This single-center, randomized open-label, single-dose, parallel group study will investigate the relative bioavailability of a high concentration liquid formulation (HCLF) versus the reference lyophilized formulation (LyoF) of gantenerumab. Healthy volunteers will be randomized 1:1 to receive single-dose gantenerumab by subcutaneous injection.

Inclusion Criteria:

• Healthy male and female subjects, 40 to 70 years of age inclusive. Healthy status is defined by absence of evidence any active or chronic disease following a detailed medical and surgical history, a complete physical examination including vital signs, 12-lead ECG, hematology, blood chemistry, coagulation, serology and urinalysis. Some medical conditions are allowed that are well controlled by single stable medication
• A BMI between 18.0 to 30.0 kg/m2 inclusive
• Use of highly effective contraception until 6 months after study follow-up visit
• Agree not to donate blood or blood products for transfusion for the duration of the study and for one year after their dosing

Exclusion Criteria:

• Suspicion of alcohol or drugs abuse addiction using DSM IV criteria
• Regular smoker (> 5 cigarettes, > 1 pipeful or > 1 cigar per day), tobacco users and subjects on nicotine replacement therapy
• Prior administration of gantenerumab
• Participation in an investigational drug or device study within 60 days before dosing
• Donation of blood over 500 mL within three months before dosing
• Pregnancy or breast-feeding
• Any abnormal skin conditions or potentially obscuring tattoos, pigmentation or lesions in the area intended for subcutaneous injection
• Any familial history of early onset Alzheimer's disease
• Claustrophobia, presence of pacemakers, aneurysm clips, artificial heart valves, ear implants, or foreign metal objects in the eyes, skin or body which would contraindicate an MRI scan