Background Metastatic thyroid cancers that are refractory to radioiodine (iodine-131) are associated with a poor prognosis. In mouse models of thyroid cancer, selective mitogen-activated protein kinase (MAPK) pathway antagonists increase the expression of the sodium–iodide symporter and uptake of iodine. Their effects in humans are not known. Methods We conducted a study to determine whether the MAPK kinase (MEK) 1 and MEK2 inhibitor selumetinib (AZD6244, ARRY-142886) could reverse refractoriness to radioiodine in patients with metastatic thyroid cancer. After stimulation with thyrotropin alfa, dosimetry with iodine-124 positron-emission tomography (PET) was performed before and 4 weeks after treatment with selumetinib (75 mg twice daily). If the second iodine-124 PET study indicated that a dose of iodine-131 of 2000 cGy or more could be delivered to the metastatic lesion or lesions, therapeutic radioiodine was administered while the patient was receiving selumetinib. Results Of 24 patients screened for the study, 20 could be evaluated. The median age was 61 years (range, 44 to 77), and 11 patients were men. Nine patients had tumors with BRAF mutations, and 5 patients had tumors with mutations of NRAS. Selumetinib increased the uptake of iodine-124 in 12 of the 20 patients (4 of 9 patients with BRAF mutations and 5 of 5 patients with NRAS mutations). Eight of these 12 patients reached the dosimetry threshold for radioiodine therapy, including all 5 patients with NRAS mutations. Of the 8 patients treated with radioiodine, 5 had confirmed partial responses and 3 had stable disease; all patients had decreases in serum thyroglobulin levels (mean reduction, 89%). No toxic effects of grade 3 or higher attributable by the investigators to selumetinib were observed. One patient received a diagnosis of myelodysplastic syndrome more than 51 weeks after radioiodine treatment, with progression to acute leukemia. Conclusions Selumetinib produces clinically meaningful increases in iodine uptake and retention in a subgroup of patients with thyroid cancer that is refractory to radioiodine; the effectiveness may be greater in patients with RAS-mutant disease. (Funded by the American Thyroid Association and others; ClinicalTrials.gov number, NCT00970359.)

Authors' Contributions 1.JF -Substantial contributions to acquisition, analysis and interpretation of data, drafting the work, final approval of the version to be published and agreement to be accountable for all aspects of the work. 2.AO -Substantial contributions to the conception and design of the work, analysis and interpretation of data, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 3.TP -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 4.SW -Substantial contributions to the conception and design of the work, analysis and interpretation of data, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 5.AL -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 6.NL -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 7.AB -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 8.RP -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 9.LK -Substantial revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 10.SG -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 11.IP -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 12.IQ -Substantial contributions to revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 13.RJ -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable ...

BACKGROUND. Adoptive transfer of donor-derived EBV-specific cytotoxic T-lymphocytes (EBV-CTLs) can eradicate EBVassociated lymphomas (EBV-PTLD) after transplantation of hematopoietic cell (HCT) or solid organ (SOT) but is unavailable for most patients. METHODS.We developed a third-party, allogeneic, off-the-shelf bank of 330 GMP-grade EBV-CTL lines from specifically consented healthy HCT donors. We treated 46 recipients of HCT (n = 33) or SOT (n = 13) with established EBV-PTLD, who had failed rituximab therapy, with third-party EBV-CTLs. Treatment cycles consisted of 3 weekly infusions of EBV-CTLs and 3 weeks of observation. RESULTS.EBV-CTLs did not induce significant toxicities. One patient developed grade I skin graft-versus-host disease. Complete remission (CR) or sustained partial remission (PR) was achieved in 68% of HCT recipients and 54% of SOT recipients. For patients who achieved CR/PR or stable disease after cycle 1, one year overall survival was 88.9% and 81.8%, respectively. In addition, 3 of 5 recipients with POD after a first cycle who received EBV-CTLs from a different donor achieved CR or durable PR (60%) and survived longer than 1 year. Maximal responses were achieved after a median of 2 cycles. CONCLUSION.Third-party EBV-CTLs of defined HLA restriction provide safe, immediately accessible treatment for EBV-PTLD. Secondary treatment with EBV-CTLs restricted by a different HLA allele (switch therapy) can also induce remissions if initial EBV-CTLs are ineffective. These results suggest a promising potential therapy for patients with rituximab-refractory EBVassociated lymphoma after transplantation.Authorship note: SP and ED contributed equally to this work. Conflict of interest: ED and ROR had consultancy agreements with Atara Biotherapeutics. ED and ROR are inventors on technology referenced in this work (SK2013-71 [patient ID], Proprietary Cell Banks for Use in 3rd-Party EBV-Specific T Cell Therapy; and SK2018-122 [patient ID], Methods of Selecting T Cell Lines for Adoptive Cellular Therapy). SP is an inventor on technology referenced in this work (SK2013-71 and SK2018-122) and has waived rights to revenue generated from these inventions. Memorial Sloan Kettering Cancer Center (MSK), which owns the technology, has licensed this technology to Atara, and MSK has interests in Atara through this licensing arrangement.

National Institutes of Health, The Dana Foundation, The Cure Starts Now, Solving Kids' Cancer, The Lyla Nsouli Foundation, Cookies for Kids' Cancer, The Cristian Rivera Foundation, Battle for a Cure, Cole Foundation, Meryl & Charles Witmer Charitable Foundation, Tuesdays with Mitch Charitable Foundation, and Memorial Sloan Kettering Cancer Center.