A Study of Gantenerumab in Participants With Prodromal Alzheimer's Disease

Alzheimer's Disease Clinical Trial

— Scarlet Road  

Official title:

Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Two Year Study to Evaluate the Effect of Subcutaneous RO4909832 on Cognition and Function in Prodromal Alzheimer's Disease With Option for up to an Additional Two Years of Treatment and an Open-Label Extension With Active Study Treatment

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01224106
• Other study ID #: WN25203
• Secondary ID: 2010-019895-66
• Status: Completed
• Phase: Phase 3
• Start date: November 30, 2010
• Est. completion date: September 10, 2020

Study information

• Verified date: December 2021
• Source: Hoffmann-La Roche
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This multi-center, randomized, double-blind, placebo-controlled parallel-group study will evaluate the effect of gantenerumab (RO4909832) on cognition and functioning and the safety and pharmacokinetics in participants with prodromal Alzheimer's Disease. Participants will be randomized to receive subcutaneous (SC) injections of either gantenerumab or placebo. Participants who consent to be part of the sub study will undergo positron emission tomography (PET) scanning to assess brain amyloid. The anticipated time on study treatment is 104 weeks in Part 1, with an option for an additional up to 2 years of treatment in Part 2, followed by an open-label extension (Part 3) until July 2020.

The dosing for Parts 1 and 2 was stopped after a planned futility interim analysis showed a low probability of meeting the primary outcome measure with the doses studied. The study has converted to open-label to investigate higher gantenerumab doses.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 799
• Est. completion date: September 10, 2020
• Est. primary completion date: September 10, 2020
• Accepts healthy volunteers: No
• Gender: All
• Age group: 50 Years to 85 Years

Eligibility

Inclusion Criteria:

• Adult participants, 50-85 years of age

• Participants with prodromal Alzheimer's disease who are not receiving memantine or cholinesterase inhibitors

• Has a study partner who in the investigator's judgement has frequent and sufficient contact with the participant as to be able to provide accurate information as to the participant's cognitive and functional abilities, who agrees to provide information at clinic visits which require partner input for scale completion

• Has had sufficient education or work experience to exclude mental retardation

• Study partner has noticed a recent gradual decrease in participant's memory (over the last 12 months), which the participant may or may not be aware of

• Screening Mini Mental State Exam (MMSE) score of 24 or above

Additional inclusion criteria for sub study:

• Able and willing to travel to PET imaging center and complete the planned scanning sessions

• Past and planned exposure to ionizing radiation not exceeding safe and permissible levels

Exclusion Criteria:

• Other prior or current neurologic or medical disorder which may currently or during the course of the study impair cognition or psychiatric functioning

• A history of stroke

• A documented history of transient ischemic attack within the last 12 months

• History of schizophrenia, schizoaffective or bipolar disorder

• Currently meets criteria for major depression

• Within the last 2 years, unstable or clinical significant cardiovascular disease (myocardial infarction, angina pectoris)

Additional exclusion criteria for sub study:

• Inclusion in a research and/or medical protocol involving PET ligands or other radioactive agents within 12 months

• Present or planned participation in a research and/or medical protocol involving PET ligands or radioactive agents other than study WN25203

• Have planned or are planning to have exposure to ionizing radiation that in combination with the planned administration with study amyloid PET ligand would result in a cumulative exposure that exceeds local recommended exposure limits

Related Conditions & MeSH terms

• Alzheimer Disease
• Alzheimer's Disease

Intervention

Drug:
• Gantenerumab
Participants received Gantenerumab at 105 mg , 225 mg, or at doses up to 1200 mg SC injection Q4W.
• Placebo
Participants received Placebo SC injection Q4W.

