Alpine Immune Sciences is launching a new study to evaluate povetacicept (ALPN-303) in adults with autoimmune cytopenias including immune thrombocytopenia, warm autoimmune hemolytic anemia, and cold agglutinin disease (CAD). The study, listed on, aims to determine whether povetacicept is safe and potentially effective for treating these conditions.

CAD is a rare autoimmune disease characterized by the premature lysis of red blood cells after exposure to cold temperatures. When these patients encounter cold temperatures, the body’s B cells produce antibodies that attack red blood cells, leading to clumping or agglutination. The resulting symptoms include anemia, pain, fatigue, headaches, digestive issues, and heart problems, among others.

Povetacicept is a dual B-cell cytokine antagonist that has been shown to inhibit 2 cytokines involved in B-cell development, differentiation, and survival: B cell-activating factor/B-lymphocyte stimulator and a proliferation-inducing ligand (APRIL). Researchers hope povetacicept will improve outcomes in patients with various autoimmune diseases by inhibiting these cytokines.

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Results from a phase 1 study of povetacicept (RUBY-1) in healthy volunteers showed it was well tolerated at doses up to 960 mg when administered intravenously or subcutaneously. Preclinical pharmacodynamics were positive and included reduced circulating immunoglobulins and antibody-secreting cells.

Adult patients will be eligible to participate in this new study if they have a diagnosis of immune thrombocytopenia, warm autoimmune hemolytic anemia, or CAD.

Study participants will receive povetacicept by subcutaneous injection every 4 weeks for 6 months during the treatment period, and there will be the possibility of an additional 6-month extension period if benefits are observed. The primary outcome measures are the type, incidence, and severity of adverse events.

The study is expected to start in May 2023, and the estimated completion date is November 2027.


An open-label study of povetacicept in subjects with autoimmune cytopenias (RUBY-4). March 7, 2023. Updated March 13, 2023. Accessed March 15, 2023.