Eplontersen linked to favorable CMR changes in ATTR cardiomyopathy

This prospective, international CMR study was embedded in the randomized, placebo-controlled phase 3 CARDIO-TTRansform trial. It included 120 participants with baseline and at least one follow-up scan (58 assigned to eplontersen and 62 to placebo); mean age was 76.7 years, 95% were men, and 12.5% were taking a transthyretin stabilizer at baseline. Planned CMR assessments were conducted through week 140. The primary imaging analysis assessed longitudinal changes in CMR measures.

At week 140, eplontersen was associated with lower extracellular volume than placebo (least-squares mean difference, −6.7 percentage points; 95% CI, −8.7 to −4.7; P<0.001), as well as lower native T1 and left ventricular mass. Left and right ventricular ejection fractions and several measures of myocardial strain also favored eplontersen. By the study’s definition, amyloid regression occurred in 12.5% of eplontersen recipients and none receiving placebo; progression occurred in 12.5% and 76%, respectively.

These findings indicate favorable changes in imaging measures over 140 weeks, but the report is a CMR substudy and does not establish that imaging changes translate into improved clinical outcomes or define how CMR should guide treatment. The cohort was mostly male and largely not receiving a stabilizer at baseline.