ASSURE: This phase III trial is evaluating the safety and effectiveness of a targeted therapy in patients with chronic lymphocytic leukaemiaA Phase 3b, Multicenter, Open-Label, Single-Arm Study of Acalabrutinib (ACP-196) in Subjects With Chronic Lymphocytic Leukemia.

Exclusion

1. Participants who have had disease progression while on a BTKi for any malignant or nonmalignant condition
2. Prior malignancy (other than CLL), except for adequately treated basal cell or squamous cell skin cancer, in situ cancer, early stage prostate cancer, or other cancer from which the participant has been disease-free for ≥2 years
3. History of confirmed progressive multifocal leukoencephalopathy
4. Significant cardiovascular disease such as symptomatic arrhythmias, congestive heart failure, or myocardial infarction within 6 months before screening, or any Class 3 or 4 cardiac disease as defined by the New York Heart Association Functional Classification, or corrected QT interval using Fridericia's formula (QTcF) >480 msec at screening. Note: Participants with rate-controlled, asymptomatic atrial fibrillation are allowed to enroll in the study (For prior ibrutinib therapy cohort only, except in Finland and the Republic of South Korea, where this is applicable to all 3 cohorts; also, the prior ibrutinib therapy cohort will not be enrolled in the US).
5. Malabsorption syndrome, disease significantly affecting gastrointestinal (GI) function, resection of the stomach, extensive small bowel resection that is likely to affect absorption, symptomatic inflammatory bowel disease, partial or complete bowel obstruction, or gastric restrictions and bariatric surgery, such as gastric bypass.
6. Evidence of active Richter's transformation. If Richter's transformation is suspected (i.e., lactate dehydrogenase [LDH] increased, asymmetric fast lymph node growth or clinical suspicion), it should be ruled out with positron emission tomographycomputed tomography (PET-CT) and/or biopsy according to guidelines.
7. Central nervous system (CNS) involvement by CLL.

8. Known history of human immunodeficiency virus, serologic status reflecting active hepatitis B virus or hepatitis C virus infection, any uncontrolled active systemic infection along with participants who are on ongoing anti-infective treatment and participants who have received vaccination with a live attenuated vaccine within 4 weeks before the first dose of study intervention.

   1. Participants who are hepatitis B core antibody (anti-HBc) positive and who are hepatitis B surface antibody (anti-HBs) negative will need to have a negative hepatitis B virus PCR result before enrollment. Those who are hepatitis B surface antigen (HBsAg) positive or hepatitis B virus PCR positive will be excluded.
   2. Participants who are hepatitis C virus antibody positive will need to have a negative hepatitis C virus PCR result before enroll.lment. Those who are hepatitis C virus PCR positive will be excluded
9. Uncontrolled autoimmune hemolytic anemia or idiopathic thrombocytopenic purpura defined as declining hemoglobin or platelet count secondary to autoimmune destruction within the screening period or requirement for high doses of steroids (>20 mg daily of prednisone or equivalent for longer than 2 weeks).
10. History of stroke or intracranial hemorrhage within 6 months before the first dose of study intervention.
11. History of bleeding diathesis (e.g., hemophilia or von Willebrand disease)
12. Presence of a gastrointestinal ulcer diagnosed by endoscopy within 3 months before screening.
13. Major surgical procedure within 4 weeks before first dose of study intervention. Note: Participants who have had major surgery must have recovered adequately from any toxicity and/or complications from the intervention before the first dose of study intervention.
14. Requires treatment with proton-pump inhibitors (e.g., omeprazole, esomeprazole, lansoprazole, dexlansoprazole, rabeprazole, or pantoprazole). Participants receiving proton-pump inhibitors who switch to H2-receptor antagonists or antacids are eligible for enrollment in this study.
15. All participants requiring or receiving anticoagulation with warfarin or equivalent vitamin K antagonists (e.g., phenprocoumon) within 7 days before first dose of study intervention. Based on the known metabolic/transport pathways involved in the disposition of acalabrutinib and the commonly known novel oral anticoagulants (eg, apixaban, rivaroxaban, and edoxaban), no clinically relevant interaction is expected following coadministration of these agents.
16. Absolute neutrophil count (ANC) <0.50 x 10^9/L or platelet count <30 x 10^9/L, unless proven due to CLL and raised above the limits by granulocyte colony-stimulating factor (G-CSF) therapy and/or pooled platelet transfusion
17. Total bilirubin >3.0x upper limit of normal (ULN); or aspartate aminotransferase or alanine aminotransferase >3.0x ULN. Exception will be for Gilbert syndrome; if an investigator feels that a participant's total bilirubin is elevated secondary to Gilbert's, the participant must have a documented unconjugated bilirubin being >80% of the total bilirubin number. The investigator must also document that hemolysis has been ruled out along with (near)-normal lactate dehydrogenase and haptoglobin
18. Estimated creatinine clearance of <30 mL/min, calculated using the formula of Cockcroft and Gault or by direct assessment (i.e., creatinine clearance or ethylene diamine tetra-acetic acid (EDTA) clearance measurement)
19. Breastfeeding or pregnant
20. Received any chemotherapy, external beam radiation, investigational drug, or any other anti-CLL therapy within 30 days before first dose of study intervention
21. Concurrent participation in another therapeutic clinical study
22. History of or ongoing interstitial lung disease
23. Requiring long-term (> 1 week) treatment with a strong cytochrome CYP3A inhibitor/inducer. In addition, the use of strong or moderate CYP3A inhibitors or inducers within 7 days of the first dose of study intervention is prohibited.