Study to Assess the Adverse Events and How Intravitreal ABBV-6628 Moves Through the Body of Adult Participants With Geographic Atrophy Secondary to Age-Related Macular Degeneration

Inclusion Criteria: Stage 1 and Stage 2 -Diagnosed with Geographic atrophy (GA) secondary to age-related macular degeneration (AMD) in the study eye. Stage 1 * Foveal or non-foveal GA with total GA lesion area ≥ 0.5 DA (1.25 mm2) in the study eye, as assessed by the investigator at Screening and confirmed by the central reading center prior to Baseline/Day 1 * Absence of choroidal neovascularization (CNV) in the study eye as assessed by the investigator at Screening and confirmed by the central reading center prior to Baseline/Day 1. In addition, investigators should confirm eligibility prior to treatment administration on Baseline/Day 1. Stage 2 * Non-foveal GA with total lesion area of 1 to 7 DA (2.5 to 17.5 mm2); within 0.5 to 1.5 mm from fovea center in the study eye, as assessed by the investigator at Screening and confirmed by the central reading center prior to Baseline/Day 1. * Absence of CNV in both eyes as assessed by the investigator at Screening and confirmed by the central reading center prior to Baseline/Day 1. In addition, investigators should confirm eligibility prior to treatment administration on Baseline/Day 1. Exclusion Criteria: Stage 1 and Stage 2 * History of recurrent or currently active ocular or intraocular inflammation (e.g., uveitis, endophthalmitis) in at least one eye at Screening and Baseline/Day 1. * Active periocular, ocular, or intraocular infection in at least one eye at Baseline/Day 1. * History or clinical signs of diabetic retinopathy, diabetic macular edema (DME), or any retinal vascular disease other than AMD in at least one eye at Screening and Baseline/Day 1.