Locations

Country	Name	City	State
Argentina	ALPI-Inst. de Rehabilitacion Marcelo Fitte	Buenos Aires
Argentina	CEMIC	Buenos Aires
Argentina	Hospital Italiano	Buenos Aires
Argentina	IME - Instituto Médico Especializado; Ensayos Clínicos	Buenos Aires
Argentina	FLENI	Caba
Argentina	Instituto De Neurología Cognitiva - INECO	Caba
Argentina	Mulieris	Caba
Argentina	Instituto Kremer	Córdoba
Argentina	CENPIA; Neurología - Psicología	La Plata
Australia	Royal Adelaide Hospital; Memory Trials Centre	Adelaide	South Australia
Australia	Heidelberg Repatriation Hospital; Medical and Cognitive Research Centre	Heidelberg West	Victoria
Australia	Hornsby Ku-ring-gai Hospital; Division of Rehabilitation & Aged Care	Hornsby	New South Wales
Australia	Australian Alzheimer's Research Foundation	Nedlands	Western Australia
Australia	Prince of Wales Hospital, Academic Department for Old Age Psychiatry	Randwick	New South Wales
Australia	The Queen Elizabeth Hospital; Neurology	Woodville	South Australia
Belgium	UZ Leuven Gasthuisberg	Leuven
Brazil	Hospital das Clinicas - UFPR; Ciencias da Saude	Curitiba	PR
Brazil	Hospital das Clinicas - UFRGS	Porto Alegre	RS
Brazil	Hospital Mae de Deus	Porto Alegre	RS
Brazil	Hospital das Clinicas - FMUSP; Psiquiatria	Sao Paulo	SP
Brazil	Universidade Federal de Sao Paulo - UNIFESPX; Neurologia	São Paulo	SP
Canada	NeuroSearch Developpements inc	Greenfield Park	Quebec
Canada	McGill University; Sir Mortimer B Davis Jewish General Hospital; Neurological and Psychiatric	Montreal	Quebec
Canada	True North Clinical Research	New Minas	Nova Scotia
Canada	Kawartha Centre - Redefining Healthy Aging	Peterborough	Ontario
Canada	CHAUQ - Hôpital Enfant-Jésus	Quebec City	Quebec
Canada	Centre for Memory and Aging	Toronto	Ontario
Canada	Toronto Memory Program	Toronto	Ontario
Chile	Biomedica Research Group	Santiago
Chile	Especialidades Medicas LYS	Santiago
Czechia	St. Anne´s University Hospital; Clinical Trials Department	Brno
Czechia	Vestra Clinics s.r.o.	Rychnov nad Kneznou
Denmark	Aarhus Universitetshospital, Neurologisk Afdeling F, Demensklinikken	Aarhus N
Denmark	Rigshospitalet, Hukommelsesklinikken	Koebenhavn Oe
Finland	CRST Oy	Turku
France	Hopital Avicenne; Neurologie	Bobigny
France	Hopital Pellegrin; Cmrr Aquitaine	Bordeaux
France	Hopital Pierre Wertheimer; Laboratoire De Neuro Psychologie	Bron
France	CHU De Caen; Service De Neurologie Dejerine	Caen
France	Hopital B Roger Salengro; Cmrr Lille	Lille
France	Ch Pitie Salpetriere; Cmrr Ile De France Salpetriere	Paris
France	CHU de Rouen Hopital; Service de Neurologie	Rouen
France	Hop Guillaume Et Rene Laennec; Cmrr St Herblain	St Herblain
France	Hopital Hautepierre; Centre dInvestigation Clinique	Strasbourg
France	Hopital de La Grave	Toulouse
Germany	Univ Berlin; Klin fur Psychi & Psycho Charite	Berlin
Germany	Universitätsklinikum Bonn; Medizinische Klinik und Poliklinik I; Allgemeine Innere Medizin	Bonn
Germany	Klinikum Joh.Wolfg.Goethe-UNI Zentrum d. Psychiatrie Klinik f. Psychiatrie Psychosomatik	Frankfurt
Germany	PANAKEIA - Arzneimittelforschung Leipzig GmbH	Leipzig
Germany	Zentralinstitut für Seelische Gesundheit Abt.Gerontopsychiatrie	Mannheim
