A Study of Acalabrutinib and Vistusertib in Subjects With Relapsed/Refractory B-cell Malignancies

Inclusion Criteria: 1. Diagnosis of relapsed/refractory diffuse large B-cell lymphoma (DLBCL) as documented by medical records and with histology based on criteria established by The World Health Organization (WHO): * If a subject has de novo DLBCL, the diagnosis is confirmed by biopsy and is immunohistologically characterized as de novo germinal center B-cell-like (GCB) DLBCL or de novo non-GCB DLBCL. * If the subjects has Richter's Syndrome (RS), the diagnosis is confirmed by biopsy and is immunohistologically characterized as transformation to DLBCL. * If the subjects has transformed DLBCL, the diagnosis is confirmed by biopsy and is immunohistologically characterized as transformation to DLBCL from indolent lymphoma (eg, follicular lymphoma). 2. Men and women ≥18 years of age. 3. Prior treatment for lymphoid malignancy: * If the subject has DLBCL, there is no curative option with conventional therapy and the prior treatment included ≥ 1 prior combination chemoimmunotherapy regimen. * If the subject has RS, the subject must have had ≥1 prior treatment with a combination chemoimmunotherapy regimen. 4. Eastern Cooperative Oncology Group (ECOG) performance status of ≤2. 5. Presence of radiographically measurable lymphadenopathy or extranodal lymphoid malignancy (defined as the presence of a ≥1.5 cm lesion, as measured in the longest dimension by computed tomography \[CT\] scan). Exclusion Criteria: 1. As judged by the Investigator, any evidence of severe or uncontrolled systemic disease (eg, severe hepatic impairment, interstitial lung disease \[bilateral, diffuse, parenchymal lung disease\]), or current unstable or uncompensated respiratory or cardiac conditions, or uncontrolled hypertension, history of, or active, bleeding diatheses (eg, hemophilia or von Willebrand disease) or uncontrolled active systemic fungal, bacterial, viral, or other infection (defined as exhibiting ongoing signs/symptoms related to the infection and without improvement, despite appropriate antibiotics or other treatment), or intravenous anti-infective treatment within 2 weeks before first dose of study drug. 2. Diagnosis of PMBCL. 3. Current refractory nausea and vomiting, 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. 4. History of central nervous system (CNS) lymphoma, leptomeningeal disease or spinal cord compression. 5. Any clinically significant pre-existing severe renal disease (eg, glomerulonephritis, nephritic syndrome, Fanconi Syndrome or renal tubular acidosis) or high risk of developing severe renal impairment. 6. Abnormal echocardiogram (ECHO) or multi-gated acquisition scan (MUGA) at baseline (left ventricular ejection fraction \[LVEF\] \<40% and shortening fraction \<15%). Appropriate correction to be used, if a MUGA is performed. 7. Mean resting corrected QT interval (QTc) calculated using Fridericia's formula (QTcF) \>450 msec obtained from 3 electrocardiograms (ECGs); family or personal history of long or short QT syndrome; Brugada syndrome or known history of QTc prolongation or torsade de pointes within 12 months of the subject entering the study.