Clinical Outcomes of Radioactive Iodine Redifferentiation Therapy in Previously Iodine Refractory Differentiated Thyroid Cancers.

Objective: Redifferentiation therapy (RDT) can restore radioactive iodine (RAI) uptake in differentiated thyroid cancer (DTC) cells to enable salvage 131I therapy for previously RAI refractory (RAIR) disease. This study evaluated the clinical outcomes of patients who underwent RDT and identified clinicopathologic characteristics predictive of RAI restoration following RDT. Methods: This is a retrospective case series of 33 patients with response evaluation criteria in solid tumors (RECIST)-progressive metastatic RAIR-DTC who underwent RDT between 2017 and 2022 at the Mayo Clinic (Rochester, MN). All patients underwent genomic profiling and received MEK, RET or ALK inhibitors alone, or combination BRAF-MEK inhibitors for 4 weeks. At week 3, those with increased RAI avidity in metastatic foci received high-dose 131I therapy. Baseline and clinicopathologic outcomes were comprehensively reviewed. Results: Of the 33 patients, 57.6% had restored RAI uptake following RDT (Redifferentiated subgroup). 42.1% (8/19) with papillary thyroid cancers (PTC), 100% (4/4) with invasive encapsulated follicular variant PTCs (IEFV-PTCs), and 100% (7/7) with follicular thyroid cancers (FTC) redifferentiated. All (11/11) RAS mutant tumors redifferentiated compared with 38.9% (7/18) with BRAF mutant disease (6 PTC and 1 IEFV-PTC). 76.5% (13/17) of redifferentiated and 66.7% (8/12) of non-redifferentiated patients achieved a best overall RECIST response of stable disease (SD) or non-complete response/non-progressive disease. Both subgroups had a median 12% tumor shrinkage at 3 weeks on drug(s) alone. The redifferentiated subgroup, following high-dose 131I therapy, achieved an additional median 20% tumor reduction at 6 months after RDT. There were no statistically significant differences between both groups in progression free survival (PFS), time to initiation of systemic therapy, and time to any additional therapy. Of the entire cohort, 6.1% (2/33) experienced histologic transformation to anaplastic thyroid cancer, 15.1% (5/33) died, and all had redifferentiated following RDT and received 131I therapy. Conclusion: RDT has the potential to restore RAI avidity and induce RECIST responses following 131I therapy in select patients with RAIR-DTC, particularly those with RAS-driven "follicular" phenotypes. In patients with PTC, none of the evaluated clinical outcomes differed statistically between the redifferentiated and non-redifferentiated subgroups. Further studies are needed to better characterize the long-term survival and/or safety outcomes of high-dose RAI following RDT, particularly whether it could be associated with histologic anaplastic transformation.

Lenvatinib as a Therapeutic Option in Unresectable Metastatic Pheochromocytoma and Paragangliomas.

Context: Metastatic pheochromocytomas and paragangliomas (mPPGL) are rare vascular neuroendocrine tumors that highly express vascular growth factors. Systemic treatment options in cases of unresectable multisite disease are limited. Multikinase inhibitors that inhibit angiogenesis, such as lenvatinib, have proven effective in several other malignancies, and may be a viable option for mPPGL. Objective: We aimed to evaluate the efficacy of lenvatinib as salvage therapy in mPPGLs. Methods: This was a retrospective analysis of mPPGL patients ≥ 18 years of age who received lenvatinib from 2015 to 2020 at a tertiary referral center. Patients were started on lenvatinib 20 mg daily and dose was adjusted according to tolerance or disease progression. Results: Eleven patients were included. Median treatment duration was 14.7 months (95% CI, 2.3-NE). Treatment was discontinued due to disease progression, adverse events, or death. Overall survival at 12 months was 80.8% (95% CI, 42.3-94.9%) but its median was not reached. Median progression-free survival was 14.7 months (95% CI, 1.7-NE). Among the 8 patients with measurable disease, overall response rate was 63%, as 5/8 experienced a partial response and 3/8 had stable disease. Worsening hypertension and anemia were the most common adverse events. Conclusion: Lenvatinib may be a viable treatment option for mPPGL, although at the potential risk of worsening hypertension. Larger, multicenter studies are needed to better characterize treatment efficacy.

Salvage Therapy With Multikinase Inhibitors and Immunotherapy in Advanced Adrenal Cortical Carcinoma.

