The purpose of this study is to test whether a new investigational drug called Pegcetacoplan can reduce some of the symptoms experienced by patients with cold agglutinin disease (CAD), also sometimes known as cold antibody hemolytic anemia. Researchers also want to test the tolerability of the drug to make sure it is safe for people with CAD to use.

Investigational means that the study drug is currently being tested and it has not yet been approved by the US Food and Drug Administration (FDA). 

CAD is a disease that makes the body’s immune system attack the red blood cells and destroy them. It’s triggered by cold temperatures, and it can cause problems that range from dizziness to heart failure.

Pegcetacoplan is a drug that interferes with some of the biologic processes known to cause this disease and, therefore, it may help treat CAD.

Participants will be randomized into one of two treatment groups. Randomization is like flipping a coin and there is a 50/50 chance of being assigned to either group.

The first group will receive pegcetacoplan given through an intravenous (IV) infusion twice a week. The second group will receive placebo, which will look like the study drug but has no active ingredients.

Total study participation will last approximately 2 years.