Germany	Pharmakologisches Studienzentrum	Mittweida
Germany	Klinikum rechts der Isar der TU München; Klinik für Psychiatrie und Psychotherapie	München
Germany	Neurologische Praxis Dr. Andrej Pauls	München
Germany	Office of Dr Klaus Steinwachs Neurology & Psychiatry	Nürnberg
Germany	Universitätsklinikum Rostock Zentrum für Nervenheilkunde	Rostock
Germany	Universitätsklinikum Ulm; Klinik für Neurologie	Ulm
Italy	Azienda Ospedaliera Spedali Civili; Scienze Neurologiche	Brescia	Lombardia
Italy	IRCCS "Centro S. Giovanni di Dio" Fatebenefratelli -UO Alzheimer	Brescia	Lombardia
Italy	Irccs Multimedica Santa Maria; Unita' Di Neurologia	Castellanza	Lombardia
Italy	Uni Di Firenze Dip. Scienze Neurol Psic Sod Neurologia 1	Firenze	Toscana
Italy	Fondazione San Raffaele Del Monte Tabor; Dipartimento Di Neurologia	Milano	Lombardia
Italy	Nuovo Ospedale Civile S. Agostino-Estense; Clinica Neurologica - Dipartimento di Neuroscienze	Modena	Emilia-Romagna
Italy	Universita' Di Parma Istituto Neurologia	Parma	Emilia-Romagna
Italy	Azienda Ospedaliero Universitaria Ospedali Riuniti Umberto I-G.M. Lancisi-G. Salesi Di Ancona	Torrette - Ancona	Marche
Korea, Republic of	Seoul National University Bundang Hospital; Neurology Department	Gyeonggi-do
Korea, Republic of	Asan Medical Center.	Seoul
Korea, Republic of	Konkuk University Medical Center	Seoul
Korea, Republic of	Samsung Medical Center	Seoul
Korea, Republic of	Seoul St Mary's Hospital	Seoul
Mexico	Hospital Angeles de Culiacán, Neurociencias Estudios Clínicos SC	Culiacan
Mexico	Hospital Mexico Americano	Guadalajara	Mexico CITY (federal District)
Mexico	Unidad de Investigacion en Enfermedades Cronico-Degenerativa; Reumatologia	Guadalajara
Mexico	Estimulacion Magnetica Trnscraneal de Mexico SC.	Mexico City
Mexico	Centro Medico San Francisco; Geriatrics	Monterrey
Mexico	Hospital Universitario; Dr. Jose E. Gonzalez	Monterrey	Nuevo LEON
Mexico	Hospital Universitario de Saltillo	Saltillo
Netherlands	Jeroen Bosch Ziekenhuis; Polikliniek Geriatrie	'S Hertogenbosch
Netherlands	Brain Research Center B.V	Amsterdam
Poland	Podlaskie Centrum Psychogeriatrii	Bialystok
Poland	PALLMED Sp. z o.o. prowadzaca NZOZ DOM SUE RYDER	Bydgoszcz
Poland	NEURO - KARD Osrodek Badan Klinicznych	Poznan
Poland	mMED Maciej Czarnecki	Warszawa
Poland	Przychodnia Specjalistyczna PROSEN	Warszawa
Portugal	Hospital Prof. Dr. Fernando Fonseca; Servico de Neurologia	Amadora
Portugal	Hospital de Santa Maria; Servico de Neurologia	Lisboa
Russian Federation	Sverdlovsk Regional Clinical Psychoneurological War Veteran Hospital	Ekaterinburg
Russian Federation	State autonomous institution of healthcare Inter-regional clinical and diagnostic center	Kazan
Russian Federation	Saint Petersburg State Institution of Healthcare City Geriatric Medico-Social Center	Saint Petersburg
Russian Federation	City Clinical Hospital # 2 n.a. V.I. Razumovsky	Saratov
Russian Federation	Russian Medical Military Academy n.a. S.M.Kirov; Neurology Department	St. Petersburg
Spain	Hospital de Cruces; Servicio de Neurologia	Barakaldo	Vizcaya
Spain	Fundació ACE	BArcelon	Barcelona
Spain	Hospital Clinic i Provincial; Servicio de Neurologia	Barcelona
