TTR and amyloidosis: ART001 is an <i>in vivo</i> gene therapy drug using lipid nanoparticle (LNP) to deliver mRNA encoding SpCas9 (<i>Streptococcus pyogenes</i> Cas9) and a single guide RNA (sgRNA) for knocking-out of the <i>TTR</i> gene in hepatocytes and reducing serum TTR levels.<h4>Methods</h4>In an investigator-initiated trial (IIT) of ART001 for 10 ATTR Amyloidosis patients, each patient was given one dose of ART001 which ranged from 0.05 mg/kg to 1.0 mg/kg.