You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Evaluation of romidepsin for clinical activity and radioactive iodine reuptake in radioactive iodine-refractory thyroid carcinoma. Background: Historically, systemic therapy for radioactive iodine (RAI)-refractory thyroid cancer has been understudied. Available drugs have modest efficacy. Romidepsin is a histone deacetylase inhibitor with potent antitumor effects both in vitro and in vivo. In thyroid cancer cell lines, romidepsin increases expression of both thyroglobulin and the sodium iodide symporter messenger RNAs, suggesting the possibility of improved iodine concentrating ability of RAI-resistant tumors. Methods: This was a single-institution Simon 2-stage phase II clinical study. Eligible patients had progressive, RAI-refractory, recurrent/metastatic, nonmedullary, nonanaplastic thyroid cancer. Response Evaluation Criteria in Solid Tumors (RECIST) 1.0 measurable disease and adequate organ/marrow function were required. Romidepsin 13 mg/m(2) was administered intravenously on days 1, 8, and 15, in cycles of 28 days. The primary endpoint was the response rate by RECIST; change in RAI avidity was a secondary endpoint. The study closed after the first stage due to the lack of response. Results: Twenty patients were enrolled: female, 50%; median age, 64 years; histology, 8 papillary/1 follicular/11 Hürthle. Grade 4-5 adverse events (AEs) possibly related to the drug: grade 5, 1 sudden death; grade 4, 1 pulmonary embolus. Twelve of 20 subjects had a reported adverse event. No RECIST major responses have been seen. Response per protocol: stable disease, 13; disease progression, 7. Restoration of RAI avidity was documented in two patients. Median overall survival and time on study was 33.2 (1-71+) and 1.7 (0.46-12) months, respectively. Conclusions: We observed preliminary signs of in vivo reversal of RAI resistance after treatment with romidepsin. However, no major responses were observed and accrual was poor after the grade 5 AE.
{"Chemical": ["sodium iodide", "romidepsin", "RAI", "radioactive iodine", "iodine", "Romidepsin"]}