Trial Outcomes & Findings for A Study to Evaluate Safety and Tolerability of Aducanumab in Participants With Alzheimer's Disease Who Had Previously Participated in the Aducanumab Studies 221AD103, 221AD301, 221AD302 and 221AD205 (NCT NCT04241068)

Last Updated: 2025-02-21

Results Overview

An AE is any untoward medical occurrence in a participant/clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with use of medicinal(investigational) product, whether or not related to medicinal (investigational) product. An SAE is any untoward medical occurrence that at any dose results in death, is a life-threatening event, requires inpatient hospitalization or prolongation of existing hospitalization, results in significant disability/incapacity or congenital anomaly, is medically important event. TEAE or Serious TEAEs are defined as any AE that has an onset date and time that is on or after date and time of first dose of study treatment, or that has worsened after date and time of first dose of study treatment.

Recruitment status

TERMINATED

Study phase

PHASE3

Target enrollment

1696 participants

Primary outcome timeframe

From the first dose of study drug to end of follow-up (up to Week 118)

Results posted on

2025-02-21

Participant Flow

Participants took part in the study at the investigative sites in the United States, Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Italy, Japan, South Korea, Netherlands, Poland, Portugal, Spain, Sweden, Switzerland, Taiwan, and United Kingdom from 02 Mar 2020 to 22 Jul 2024.

A total of 1696 participants were enrolled and treated in the core period, of which 1118 participants completed the core period. Out of the participants who completed the core period, 1041 participants entered the long-term extension (LTE) period, and 508 participants completed the LTE period.

Participant milestones

Participant milestones
Measure	Aducanumab Participants were administered aducanumab 10 milligrams per kilogram (mg/kg) by intravenous (IV) infusions every four weeks (Q4W) for 100 weeks during the Core Treatment Period. Eligible participants continued to receive aducanumab 10 mg/kg IV infusion, Q4W, for 52 weeks during the LTE Treatment Period.
Core Treatment Period STARTED	1696
Core Treatment Period COMPLETED	1118
Core Treatment Period NOT COMPLETED	578
LTE Period STARTED	1041
LTE Period COMPLETED	508
LTE Period NOT COMPLETED	533

Reasons for withdrawal

Reasons for withdrawal
Measure	Aducanumab Participants were administered aducanumab 10 milligrams per kilogram (mg/kg) by intravenous (IV) infusions every four weeks (Q4W) for 100 weeks during the Core Treatment Period. Eligible participants continued to receive aducanumab 10 mg/kg IV infusion, Q4W, for 52 weeks during the LTE Treatment Period.
Core Treatment Period Adverse Event	91
Core Treatment Period Change of Treatment	4
Core Treatment Period Consent Withdrawn	143
Core Treatment Period Death	26
Core Treatment Period Disease Progression	67
Core Treatment Period Investigator Decision	40
Core Treatment Period Loss of Capacity	9
Core Treatment Period Lost to Follow-up	11
Core Treatment Period Relocation	4
Core Treatment Period Study Terminated by Sponsor	1
Core Treatment Period Study Visit Burden	40
Core Treatment Period Withdrawal by Guardian/caretaker	99
Core Treatment Period Missing	2
Core Treatment Period Reason Not Specified	41
LTE Period Adverse Event	19
LTE Period Change of Treatment	1
LTE Period Consent Withdrawn	71
LTE Period Death	8
LTE Period Disease Progression	11
LTE Period Investigator Decision	12
LTE Period Loss of Capacity	2
LTE Period Lost to Follow-up	7
LTE Period Relocation	6
LTE Period Site Terminated by Sponsor	26
LTE Period Study Terminated by Sponsor	276
LTE Period Study Visit Burden	10
LTE Period Withdrawal by Guardian/caretaker	19
LTE Period Reason Not Specified	65

Baseline Characteristics

A Study to Evaluate Safety and Tolerability of Aducanumab in Participants With Alzheimer's Disease Who Had Previously Participated in the Aducanumab Studies 221AD103, 221AD301, 221AD302 and 221AD205

