Sunitinib for Advanced Thymus Cancer Following Earlier Treatment

BACKGROUND: Platinum-based chemotherapy is the standard of care for advanced unresectable thymoma and thymic carcinoma. However over 50% of these patients may fail initial therapy and therefore require second-line therapy. New therapeutic options are needed for patients who have disease progression on or after platinum-containing therapy. Results obtained from protocol 12-C-0118 so far have shown impressive clinical activity of sunitinib in patients with recurrent thymic carcinoma with an objective response rate of 23% and disease control rate of 91% which is unprecedented for this histology. Treatment at a dose of 50 mg once daily for four weeks followed by 2 weeks off was poorly tolerated. Twenty five out of 41 patients needed dose reductions due to development of intolerable adverse events. OBJECTIVES: Primary objective: \- To evaluate the objective response rate (Partial Response (PR)+Complete Response (CR) for sunitinib in patients with relapsed or refractory thymoma or thymic carcinoma MAIN ELIGIBILITY: * Patients with histologically confirmed thymoma (Group 1 only) or thymic carcinoma who have previously been treated with at least one platinum-containing chemotherapy regimen with progressive disease prior to study entry * Measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria * Adequate renal, hepatic and hematopoietic function * No major surgery, radiotherapy, chemotherapy or biologic therapy within 28 days of sunitinib DESIGN: * In the first group (Group 1), sunitinib will be administered orally using a continuous schedule at 50 mg per day for 4 weeks with 2 weeks off to constitute a 6-week cycle (Schedule 4/2) until disease progression or development of intolerable side-effects. * In the second group (Group 2), sunitinib will be administered orally using a continuous schedule at 50 mg per day for 2 weeks with 1 week off to constitute a 3-week cycle (Schedule 2/1) until disease progression or development of intolerable side-effects. * Toxicity will be assessed every cycle by Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 * Tumor response assessments by RECIST 1.1 criteria will be performed every cycle for Group 1 and every other cycle for Group 2 (every 6 weeks) for patients receiving treatment for less than one year, and every two cycles for Group 1 and every four cycles for Group 2 (every 12 weeks) for patients who have been receiving treatment one year or longer. * Exploratory studies include evaluation of serum vascular endothelial growth factor (VEGF), placental growth factor (PlGF), interleukin 4 (IL-4), interleukin 12 (IL-12), hepatocyte growth factor (HGF), and basic fibroblast growth factor (bFGF) (Group 1 only); and circulating tumor cells, endothelial progenitors, and mature apoptotic endothelial cells (both groups). In Group 2, regulatory T cells (Tregs), exhausted cluster of differentiation 8 (CD8) T cells, myeloid-derived suppressor cells (MDSCs), and Type 1 T helper (Th1)/Type 2 T helper (Th1) T cell populations will also be evaluated. Where tumor samples are available, intra-tumoral immune infiltrate will be assessed (both groups). Exploratory studies apply to National Cancer Institute (NCI) only.