This study is for participants with Sickle Cell Disease (SCD), a condition where red blood cells are shaped like a sickle, causing pain and other issues. The study is testing a new medicine called DISC-3405 to see if it's safe and how it affects people. Participants must be 18 or older and either male or female with specific types of SCD. They should have had some SCD-related problems before, like pain episodes or other complications.

Participants shouldn't have had recent blood transfusions, certain infections, or major health problems. They also shouldn't be pregnant or breastfeeding, and must agree to use effective birth control. This study, which will take place at multiple locations, will increase doses to see how the medicine works and if it's safe.

• Study length and visits: Multiple visits over time to check effects and safety.
• Participants may need to adjust current SCD treatments.
• Potential risks: Typical of new medicines, like side effects or reactions.