CompletedPhase 2Results posted

A Long-Term Safety Extension of Studies ABE4869g and ABE4955g in Participants With Mild to Moderate Alzheimer's Disease Treated With Crenezumab

A Multicenter, Open-Label, Long-Term Safety Extension of Phase II Studies ABE4869g and ABE4955g in Patients With Mild to Moderate Alzheimer's Disease

Lead sponsor

Genentech, Inc.

Asset

Crenezumab

Listed sites

Recruiting sites

Enrollment

360

actual

Study population

Alzheimer’s disease

Key I/E criteria

•Alzheimer's disease•MMSE 10•MRI contraindications excluded•Brain MRI excludes superficial siderosis

Primary endpoints

•Adverse Events (AEs)•Percentage of Participants by Nature of AEs•Percentage of Participants by Severity of AEs

Footprint

Where this trial recruits

Site locations as reported to ClinicalTrials.gov. Site count is not enrollment count; per-site enrollment is not available from source.

Identifiers

Registered as

Eudract number2012-003242-33

Org study IDGN28525

NCT IDNCT01723826

Timeline

Milestones

Study first posted2012-11-08estimated

Study start2012-12-07actual

Primary completion2017-02-08actual

Study completion2017-02-08actual

Results first posted2020-02-12actual

Last update posted2020-02-20actual

Assets

Drug assets

Crenezumab

Study populations

Who this study enrolls

Alzheimer’s disease

Eligibility

Who can enroll

Minimum age50 Years

SexAll

Healthy volunteersNot accepted

Inclusion criteria

•Previous participation in Study ABE4869g or ABE4955g and completion of the Week 73 visit

•Adequate visual and auditory acuity, in the investigator's judgment, to allow for neuropsychological testing

•Availability of a person ("caregiver") who can provide information on activities of daily living and behavior in order to complete the study-specific assessments

•Diagnosis of probable Alzheimer's disease according to the National Institute on Neurological and Communication Disease and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria (McKhann et al. 1984)

•Mini-Mental State Examination (MMSE) score of 10 or more at screening (Folstein et al. 1975)

•For male participants with partners with reproductive potential, agreement to use a reliable means of contraception (e.g., condoms) during the study and for at least 8 weeks following the last dose of study drug

•For female participants, a negative pregnancy test at screening

Exclusion criteria

•Early treatment and/or study discontinuation prior to completion of the Week 73 visit of Genentech Study ABE4869g or ABE4955g

•Early discontinuation from the treatment schedule of a prior version of Study GN28525 for safety reasons. If treatment discontinuation occurred for safety reasons, participants may not re-start dosing on extended treatment schedules offered in amendments to Study GN28525

•Inability to tolerate Magnetic Resonance Imaging (MRI) procedures or contraindication to MRI

•Female participants with reproductive potential: Female participants must either have undergone documented surgical sterilization or have not experienced menstruation for at least 12 consecutive months

•Severe or unstable medical condition that, in the opinion of the investigator or Sponsor, would interfere with the participant's ability to complete the study assessments or would require the equivalent of institutional or hospital care

•History or presence of clinically evident vascular disease potentially affecting the brain

•History of severe, clinically significant central nervous system trauma

•History or presence of clinically relevant intracranial tumor

•Presence of infections that affect the brain function or history of infections that resulted in neurologic sequelae

•History or presence of systemic autoimmune disorders potentially causing progressive neurologic disease

•History or presence of a neurologic disease other than Alzheimer's disease that may affect cognition

•History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric, human, or humanized antibodies or fusion proteins

•Evidence of malignancies (except squamous cell cancer or basal cell cancer of the skin), acute infections, renal failure that requires dialysis, or other unstable medical disease not related to Alzheimer's disease that, in the investigator's opinion, would preclude participant's participation. Cancer that is not being actively treated with anti-cancer therapy or radiotherapy as well as cancers which are considered to have low probability of recurrence are allowed

•History or presence of atrial fibrillation that, in the investigator's judgment, poses a risk for future stroke

•Chronic kidney disease of Stage greater than or equal to (>=) 4, according to the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) guidelines for chronic kidney disease (CKD)

•Impaired hepatic function

•Impaired coagulation (activated partial thromboplastin time [aPTT] greater than [>] 1.2 times upper limit of normal [ULN])