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Aducanumab n=1696 Participants Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period. Eligible participants continued to receive aducanumab 10 mg/kg IV infusion, Q4W, for 52 weeks during the LTE Treatment Period.
Age, Continuous	73.1 years STANDARD_DEVIATION 7.34 • n=5 Participants
Sex: Female, Male Female	881 Participants n=5 Participants
Sex: Female, Male Male	815 Participants n=5 Participants
Race/Ethnicity, Customized Race · Asian	185 Participants n=5 Participants
Race/Ethnicity, Customized Race · Black or African American	8 Participants n=5 Participants
Race/Ethnicity, Customized Race · White	1399 Participants n=5 Participants
Race/Ethnicity, Customized Race · Not Reported Due to Confidentiality Regulations	55 Participants n=5 Participants
Race/Ethnicity, Customized Race · Other	3 Participants n=5 Participants
Race/Ethnicity, Customized Race · Unknown	46 Participants n=5 Participants
Race/Ethnicity, Customized Ethnicity · Hispanic or Latino	61 Participants n=5 Participants
Race/Ethnicity, Customized Ethnicity · Not Hispanic or Latino	1562 Participants n=5 Participants
Race/Ethnicity, Customized Ethnicity · Not Reported Due to Confidentiality Regulations	73 Participants n=5 Participants

PRIMARY outcome

Timeframe: From the first dose of study drug to end of follow-up (up to Week 118)

Population: The safety population for the core period included all participants who had received at least one dose of aducanumab in the core period.

Outcome measures

Outcome measures
Measure	Aducanumab n=1696 Participants Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period.
Core Treatment Period: Number of Participants With Treatment-Emergent Adverse Events (TEAEs) and Serious TEAEs TEAEs	1549 Participants
Core Treatment Period: Number of Participants With Treatment-Emergent Adverse Events (TEAEs) and Serious TEAEs Serious TEAEs	318 Participants

PRIMARY outcome

Timeframe: From the first dose of study drug to end of follow-up (up to Week 118)

Population: The safety population for the core period included all participants who had received at least one dose of aducanumab in the core period.

An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product.

Outcome measures

Outcome measures
Measure	Aducanumab n=1696 Participants Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period.
Core Treatment Period: Number of Participants With AEs Leading to Treatment Discontinuation (TD) and Study Withdrawal (SW) AEs leading to TD	168 Participants
Core Treatment Period: Number of Participants With AEs Leading to Treatment Discontinuation (TD) and Study Withdrawal (SW) AEs leading to SW	129 Participants

PRIMARY outcome

Timeframe: Up to Week 118

Population: The safety magnetic resonance imaging (MRI) population for the core period included all participants who had received at least one dose of aducanumab in the core period and had at least one post-baseline MRI assessment in the core period. Here, 'overall number of participants analyzed' signifies the number of participants with data available for outcome measure analysis.

Number of participants diagnosed with ARIA edema are reported.

Outcome measures

Outcome measures
Measure	Aducanumab n=1656 Participants Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period.
Core Treatment Period: Number of Participants With Amyloid-Related Imaging Abnormality-Edema (ARIA-E)	422 Participants

PRIMARY outcome

Timeframe: Up to Week 118

Population: The safety MRI population for the core period included all participants who had received at least one dose of aducanumab in the core period and had at least one post-baseline MRI assessment in the core period. Here, 'overall number of participants analyzed' signifies the number of participants with data available for outcome measure analysis.

Number of participants diagnosed with ARIA hemmorrhage or superficial siderosis are reported.

Outcome measures

Outcome measures
Measure	Aducanumab n=1656 Participants Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period.
Core Treatment Period: Number of Participants With Amyloid-Related Imaging Abnormality- Hemorrhage or Superficial Siderosis (ARIA-H)	505 Participants

PRIMARY outcome

Timeframe: Up to Week 102

Population: The immunogenicity population for the core period included all participants who had received at least one dose of aducanumab in the core period and had at least one post-dose sample evaluated for immunogenicity in the core period. Here, 'overall number of participants analyzed' signifies the number of participants with data available for outcome measure analysis.

