Study of Idelalisib in Combination With BI 836826 in Participants With Chronic Lymphocytic Leukemia

Key Inclusion Criteria:

* Diagnosis of B-cell CLL, established according to International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria and having received at least 2 prior treatment regimens
* CLL that warrants treatment
* Clinically quantifiable disease burden defined as:

  * For Phase 1b individuals: absolute lymphocyte count (ALC) \> 5000/μL in peripheral blood.
  * For Phase 2 individuals either:

    * At least 1 node ≥ 2 cm on computed tomography (CT) or magnetic resonance imaging (MRI) or
    * bone marrow exam is performed at screening and demonstrates quantifiable CLL.
* Discontinuation of all cytotoxic chemotherapy and anti-CD20 antibody therapy for ≥ 4 weeks, alemtuzumab for ≥ 8 weeks, targeted therapy for ≥ 2 weeks, and investigational therapy for ≥ 3 weeks before enrollment (Phase 1b) or randomization (Phase 2). For individuals with relapsed CLL most recently treated with B-cell receptor (BCR) pathway inhibitors who, in the opinion of the investigator, will not tolerate waiting 3 weeks, a washout period of \> 5 half-lives is allowed. If on a systemic corticosteroid, the dose must be stable for the previous 4 weeks.
* Eastern Cooperative Oncology Group (ECOG) score of ≤ 2

Key Exclusion Criteria:

* Known histological transformation from CLL to an aggressive lymphoma (ie, Richter transformation)
* Known presence of myelodysplastic syndrome
* History of a non-CLL malignancy except for the following: adequately treated local basal cell or squamous cell carcinoma of the skin, cervical carcinoma in situ, superficial bladder cancer, asymptomatic prostate cancer without known metastatic disease and with no requirement for therapy or requiring only hormonal therapy and with normal prostate-specific antigen for ≥ 1 year prior to enrollment, other adequately treated Stage 1 or 2 cancer currently in complete remission, or any other cancer that has been in complete remission for ≥ 2 years.
* Evidence of ongoing systemic bacterial, fungal, or viral infection at the time of enrollment
* Ongoing drug-induced liver injury, chronic active hepatitis C (HCV), chronic active hepatitis B (HBV), alcoholic liver disease, non-alcoholic steatohepatitis, primary biliary cirrhosis, extrahepatic obstruction caused by cholelithiasis, cirrhosis of the liver, or portal hypertension.
* History of drug-induced pneumonitis
* Ongoing inflammatory bowel disease
* Ongoing alcohol or drug addiction
* History of prior allogeneic bone marrow progenitor cell or solid organ transplantation
* Ongoing systemic immunosuppressive therapy other than corticosteroids
* History of prior therapy with any phosphatidylinositol 3-kinase (PI3K) inhibitor (including idelalisib), or any anti-CD37 agent
* Ongoing infection with, or treatment or prophylaxis for, CMV within the past 28 days.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.