Safety, Tolerability, Pharmacokinetic, and Pharmacodynamic Study in Healthy Male and Female Subjects and Safety, Tolerability, Pharmacokinetics, and Pilot Efficacy Biomarkers in Subjects With Cold Agglutinin Disease

This study is testing a new experimental drug (GL-0719) to see how safe it is and how the body handles it. The first part tests it in healthy volunteers, and the second part tests it in people who have Cold Agglutinin Disease (CAD) — a rare condition where the immune system attacks and destroys red blood cells, causing anemia. You may be eligible if... - You are 18 or older - For healthy volunteer cohorts: you are between 18–65 years old with a BMI of 18–32 and no significant health conditions - For CAD cohorts: you have diagnosed primary Cold Agglutinin Disease or CAD secondary to a blood cancer, with low hemoglobin and elevated bilirubin - You have received the required meningococcal vaccine within the past 5 years (or can get it at least 14 days before starting the study) - You are willing and able to provide informed consent and follow study procedures You may NOT be eligible if... - You have a history of autoimmune disease or positive ANA titer above 1:160 - You have active hepatitis B, C, or HIV - You have had a recent significant infection in the past month - You are currently receiving plasma exchange therapy (for CAD cohorts) - You have participated in another investigational drug study within 90 days - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.