A Phase Ib Study of the Selective PKC-β Inhibitor MS-553 in Patients With Refractory or Relapsed CLL/SLL

Inclusion Criteria: 1. Age 18 years or older. 2. Diagnosis of CLL or SLL: 1. History of histologically documented CLL or SLL that meets iwCLL diagnostic criteria according to the 2018 guidelines, and 2. Indication for treatment as defined by the 2018 iwCLL guidelines, or the need for disease reduction prior to allogeneic transplantation.- Exclusion Criteria: 1. Current transformation of CLL/SLL non-Hodgkin lymphoma or Hodgkin lymphoma. 2. Active and uncontrolled autoimmune cytopenia(s).