Spain	Hospital de la Santa Creu i Sant Pau; Servicio de Neurologia	Barcelona
Spain	Hospital del Mar; Servicio de Neurologia	Barcelona
Spain	Hospital Ramon y Cajal; Servicio de Neurologia	Madrid
Spain	Hospital Universitario 12 de Octubre; Servicio de Neurologia	Madrid
Spain	Hospital Universitario La Paz; Servicio de Neurologia	Madrid
Spain	Hospital Mutua De Terrasa; Servicio de Neurologia	Terrassa	Barcelona
Spain	Hospital Universitario Dr. Peset; Servicio de Neurologia	Valencia
Sweden	Skånes Universitetssjukhus Malmö, Minneskliniken	Malmö
Switzerland	Felix Platter-Spital Medizin Geriatrie	Basel
Switzerland	HUG; Département de santé mentale et de psychiatrie Unité de psychiatrie gériatrique	Chêne-Bourg
Turkey	Akdeniz University School of Medicine, Neurology Department	Antalya
Turkey	Istanbul University Istanbul School of Medicine; Neurology	Istanbul
Turkey	Ondokuz Mayis University School of Medicine; Neurology	Samsun
United Kingdom	Addenbrooke's Hospital	Cambridge
United Kingdom	Llandough Hospital; Llandough Hospital Memory Team 3rd Floor Academic Building	Cardiff
United Kingdom	St Margaret's Hospital	Epping
United Kingdom	Glasgow Memory Clinic	Glasgow
United Kingdom	Charing Cross Hospital; Dept of Neurosciences	London
United Kingdom	Campus for Ageing & Vitality; Clincal Ageing Research Unit	Newcastle
United Kingdom	Moorgreen Hospital; Memory Assessment & Rsch Ctr	Southampton
United Kingdom	Victoria Centre; Kingshill Research Centre	Swindon
United Kingdom	Hollins Park Hospital	Warrington
United States	Senior Adults Specialty Research	Austin	Texas
United States	Clinical Neuroscience Research Associates, Inc.	Bennington	Vermont
United States	Texas Neurology PA	Dallas	Texas
United States	Brain Matters Research, Inc.	Delray Beach	Florida
United States	Rhode Island Mood & Memory Research Institute	East Providence	Rhode Island
United States	Neurological Research Center	Hattiesburg	Mississippi
United States	Infinity Clinical Research	Hollywood	Florida
United States	Indiana University	Indianapolis	Indiana
United States	Western Michigan University Homer Stryker M.D. School of Medicine Center for Clinical Research	Kalamazoo	Michigan
United States	University of California, San Diego	La Jolla	California
United States	Alzheimer's Memory Center	Matthews	North Carolina
United States	Yale University ADRU	New Haven	Connecticut
United States	Boston Center for Memory	Newton	Massachusetts
United States	Nathan Kline Institute	Orangeburg	New York
United States	Accelerated Enrollment Solutions	Orlando	Florida
United States	Banner Alzheimer's Institute	Phoenix	Arizona
United States	Northeastern Pennsylvania Memory	Plains	Pennsylvania
United States	Oregon Health and Science University, Layton Aging and Alzheimer's Disease Center	Portland	Oregon
United States	Princeton Medical Institute	Princeton	New Jersey
United States	Butler Hospital	Providence	Rhode Island
United States	University of Rochester Medical Center; Monroe Community Hospital	Rochester	New York
United States	Roskamp Institute, Inc.	Sarasota	Florida
United States	Compass Research	The Villages	Florida
United States	Premiere Research Institute	West Palm Beach	Florida

