Low-density lipoprotein cholesterol ( LDL-C) is a key risk factor for atherosclerotic cardiovascular disease ( A SC VD) .Despite significant advancements in lipid modification therapies, including st atins , many patients with heterozygous familial hypercholesterolemia ( HeFH) fail to reach the desired LDL-C target levels.PCSK9, a newly identified enzyme, binds to the LDL receptor and promotes its degradation.While antibodies or siRNA against PCSK9 can significantly reduce LDL-C and cardiovascular events, 1 , 2 they require regular, long-term administration.Recent breakthroughs in CRISPR-based genome editing, specifically the CRISPR-Cas9 base editor, allow for the modification of single nucleotide bases without necessitating double-stranded DNA breaks. 3 , 4 This technology reduces off-target effects and enhances accuracy, making it suitable for clinical applications.VERVE-101, a CRISPR-based gene editing therapy, uses messenger RNA for an adenine base editor and a guide RNA targeting the PCSK9 gene.Packaged in a lipid nanoparticle delivery vehicle, it is administered systemically as a onetime intravenous infusion.This A/T to G/C base pair editing disrupts the PCSK9 splice donor site, inactivating the PCSK9 gene in the liver.This method has proven effective in reducing PCSK9 and LDL-C levels in both nonhuman primates and mice, with the LDL-C lowering effect in nonhuman primates lasting for over a year. 5The heart-1 clinical trial ( NCT05398029) , a first-in-human phase 1b, open-label study, was designed to assess the safety and tolerability of VERVE-101.Its interim results were presented at the American Heart Association's Scientific Sessions 2023 in Philadelphia on 12 November, 2023.In the heart-1 clinical trial, VERVE-101 was administered as a singular peripheral intravenous infusion.Ten participants, comprising eight males and two females with an average age of 54 years, received VERVE-101 across four dose cohorts ranging from 0.1 to 0.6 mg/k g .These individuals exhibited HeFH, with a mean LDL-C of 193 mg/dL at screening.Nearly all participants had a history of coronary revascularization, including coronary artery bypass and percutaneous coronary intervention.Sub-therapeutic doses ( 0.1 mg/kg: n = 3, 0.3 mg/kg: n = 3) were administered to six participants, while four individuals received potentially therapeutic doses ( 0.45 mg/kg: n = 3, 0.6 mg/kg: n = 1) .Nine participants reached a minimum of 28 days of follow-up and underwent analysis; one participant who received the 0.45 mg/kg dose had not reached day 28.