The presence of serum ADAs was determined using a validated assay. A standard 3-tiered approach was used including screening assay, confirmatory assay, and titration assay. The number of participants with a positive response to ADAs are reported.

Outcome measures

Outcome measures
Measure	Aducanumab n=1595 Participants Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period.
Core Treatment Period: Number of Participants With Positive Antidrug Antibodies (ADAs) in Serum	19 Participants

Adverse Events

Aducanumab

Serious events: 416 serious events

Other events: 1351 other events

Deaths: 37 deaths

Serious adverse events

Serious adverse events
Measure	Aducanumab n=1696 participants at risk Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period. Eligible participants continued to receive aducanumab 10 mg/kg IV infusion, Q4W, for 52 weeks during the LTE Treatment Period.
General disorders General physical health deterioration	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Malaise	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Multiple organ dysfunction syndrome	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Non-cardiac chest pain	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Pyrexia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Sudden death	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Blood and lymphatic system disorders Anaemia vitamin b12 deficiency	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Blood and lymphatic system disorders Normocytic anaemia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Acute coronary syndrome	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Acute myocardial infarction	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Atrial fibrillation	0.77% 13/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Atrioventricular block	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Atrioventricular block complete	0.29% 5/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Atrioventricular block second degree	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Bradyarrhythmia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Bradycardia	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Cardiac arrest	0.41% 7/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Cardiac failure	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Cardiac failure chronic	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Cardiac failure congestive	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Cardio-respiratory arrest	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Coronary artery occlusion	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Left ventricular failure	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Myocardial infarction	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Pericarditis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Sinus node dysfunction	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Stress cardiomyopathy	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Supraventricular tachycardia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Tachycardia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Ventricle rupture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Ventricular extrasystoles	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Cardiac disorders Ventricular tachycardia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Ear and labyrinth disorders Vertigo positional	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Eye disorders Cataract	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Eye disorders Retinal detachment	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Abdominal hernia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Anorectal disorder	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Ascites	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Colitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Colitis ischaemic	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Constipation	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Diverticulum intestinal haemorrhagic	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Duodenal perforation	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Duodenal ulcer	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Duodenal ulcer haemorrhage	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Enteritis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Faecaloma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Gastrointestinal disorder	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Gastrointestinal haemorrhage	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Gastrooesophageal reflux disease	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Haemorrhoidal haemorrhage	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Inguinal hernia	0.29% 5/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Intestinal ischaemia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Intestinal obstruction	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Large intestine polyp	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Leukoplakia oral	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Obstructive pancreatitis	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Oesophageal motility disorder	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Pancreatitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Rectal prolapse	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Small intestinal obstruction	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Small intestinal perforation	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Umbilical hernia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Vomiting	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Asthenia	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Chest pain	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Death	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Gait disturbance	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Systemic inflammatory response syndrome	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Hepatobiliary disorders Bile duct stone	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Hepatobiliary disorders Biliary colic	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Hepatobiliary disorders Cholecystitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Hepatobiliary disorders Cholecystitis acute	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Hepatobiliary disorders Cholelithiasis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Immune system disorders Anaphylactic reaction	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Immune system disorders Anaphylactic shock	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Acute sinusitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Appendicitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Appendicitis perforated	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Bacterial infection	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Bronchitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Cat scratch disease	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Cellulitis	0.29% 5/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Clostridium difficile colitis	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Covid-19	0.94% 16/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Covid-19 pneumonia	0.47% 8/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Cystitis	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Diverticulitis	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Diverticulitis intestinal perforated	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Enterococcal sepsis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Enterovirus infection	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Escherichia urinary tract infection	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Gastroenteritis	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Gingivitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Infective exacerbation of bronchiectasis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Influenza	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Klebsiella urinary tract infection	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Lower respiratory tract infection	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Meningitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Nasopharyngitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Neuroborreliosis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Neutropenic sepsis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Osteomyelitis	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Pneumonia	0.59% 10/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Pneumonia aspiration	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Post procedural infection	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Pyelonephritis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Pyelonephritis acute	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Respiratory tract infection	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Sepsis	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Septic shock	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Staphylococcal sepsis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Streptococcal infection	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Subdural abscess	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Tracheobronchitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Urinary tract infection	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Urinary tract infection pseudomonal	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Urosepsis	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Accident	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Accidental overdose	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Acetabulum fracture	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Ankle fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Arthropod sting	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Cardiac valve replacement complication	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Cervical vertebral fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Concussion	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Contusion	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Craniocerebral injury	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Fall	3.5% 59/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Femoral neck fracture	0.83% 14/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Femur fracture	0.35% 6/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Forearm fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Foreign body in urogenital tract	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Fractured sacrum	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Hand fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Head injury	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Hip fracture	0.41% 7/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Humerus fracture	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Incisional hernia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Lumbar vertebral fracture	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Multiple fractures	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Patella fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Pelvic fracture	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Post procedural haemorrhage	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Procedural pain	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Procedural pneumothorax	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Radius fracture	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Rib fracture	