Sponsors (1)

Lead Sponsor	Collaborator
Hoffmann-La Roche

Countries where clinical trial is conducted

United States,  Argentina,  Australia,  Belgium,  Brazil,  Canada,  Chile,  Czechia,  Denmark,  Finland,  France,  Germany,  Italy,  Korea, Republic of,  Mexico,  Netherlands,  Poland,  Portugal,  Russian Federation,  Spain,  Sweden,  Switzerland,  Turkey,  United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Mean Change From Baseline in Clinical Dementia Rating Scale Sum of Boxes (CDR-SOB) Total Score at Week 104 (Double-Blind Treatment Phase)	The CDR (Clinical Dementia Rating) is obtained through semi-structured interviews of participants and informants, and cognitive functioning is rated in six domains of functioning: memory, orientation, judgement and problem solving, community affairs, home and hobbies, and personal care. Each domain is rated on a five-point scale of functioning as follows: 0, no impairment; 0.5, questionable impairment; 1, mild impairment; 2, moderate impairment; and 3, severe impairment. The CDR-SOB (Clinical Dementia Rating-Sum of Boxes) is based on summing each of the domain box scores with total scores ranging from 0-18, where lower total scores represent better outcomes and higher total scores represent worse outcomes.	Baseline, Week 104
Primary	Number of Participants With Adverse Events (AEs) or Serious Adverse Events (SAEs) (OLE Phase)	An Adverse Event is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An adverse event can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as adverse events.	Baseline up until a maximum of 5 years
Secondary	Mean Change From Baseline in Alzheimer Disease Assessment Scale-Cognitive Subscale 11 (ADAS-Cog-11) Scores at Week 104 (Double-Blind Treatment Phase)	The ADAS-Cog-11 assesses multiple cognitive domains including memory, comprehension, praxis, orientation, and spontaneous speech. Most of these are assessed by tests although some are rated by the clinician on a 5-point scale. The score range for ADAS-Cog-11 is from 0 to 70 with higher scores representing severe dysfunction.	Baseline, Week 104
Secondary	Time to Onset of Dementia at Week 104 (Double-Blind Treatment Phase)	Time to Onset of Dementia was defined as the time interval between the first treatment date and the date that participant is assessed as having Alzheimer-type dementia by investigators.	Baseline, Week 104
Secondary	Mean Change From Baseline in Cambridge Neuropsychological Test Automated Battery (CANTAB) Composite Score at Week 104 (Double-Blind Treatment Phase)	The Cambridge Neuropsychological Test Automated Battery (CANTAB) ® is a cognitive test battery that incorporates a variety of executive and memory tasks in order to assess neuropsychological function. The end outcome as reported below, is a Z-Composite Score. The score range of the Z-Composite Score is from (-) infinity to (+) infinity with a score of zero representing the population mean, lower (negative) scores representing poorer cognitive outcomes and higher (positive) scores representing better cognitive outcomes.	Baseline, Week 104
Secondary	Mean Change From Baseline in Free and Cued Selective Reminding Test (FCSRT) Score at Week 104 (Double-Blind Treatment Phase)	FCSRT assesses verbal episodic memory. Performances in free recalls, cued recalls and in a recognition task were analyzed, as the process of encoding is controlled. Participants were asked to remember a list of 16 words. Three tasks of free and cued recalls, as well as 1 recognition task and one delayed recall give the scores. Total recall was obtained by the addition of cued recalls to free recalls. Maximum score is 48 for immediate: 16 words multiplied by (*) 3 corresponding to immediate free recall + immediate cued recall + immediate recognition test. Maximum score is 64 (better score) when delayed recall: 16 words*4. The minimum score is 0 (worse).	Baseline, Week 104
Secondary	Mean Change From Baseline in Functional Activities Questionnaire (FAQ) Score at Week 104 (Double-Blind Treatment Phase)	Participants completed the FAQ for physical function. Overall scores ranged from 0 (independent) to 30 (dependent) where lower scores represented an improvement in physical function.	Baseline, Week 104
Secondary	Mean Change From Baseline in CDR-Global Score at Week 104 (Double-Blind Treatment Phase)	The CDR-GS represents a semi-structured interview which rates impairment in 6 categories (memory, orientation, judgement and problem solving, community affairs, home and hobbies, and personal care) on a 5-point scale in which CDR 0 = no dementia and CDR 0.5, 1, 2 or 3 = questionable, mild, moderate or severe dementia respectively. The range in scores for the CDR-GS is from 0 to 3 and a high score on the CDR-GS would indicate a high disease severity.	Baseline, Week 104
