Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of ANX005 in Participants With Warm Autoimmune Hemolytic Anemia (wAIHA)

NCT04691570 | Completed Phase 2 Results FDA Drug

• 1 other identifier: ANX005-wAIHA-02
• Study Type: interventional
• Target: 7
• Locations: 3 countries
• Sites: 3

Brief Summary

This study will evaluate the safety and tolerability of ANX005 in participants with Warm Autoimmune Hemolytic Anemia (wAIHA).

Conditions

Warm Autoimmune Hemolytic Anemia (wAIHA)

Keywords

AIHA; C1q; complement; RBC lysis

Outcome Measures

Primary Outcomes (7)

• Number of Participants With Treatment-emergent Adverse Events (TEAEs)

  An adverse event (AE) was any untoward medical occurrence in a participant who had been administered a pharmaceutical product. An AE did not necessarily have a causal relationship with the product and therefore could be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a pharmaceutical product. An AE could arise with any use, route of administration, formulation, dose (including an overdose), or when used in combination with another pharmaceutical product. A TEAE was an AE with an onset date/time after the first infusion of ANX005 until the end of the study. A summary of serious and all other non-serious adverse events regardless of causality is located in the Adverse Events module.

  Day 1 through Day 71

• Maximum Change From Baseline in Hemoglobin Levels

  Maximum change from Baseline was calculated as the maximum post-Baseline value observed up to Day 71 minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005.

  Baseline up to Day 71

• Change From Baseline in Lactate Dehydrogenase Levels at Day 71

  Change from Baseline was calculated as the post-Baseline value at Day 71 minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005.

  Baseline, Day 71

• Change From Baseline in Percentage of Reticulocytes/Total Cells Count at Day 71

  Change from Baseline was calculated as the post-Baseline value at Day 71 minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005.

  Baseline, Day 71

• Change From Baseline in Haptoglobin Levels at Day 71

  Change from Baseline was calculated as the post-Baseline value at Day 71 minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005.

  Baseline, Day 71

• Change From Baseline in Total Bilirubin Levels at Day 71

  Change from Baseline was calculated as the post-Baseline value at Day 71 minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005.

  Baseline, Day 71

• Change From Baseline in Indirect Bilirubin Levels at Day 71

  Change from Baseline was calculated as the post-Baseline value at Day 71 minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005.

  Baseline, Day 71

Secondary Outcomes (3)

• Change in Percent Inhibition Complement CH50 From Baseline Through Day 71

  Baseline, Days 2, 4, 8, 15, 22, 29, 36, 43, 50, 57, and 71

• Change From Baseline in Complement C4 Level Through Day 71

  Baseline, Days 2, 4, 8 (pre-dose and end of infusion), 15, 22, 29, 36, 43, 50, 57, and 71

• Change From Baseline in Complement C1q Level Through Day 71

  Baseline, Days 2 (4 hours [hr] after Infusion and end of infusion), 4, 8 (pre-dose, 4 hr after Infusion, and end of infusion), 15, 22, 29, 36, 43, 50, 57, and 71

Study Arms (1)

ANX005

EXPERIMENTAL

Participants will receive two once-weekly doses of ANX005 at specific time points

Drug: ANX005

Interventions

ANX005 DRUG

ANX005 is provided as a solution for IV infusion

ANX005

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or non-pregnant, non-lactating female ≥18 years of age (no maximum age).
• Diagnosis of wAIHA at least 3 months prior to screening with a direct antiglobulin test (DAT) ≥1 positive for immunoglobulin G (IgG)±C3, or a diagnosis of mixed autoimmune hemolytic anemia (AIHA) that is DAT positive for both IgG and C3, with a presence of a cold antibody with a thermal amplitude ≥30ºCelcius.
• Hemoglobin (Hgb) level ≤10.0 grams/deciliter (pre-transfusion).
• Evidence of classical complement pathway activation.
• Evidence of active hemolysis.
• Stable use of glucocorticoids and immunosuppressants are permitted.
• Vaccinations against encapsulated bacterial organisms within 5 years prior to screening or participant must be willing to receive prophylaxis against infections with encapsulated bacteria via vaccination and/or the use of prophylactic antibiotics in accordance with local standards of practice and/or guidelines.

You may not qualify if:

• Elevated aspartate aminotransferase or alanine aminotransferase levels \>2.5 times the upper limit of normal.
• Platelet count \<30 X 10\^9/liter.
• History of cold agglutinin disease.
• History of solid organ, bone marrow, or stem cell transplantation.
• History of splenectomy within the 3 months prior to screening.
• Received rituximab or other anti-CD20 monoclonal antibody \<3 months prior to screening.
• Intravenous immunoglobulin (IVIg) treatment within 3 months prior to screening or plasmapheresis or immunoadsorption treatment within 60 days prior to screening.
• Clinically significant, recent, or ongoing illness or medical condition, including coexistent autoimmune disorder, malignancy, HIV, hepatitis B virus, and hepatitis C virus.
• History of meningitis or septicemia within the past 2 years.
• Treatment with an investigational therapeutic agent within 30 days prior to screening.
• Hypersensitivity to any drug product or excipients used in this study or to previous IV medication administration.
• Body weight less than 50 kilograms (kg) or greater than 100 kg

Sponsors & Collaborators

• Annexon, Inc.: lead

Study Sites (4)

Investigational Site 01

Rochester, Minnesota, 55905, United States

Location

Investigational Site 03

Melbourne, Australia

Location

Investigational Site 04

Vienna, Austria

Location

Investigational Site 02

Sofia, Bulgaria

Location

Limitations and Caveats

None reported

Results Point of Contact

• Title: Study Coordinator
• Organization: Annexon, Inc.

clinicaltrials@annexonbio.com

650-822-5500

Study Officials

• Study Director

  Annexon, Inc.

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 28, 2020
• First Posted: December 31, 2020
• Study Start: November 10, 2021
• Primary Completion: January 17, 2023
• Study Completion: January 17, 2023
• Last Updated: June 30, 2026
• Results First Posted: June 30, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1); AU (1); BU (1)