BACKGROUND: Median overall survival is 12 to 15 months in patients with metastatic adrenal cortical carcinoma (ACC). Etoposide, doxorubicin, and cisplatin with or without the adrenolytic agent mitotane is considered the best first-line approach in this context, but has limited activity and no curative potential; additional salvage therapeutic options are needed. METHODS: Fifteen total patients with recurrent/metastatic ACC were treated with single-agent multikinase inhibitors (MKI) (n = 8), single-agent PD-1 inhibition (n = 8), or cytotoxic chemotherapy plus PD-1 inhibition (n = 4) at our institution as later-line systemic therapies in efforts to palliate disease and attempt to achieve a therapeutic response when not otherwise possible using standard approaches. RESULTS: Two of 8 patients (25%) treated with single-agent MKI achieved a partial response (PR), including 1 PR lasting 23.5 months. Another 3 patients (38%) had stable disease (SD); median progression-free survival (PFS) with single-agent MKI was 6.4 months (95% confidence interval [CI] 0.8-not reached). On the other hand, 2 of 12 patients (17%) treated with PD-1 inhibitors (either alone or in combination with cytotoxic chemotherapy) attained SD or better, with 1 patient (8%) achieving a PR; median PFS was 1.4 months (95% CI 0.6-2.7). CONCLUSIONS: Our single-institution experience suggests that select ACC patients respond to late-line MKI or checkpoint inhibition despite resistance to cytotoxic agents. These treatments may be attractive to ACC patients with limited other therapeutic options. The use of MKI and immunotherapy in ACC warrants prospective investigation emphasizing parallel correlative studies to identify biomarkers that predict for response.

Foundation One Genomic Interrogation of Thyroid Cancers in Patients With Metastatic Disease Requiring Systemic Therapy.

CONTEXT: Clinical applications of genomic assessment of thyroid cancers are rapidly evolving. OBJECTIVES, DESIGN, AND SETTING: We studied tumor samples from patients with imminently threatening and rare thyroid cancers to identify genomic alterations that might correlate with outcomes and/or be productively therapeutically targetable. PATIENT CONTEXT: Progressive and metastatic, and/or rare, thyroid cancers were studied, 2012 to 2016, at Mayo Clinic sites. INTERVENTION: The intervention was Foundation One tumor interrogation. MAIN OUTCOME MEASURES: Main outcome measures included genomic alterations, patient characteristics, and overall survival. RESULTS: Samples from 55 patients were evaluated: 20 anaplastic thyroid cancers (ATCs) (36%), 25 radioactive iodine-refractory differentiated thyroid cancers (DTCs)/poorly differentiated thyroid cancers (PDTCs) (45%; 14 papillary thyroid cancer [PTCs], 6 PDTCs, 5 Hürthle cell cancers), 8 medullary thyroid cancers (MTCs) (15%), and 2 others (a spindle epithelial tumor with thymus-like differentiation, and a primary thyroid sarcoma). Overall, 72% of DTCs, 79% of ATCs, and 75% of MTCs were deemed to have potentially productively targetable alterations. The most commonly encountered mutation was of TERT promoter (56% of DTCs, 68% of ATCs)-but this is not presently targetable. Targetable BRAFV600E mutations were found in 40% of DTCs/PDTCs (83% of PTCs) and 32% of ATCs; of MTCs, 75% had targetable RET mutations, and 25% HRAS mutations. Of patient tumors with nonmutated BRAFV600E, 53% of DTC/PDTCs and 69% of ATCs had other potentially productively targetable mutations. Genomic alterations in our series of poor prognosis metastatic DTC/PDTCs also closely resembled those seen in ATC. CONCLUSIONS: Whereas genomic interrogation of favorable prognosis thyroid cancer seems ill advised, potentially productively targetable mutations were demonstrated in the majority of tumors from patients with metastatic thyroid cancers requiring systemic therapy, suggesting a rationale for the selective application of this technology.

A Phase 2 Study of Pembrolizumab Combined with Chemoradiotherapy as Initial Treatment for Anaplastic Thyroid Cancer.

