Nintedanib in Treating Patients With Locally Advanced or Metastatic Neuroendocrine Tumors

PRIMARY OBJECTIVES: I. To assess progression free survival (PFS), defined as the time interval from initiation of therapy, to its cessation for documentation of progressive disease (PD) or death. SECONDARY OBJECTIVES: I. To assess the clinical response (complete response + partial response) in all patients with measurable disease (using standard Response Evaluation Criteria in Solid Tumors \[RECIST\] version \[v\]1.1 criteria). II. To assess overall survival (OS) in all patients. III. Assess changes in quality of life (QOL) throughout treatment using the European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaire (QLQ) - Gastrointestinal Neuroendocrine Tumors (NET) 21 (GI.NET21) questionnaire for carcinoid patients with gastrointestinal neuroendocrine tumors, in all patients who have filled out at least two QOL questionnaires and, will be reported by groups based on response (response, stable disease or progressive disease). IV. Steady-state pharmacokinetics (PK) of nintedanib, biomarkers, regulatory T cell (Treg) and cytokine expression and growth factors will be analyzed for all patients and reported in groups based on response. V. Gene mutations and copy number alterations analysis in the mammalian target of rapamycin (mTOR) pathway (will be performed only on the first 10 patients), protein expression of activation of protein kinase B (Akt) (as well as other downstream targets). VI. Toxicity (graded using the National Cancer Institute \[NCI\] Common Terminology Criteria for Adverse Events \[CTCAE\] version 4.0) will be closely monitored and all toxicities will be tabulated. OUTLINE: Patients receive nintedanib orally (PO) twice daily (BID) on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days and then every 3 months for 2 years.