A Phase 1/2a, Single- and Multiple-dose Escalation Study of KRRO-110

Inclusion Criteria: Part A SAD cohort Inclusion Criteria (Healthy Volunteers) * Adult male or female participants, 18 to 65 years of age * Documented PiMM genotype * Participants who are willing to and able to provide signed written informed consent PiZZ Genotype (Part A SAD and Part B MAD cohorts) Inclusion Criteria (PiZZ Genotype) * Adult male or female participants 18 to 70 years of age (inclusive) * Documented PiZZ genotype * Baseline blood total AAT level \< 11 µM/L Exclusion Criteria: Exclusion Criteria (Healthy Volunteers) * Female participant of childbearing potential or male participant that is unable or unwilling to use an approved, reliable means of contraception * Body mass index (BMI) \> 32 or \< 18.5 kg/m2 * History or current clinical evidence of hepatic disease * Evidence of active infection * History of medical condition(s), eg, advance cardiac disease, current or recent malignancy, organ transplantation, or other illness * Serology result indicative of any exposure (past or active) to hepatitis C, hepatitis B, or human immunodeficiency virus (HIV) * Respiratory or other acute illness within 8 weeks * Tobacco use of any kind within 6 months Exclusion Criteria (PiZZ Genotype) * Female participant of childbearing potential or male participant that is unable or unwilling to use an approved, reliable means of contraception * BMI \> 32 or \< 18.5 kg/m2 or weight \> 90 kg * History of FEV1 \< 35% * History or current clinical evidence of advanced hepatic disease and/or pulmonary disease * Use of an experimental therapy except KRRO-110 within 6 months or 5 half-lives for the experimental therapy, whichever is greater * Tobacco use of any kind within 6 months * Use of conventionally dosed AAT augmentation therapy within 5 half-lives * Serology result consistent with exposure to HIV, or serology consistent with active hepatitis B or hepatitis C infection