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

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).

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.

Inclusion Criteria:

• 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.

Exclusion Criteria:

• 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