Chen, Chongshu

Abstract Aims HELIOS-A was a Phase 3, open-label study of vutrisiran, an RNA interference therapeutic, in patients with hereditary transthyretin (ATTRv) amyloidosis with polyneuropathy. This analysis evaluated vutrisiran's impact on exploratory cardiac endpoints in HELIOS-A patients. Methods and results Patients were randomized 3:1 to subcutaneous vutrisiran 25 mg every 3 months or intravenous patisiran 0.3 mg/kg every 3 weeks (reference group) for 18 months. Exploratory cardiac endpoints included change from baseline in N-terminal prohormone of brain-type natriuretic peptide (NT-proBNP) and echocardiographic parameters versus external placebo (APOLLO study). The modified intent-to-treat (mITT) population comprised randomized patients receiving any study drug (n = 122). A cardiac subpopulation with evidence of cardiac amyloid involvement (n = 40) was prespecified. 99mTc scintigraphy exploratory assessments in a planned vutrisiran-treated cohort at select sites were compared with baseline. At Month 18, vutrisiran demonstrated beneficial effects on NT-proBNP versus external placebo in the mITT and cardiac subpopulations (adjusted geometric mean fold change ratio [95% confidence interval] 0.480 [0.383–0.600], p = 9.606 × 10−10 and 0.491 [0.337–0.716], p = 0.0004, respectively). Benefits or trends towards benefit in echocardiographic parameters versus external placebo were observed for both populations. In 99mTc scintigraphy assessments, 32/47 (68.1%) and 31/48 (64.6%) patients exhibited reduced normalized left ventricular total uptake and heart-to-contralateral lung ratio, respectively. Perugini grade was reduced or unchanged versus baseline in 55/57 (96.5%) evaluable patients. No increase in cardiac adverse events was observed with vutrisiran versus external placebo. Conclusions Vutrisiran demonstrated evidence of potential benefit on cardiac manifestations in patients with ATTRv amyloidosis with polyneuropathy, with an acceptable safety profile.

Abstract Background Hereditary transthyretin-mediated (hATTR) amyloidosis, also known as ATTRv amyloidosis, is a fatal, multisystem disease that presents with progressive polyneuropathy and/or cardiomyopathy. HELIOS-A (NCT03759379) assessed the efficacy of vutrisiran, an investigational RNA interference therapeutic, in patients with hATTR amyloidosis with polyneuropathy. Purpose To evaluate the effect of 18 months of vutrisiran treatment on exploratory cardiac endpoints in the HELIOS-A Phase 3 study. Methods Patients were randomised (3:1) to vutrisiran (25 mg SC, q3m) or patisiran (0.3 mg/kg IV, q3w), a reference comparator. The APOLLO placebo group (n=77) was an external control. Primary endpoint was change from baseline in the modified Neuropathy Impairment Score +7 (mNIS+7) at 9 months, vs. external placebo. Exploratory cardiac endpoints included change from baseline in NT-proBNP levels, echocardiography parameters, and technetium (Tc) scintigraphy parameters at 18 months. A prespecified cardiac subpopulation was included (baseline left ventricular wall thickness ≥1.3 cm and no medical history of aortic valve disease or hypertension). Results HELIOS-A enrolled 164 patients and the primary endpoint was met. In the cardiac subpopulation (n=40/122 vutrisiran; n=36/77 placebo), 18 months of vutrisiran treatment significantly improved NT-ProBNP levels vs. external placebo (adjusted geometric fold change ratio: 0.49; p=0.0004) and demonstrated a trend towards improvement in echocardiographic parameters vs. external placebo (including a significant difference in cardiac output [least squares mean difference: 0.41; p=0.043]). Of the 122 vutrisiran-treated patients, 99mTc scintigraphy assessment was captured for 64 vutrisiran-treated patients at baseline, 35 (54.7%) of whom had Perugini grade ≥2 (moderate/intense) cardiac uptake of 99mTc. Among patients with evaluable scintigraphy parameters repeated at 18 months (evaluable patients), heart-to-contralateral lung ratio and normalised LV total uptake on scintigraphy improved (decrease from baseline) in 64.6% (31/48) and 68.1% (32/47), respectively, at 18 months. Of the evaluable patients, 28.1% (16/57) had an improvement (reduction from baseline) in Perugini grade of cardiac uptake, 68.4% (39/57) had no change in grade, and 3.5% (2/57) worsened in grade. Of evaluable patients with baseline Perugini grade ≥2, the proportion with improvement in heart-to-contralateral lung ratio and normalised LV total uptake was 76.9% (20/26) and 100% (25/25) respectively. No cardiac safety concerns were identified with vutrisiran treatment. Conclusions In this exploratory analysis, vutrisiran treatment was associated with a positive impact on NT-ProBNP levels and echocardiographic parameters vs. external placebo in the cardiac subpopulation. Vutrisiran treatment also reduced cardiac uptake of 99mTc potentially suggesting reduction in cardiac amyloid, although the clinical significance of this is not yet clear.