This study tests a drug called DISC-3405, which might help people with Sickle Cell Disease (SCD). Sickle Cell Disease is a condition that affects the blood, causing red blood cells to become sickle-shaped (like a crescent), which can cause pain and other problems. This study is "open-label," meaning both the researchers and participants know they are getting the drug. It will test different doses to see if the drug is safe and how well it works in humans.

Participants must be at least 18 years old and have SCD. They should not have had a blood transfusion in the last 60 days and should not be pregnant. The study will check the drug's effects on the body, called pharmacokinetics (PK) and pharmacodynamics (PD).

• The study takes place in multiple centers, so participants may need to travel.
• Participants need to follow specific birth control guidelines if they are sexually active.
• People with certain medical conditions or recent surgeries might not be eligible to join.