Study of ALXN2220 Versus Placebo in Adults With ATTR-CM

Open to people ages 18-90

• Centrally confirmed diagnosis of ATTR-CM with either wild-type or variant TTR genotype
• End-diastolic interventricular septal wall thickness ≥ 11 mm for women or ≥ 12 mm for men on echocardiography measured at Screening
• NT-proBNP > 2000 pg/mL at Screening
• Treatment with a loop diuretic for at least 30 days prior to Screening
• History of heart failure NYHA Class II-IV at Screening
• Life expectancy of ≥ 6 months as per the Investigator's judgment
• Males and females of childbearing ability must use contraception

• Known leptomeningeal amyloidosis
• Known light chain (AL) or secondary amyloidosis (AA), or any other form of systemic amyloidosis
• Acute coronary syndrome, unstable angina, stroke, transient ischemic attack, coronary revascularization, cardiac device implantation, cardiac valve repair, or major surgery within 3 months of Screening
• Uncontrolled clinically significant cardiac arrhythmia, per Investigator's assessment
• LVEF < 30% on echocardiography
• Renal failure requiring dialysis or an eGFR < 20 mL/min/1.73 m2 at Screening
• Polyneuropathy with PND score IV