Background: Anaplastic thyroid cancer (ATC) has poor prognosis with median overall survival (OS) of ∼6 months. We previously reported high PD-1/PDL-1 staining in ATC, raising the possibility of the productive application of the immunotherapeutic pembrolizumab. However, having found pembrolizumab to anecdotally have limited single-agent activity in ATC, we sought to alternatively define whether pembrolizumab might synergistically combine with chemoradiotherapy as initial ATC therapy. Methods: An investigator-initiated therapeutic phase 2 trial of pembrolizumab, 200 mg intravenously (IV) every 3 weeks, combined with chemoradiotherapy (docetaxel/doxorubicin, 20 mg/m2 each IV weekly plus volumetric modulated arc therapy) was initiated as frontline therapy (with or without surgery) in ATC to assess efficacy and toxicities. Six-month OS was selected as the primary endpoint using a Simon's optimal design with interim analysis (targeting accrual of 25 patients; Cohort A: prior resection, Cohort B: no resection). Based on a prior patient cohort-treated similarly, but without pembrolizumab, the design was such that, if 6-month true survival is 75%, the probability of declaring the approach worthy of further pursuit would be 91%. Results: Three patients were enrolled, two with rapidly enlarging unresectable neck masses. Early tumor responses were favorable in all three, and all three satisfactorily completed: intended radiotherapy, preceding and radiotherapy-concurrent pembrolizumab, and concurrent chemoradiotherapy. However, all three patients died <6 months following therapy initiation-one from pulmonary metastases and two from otherwise unexpected fatal pulmonary complications occurring subsequent to chemoradiotherapy completion-prompting study closure. Conclusions: Although initially tolerated and effective in terms of locoregional disease control, disappointing survival outcomes compared with historical controls raise uncertainty that the piloted approach merits further pursuit in ATC.

OPTIMIZING LENVATINIB THERAPY IN PATIENTS WITH METASTATIC RADIOACTIVE IODINE-RESISTANT DIFFERENTIATED THYROID CANCERS.

OBJECTIVE: Lenvatinib is approved for use in advanced radioactive iodine-resistant differentiated thyroid cancers (RAIR-DTCs). Its efficacy is indisputable, but toxicities are great, creating daunting challenges for patients and providers. Few data regarding early adverse events and impact on quality of life (QOL) exist; we sought to clarify these issues by analyzing our initial postapproval lenvatinib experience. METHODS: Standardized patient education was implemented, providing detailed instructions and expert provider contacts to facilitate timely reporting of toxicities and guide responsive actions. Early adverse events, QOL outcomes, and response data from 25 consecutively treated DTC patients (02/2015 and 05/2016) were retrospectively analyzed. RESULTS: The median age was 55 years (range 27-81); 52% were female. Fourteen (56%) were on antihypertensive medication(s) at baseline. Most patients (21/25, 84%) developed adverse events during the first month of therapy. Hypertension arose in 16/25 (64%), requiring antihypertensive dose adjustment/addition in 6 (24%)/12 (48%) patients, respectively, during the first month of therapy. Dose reduction was required in 11 (44%) due to multiple adverse events; the median time to first dose reduction was 33 days (range 11-84); 8 (32%) required multiple dose reductions. Therapy interruption >3 weeks occurred in 4 (16%). The median change in patient-reported fatigue score was +2 (worsening, range -2 to +10, P<.007; 0-10 scales), but the median QOL change was 0 (range +4 to -9, P = .57). The mean duration of lenvatinib therapy was 6.5 months (range 1-12); median overall and progression-free survival have not yet been reached. Lenvatinib was discontinued in 7 (28%) patients; among 20 patients with available RECIST (Response Evaluation Criteria In Solid Tumors) measurements, 10 (50%) achieved partial response. CONCLUSION: Lenvatinib has promising efficacy in RAIR-DTC, but toxicities require frequent early interventions. QOL can be maintained on lenvatinib therapy. ABBREVIATIONS: DTC = differentiated thyroid cancer; LASA = linear analog self-assessment; PR = partial response; QOL = quality of life; RAI = radioactive iodine; RAIR = RAI-resistant; RECIST = Response Evaluation Criteria In Solid Tumors; Tg = thyroglobulin; VEGFR = vascular endothelial growth factor receptor.

Salvage Lenvatinib Therapy in Metastatic Anaplastic Thyroid Cancer.

