Ibrutinib in Treating Patients With Relapsed or Refractory Follicular Lymphoma

PRIMARY OBJECTIVES: I. Evaluate the overall response rate of ibrutinib in patients with relapsed or refractory follicular lymphoma. SECONDARY OBJECTIVES: I. Assess the safety and tolerability of ibrutinib in patients with follicular lymphoma. II. Evaluate overall survival, time to response, duration of response, progression-free survival, time to treatment failure, and time to subsequent treatment. TERTIARY OBJECTIVES: I. Describe the relationship between interim positron emission tomography (PET)/computed tomography (CT) scan results, CT response, and response duration. II. Biomarker studies including exploring associations between ibrutinib response and somatic mutations identified in follicular lymphoma, whole transcriptome shotgun sequencing (ribonucleic acid-sequencing \[RNA-seq\]), exploration of inhibition of Bruton's tyrosine kinase (BTK) and other kinases, expression of cytokines, chemokines, and other proteins with an aim to develop predictors of response and resistance. III. Assess changes in various cancer-derived molecules in the blood over the course of treatment with ibrutinib. IV. As part of ongoing research for Phase II Consortium (P2C) studies, we are banking paraffin-embedded tissue blocks/slides and blood products for future studies. OUTLINE: Patients receive ibrutinib orally (PO) once daily (QD) on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients with progressive disease at the end of course 2 may continue on therapy until the end of course 5 at the discretion of the treating physician. After completion of study treatment, patients are followed up every 3 months until progressive disease, and then every 6 months for 5 years.