This study is terminated due to a business decision not to pursue INCB059782 in Sickle Cell Disease indication.

The purpose of this study was to evaluate the safety and tolerability, and the pharmacokinetic and biologic activity of INCB059872 in participants with sickle cell disease.

Inclusion Criteria:

• Diagnosis of SCD (sickle cell SS) confirmed through hemoglobin electrophoresis.

• Must be red blood cell (RBC) transfusion-independent (not currently on regularly scheduled transfusions) for ≥ 3 months from the time of first dose of study drug.

• No RBC transfusion within 30 days of first dose of study drug.

• Hydroxyurea (HU) refractory

  -Must not have received HU therapy during the 3 months before receiving study drug.

• Creatinine clearance ≥ 60 mL/min based on the institutional formula.

• Willingness to avoid pregnancy or fathering children.

Exclusion Criteria:

• Any unresolved toxicity ≥ Grade 2 from previous therapy except for stable chronic toxicities not expected to resolve.
• Pregnant or nursing women or participants expecting to conceive or father children within the projected duration of the study, starting with screening visit through completion of safety follow-up.
• Received an investigational study drug within 28 days or 5 half-lives (whichever is longer) before receiving the first dose of study drug (requirement may be waived with medical monitor approval).
• Chronic or current active infectious disease requiring systemic antibiotics, antifungal, or antiviral treatment.
• Prior receipt of LSD1 inhibitor therapy for any indication.