Warm Autoimmune Hemolytic Anemia (wAIHA)Phase 2NCT04691570
Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of ANX005 in Participants With Warm Autoimmune Hemolytic Anemia (wAIHA)
A Phase 2 study testing ANX005 in people with Warm Autoimmune Hemolytic Anemia (wAIHA), run by Annexon, Inc. at 4 sites in 4 countries.
Trial summary
This study will evaluate the safety and tolerability of ANX005 in participants with Warm Autoimmune Hemolytic Anemia (wAIHA). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Warm Autoimmune Hemolytic Anemia (wAIHA)
- What is being tested?
- ANX005
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 7 participants
- Where
- 4 sitesin 4 countries
- Study dates
- 10 Nov 2021to 17 Jan 2023
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
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- 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
Trial locations and contacts
4 sites in 4 countries.
4 sites in 4 countries
About this study
Official title: A Phase 2, Open-Label, Repeat Dose Study to Assess the Safety, Tolerability, Pharmacokinetics (PK) and Pharmacodynamics (PD) of Intravenous ANX005 in Subjects With Warm Autoimmune Hemolytic Anemia (wAIHA)
This study will evaluate the safety and tolerability of ANX005 in participants with Warm Autoimmune Hemolytic Anemia (wAIHA).
Read the detailed description
After being informed of study details and potential risks, all participants who provide written informed consent will undergo an up to 6-week screening period to determine eligibility. Participants who meet the eligibility criteria will receive two once-weekly intravenous (IV) infusions of ANX005. Participants will return to the clinic weekly through Week 10 for study assessments. The total duration of individual participation in this study will be up to 16 weeks.
- Conditions
- Warm Autoimmune Hemolytic Anemia (wAIHA)
- Being tested
- ANX005
- Keywords
- AIHA, C1q, complement, RBC lysis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ANX005Drug
ANX005 is provided as a solution for IV infusion
| Study group | Role | What they receive |
|---|---|---|
| ANX005 | Experimental | Participants will receive two once-weekly doses of ANX005 at specific time points Receives: Drug: ANX005 |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Baseline, Day 71
Secondary outcomes (3)
Change in Percent Inhibition Complement CH50 From Baseline Through Day 71
Change in percent inhibition complement CH50 from Baseline was calculated as the post-Baseline value minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005. A decrease form baseline indicated a better outcome.
Measured: Baseline, Days 2, 4, 8, 15, 22, 29, 36, 43, 50, 57, and 71
Change From Baseline in Complement C4 Level Through 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.
Measured: 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
Change from Baseline was calculated as the post-Baseline value minus the Baseline value. Baseline was defined as the last non-missing observation recorded before the first dose of ANX005.
Measured: 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
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Dec 2020
- Study start10 Nov 2021
- Primary completion17 Jan 2023
- Study completion17 Jan 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Warm Autoimmune Hemolytic Anemia (wAIHA)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 7 participants (actual)
Sponsor and investigators
- Lead sponsor
- Annexon, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Study Director, Study director, Annexon, Inc.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04691570
- Sponsor's protocol ID
- ANX005-wAIHA-02
- Status last verified
- Jun 2026
- First submitted
- 28 Dec 2020
- Last updated
- 30 Jun 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 30 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2, Open-Label, Repeat Dose Study to Assess the Safety, Tolerability, Pharmacokinetics (PK) and Pharmacodynamics (PD) of Intravenous ANX005 in Subjects With Warm Autoimmune Hemolytic Anemia (wAIHA)
- ClinicalTrials.gov ID
- NCT04691570
- Acronym / sponsor ID
- ANX005-wAIHA-02
- Conditions
- Warm Autoimmune Hemolytic Anemia (wAIHA)
- Keywords
- AIHA, C1q, complement, RBC lysis
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 7 participants (actual)
- Lead sponsor
- Annexon, Inc.Industry (pharma, biotech, devices)
- Study start
- 10 Nov 2021 (actual)
- Primary completion
- 17 Jan 2023 (actual)
- Study completion
- 17 Jan 2023 (actual)
- First posted
- 31 Dec 2020 (actual)
- Results
- Posted 30 Jun 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the safety and tolerability of ANX005 in participants with Warm Autoimmune Hemolytic Anemia (wAIHA).
Detailed description
After being informed of study details and potential risks, all participants who provide written informed consent will undergo an up to 6-week screening period to determine eligibility. Participants who meet the eligibility criteria will receive two once-weekly intravenous (IV) infusions of ANX005. Participants will return to the clinic weekly through Week 10 for study assessments. The total duration of individual participation in this study will be up to 16 weeks.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| ANX005 | Experimental | Drug: ANX005Participants will receive two once-weekly doses of ANX005 at specific time points |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- 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.
Key exclusion criteria (12 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ANX005ANX005 is provided as a solution for IV infusion | Drug | ANX005 |
Primary outcome
Number of Participants With Treatment-emergent Adverse Events (TEAEs)
Time frame: Day 1 through Day 71
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.
Maximum Change From Baseline in Hemoglobin Levels
Time frame: Baseline up to Day 71
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.
Change From Baseline in Lactate Dehydrogenase Levels at Day 71
Time frame: Baseline, 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.
Change From Baseline in Percentage of Reticulocytes/Total Cells Count at Day 71
Time frame: Baseline, 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.
Change From Baseline in Haptoglobin Levels at Day 71
Time frame: Baseline, 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.
Change From Baseline in Total Bilirubin Levels at Day 71
Time frame: Baseline, 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.
Change From Baseline in Indirect Bilirubin Levels at Day 71
Time frame: Baseline, 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.
3 secondary outcomes
Change in Percent Inhibition Complement CH50 From Baseline Through Day 71
Time frame: Baseline, Days 2, 4, 8, 15, 22, 29, 36, 43, 50, 57, and 71
Change From Baseline in Complement C4 Level Through Day 71
Time frame: 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
Time frame: 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
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jun 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Study Director study director
Annexon, Inc.
4 sites in 4 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing ANX005 in people with Warm Autoimmune Hemolytic Anemia (wAIHA), run by Annexon, Inc. at 4 sites in 4 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 30 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in United States, Australia, Austria, Bulgaria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 30 Jun 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With Treatment-emergent Adverse Events (TEAEs) (time frame: Day 1 through Day 71). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jun 2026.