The purpose of this study is to assess the relative bioavailability of the high concentration liquid formulation (HCLF) of gantenerumab produced with the G4 process in comparison to the same HCLF of gantenerumab produced with the G3 process in healthy participants following single SC dose administration.

This multi-center, randomized, open-label, single dose, parallel-group study will assess the relative bioavailability and the safety and tolerability of gantenerumab produced with the G4 process in comparison to gantenerumab produced with the G3 process. All participants will receive single SC dose of gantenerumab (manufactured by either the G3 or G4 process) on Day 1. The total duration of the study for each participant will be up to 21 weeks: Screening (up to 8 weeks); In-clinic period (Days -1 to 3); Out-patient period (Days 4 up to 68); and Safety Follow-up (up to 90 days after dosing).

Inclusion Criteria:

• Healthy participant
• Body mass index (BMI) between 18.0 and 30.0 kilograms per meter-square (kg/m^2), inclusive
• Body weight between 55 to 110 kg inclusive
• Female participants with either non-childbearing potential or with childbearing potential who commit to remain abstinent or use acceptable contraceptive methods during the treatment period and until at least 6 months after the follow-up visit
• Women of childbearing potential must have a negative serum pregnancy test result at screening and Day 1

Exclusion Criteria:

• History of any clinically significant gastrointestinal, renal, hepatic, broncho-pulmonary, neurological, psychiatric, cardio-vascular, endocrinological, hematological or allergic disease, metabolic disorder, cancer, or cirrhosis
• History or suspicion of drugs of abuse addiction
• History or suspicion of alcohol addiction
• Pregnant or breastfeeding, or intending to become pregnant during the study or within 17 weeks after the last dose of study drug
• Prior administration of gantenerumab
• Clinically significant abnormalities (as judged by the investigator) in laboratory test results (including complete blood count, chemistry panel, and urinalysis)
• Concomitant disease or condition that could interfere with, or treatment of which might interfere with, the conduct of the study, or that would, in the opinion of the investigator, pose an unacceptable risk to the participant in this study