Siddhanti, Suresh

Abstract Background The National Amyloidosis Centre (NAC) staging system for transthyretin amyloid cardiomyopathy (ATTR-CM) is used to classify patients into prognostic categories based on N-terminal pro-B-type natriuretic peptide (NT-proBNP) level and estimated glomerular filtration rate (eGFR). The NAC staging system has been shown to predict ongoing survival throughout the course of ATTR-CM, with survival progressively decreasing from stage I to stage III. Acoramidis, a highly selective, oral transthyretin stabilizer that achieves near-complete (≥90%) transthyretin stabilization, has recently been approved in Europe and the USA for the treatment of wild-type or variant ATTR-CM in adults. In the phase 3 ATTRibute-CM study, acoramidis treatment was well tolerated and led to a 42% relative risk reduction in the composite of all-cause mortality and recurrent cardiovascular hospitalizations over 30 months compared with placebo (p=0.0005). Purpose To evaluate the ability of acoramidis treatment, as compared with placebo, to stabilize or improve NAC stage after 30 months in participants with ATTR-CM from the ATTRibute-CM study. Methods Participants in ATTRibute-CM were randomized 2:1 to receive acoramidis or placebo for 30 months. Efficacy analyses were conducted in the modified intention-to-treat population, which consisted of all randomized participants who had received at least one dose of acoramidis or placebo, had at least one efficacy evaluation after baseline and had a baseline eGFR ≥30 mL/min/1.73 m2. NAC stage at baseline and Month 30 was assessed. Changes from baseline to Month 30 were categorized as "stable", "improved" or "worsened". The "stable" category comprised participants who stayed within the same NAC stage at baseline and Month 30. The "improved" category comprised participants who moved from a higher NAC stage at baseline to a lower stage at Month 30. The "worsened or missing" category comprised participants who moved from a lower NAC stage at baseline to a higher stage at Month 30 and participants whose Month 30 NAC stage was missing. The change in NAC stage was compared between treatment groups using a stratified Cochran-Mantel-Haenszel test with stratification factors of genotype, NT-proBNP level and eGFR as recorded in the interactive voice/web response system at randomization. Results Overall, 611 participants were analysed (acoramidis: n=409; placebo: n=202). Baseline characteristics were comparable between treatment groups. Most participants had NAC stage I at baseline (acoramidis: 58.9%; placebo: 59.4%; Table). At Month 30, NAC stage remained stable or improved in 52.1% of acoramidis participants compared with 43.1% of placebo participants (p=0.0351; Figure). Conclusions Acoramidis treatment resulted in a greater proportion of participants whose NAC stage improved or remained stable at Month 30 compared with placebo, indicating better stabilization of their disease.

Introduction: Acoramidis, an oral transthyretin (TTR) stabilizer achieving near-complete (≥90%) TTR stabilization, is now approved in the USA, EU, Japan, and UK for the treatment of TTR amyloid cardiomyopathy (ATTR-CM). In the 30-month phase 3 ATTRibute-CM study, acoramidis reduced all-cause mortality (ACM) or first cardiovascular-related hospitalization (CVH) vs placebo. Through Month 42 (M42) of the open-label extension (OLE; 30 months ATTRibute-CM + 12 months OLE), the clinical benefit of acoramidis was sustained, resulting in a 36% and 43% risk reduction in ACM and ACM/first CVH, respectively, compared with the placebo to acoramidis group Research Question: Are the long-term clinical benefits of acoramidis on ACM and ACM/first CVH in ATTR-CM over 42 months consistent across patient subgroups? Methods: ATTRibute-CM study design has been previously described. At the end of the 30-month double-blind period, patients enrolled into OLE continued acoramidis or switched from placebo to acoramidis; all patients received open-label acoramidis HCI 800 mg BID. Data cut was performed after 12 months in OLE. Subgroup analysis for ACM and ACM/first CVH through M42 were conducted for randomization stratification factors (genotype, NT-proBNP, and eGFR levels) and other pre-specified subgroups. ACM included death due to any cause, cardiac mechanical assist device placement, and heart transplant. CVH included CV hospitalizations (≥24 h) and urgent visits (<24 h) for decompensated heart failure requiring IV diuretics and was adjudicated by an independent Clinical Events Committee. Results: Overall, 389 patients enrolled in the OLE (263 continuous acoramidis and 126 placebo to acoramidis). The analyses of ACM/first CVH ( Figure 1 ) and ACM ( Figure 2 ) through M42 consistently favored patients initially randomized to acoramidis across all patient subgroups, including those based on sex, age, country, ATTR-CM genotype, baseline NT-proBNP, baseline eGFR, NYHA class, and NAC stage. The largest effect size for the reduction in ACM/first CVH (HR <0.50) was observed in the following subgroups: female, non-Caucasian patients, variant ATTR-CM, or NAC stage 2. Conclusions: The long-term benefit of acoramidis was consistently shown in patients initially randomized to acoramidis treatment compared with placebo to acoramidis switch after 30 months across multiple clinically relevant subgroups, underscoring the importance of early initiation of acoramidis to reduce the long-term risk of ACM or CVH.

