This is a two-cohort, multicenter, open-label study of tafasitamab (MOR208) combined with idelalisib or venetoclax in adult patients with R/R CLL or R/R SLL pretreated with a BTK inhibitor (e.g., ibrutinib) as single agent or as part of combination therapy. Patients completing the study treatment are invited to participate in an optional biomarker sub-study.

The purpose of this study is to evaluate the clinical safety and preliminary efficacy of tafasitamab (MOR208) combined with idelalisib or venetoclax. The study will include safety run-in phase for each cohort with an evaluation of the safety data by an Independent Data Monitoring Committee.

An optional sub-study has been introduced to collect biological samples for investigations on biomarkers (e.g., CD19 expression) after tafasitamab treatment.

Major inclusion criteria

Diagnosis/Trial Population

• Chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL):

  • history of diagnosis of CLL or SLL that meets IWCLL diagnostic criteria
  • histologically confirmed diagnosis of SLL by lymph node biopsy
  • indication for treatment as defined by the IWCLL guidelines

• Patients must have both of the following:

  • relapsed or refractory disease while receiving a BTKi therapy or intolerance of such therapy
  • single-agent or combination therapy with a BTKi for at least one month must be the patient's most recent prior anticancer therapy

• ECOG performance status of 0 to 2

• Patients with a past medical history of autologous or allogeneic stem cell transplantation must exhibit full hematological recovery

Laboratory Values

• Patients must meet adequate bone marrow function and adequate hepatic and renal function

Other Inclusion Criteria

• Females of childbearing potential must use a highly effective method of contraception

Major exclusion criteria

Diagnosis

• Patients who have:

• non-Hodgkin's lymphomas other than CLL/SLL
• transformed CLL/SLL or Richter's syndrome
• active and uncontrolled autoimmune cytopenia

Previous and Current Treatment

• Patients who have received treatment with a BTK inhibitor within 5 days prior to Day 1 dosing

• Patients who have, within 14 days prior to D1 dosing:

  • not discontinued CD20-targeted therapy, chemotherapy, radiotherapy, investigational anticancer therapy or other lymphoma specific therapy
  • systemic corticosteroids in doses greater than prednisone equivalent to 20 mg/day with the exception of patients with signs of rapidly progressing disease
  • received live vaccines with the exception of vaccination against influenza with inactivated virus or for pneumococcal diseases