A phase 1b clinical trial that was testing the safety and tolerability of the experimental drug BIVV020 in adult patients with cold agglutinin disease (CAD) has been completed. BIVV020 is a humanized monoclonal antibody that targets complement C1s.

Study locations for the open-label, nonrandomized trial were established in the US, Netherlands, Germany, Italy, Norway, and the UK. The drug is being developed by Bioverativ, a Sanofi company.

The study started on June 15, 2020, and recruited 12 participants, aged 18 years and over with a confirmed diagnosis of CAD. During the trial, the participants received a single intravenous administration dose of BIVV020, plus 2 optional doses of the treatment. 

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The primary objective of the trial was to assess the safety and tolerability of the treatment as measured by the number of participants with adverse events. Secondary objectives were the effect of the treatment on complement-mediated hemolysis, as well as its pharmacodynamics, pharmacokinetics, and immunogenicity.

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Complement system classical and alternative pathway levels were measured using the Wieslab® assay. Total complement CH50 levels and total complement factor C4 levels were also measured. 

Finally, the study assessed the number of participants with anti-BIVV antibodies and the mean change from baseline in bilirubin and hemoglobin levels over time. No results from the trial have been posted yet.

In CAD, the complement system is overactive leading to the body mistakenly attacking its own erythrocytes in cold temperatures. The exact cause of the disease is not known but multiple genetic and environmental factors such as viral bacteria and parasitic infections are thought to be involved.

Although there is currently no cure for CAD, a number of so-called complement therapeutics are being tested in clinical trials as a potential treatment for the disease and other diseases caused by complement overactivation.


A safety and tolerability study of BIVV020 in adults with cold agglutinin disease. US National Library of Medicine. Updated January 31, 2022. Accessed February 2, 2022.