This study was discontinued due to an interim analysis in the BN29552 study, which indicated that Crenezumab was unlikely to meet its primary endpoint.

In the BN40031 OLE study, a dose of crenezumab of 60 mg/kg intravenous (IV) every 4 weeks (Q4W) will be offered to all participants who complete Study BN29552 or BN29553 and who meet eligibility criteria in order to evaluate safety in participants on long-term crenezumab treatment and to investigate the effect of crenezumab on the underlying disease process and disease course as an exploratory efficacy objective.

Inclusion Criteria:

• Previous participation in Study BN29552 or BN29553 and completion of the Week 105 visit.
• Able to provide written informed consent by the patient or legally authorized representative, if required.
• Every effort to have the same caregiver participate throughout the duration of the OLE (Open Label Extension) study who also participated in Study BN29552 or BN29553.
• Willingness and ability to complete all aspects of the study [including MRI (Magnetic Resonance Imaging), lumbar puncture [if applicable], and PET (Positron Emission Tomography) imaging [if applicable].
• Adequate visual and auditory acuity, in the investigator's judgment, sufficient to perform the neuropsychological testing.
• For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use a protocol approved contraceptive method and agreement to refrain from donating eggs for at least 8 weeks after last dose.
• For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use a protocol approved contraceptive method for at least 8 weeks after last dose.

Exclusion Criteria:

• Patients who discontinued treatment permanently in Study BN29552 or BN29553 for safety reasons.
• Impaired coagulation.
• Evidence of more than 10 microbleeds and/or ARIA-H (amyloid-related imaging abnormalities-hemosiderin deposition) at the Study BN29552 or BN29553 Week 105 visit, as assessed by central review of MRI.
• Diagnosed with three recurrent, symptomatic ARIA-E (amyloid-related imaging abnormalities-edema/effusion) events or exacerbations of previous events.
• Presence of intracranial lesion that could potentially increase the risk of CNS (Central Nervous System) bleeding.
• At risk of suicide in the opinion of the investigator.
• Alcohol and/or substance abuse or dependence within the past 2 years and during the study.
• Inability to tolerate MRI procedures or contraindication to MRI, including, but not limited to, presence of pacemakers not compatible with MRI, aneurysm clips, artificial heart valves, ear implants, or foreign metal objects in the eyes, skin, or body that would contraindicate an MRI scan; or any other clinical history or examination finding that, in the judgment of the investigator, would pose a potential hazard in combination with MRI.
• Pregnant or lactating, or intending to become pregnant during the study.
• Any other severe or unstable medical condition that, in the opinion of the investigator or Sponsor, could be expected to progress, recur, or change to such an extent that it could put the patient at special risk, bias the assessment of the clinical or mental status of the patient to a significant degree, or interfere with the patient's ability to complete the study assessments.
• Chronic use of anticoagulants or participation in any other investigational drug treatment trial.](streamdown:incomplete-link)

The Study being conducted under this Agreement is part of the Overall Study. Investigator is free to publish in reputable journals or to present at professional conferences the results of the Study, but only after the first publication or presentation that involves the Overall Study. The Sponsor may request that Confidential Information be deleted and/or the publication be postponed in order to protect the Sponsor's intellectual property rights.