Inclusion Criteria:

• Age ≥18 years.
• Karnofsky performance score of ≥60 (Eastern Cooperative Oncology Group [ECOG] performance score of 0, 1, or 2).

• Histologically confirmed diagnosis of B-cell iNHL, with histological subtype limited to the following:

  • Follicular lymphoma (FL)
  • Small lymphocytic lymphoma (SLL) with absolute lymphocyte count
  • Lymphoplasmacytoid lymphoma (LPL)
  • Marginal zone lymphoma (MZL) (splenic, nodal, or extranodal)
• Prior treatment with ≥2 prior chemotherapy- or immunotherapy-based regimens for iNHL.
• Prior treatment with rituximab and with an alkylating agent (eg, bendamustine, cyclophosphamide, ifosfamide, chlorambucil, melphalan, busulfan, nitrosoureas) for iNHL.
• Lymphoma that is refractory to rituximab and to an alkylating agent.
• For men and women of childbearing potential, willingness to abstain from sexual intercourse or employ an effective method of contraception during the study drug administration and follow-up periods.
• Willingness and ability to provide written informed consent and to comply with the protocol requirements.

Exclusion Criteria:

• Central nervous system or leptomeningeal lymphoma.
• Known histological transformation from iNHL to diffuse large B-cell lymphoma.
• History of a non-lymphoma malignancy except for the following: adequately treated local basal cell or squamous cell carcinoma of the skin, cervical carcinoma in situ, superficial bladder cancer, localized prostate cancer, other adequately treated Stage 1 or 2 cancer currently in complete remission, or any other cancer that has been in complete remission for ≥5 years.
• Evidence of ongoing systemic bacterial, fungal, or viral infection (excluding viral upper respiratory tract infections) at the time of initiation of study treatment.
• Pregnancy or breastfeeding.
• Ongoing alcohol or drug addiction.
• Known history of drug-induced liver injury, chronic active HCV, chronic active HBV, alcoholic liver disease, non-alcoholic steatohepatitis, primary biliary cirrhosis, ongoing extrahepatic obstruction caused by stones, cirrhosis of the liver or portal hypertension.
• History of prior allogeneic bone marrow progenitor cell or solid organ transplantation.
• Ongoing immunosuppressive therapy, including systemic corticosteroids. Patients may be using topical or inhaled corticosteroids.
• Prior therapy with CAL 101
• Exposure to another investigational drug within 3 weeks prior to start of study treatment.
• Concurrent participation in another therapeutic treatment trial.
• Prior or ongoing clinically significant illness, medical condition, surgical history, physical finding, ECG finding, or laboratory abnormality that, in the investigator's opinion, could affect the safety of the patient; alter the absorption, distribution, metabolism or excretion of the study drug; or impair the assessment of study results.