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An Open Label Study of ANX005 in Participants With, or at Risk for, Manifest Huntington's Disease

A Phase 2a Open Label Study to Assess the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Intravenous ANX005 in Subjects With, or at Risk for, Manifest Huntington's Disease

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04514367
Enrollment
28
Registered
2020-08-14
Start date
2020-09-29
Completion date
2022-08-29
Last updated
2026-08-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Huntington Disease

Brief summary

This study is a multi-center, open-label study of intravenous (IV) ANX005 in participants with, or at risk for, manifest Huntington's Disease (HD).

Detailed description

The objective of this study is to evaluate the effects of IV ANX005 administered for up to 22 weeks in participants with, or at risk for, manifest HD. Participants will receive induction dosing of ANX005 administered by IV infusion on Days 1 and 5 or 6, followed by maintenance dosing every 2 weeks through Week 22, with follow up visits on Weeks 24, 28, and 36. All participants will be contacted (in clinic visit or phone call) 6 months after study completion.

Interventions

DRUGANX005

Intravenous Infusion

Sponsors

Annexon, Inc.
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

ANX005 administered for up to 22 weeks

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

1. Diagnosis of or at risk for HD: Genetically confirmed disease by direct deoxyribonucleic acid (DNA) testing, total cytosine-adenine-guanine (CAG)-Age Product (CAP) score \> 400 and UHDRS independence score ≥ 80. 2. Able to walk independently and self-sufficient in basic activities of daily living (for example, eating, dressing, bathing). 3. All HD concomitant medications stable. 4. If female, must be postmenopausal (no menses for at least 2 years without an alternative medical cause), surgically sterilized (bilateral tubal ligation, bilateral oophorectomy, or hysterectomy), or agree to use highly effective methods of contraception. 5. Males with a woman of childbearing potential partner must agree to use highly effective methods of contraception. 6. Previously vaccinated against encapsulated bacterial pathogens (Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae) or willing to undergo vaccination. 7. Able to tolerate electroencephalogram (EEG) and lumbar puncture (LP) procedures.

Exclusion criteria

1. Be at risk of suicide or self-harm within the preceding 12 months. 2. Chorea and/or cognitive deficits severe enough to interfere with study assessments. 3. Participants with body weight \> 150 kilograms (kg). 4. Clinically significant findings on the screening laboratory testing or physical examination that are not specific to HD and may interfere with the conduct of the study or the interpretation of the data or increase participant risk. 5. Signs and symptoms of, or a diagnosis consistent with a chronic autoimmune disorder and/or an antinuclear antibody (ANA) titer ≥ 1:160. 6. History of previous infusion reactions, sensitivities, allergic, or anaphylactic reactions to previous medications, environmental stimuli or other substances. 7. Use of an experimental agent within 60 days or five half-lives prior to Screening or anytime over the duration of this study. 8. Prior treatment with any monoclonal antibody. 9. Presence of an implanted deep brain stimulation device. 10. Any history of gene therapy, ribonucleic acid (RNA) or DNA targeted HD specific investigational agents such as antisense oligonucleotides, cell transplantation or any experimental brain surgery. 11. Brain and spinal pathology that may interfere with cerebrospinal fluid homeostasis and circulation, increases intracranial pressure (implanted shunt or catheter), malformations or tumor. 12. Contraindication to undergoing an LP. 13. Hypersensitivity to any of the excipients in the ANX005 drug product. 14. Clinically significant intercurrent illness, medical condition, or medical history (including neurological or mental illness, human immunodeficiency virus \[HIV\], any active infection, including Hepatitis B or C) that would jeopardize the safety of the participant, limit participation, or compromise the interpretation of the data derived from the participant. 15. Any known genetic deficiencies of the complement-cascade system. 16. History of chronic oral or intravenous steroid use or immunosuppressant medication use. 17. Hemoglobin, bilirubin, or lactate dehydrogenase (LDH) values that are outside normal limits and clinically significant or suggestive of hemolytic anemia.

Design outcomes

Primary

MeasureTime frameDescription
Number of Participants With Treatment-Emergent Adverse Events (TEAEs)From first dose of study drug up to end of study (Week 36)An adverse event (AE) was defined as any untoward medical occurrence that developed or worsened in severity during the conduct of a clinical study and does not necessarily have a causal relationship to study drug. Serious AEs (SAEs) included death, a life-threatening AE, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability or, a congenital anomaly or birth defect, or an important medical event that jeopardized the participant and required medical intervention to prevent 1 of the outcomes listed in this definition. A TEAE was any AE with an onset on or after the day of infusion through Week 36 (end of study). AEs were graded per National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE): Grade: 1=Mild, 2=Moderate, 3=Severe or medically significant but not immediately life-threatening. A summary of serious and non-serious AEs regardless of causality is located in 'Reported Adverse Events module'.
Actual Dose of ANX005 Administered on Day 1Day 1
Actual Dose of ANX005 Administered on Week 22Week 22
Area Under the Concentration Versus Time Curve From Time 0 to t (AUC0-t) of ANX005 at Day 1Pre-dose up to 4 hours post-dose on Day 1
CSF Free Complement Component 1q (C1q) at Day 1Predose at Baseline (Day 1)
Blood Free C1q at Day 1Predose at Baseline (Day 1)
Change From Baseline in Complement C4a in CSF at Week 24Baseline, Week 24
Change From Baseline in Complement C4a in CSF at Week 36Baseline, Week 36
Change From Baseline in CSF NfL Level at Week 24Baseline, Week 24
Change From Baseline in CSF NfL Level at Week 36Baseline, Week 36
Change From Baseline in Blood NfL Level at Week 24Baseline, Week 24
Change From Baseline in Blood NfL Level at Week 36Baseline, Week 36

Countries

United States

Contacts

STUDY_DIRECTORBenjamin Hoehn, MD

Annexon, Inc.

Baseline characteristics

Characteristic
Age, Continuous49.7 years
STANDARD_DEVIATION 12.51
Blood C1q85.589 µg/mL
STANDARD_DEVIATION 14.0165
Blood NfL Level39.51 ng/L
STANDARD_DEVIATION 11.661
Complement C4a in Cerebrospinal Fluid (CSF)15.16 micrograms (µg)/liter (L)
STANDARD_DEVIATION 6.092
CSF C1q0.2297 µg/mL
STANDARD_DEVIATION 0.06239
CSF Neurofilament Light Chain (NfL) Level3236.1 nanograms (ng)/L
STANDARD_DEVIATION 816.74
Ethnicity (NIH/OMB)
Hispanic or Latino
1 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
27 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
Race (NIH/OMB)
Asian
0 Participants
Race (NIH/OMB)
Black or African American
0 Participants
Race (NIH/OMB)
More than one race
0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
Race (NIH/OMB)
White
28 Participants
Sex: Female, Male
Female
12 Participants
Sex: Female, Male
Male
16 Participants

Adverse events

Event typeEG000
affected / at risk
deaths
Total, all-cause mortality
0 / 28
other
Total, other adverse events
28 / 28
serious
Total, serious adverse events
2 / 28

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Aug 26, 2026