Section 4.1 Inclusion criteria: #1 updated to remove upper limit of age <75 years for inclusion. #8 to remove requirement of negative serum pregnancy tests at Days +28 and +63 post-HSCT. Section 4.2 Exclusion criteria: #3 updated to clarify that use of heparin or other anticoagulants for routine central venous line management, and intermittent dialysis or ultrafiltration as well as fibrinolytic instillation for central venous line occlusion will be allowed. #5 updated to exclude patients receiving or planning to receive other investigational therapy #11 updated to add description on hypersensitivity to any agent in patient’s planned immunoprophylaxis regimen. Added #12 on patient having any contraindications to agent(s) within immunoprophylaxis regimens allowed by protocol order to address contraindications, special precautions, and warnings for medicinal products used as standard of care (SoC). Section 5.1.2 & 5.2.2 updated to add a clarification to a reference SmPC or approved label for warnings and precautions associated with reference therapy. Section 5.2.1 to provide info on administration setting and guidance on defibrotide dosing window. Section 5.7.5 to remove prohibition against all investigational therapies. Section 6.8 to clarify that clinically significant laboratory values are to be reported as adverse events only if they are clinically significant as assessed by the investigator. Patients who do not receive HSCT, AEs will be collected up to 70 days after baseline. Section 6.8.1.7 Pregnancy has been harmonised with language in Section 6.9.1pregnancy is a reason why study drug must be permanently discontinued. Section 6.9.1 to differentiate reasons for discontinuation of a patient from the study and discontinuation from the study drug, and to differentiate between reason that ‘must’ and that ‘may’ lead to an early termination. Section 7.1 & 7.3 to clarify that bone marrow aspirate and biopsy are required for assessment of disease relapse.