Secondary	Mean Change From Baseline in Neuropsychiatric Inventory (NPI) Questionnaire Score at Week 104 (Double-Blind Treatment Phase)	The NPI is a retrospective (to 1 month) caregiver-informant interview assessing frequency and severity of 12 neuropsychiatric symptom domains. The NPI score is based on the sum of the severity ratings (0=absent, 1=mild, 3=severe). The 12 symptom domains include delusions, hallucinations, agitation/aggression, dysphoria/depression, anxiety, euphoria/elation, apathy/indifference, disinhibition, irritability/lability, aberrant motor behaviors, nighttime behavioral disturbances, and appetite/eating abnormalities. The NPI severity score is based on severity ratings (0=absent, 1=mild to 3=severe).	Baseline, Week 104
Secondary	Percentage Change From Baseline in Cerebrospinal Fluid Biomarkers (Phosphorylated-tau [P-tau], Amyloid Beta 1-42 [Abeta 1-42], Total Tau [T-tau]) at Week 104 (Double-Blind Treatment Phase)	CSF biomarker phospho-tau (p-tau) is an indicator of neuronal injury and neurodegeneration. An elevation in levels of tau, as well as specific p-tau species, is thought to be a marker for progressive cellular degeneration in AD.	Baseline, Week 104
Secondary	Percentage Change From Baseline in Hippocampal Volume at Week 104 (Double-Blind Treatment Phase)	Change from baseline in hippocampal right volume (HRV) and hippocampal left volume (HLV) were analysed at Week 104 using magnetic resonance imaging.	Baseline, Week 104
Secondary	Percentage Change From Baseline in Cortical Composite Sustained Uptake Volume Ratio (SUVr) in Different Brain Regions at Week 156 (Double-Blind Treatment Phase)	The different regions of the brain that were analyzed included cerebellum gray, whole cerebellum, composite white matter, subcortical white matter, pons and composite reference.	Baseline, Week 156
Secondary	Gantenerumab Plasma Concentrations at Different Time Points (Double-Blind Treatment Phase)	The PK analyses includes tabulation of plasma concentration data and summarisation of plasma concentrations by visits with participants grouped according to treatment received. Descriptive summary statistics for the Arithmetic Mean and Standard Deviation are presented below.	Pre-Dose: Weeks 8, 20, 44, 68 and 100; Post-Dose: Weeks 1, 53 and 101
Secondary	Mean Change From Baseline in Mini Mental State Exam (MMSE) Score at Week 104 (Double-Blind Treatment Phase)	The MMSE is a brief, practical screening test for cognitive dysfunction. The test consists of five sections (orientation, registration, attention-calculation, recall, and language); the total score can range from 0 to 30, with a higher score indicating better function. A positive change score indicates improvement.	Baseline, Week 104
Secondary	Number of Participants With Adverse Events (AEs) or Serious Adverse Events (SAEs) (Double-Blind Treatment Phase)	An Adverse Event is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An adverse event can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as adverse events.	Baseline up until a maximum of 4.5 years
Secondary	Percentage of Participants With Anti-Drug Antibodies (ADAs) (Double-Blind Treatment Phase)	Participants were considered positive or negative for ADA based on their baseline and post-baseline sample results. The number and percentage of participants with confirmed positive ADA levels were determined for Gantenerumab and Placebo groups. The prevalence of ADA at baseline was calculated as the proportion of participants with confirmed positive ADA levels at baseline relative to the total number of participants with a sample available at baseline. The incidence of treatment-emergent ADAs was determined as the proportion of participants with confirmed post-baseline positive ADAs relative to the total number of participants that had at least one post-baseline sample available for ADA analysis.	Baseline up until a maximum of 4.5 years
Secondary	Mean Change From Baseline in Alzheimer Disease Assessment Scale-Cognitive Subscale 11 (ADAS-Cog-11) Scores at Week 156 (OLE Phase)	The ADAS-Cog-11 assesses multiple cognitive domains including memory, comprehension, praxis, orientation, and spontaneous speech. Most of these are assessed by tests although some are rated by the clinician on a 5-point scale. The score range for ADAS-Cog-11 is from 0 to 70 with higher scores representing severe dysfunction.	Baseline, Week 156
Secondary	Mean Change From Baseline in Clinical Dementia Rating Scale Sum of Boxes (CDR-SOB) Total Score at Week 156 (OLE Phase)	The CDR (Clinical Dementia Rating) is obtained through semi-structured interviews of participants and informants, and cognitive functioning is rated in six domains of functioning: memory, orientation, judgement and problem solving, community affairs, home and hobbies, and personal care. Each domain is rated on a five-point scale of functioning as follows: 0, no impairment; 0.5, questionable impairment; 1, mild impairment; 2, moderate impairment; and 3, severe impairment. The CDR-SOB (Clinical Dementia Rating-Sum of Boxes) is based on summing each of the domain box scores with total scores ranging from 0-18, where lower total scores represent better outcomes and higher total scores represent worse outcomes.	Baseline, Week 156
