Intensity-Modulated Radiation Therapy and Paclitaxel With or Without Pazopanib Hydrochloride in Treating Patients With Anaplastic Thyroid Cancer

PRIMARY OBJECTIVES: I. To evaluate the safety of IMRT, paclitaxel, and pazopanib (pazopanib hydrochloride) suspension. (Run-in component) II. To evaluate and compare overall survival at 1 year from study registration. (Phase II component) SECONDARY OBJECTIVES: I. To evaluate local-regional control at 6 and 12 months. (Phase II component) II. To evaluate the rate of grade 4 (Common Terminology Criteria for Adverse Events version 4.0 \[CTCAE, v. 4.0\]) hemorrhage, grade 4 febrile neutropenia, or any grade 5 adverse event assessed to be definitely, probably, or possibly related to the induction or concurrent treatment components of the protocol regimen. (Phase II component) III. To evaluate the rates of other adverse events (CTCAE, v. 4.0) assessed to be definitely, probably, or possibly related to the induction or concurrent treatment components of the protocol regimen. (Phase II component) IV. To evaluate the rate of treatment discontinuation due to toxicity during the induction or concurrent treatment components of the protocol regimen. (Phase II component) V. To evaluate response (as per Response Evaluation Criteria in Solid Tumors \[RECIST\]) of the primary site following the treatment component in subjects with measurable disease prior to chemoradiation. (Phase II component) OUTLINE: RUN-IN COMPONENT: Patients receive paclitaxel intravenously (IV) over 1 hour once weekly and pazopanib hydrochloride orally (PO) once daily (QD) for 2-3 weeks. Patients then receive concurrent paclitaxel IV over 1 hour once weekly and pazopanib hydrochloride PO QD for 6-7 weeks (or until radiation treatment is completed) and intensity-modulated radiotherapy (IMRT) 5 days per week for 6.5 weeks (total of 66 Gy in 33 fractions). Beginning 25-31 days after the completion of IMRT, patients receive paclitaxel IV over 1 hour once weekly and pazopanib hydrochloride PO QD. Treatment repeats every 3 weeks for 4 cycles (for patients with no measurable disease) or continues in the absence of disease progression or unacceptable toxicity (for patients with measurable disease). RANDOMIZED PHASE II COMPONENT: Patients are randomized to 1 of 2 treatment arms. ARM I: Patients receive paclitaxel IV over 1 hour once weekly and pazopanib hydrochloride PO QD for 2-3 weeks. Patients then receive concurrent paclitaxel IV over 1 hour once weekly and pazopanib hydrochloride PO QD for 6-7 weeks (or until radiation treatment is completed) and IMRT 5 days per week for 6.5 weeks (total of 66 Gy in 33 fractions). Beginning 25-31 days after the completion of IMRT, patients receive paclitaxel IV over 1 hour once weekly and pazopanib hydrochloride PO QD. Treatment repeats every 3 weeks for 4 cycles (for patients with no measurable disease) or continues in the absence of disease progression or unacceptable toxicity (for patients with measurable disease). ARM II: Patients receive paclitaxel IV over 1 hour once weekly and placebo PO QD for 2-3 weeks. Patients then receive concurrent paclitaxel IV over 1 hour once weekly and placebo PO QD for 6-7 weeks (or until radiation treatment is completed) and IMRT 5 days per week for 6.5 weeks (total of 66 Gy in 33 fractions). Beginning 25-31 days after the completion of IMRT, patients receive paclitaxel IV over 1 hour once weekly and placebo PO QD. Treatment repeats every 3 weeks for 4 cycles (for patients with no measurable disease) or continues in the absence of disease progression or unacceptable toxicity (for patients with measurable disease). After completion of study treatment, patients are followed up every 3 months for 2 years, every 6 months for 1 year, and then annually thereafter.