An Open-label Study of Povetacicept in Participants With Autoimmune Cytopenias

Key Inclusion Criteria:

1. Indication-specific Criteria

2. Immune Thrombocytopenia (ITP)

• Documented persistent or chronic primary ITP of at least 12 weeks durationfrom diagnosis to Cycle 1 Day 1
• History of failure or relapse to at least 2 treatment regimens for ITP
• History of exposure to a TPO-RA unless otherwise contraindicated orunavailable
• Documented history of platelets <30 × 10^9/L

2. Warm Autoimmune Hemolytic Anemia (wAIHA)

• Diagnosis of primary wAIHA of at least 12 weeks duration documented with acurrent or prior positive direct antiglobulin test (DAT) for anti-IgG (±C3d)
• Documented history of anemia with hemoglobin ≤10 g/dL
• At least one of the following: (i) haptoglobin < lower limit of normal (LLN) (ii) indirect bilirubin > upper limit of normal (ULN) (iii) lactatedehydrogenase>ULN
• History of failure or relapse to at least 2 treatment regimens for wAIHA

3. Cold Agglutinin Disease (CAD)

• Diagnosis of primary CAD of at least 12 weeks duration with all of thefollowing: (i) chronic hemolysis (ii) polyspecific DAT positive (iii)monospecific DAT strongly positive for C3d (iv) cold agglutinin titer ≥64at 4°C (v) IgG DAT ≤1+ (vi) no overt malignant disease
• Documented history of anemia with hemoglobin ≤10 g/dL
• Evidence of hemolysis during screening: (i) indirect bilirubin >ULN and (ii) lactate dehydrogenase>ULN or haptoglobin <LLN
• History of failure or relapse to at least 1 treatment regimen for CAD

2. (All indications) If receiving protocol-specified standard-of-care medications,doses must be stable for protocol-specified durations

Key Exclusion Criteria:

1. Secondary AIHA, CAD, or ITP

2. Treatment with any of the following within the noted period prior to study entry

3. rituximab: <12 weeks

4. IVIg: <4 weeks

5. sutimlimab, any use after initiation of screening is exclusionary

6. plasmapheresis, plasma exchange, or double-filtration plasmapheresis: <8 weeks

7. transfusions with blood, blood products or other rescue medications: <2 weeks

8. splenectomy: <12 weeks

9. other immunomodulatory or investigational agents, except for investigationalagents for COVID-19 that have been granted emergency use authorization orapproved by the applicable national health authority: <5 half-lives andrequires agreement of the Medical Monitor

10. Recent serious or ongoing infection; risk or history of serious infection

Other protocol defined Inclusion/Exclusion criteria may apply.