Secondary	Mean Change From Baseline in Alzheimer Disease Assessment Scale-Cognitive Subscale 13 (ADAS-Cog-13) Scores at Week 156 (OLE Phase)	The ADAS-Cog-13 assesses multiple cognitive domains including memory, comprehension, praxis, orientation, and spontaneous speech. The score range for ADAS-Cog-13 is from 0 to 85 with higher scores representing severe dysfunction.	Baseline, Week 156
Secondary	Time to Onset of Dementia at Week 156 (OLE Phase)	Time to Onset of Dementia was defined as the time interval between the first treatment date and the date that participant is assessed as having Alzheimer-type dementia by investigators.	Baseline, Week 156
Secondary	Mean Change From Baseline in Free and Cued Selective Reminding Test (FCSRT) Score at Week 156 (OLE Phase)	FCSRT assesses verbal episodic memory. Performances in free recalls, cued recalls and in a recognition task were analyzed, as the process of encoding is controlled. Participants were asked to remember a list of 16 words. Three tasks of free and cued recalls, as well as 1 recognition task and one delayed recall give the scores. Total recall was obtained by the addition of cued recalls to free recalls. Maximum score is 48 for immediate: 16 words multiplied by (*) 3 corresponding to immediate free recall + immediate cued recall + immediate recognition test. Maximum score is 64 (better score) when delayed recall: 16 words*4. The minimum score is 0 (worse).	Baseline, Week 156
Secondary	Mean Change From Baseline in Functional Activities Questionnaire (FAQ) Score at Week 156 (OLE Phase)	Participants completed the FAQ for physical function. Overall scores ranged from 0 (independent) to 30 (dependent) where lower scores represented an improvement in physical function.	Baseline, Week 156
Secondary	Mean Change From Baseline in CDR-Global Score at Week 156 (OLE Phase)	The CDR-GS represents a semi-structured interview which rates impairment in 6 categories (memory, orientation, judgement and problem solving, community affairs, home and hobbies, and personal care) on a 5-point scale in which CDR 0 = no dementia and CDR 0.5, 1, 2 or 3 = questionable, mild, moderate or severe dementia respectively. The range in scores for the CDR-GS is from 0 to 3 and a high score on the CDR-GS would indicate a high disease severity.	Baseline, Week 156
Secondary	Percentage Change From Baseline in Hippocampal Volume at Week 152 (OLE Phase)	Change from baseline in hippocampal right volume (HRV) and hippocampal left volume (HLV) were analysed at Week 152 using magnetic resonance imaging.	Baseline, Week 152
Secondary	Percentage Change From Baseline in Cortical Composite Sustained Uptake Volume Ratio (SUVr) in Different Brain Regions at Week 156 (OLE Phase)	The regions of the brain that were analyzed included cerebellum gray and composite reference.	Baseline, Week 156
Secondary	Gantenerumab Plasma Concentrations at Different Time Points (OLE Phase)	The PK analyses includes tabulation of plasma concentration data and summarisation of plasma concentrations by visits with participants grouped according to treatment received. Descriptive summary statistics for the Arithmetic Mean and Standard Deviation are presented below.	Pre-Dose: Weeks 64, 100, 104, 136, 156 and 208; Post-Dose: Week 101
Secondary	Mean Change From Baseline in Mini Mental State Exam (MMSE) Score at Week 156 (OLE Phase)	The MMSE is a brief, practical screening test for cognitive dysfunction. The test consists of five sections (orientation, registration, attention-calculation, recall, and language); the total score can range from 0 to 30, with a higher score indicating better function. A positive change score indicates improvement.	Baseline, Week 156
Secondary	Percentage of Participants With Anti-Drug Antibodies (ADAs) (OLE Phase)	Participants were considered positive or negative for ADA based on their baseline and post-baseline sample results. The number and percentage of participants with confirmed positive ADA levels were determined. The prevalence of ADA at baseline was calculated as the proportion of participants with confirmed positive ADA levels at baseline relative to the total number of participants with a sample available at baseline. The incidence of treatment-emergent ADAs was determined as the proportion of participants with confirmed post-baseline positive ADAs relative to the total number of participants that had at least one post-baseline sample available for ADA analysis.	Baseline up until a maximum of 5 years