A Study of AZD6738 and Acalabrutinib in Subjects With Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL)

Inclusion Criteria:

* Diagnosis of relapsed or refractory CLL that meets published diagnostic criteria (International Workshop on Chronic Lymphocytic Leukemia \[IWCLL\] Hallek 2008) and supported/documented by medical records
* Subjects must be Relapse/Refractory high risk CLL and have exhausted other therapeutic options according to local/regional standard of care
* Must have received ≥1 prior therapy for treatment of their disease.

Exclusion Criteria:

* A diagnosis of ataxia telangiectasia
* Any prior exposure to an ATR inhibitor or known hypersensitivity to an excipient of the product.
* Known history of infection with human immunodeficiency virus (HIV).
* A life-threatening illness, medical condition or organ system dysfunction which, in the investigator's opinion, could compromise the subject's safety, interfere with the absorption or metabolism of ACP-196 (acalabrutinib) and/or Ceralasertib
* Significant cardiovascular disease such as uncontrolled or symptomatic arrhythmias, congestive heart failure, or myocardial infarction within 6 months of screening, or any Class 3 or 4 cardiac disease as defined by the New York Heart Association Functional Classification, or corrected QT interval (QTc) \> 480 msec.
* Malabsorption syndrome, disease significantly affecting gastrointestinal function, or resection of the stomach or small bowel or ulcerative colitis, symptomatic inflammatory bowel disease, or partial or complete bowel obstruction.
* Requirement of treatment with proton-pump inhibitors (e.g., omeprazole, esomeprazole, lansoprazole, dexlansoprazole, rabeprazole, or pantoprazole). Subjects receiving proton-pump inhibitors who switch to H2-receptor antagonists or antacids are eligible for enrollment to this study.
* Breast feeding or pregnant