Two patients with cold agglutinin disease (CAD) showed sustained hematologic remission after they discontinued sutimlimab, according to a new study published in Blood Advances.
“This is the first clinical evidence of sustained hematologic remission in some patients with CAD following discontinuation of anti-C1s treatment. The underlying immunomodulatory mechanism may be explained by sutimlimab-induced inhibition of complement-mediated activation and proliferation of B cells,” the authors said.
Twelve months after sutimlimab discontinuation, the 2 patients showed sustained hematologic remission and had no symptoms of the disease, including acrocyanosis. Their hemoglobin levels were stable without evidence of overt hemolysis. Moreover, they remained negative for immunoglobulin (Ig) M and IgG autoantibodies.
One of the patients showed subtle alterations during follow-up, including slightly increased bilirubin levels and mildly increased lactate dehydrogenase levels, but hemoglobin levels remained stable and within the normal range throughout the study, and the patient did not complain of CAD-related symptoms.
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The study included a third patient who experienced relapse of hemolysis and developed severe transfusion-dependent hemolysis. The relapsing patient suffered from mixed-type autoimmune hemolytic anemia, which might have compromised treatment response according to the authors. In contrast to the other 2 participants, the relapsing patient showed signs of residual hemolysis and tested positive for IgM autoantibodies at study start and during follow-up.
The 3 patients (age range, 72-78 years, all females) enrolled in the observational study participated in an open-label extension of the original phase 1b study. They received weight-adapted, fixed-dose 1-hour infusions of sutimlimab every other week for approximately 3 years. After study termination, they maintained regular follow-up visits because the clinical team was expecting relapse of hemolysis to occur when sutimlimab concentrations dropped to less than 20 μg/mL.
Gelbenegger G, Jaeger U, Fillitz M, Schoergenhofer C, Sillaber C, Jilma B. Sustained hematologic remission after discontinuation of sutimlimab treatment in patients with cold agglutinin disease. Blood Adv. Published online November 4, 2022. doi10.1182/bloodadvances.2022008574