). Thus, these observations demonstrate that higher sTTR levels over time may have the potential for clinical benefits in both CVM and CVH.