Bioverativ’s Experimental Therapy Sutimlimab Shows Promise in Rare Blood Disorder

Rare Daily Staff

Bioverativ’s experimental drug sutimlimab appeared to be effective in treating cold agglutinin disease, a rare chronic blood disorder for which there are currently no approved treatments.

Cold agglutinin disease is caused by a malfunction in the immune system that causes antibodies to attack and kill a person’s own red blood cells. The disease can lead to chronic anemia, severe fatigue, and potentially fatal thrombotic events, such as pulmonary embolism and stroke.

Sutimlimab is a monoclonal antibody that is designed to selectively inhibit the part of the immune system known as the classical complement pathway. It selectively targets the protein complex known as C1s, which initiates

In the study, published in the journal Blood, found sutimlimab halted the destruction of red blood cells, increased hemoglobin levels, and eliminated patients’ need for blood transfusions. There were no serious adverse effects.

“The drug was well tolerated, produced clinically meaningful increases in hemoglobin levels, and precluded the need for transfusions, even in patients for whom multiple prior therapies had failed,” said senior author Bernd Jilma of the Medical University of Vienna.

The study included 10 patients 56 to 76 years old. Patients had cold agglutinin disease for a median of five years, and many had received multiple prior treatments that had been unsuccessful. At enrollment, all patients had below-normal levels of hemoglobin. Six patients were receiving regular blood transfusions to control their symptoms.

Of those patients who responded, within the first week of treatment with a full dose of sutimlimab, destruction of red blood cells stopped, and patients’ hemoglobin levels significantly increased. Seven patients responded and had a median increase in hemoglobin levels of 4 grams per deciliter (g/dL) over a baseline of 7.5 g/dL within six weeks. Four patients had their hemoglobin levels return to normal.

When sutimlimab treatment was discontinued and the drug had left the patients’ blood, hemoglobin levels dropped, and destruction of red blood cells began again. However, when treatment resumed, these effects were once again reversed. The six patients who had been sustained by regular blood transfusions remained transfusion-free for up to 18 months while receiving sutimlimab treatment.

The U.S. Food and Drug Administration granted sutimlimab Breakthrough Therapy designation. Phase 3 studies are ongoing to determine its safety and efficacy in primary cold agglutinin disease patients.

December 18, 2018
Photo: Bernd Jilma of the Medical University of Vienna