•Platelet count less than (<) 100,000 per microliter (mcL)

•Presence at screening of superficial siderosis of central nervous system, more than 8 cerebral microhemorrhages, or evidence of a prior cerebral macrohemorrhage

•Presence at screening of any other significant cerebral abnormalities, including ARIA-E

•Treatment with anticoagulation medications within 2 weeks prior to enrollment. Clopidogrel, dipyridamole, and aspirin are permitted

•Treatment with anticholinergic antidepressants, typical antipsychotics, or barbiturates within 2 weeks prior to enrollment. All other antidepressants and atypical antipsychotics are allowed with certain restrictions as defined in the protocol

•Chronic use of opiates, opioids, or benzodiazepines

•Any biologic therapy within 75 weeks prior to enrollment

•Any investigational agent (other than crenezumab) within 75 weeks prior to enrollment

•Treatment with anticholinergic antidepressants, typical antipsychotics, barbiturates, or narcotics within 5 half-lives or 3 months prior to screening, whichever is longer. All other antidepressants and atypical antipsychotics are allowed. Chronic use of benzodiazepines is not allowed; however, the intermittent use of benzodiazepines is allowed, except within 2 days prior to any neurocognitive assessment

Endpoints (12)

What's being measured

Protocol endpoints and posted registry outcome measures, grouped into outcome categories. Composite endpoints show their component event types. Standard codes (LOINC, SNOMED CT) are shown where available.

Coverage by outcome category

Safety / tolerability / PK

Amyloid biomarkers

Function / daily living

2 endpoints

Primary/protocol endpoint

Percentage of Participants by Severity of AEs

Time frame:Up to 50 months

threshold achievement, improvement

Primary/registry result

Percentage of Participants by Severity of AEs

Time frame:Up to 50 months

threshold achievement, improvement

Posted result

Group	Value (number), percentage of participants	Reported bounds
PCP PL - OLE CREN SC - OLE CREN IVGrade 1n=47 Participants	19.1	-
Grade 2n=47 Participants	44.7	-
Grade 3n=47 Participants	12.8	-
Grade 4n=47 Participants	8.5	-
Grade 5n=47 Participants	4.3	-
PCP PL - OLE CREN IVGrade 1n=63 Participants	34.9	-
Grade 2n=63 Participants	31.7	-
Grade 3n=63 Participants	17.5	-
Grade 4n=63 Participants	1.6	-
Grade 5n=63 Participants	4.8	-
PCP CREN - OLE CREN SC -OLE CREN IVGrade 1n=101 Participants	29.7	-
Grade 2n=101 Participants	43.6	-
Grade 3n=101 Participants	16.8	-
Grade 4n=101 Participants	3.0	-
Grade 5n=101 Participants	3.0	-
PCP CREN - OLE CREN IVGrade 1n=149 Participants	22.1	-
Grade 2n=149 Participants	40.3	-
Grade 3n=149 Participants	19.5	-
Grade 4n=149 Participants	1.3	-
Grade 5n=149 Participants	4.7	-

Amyloid biomarkers

4 endpoints

Primary/protocol endpoint

Percentage of Participants With Amyloid-Related Imaging Abnormalities Edema/Effusions (ARIA-E)

Time frame:Baseline, Weeks 23, 47, 71, 97, 121 and 153

threshold achievement, improvement

Primary/protocol endpoint

Percentage of Participants With Amyloid-Related Imaging Abnormalities-Hemorrhage (ARIA-H)

Time frame:Baseline, Weeks 23, 47, 71, 97, 121 and 153

threshold achievement, improvement

Primary/registry result

Percentage of Participants With Amyloid-Related Imaging Abnormalities Edema/Effusions (ARIA-E)

Time frame:Baseline, Weeks 23, 47, 71, 97, 121 and 153

threshold achievement, improvement

Posted result

Group	Value (number), percentage of participants	Reported bounds
PCP PL - OLE CREN SC - OLE CREN IVSymptomaticn=47 Participants	0	-
Asymptomaticn=47 Participants	0	-
PCP PL - OLE CREN IVSymptomaticn=63 Participants	0	-
Asymptomaticn=63 Participants	0	-
PCP CREN - OLE CREN SC -OLE CREN IVSymptomaticn=101 Participants	0	-
Asymptomaticn=101 Participants	0	-
PCP CREN - OLE CREN IVSymptomaticn=149 Participants	0	-
Asymptomaticn=149 Participants	0.7	-

