The purpose of this study is to assess the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and preliminary antitumor activity of AZD4573 in subjects with relapsed or refractory haematological malignancies.

Main Inclusion Criteria (cohorts 1, 2, 3):

• Patients with histologically confirmed, relapsed or refractory haematological malignancies. Patients will include but are not limited to the following: Arm A : B-cell Non-Hodgkin lymphoma , T-cell Non-Hodgkin lymphoma , Small lymphocytic lymphoma (SLL) , Multiple myeloma (MM) Arm B: CLL (chronic lymphocytic leukaemia), Richter's syndrome , AML/secondary AML, ALL , High-risk myelodysplastic syndrome (MDS), CMML (chronic myelomonocytic leukemia)

• Eastern Cooperative Oncology Group (ECOG) performance status of ≤2.
• Must have received at least 2 prior lines of therapy
• Documented active disease requiring treatment per respective NCCN/ESMO guideline that is relapsed or refractory defined as: Recurrence of disease after response to prior line(s) of therapy Or progressive disease after completion of the treatment regimen preceding entry into the study
• Adequate hematologic, hepatic and renal function
• Women should be using adequate contraceptive measures, should not be breast feeding and must have a negative pregnancy test before start of dosing if of child-bearing potential or must have evidence of nonchildbearing potential
• Men should be willing to use barrier contraception (ie, condoms) and refrain from sperm donation during and after the conduct of the trial.

Main Exclusion Criteria (cohorts 1,2, 3):

• Treatment with any of the following: any other chemotherapy, immunotherapy or anticancer agents within 2 weeks, any hematopoietic growth factors (e.g., filgrastim; [G-CSF] or sargramostin [GM-CSF]) within 7 days of the first dose of investigational product or pegylated G-CSF (pegfilgrastim) or darbepoetin within 14 days, any full-dose level anti-coagulation treatment sufficiently prior to treatment that INR is <1.5 (DVT/PE prophylaxis dose is allowed) or Major surgery (excluding placement of vascular access) within 4 weeks (with regard to the first dose of study treatment on this protocol).
• With the exception of alopecia, any unresolved toxicities from prior therapy greater than CTCAE Grade 1 at the time of starting study treatment.
• Presence of, or history of, CNS lymphoma, leptomeningeal disease or spinal cord compression.
• History of prior nonhematologic malignancy with exceptions mentioned in protocol
• Undergone any procedures or experienced any of the conditions listed in protocol exclusion criteria currently or in the preceding 6 months
• Patients with any of the following: evidence of severe or uncontrolled systemic disease, asecretory myeloma, a known history of infection with human immunodeficiency virus (HIV), serological evidence of active Hepatitis B infection, cardiac abnormalities as mentioned in the protocol, previous allogeneic bone marrow transplant, adrenal gland insufficiency or pancreatitis.
• History of severe allergic or anaphylactic reactions to BH3 mimetics or history of hypersensitivity to active or inactive excipients of AZD4573.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal. All request will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the de-identified individual patient-level data in an approved sponsored tool . Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.