Efficacy and Safety of Vutrisiran in Patients with Hereditary Transthyretin-mediated Amyloidosis with Polyneuropathy: Analysis of the East Asian Subpopulation from HELIOS-A.

INTRODUCTION

In the phase 3 HELIOS-A study (NCT03759379), vutrisiran significantly improved a range of disease-related endpoints compared with an external placebo in patients with hereditary transthyretin amyloidosis (ATTRv) with polyneuropathy (ATTRv-PN). This post hoc analysis examined the effects of vutrisiran in East Asian participants of HELIOS-A.

METHODS

HELIOS-A was a global, open-label, phase 3 study in which patients with ATTRv-PN were randomized 3:1 to receive subcutaneous vutrisiran 25 mg every 3 months or intravenous patisiran 0.3 mg/kg every 3 weeks for 18 months. The placebo group of the APOLLO study was used as an external placebo control. The primary endpoint was the change from baseline in the modified Neuropathy Impairment Score + 7 (mNIS + 7) score versus placebo at month 9; secondary endpoints included change from baseline in: Norfolk Quality of Life-Diabetic Neuropathy questionnaire score and 10-meter walk test speed at months 9 and 18, mNIS + 7 score, modified body mass index and Rasch-built Overall Disability Scale score at month 18, and serum transthyretin level through month 18.

RESULTS

Of the 122 patients receiving vutrisiran in HELIOS-A and 77 patients receiving placebo in APOLLO, 33 were East Asian (vutrisiran: 12, placebo: 21) and had similar baseline characteristics to the overall study cohorts. All outcomes, including the primary endpoint of change from baseline in mNIS + 7 score, showed changes that were consistent in direction and magnitude with the changes seen in the overall HELIOS-A analysis set. Adverse events (AEs) were broadly similar between the East Asian subpopulation and the overall HELIOS-A population; compared with the APOLLO placebo group, fewer patients died or experienced treatment-related AEs and serious AEs.

CONCLUSION

Although the number of East Asian patients in HELIOS-A was small, this post hoc analysis showed similar outcomes to those in the overall study populations, indicating that vutrisiran is effective and well tolerated in East Asian patients.