Primary/registry result

Percentage of Participants With Amyloid-Related Imaging Abnormalities-Hemorrhage (ARIA-H)

Time frame:Baseline, Weeks 23, 47, 71, 97, 121 and 153

threshold achievement, improvement

Posted result

Group	Value (number), percentage of participants	Reported bounds
PCP PL - OLE CREN SC - OLE CREN IVSuperficial Siderosisn=47 Participants	2.1	-
New Micro-hemorrhagen=47 Participants	6.4	-
PCP PL - OLE CREN IVSuperficial Siderosisn=63 Participants	0	-
New Micro-hemorrhagen=63 Participants	9.5	-
PCP CREN - OLE CREN SC -OLE CREN IVSuperficial Siderosisn=101 Participants	3.0	-
New Micro-hemorrhagen=101 Participants	4.0	-
PCP CREN - OLE CREN IVSuperficial Siderosisn=149 Participants	0.7	-
New Micro-hemorrhagen=149 Participants	6.0	-

Safety / tolerability / PK

6 endpoints

Primary/protocol endpoint

Percentage of Participants With Adverse Events (AEs)

Time frame:Up to 50 months

threshold achievement, event

Primary/protocol endpoint

Percentage of Participants by Nature of AEs

Time frame:Up to 50 months

threshold achievement, event

Primary/protocol endpoint

Percentage of Participants With Human Anti-Therapeutic Antibody (ATA) Formation

Time frame:Pre-dose (Day-14), predose at Week 25, 49, 97, Follow-up Week 8 (Week 153) and 12 (Week 157)

threshold achievement, event

Primary/registry result

Percentage of Participants With Adverse Events (AEs)

Time frame:Up to 50 months

threshold achievement, event

Posted result

Group	Value (number), percentage of participants	Reported bounds
PCP PL - OLE CREN SC - OLE CREN IVn=47 Participants	89.4	-
PCP PL - OLE CREN IVn=63 Participants	90.5	-
PCP CREN - OLE CREN SC -OLE CREN IVn=101 Participants	96.0	-
PCP CREN - OLE CREN IVn=149 Participants	87.9	-

Primary/registry result

Percentage of Participants by Nature of AEs

Time frame:Up to 50 months

threshold achievement, event

Posted result

Group	Value (number), percentage of participants	Reported bounds
PCP PL - OLE CREN SC - OLE CREN IVSAEn=47 Participants	19.1	-
Non-SAEn=47 Participants	87.2	-
PCP PL - OLE CREN IVSAEn=63 Participants	22.2	-
Non-SAEn=63 Participants	88.9	-
PCP CREN - OLE CREN SC -OLE CREN IVSAEn=101 Participants	21.8	-
Non-SAEn=101 Participants	94.1	-
PCP CREN - OLE CREN IVSAEn=149 Participants	23.5	-
Non-SAEn=149 Participants	87.2	-

Primary/registry result

Percentage of Participants With Human Anti-Therapeutic Antibody (ATA) Formation

Time frame:Pre-dose (Day-14), predose at Week 25, 49, 97, Follow-up Week 8 (Week 153) and 12 (Week 157)

threshold achievement, event

Posted result

Group	Value (number), percentage of participants	Reported bounds
PCP PL - OLE CREN SC - OLE CREN IVn=47 Participants	9.1	-
PCP PL - OLE CREN IVn=63 Participants	3.4	-
PCP CREN - OLE CREN SC -OLE CREN IVn=101 Participants	9.1	-
PCP CREN - OLE CREN IVn=149 Participants	0.7	-

Provenance

Sources

Trial identity, design, statusClinicalTrials.gov API v2

Snapshot dateJuly 21, 2026

Endpoint classificationDelfa ADRD endpoint taxonomy

Results tableClinicalTrials.gov results section

Trial facts come from public ClinicalTrials.gov records. Endpoint categories are Delfa's classification of those records, not a ClinicalTrials.gov field. All figures reflect the July 21, 2026 snapshot.