BACKGROUND: Historical anaplastic thyroid cancer (ATC) outcomes have been terrible, with a median survival of only five months and <20% one-year survival. Improved outcomes are now achieved with aggressive initial therapy in stages IVA and IVB disease, but patients with distant metastatic disease (stage IVC) still do poorly; improved therapies are sorely needed. Kinase inhibitors have emerged as promising agents in the therapy of advanced medullary and differentiated thyroid cancer, but there are limited data regarding the use of lenvatinib in ATC. The aim of this study was to delineate clinical outcomes in a series of patients with advanced ATC in response to lenvatinib therapy. METHODS: A retrospective analysis was conducted involving all lenvatinib-treated Mayo Clinic ATC patients in 2015. RESULTS: Of 28 distinct ATC patients seen in 2015, three (11%) with metastatic disease of ECOG performance status 2-3 were treated with lenvatinib. Two patients were male; age range at ATC diagnosis was 57-84 years. All three patients attained successful local control of their disease with surgery and/or combined chemoradiotherapy. Lenvatinib was offered as the second, third, or fourth line of therapy at the time of metastatic disease progression. Two patients incurred minor responses to therapy, with structural regression of distant metastatic tumor disease soon after starting lenvatinib treatment (at one to two months), while one patient achieved stable disease, but no Response Evaluation Criteria In Solid Tumors partial responses resulted. Overall survival after starting lenvatinib was two, six, and seven months. Fatigue and hypertension were prominent, and one patient developed pulmonary emboli while on lenvatinib. CONCLUSION: This initial single-institution experience suggests that lenvatinib may have some disease-modifying activity in metastatic ATC that is otherwise refractory to cytotoxic chemotherapy. Unfortunately, observed benefits were transient, and toxicities were prominent. Clinical trials are required to ascertain better the utility of lenvatinib in the management of advanced ATC.

Expression of PD-1 and PD-L1 in Anaplastic Thyroid Cancer Patients Treated With Multimodal Therapy: Results From a Retrospective Study.

Context: Anaplastic thyroid cancer (ATC) is rare and a highly fatal malignancy. The role of programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) as prognostic and/or predictive markers in ATC is unknown. Objective: Multimodal therapy offers the best chance at tumor control. The objective of this study was to detect potential associations of PD-1/PD-L1 axis variables with outcome data in ATC. Design: Retrospective study of a uniformly treated cohort. Setting: Single institution retrospective cohort study. Patients or Other Participants: Sixteen patients who received intensity-modulated radiation therapy (15 had preceding surgery) were studied. Main Outcome Measure: Patients treated with multimodal therapy were followed and assessed for overall survival (OS) and progression-free survival (PFS). Results: All samples demonstrated PD-1 expression in inflammatory cells whereas tumor cells were primarily negative. PD-L1 was expressed on ATC tumor cells in most samples and showed mainly membranous staining. High PD-1 expression (>40% staining) in inflammatory cells was associated with worse overall survival (OS; hazard ratio, 3.36; 95% confidence interval, 1.00 to 12.96; P < 0.05) and trended toward worse PFS, whereas high PD-L1 expression in tumor cells (>33% staining) trended toward worse PFS and OS. Conclusion: PD-1/PD-L1 pathway proteins are highly expressed in ATC tumor samples and appear to represent predictive markers of PFS and OS in multimodality-treated ATC patients.

An analysis of fosaprepitant-induced venous toxicity in patients receiving highly emetogenic chemotherapy.

PURPOSE: Fosaprepitant is an antiemetic used for chemotherapy-induced nausea and vomiting. We recently reported increased infusion site adverse events (ISAE) in a cohort of breast cancer patients receiving chemotherapy with doxorubicin and cyclophosphamide (AC). In this current study, we evaluated the venous toxicity of fosaprepitant use with non-anthracycline platinum-based antineoplastic regimens. METHODS: A retrospective review was conducted of the first 81 patients initiated on fosaprepitant among patients receiving highly emetogenic chemotherapy, on or after January 1, 2011 at Mayo Clinic Rochester. None of these regimens included an anthracycline. Data collected included baseline demographics, chemotherapy regimen, type of intravenous access and type, and severity of ISAE. Data from these patients were compared to previously collected data from patients who had received AC. Statistical analysis using χ 2 and univariate logistic regression was used to evaluate the association between treatment regimen, fosaprepitant, and risk of ISAE. RESULTS: Among these 81 patients, the incidence of ISAE was 7.4% in the non-anthracycline platinum group. The most commonly reported ISAE were swelling (3%), extravasation (3%), and phlebitis (3%). When stratified by regimen, fosaprepitant was associated with a statistically significant increased risk of ISAE in the anthracycline group (OR 8.1; 95% CI 2.0-31.9) compared to the platinum group. CONCLUSIONS: Fosaprepitant antiemetic therapy causes significant ISAE that are appreciably higher than previous reports. Patients receiving platinum-based chemotherapy appear to have less significant ISAE than do patients who receive anthracycline-based regimens.