A Study of Duvelisib in Participants With Refractory Indolent Non-Hodgkin Lymphoma

Inclusion Criteria:

* Participants who had been diagnosed with iNHL that had progressed.
* Participants must have exhibited lack of CR or progressive disease (PR) or progression within 6 months after the last dose of a chemotherapy induction regimen or RIT.
* Participants must have had rituximab-refractory disease, defined as lack of CR or PR or PD within 6 months of last dose.
* Measurable disease with a lymph node or tumor mass ≥1.5 centimeters in at least one dimension by computed tomography (CT), positron emission tomography/CT or magnetic resonance imaging.
* Adequate renal and hepatic function.

Exclusion Criteria:

* Candidate for potentially curative therapies in the opinion of the investigator.
* Previous treatment with a PI3K inhibitor or Bruton's tyrosine kinase inhibitor.
* Prior history of allogeneic hematopoietic stem cell transplant.
* Prior chemotherapy, cancer immunosuppressive therapy, or other investigational agents within 4 weeks before first dose of study drug.
* Grade 3B FL and/or clinical evidence of transformation to a more aggressive subtype of lymphoma.
* Symptomatic central nervous system NHL.
* Ongoing systemic bacterial, fungal, or viral infections at the time of initiation of study treatment.
* Prior, current, or chronic hepatitis B or hepatitis C infection, positive result for hepatitis C virus antibodies, hepatitis B surface antigen, or hepatitis B core antibodies.
* History of stroke, unstable angina, myocardial infarction, or ventricular arrhythmia requiring medication or mechanical control within the last 6 months prior to first dose of study drug.