ANX1502 proof-of-concept trial to wrap up next year, Annexon says
Dosing continues as company builds on promising early data
A proof-of-concept study designed to test a new tablet formulation of the experimental therapy ANX1502 in people with cold agglutinin disease (CAD) is continuing dosing to provide further insights into the therapy’s pharmacological profile and its impact on disease biomarkers.
Data so far have been promising, showing that blood therapy levels exceeded those expected to be effective in fasting CAD patients, and that ANX1502 reduced disease biomarkers.
Therapy developer Annexon Biosciences hasn’t disclosed details about where the trial is being conducted. With ongoing dosing, the trial is expected to wrap up in 2026.
“We are building on the early learnings from our ANX1502 program,” Douglas Love, president and CEO of Annexon, said in a company press release. “We’ve observed targeted drug levels in fasted CAD patients, and we continue to dose to deepen our understanding of ANX1502’s profile, anticipating study completion in 2026.”
CAD is caused by self-reactive antibodies known as cold agglutinins that bind to red blood cells at low temperatures. This activates the complement system, a group of immune proteins that drive the destruction of red blood cells (hemolysis), leading to CAD symptoms including fatigue, weakness, and pale skin.
Treatment aims to block abnormal immune activity
ANX1502 is a first-in-class oral therapy that suppresses the active form of the complement protein C1s, which, along with C1q, initiates the activation of the classical complement pathway.
By blocking this pathway, ANX1502 aims to reduce or prevent the abnormal immune activity underlying CAD, thereby lessening or preventing hemolysis and easing disease symptoms.
A Phase 1 study (NCT05521269) demonstrated that a liquid formulation of ANX1502 was safe and achieved expected levels in the blood of healthy volunteers, regardless of dose. The therapy was generally well tolerated at all doses, and the most common side effects reported were nausea, vomiting, and diarrhea.
Initially planned for 2023 and launched in 2024, the ongoing proof-of-concept study is testing a coated tablet formulation of ANX1502, which prevents the medication from being released until it reaches the small intestine. The company believes this new formulation may enhance tolerability and improve the patient experience.
Study participants are taking the ANX1502 oral tablet twice a day. The trial’s main goals are to assess the therapy’s safety and its pharmacological properties, including its effects on objective markers of complement activation and hemolysis.
Trial data so far have found that blood levels of ANX1502 exceeded target drug levels in fasting CAD patients, demonstrating promising pharmacokinetics (how the medication moves into, through, and out of the body).
In the first three CAD patients enrolled in the study, ANX1502 was also shown to reduce key clinical and biomarker measures.
Annexon said it would provide an update on the ANX1502 program upon completion of the CAD trial in 2026. After that, the company plans to continue testing the therapy in other complement-mediated autoimmune diseases.
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