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Road traffic accident	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Spinal compression fracture	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Spinal fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Subdural haematoma	0.41% 7/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Subdural haemorrhage	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Thoracic vertebral fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Tibia fracture	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Tooth injury	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Toxicity to various agents	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Traumatic intracranial haemorrhage	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Ulna fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Urinary retention postoperative	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Wrong product administered	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Investigations Colonoscopy	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Metabolism and nutrition disorders Decreased appetite	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Metabolism and nutrition disorders Dehydration	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Metabolism and nutrition disorders Failure to thrive	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Metabolism and nutrition disorders Hyponatraemia	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Metabolism and nutrition disorders Hypovolaemia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Metabolism and nutrition disorders Malnutrition	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Arthralgia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Back pain	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Chest wall haematoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Chondrocalcinosis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Lumbar spinal stenosis	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Muscular weakness	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Osteoarthritis	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Osteoporotic fracture	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Polymyalgia rheumatica	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Systemic lupus erythematosus	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Adenocarcinoma of colon	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Adenocarcinoma pancreas	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Atypical fibroxanthoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Basal cell carcinoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Benign nipple neoplasm	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Bladder cancer	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Bladder transitional cell carcinoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Breast cancer	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Endometrial cancer stage i	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Follicular lymphoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Gastric cancer	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Gastric cancer recurrent	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Glioblastoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Glioblastoma multiforme	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Intraductal papillary mucinous neoplasm	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Invasive ductal breast carcinoma	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Invasive lobular breast carcinoma	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Invasive papillary breast carcinoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Lung adenocarcinoma	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Lung adenocarcinoma stage iii	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Lung cancer metastatic	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Lung neoplasm malignant	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Lung squamous cell carcinoma stage iii	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Malignant melanoma	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Malignant peritoneal neoplasm	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Meningioma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Metastatic bronchial carcinoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Metastatic uterine cancer	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Ovarian cancer	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Pancreatic carcinoma	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Prostate cancer	0.29% 5/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Prostatic adenoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Squamous cell carcinoma of lung	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Squamous cell carcinoma of the tongue	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Uterine cancer	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Waldenstrom's macroglobulinaemia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Amyloid related imaging abnormality-microhaemorrhages and haemosiderin deposits	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Amyloid related imaging abnormality-oedema/effusion	0.53% 9/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Autonomic nervous system imbalance	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Bell's palsy	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Carotid artery occlusion	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Carotid artery stenosis	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Cerebellar haematoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Cerebellar stroke	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Cerebral haemorrhage	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Cerebral infarction	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Cerebral ischaemia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Cerebrovascular accident	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Dementia alzheimer's type	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Dementia of the alzheimer's type, with delirium	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Dementia with lewy bodies	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Dizziness	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Embolic stroke	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Encephalopathy	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Epilepsy	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Generalised tonic-clonic seizure	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Haemorrhagic cerebral infarction	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Haemorrhagic stroke	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Idiopathic generalised epilepsy	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Ischaemic cerebral infarction	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Ischaemic stroke	0.53% 9/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Loss of consciousness	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Mental impairment	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Metabolic encephalopathy	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Myelopathy	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Presyncope	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Psychomotor hyperactivity	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Seizure	0.77% 13/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Small fibre neuropathy	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Status epilepticus	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Subarachnoid haemorrhage	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Syncope	1.4% 23/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Transient global amnesia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Transient ischaemic attack	0.47% 8/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Aggression	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Agitation	0.59% 10/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Behaviour disorder	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Confusional state	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Delirium	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Disorientation	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Mental status changes	0.41% 7/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Neuropsychological symptoms	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Psychiatric decompensation	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Somatic symptom disorder	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Suicidal ideation	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Suicide attempt	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Tic	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders Acute kidney injury	0.24% 4/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders Chronic kidney disease	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders End stage renal disease	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders Haematuria	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders Hydronephrosis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders Nephrolithiasis	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders Renal colic	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Renal and urinary disorders Urinary retention	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Reproductive system and breast disorders Benign prostatic hyperplasia	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Reproductive system and breast disorders Breast haematoma	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Reproductive system and breast disorders Breast swelling	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Reproductive system and breast disorders Colpocele	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Reproductive system and breast disorders Female genital tract fistula	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Reproductive system and breast disorders Prostatitis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Acute respiratory failure	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Atelectasis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Choking	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Chronic obstructive pulmonary disease	0.12% 2/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Dyspnoea	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Hypoxia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Obstructive sleep apnoea syndrome	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Pulmonary embolism	0.59% 10/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Pulmonary fibrosis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Respiratory failure	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Skin and subcutaneous tissue disorders Angioedema	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Skin and subcutaneous tissue disorders Leukoplakia	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Social circumstances Loss of personal independence in daily activities	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Aortic stenosis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Deep vein thrombosis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Hypertension	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Hypertensive crisis	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Hypotension	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Internal haemorrhage	0.06% 1/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Orthostatic hypotension	0.18% 3/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).

