Fazirsiran for Adults With Alpha-1 Antitrypsin Deficiency Liver Disease: A Phase 2 Placebo Controlled Trial (SEQUOIA)

Homozygous ZZ alpha-1 antitrypsin (AAT) deficiency produces mutant AAT (Z-AAT) proteins in hepatocytes, leading to progressive liver fibrosis. We evaluated the safety and efficacy of an investigational RNA interference therapeutic, fazirsiran, that degrades Z-AAT messenger RNA, reducing deleterious protein synthesis.

This ongoing, phase 2 study randomized 40 patients to subcutaneous placebo or fazirsiran 25, 100, or 200 mg. The primary endpoint was percent change in serum Z-AAT concentration from baseline to week 16. Patients with fibrosis on baseline liver biopsy received treatment on day 1, at week 4, and then every 12 weeks and had a second liver biopsy at or after weeks 48, 72, or 96. Patients without fibrosis received 2 doses on day 1 and at week 4.

At week 16, least-squares mean percent declines in serum Z-AAT concentration were -61%, -83%, and -94% with fazirsiran 25, 100, and 200 mg, respectively, vs placebo (all P < .0001). Efficacy was sustained through week 52. At postdose liver biopsy, fazirsiran reduced median liver Z-AAT concentration by 93% compared with an increase of 26% with placebo. All fazirsiran-treated patients had histologic reduction from baseline in hepatic globule burden. Portal inflammation improved in 5 of 12 and 0 of 8 patients with a baseline score of >0 in the fazirsiran and placebo groups, respectively. Histologic meta-analysis of histologic data in viral hepatitis score improved by >1 point in 7 of 14 and 3 of 8 patients with fibrosis of >F0 at baseline in the fazirsiran and placebo groups, respectively. No adverse events led to discontinuation, and pulmonary function tests remained stable.

Fazirsiran reduced serum and liver concentrations of Z-AAT in a dose-dependent manner and reduced hepatic globule burden. (ClinicalTrials.gov, Number NCT03945292).