Mechanisms of Idelalisib-Associated Diarrhea in Patients With Relapsed Chronic Lymphocytic Leukemia, Indolent Non-hodgkin Lymphoma, or Small Lymphocytic Lymphoma

PRIMARY OBJECTIVES: I. To explore the cellular and molecular mechanisms of idelalisib-induced diarrhea/colitis in relapsed chronic lymphocytic leukemia (CLL), relapsed indolent non-hodgkin lymphomas (iNHL), or relapsed small lymphocytic lymphoma (SLL). II. To further understand the mechanism of action (MOA) of idelalisib in context of the nodal microenvironment and the possible involvement of the immune system in idelalisib's anti-lymphoma activity. OUTLINE: Patients receive a physical examination during visit 1. A stool sample, blood sample, and 6 biopsies are collected at visit 2, and patients undergo a flexible fiberoptic sigmoidoscopy. Patients receive idelalisib orally (PO) twice daily (BID) after visit 2. Treatment continues in the absence of disease progression or unacceptable toxicity. A third research visit occurs upon development of idelalisib-associated diarrhea/colitis symptoms. Patients with diarrhea/colitis symptoms undergo a full colonoscopy and collection of stool and blood samples. Control patients with no diarrhea/colitis symptoms undergo all needed tests and assessments including a flexible fiberoptic sigmoidoscopy and collection of stool and blood samples. All patients undergo optional biospecimen collection at the time of disease progression.