Other adverse events

Other adverse events
Measure	Aducanumab n=1696 participants at risk Participants were administered aducanumab 10 mg/kg by IV infusions, Q4W for 100 weeks during the Core Treatment Period. Eligible participants continued to receive aducanumab 10 mg/kg IV infusion, Q4W, for 52 weeks during the LTE Treatment Period.
Gastrointestinal disorders Constipation	5.1% 87/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Gastrointestinal disorders Diarrhoea	7.7% 130/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
General disorders Fatigue	5.8% 98/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Covid-19	25.2% 427/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Nasopharyngitis	6.3% 107/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Infections and infestations Urinary tract infection	7.2% 122/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Contusion	5.4% 92/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Injury, poisoning and procedural complications Fall	20.9% 355/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Investigations Weight decreased	5.4% 91/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Arthralgia	9.3% 158/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Musculoskeletal and connective tissue disorders Back pain	8.3% 140/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Amyloid related imaging abnormality-microhaemorrhages and haemosiderin deposits	26.1% 443/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Amyloid related imaging abnormality-oedema/effusion	25.0% 424/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Dizziness	8.6% 146/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Headache	14.5% 246/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Nervous system disorders Superficial siderosis of central nervous system	13.7% 232/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Psychiatric disorders Anxiety	6.1% 104/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Respiratory, thoracic and mediastinal disorders Cough	6.1% 103/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).
Vascular disorders Hypertension	7.7% 130/1696 • From first dose of study drug up to last follow-up visit (up to Week 170) The safety population included all participants who had received at least one dose of aducanumab in this study (221AD304).

Additional Information

US Biogen Clinical Trial Center

Biogen

Phone: 866-633-4636

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee Our agreement is subject to confidentiality but generally the PI can publish, for non-commercial purposes only, results and methods of the trial, but no other Sponsor Confidential Information. PI must give Sponsor no less than 60 days to review any manuscript for a proposed publication and must delay publication for up to an additional 90 days thereafter if Sponsor needs to file any patent application to protect any of Sponsor's intellectual property contained in the proposed publication.
Publication restrictions are in place

Restriction type: OTHER