Background: Acoramidis is a novel, potent, investigational, transthyretin (TTR) stabilizer under development for the treatment of TTR amyloidosis that results in near-complete (≥90%) TTR stabilization. In a phase 3 study, ATTRibute-CM, acoramidis demonstrated improved clinical outcomes in participants with transthyretin amyloid cardiomyopathy (ATTR-CM), including a 50% reduction in the risk of CVH compared to placebo over 30 months. The study also demonstrated that cardiovascular hospitalization (CVH) during the study predicted a higher subsequent mortality in participants with ATTR-CM. Hypothesis: CVH portends a higher risk of mortality in participants with ATTR-CM. Since acoramidis reduces CVH, it can improve the prognosis of participants with ATTR-CM. Aim: To evaluate the relationship between CVH and survival in the acoramidis group within ATTRibute-CM. Methods: In this post-hoc analysis, the relationship between those with or without CVH and survival was analyzed within the acoramidis treatment group using the Kaplan-Meier (KM) estimator method. Results: Demographics and baseline disease characteristics were mostly comparable between acoramidis-treated participants with and without CVH, although participants with CVH had a higher baseline NT-proBNP and lower eGFR. At Month 30, in acoramidis-treated participants, those without any CVH (n=300) had a higher survival [86.8% (95% CI = 82.2, 90.3)] versus 62.4% (95% CI = 52.6, 70.7) in those who had any CVH (n=109); p<0.0001 from log-rank test (Figure). Conclusion: In the ATTRibute-CM study, pts without any CVH receiving acoramidis have a higher survival rate. CVHs remain a powerful predictor of mortality. This reinforces the importance of an effective therapy that reduces CVH and in turn may improve survival in patients with ATTR-CM.

Abstract Background/Introduction Patients with ATTR-CM can have lower circulating TTR levels, which is associated with worsening of cardiac function and increased risk of cardiovascular mortality.[1] Acoramidis has been shown to reduce cardiovascular mortality and hospitalization, while increasing circulating TTR levels, in the ATTRibute-CM phase 3 study.[2] Purpose I. Evaluate serum TTR levels in participants (pts) receiving acoramidis vs those who received tafamidis in the placebo group in ATTRibute-CM at Month 30. II. Evaluate serum TTR levels in pts who transitioned from placebo+tafamidis to acoramidis in the open-label long term extension (OLE) study. Methods ATTRibute-CM study: Eligible pts with ATTR-CM were randomized in a 2:1 ratio to receive acoramidis or placebo for 30 months. Pts in both groups had the option of initiating open-label, commercially available tafamidis after 12 months in the study. Upon completion of Month 30, pts were invited to participate in the OLE study. In OLE, pts who had previously received acoramidis continued acoramidis, and those who had previously received placebo+tafamidis were switched to acoramidis-only treatment. All pts in the OLE study received acoramidis only. Change in serum TTR levels in ATTRibute-CM and OLE at data cutoff (Oct 9, 2023) are summarised using descriptive statistics. Results In the phase 3 study, efficacy analyses were performed in 611 pts, of which 61 of 409 (14.9%) and 46 of 202 (22.8%) received tafamidis in acoramidis and placebo groups, respectively. The median time until tafamidis initiation was 17.8 and 16.1 months, respectively; median exposure duration was 11.6 and 10.5 months, for acoramidis and placebo groups, respectively.[3] Change from baseline (CFB) in serum TTR levels remained unchanged at Month 30 in the placebo-only group (mean [SD] = –0.4 [4.92] mg/dL). Characteristics of pts analysed are described in Fig. 1. A total of 380/611 pts (62.2%) entered the OLE study (229 pts continued acoramidis only, and 23 switched from placebo+tafamidis to acoramidis). At the time of data cutoff, 214 pts who had received acoramidis only completed Month 6 in OLE versus 18 who switched from placebo+tafamidis to acoramidis. At Month 30 in ATTRibute-CM, CFB in serum TTR levels were higher for patients who received acoramidis only than those receiving placebo+tafamidis (Fig 2A). Serum TTR levels increased further in pts who switched from placebo+tafamidis to acoramidis in OLE (Fig. 2B). The OLE study is ongoing, and this analysis includes pts who completed the Month 6 visit at time of data-cut. Conclusion(s) CFB in serum TTR levels were higher in pts receiving acoramidis only than those receiving placebo+tafamidis at Month 30 in the double-blind study. A further significant increase in serum TTR levels was observed in those who received placebo+tafamidis and switched to acoramidis in OLE.