Initial Management of BRAF V600E-Variant Anaplastic Thyroid Cancer: The FAST Multidisciplinary Group Consensus Statement.

Importance: BRAF/MEK inhibitors revolutionized the treatment of BRAF V600E-variant anaplastic thyroid carcinoma (BRAFv-ATC), offering improved outcomes for patients with this previously incurable disease. Observations: Anaplastic thyroid carcinoma (ATC) accounts for approximately half of thyroid cancer-related deaths. It presents as a rapidly growing tumor that often invades locoregional structures and spreads to distant sites early; therefore, prompt diagnosis, staging, and treatment initiation are of the essence in the treatment of ATC. Although most oncologists will encounter a patient with ATC in their practice, the rarity of this disease makes treatment challenging, particularly because those with BRAFv-ATC no longer have a dismal prognosis. BRAF/MEK kinase inhibitors have transformed the outlook and treatment of BRAFv-ATC. Therefore, molecular profiling to identify these patients is critical. More recently, the addition of immunotherapy to BRAF/MEK inhibitors as well as the use of the neoadjuvant approach were shown to further improve survival outcomes in BRAFv-ATC. Many of these recent advances have not yet been incorporated in the currently available guidelines, allowing for disparities in the treatment of patients with BRAFv-ATC across the US. With the increasing complexity in the management of BRAFv-ATC, this Consensus Statement aims to formulate guiding recommendations from a group of experts to facilitate therapeutic decision-making. Conclusions and Relevance: This Consensus Statement from the FAST (Facilitating Anaplastic Thyroid Cancer Specialized Treatment) group at MD Anderson Cancer Center emphasizes that rapid identification of a BRAF V600E pathogenic variant and timely initiation of sequential therapy are critical to avoid excess morbidity and mortality in patients with BRAFv-ATC. In the past decade, remarkable progress has been made in the treatment of patients with BRAFv-ATC, justifying these new evidence-based recommendations reached through a consensus of experts from a high-volume center.

Combination Targeted Therapy with Lenvatinib and Pembrolizumab in Progressive, Radioiodine-Refractory Differentiated Thyroid Cancers.

PURPOSE: Lenvatinib, a potent multi-kinase inhibitor, improves progression-free survival (PFS) in patients with radioiodine (RAI)-refractory differentiated thyroid cancer (DTC); however, most patients experience disease progression, warranting further therapy. We evaluated the efficacy and safety of combination lenvatinib plus pembrolizumab (LP) in these patients. PATIENTS AND METHODS: We enrolled patients with progressive, RAI-refractory DTC that were either naïve to multi-kinase inhibitors (cohort 1) or who had progressed on lenvatinib (cohort 2). Patients received oral lenvatinib daily (cohort 1, 20 mg; cohort 2, dose at progression ) and intravenous pembrolizumab (200 mg) every 21 days. RESULTS: 30 and 27 patients were enrolled in cohort 1 and 2, respectively. Adverse events were consistent with those observed in other cancers. In cohort 1, the confirmed overall response rate (ORR) was 65.5%. There were no complete responses (CR, primary endpoint). The 12 and 18-month PFS were 72.0% and 58.0%, respectively, and median PFS was 26.8 months. In cohort 2, the confirmed ORR was 16% (primary endpoint), and median PFS was 10.0 months (95% CI; 7.0-17.9 months). Tumor histology, driver mutations, and immune-related biomarkers, including PD-L1 expression, thyroid-specific antibody levels, and CD8+ T cell tumor infiltrate, did not correlate with response to therapy. Increased baseline peripheral blood monocytes and neutrophil to lymphocyte ratio were associated with a worse PFS in cohort 1. CONCLUSIONS: Combination lenvatinib plus pembrolizumab may enhance the durability of lenvatinib monotherapy in lenvatinib-naïve patients. Furthermore, the addition of pembrolizumab may be a viable salvage therapy for patients who have progressed on lenvatinib.

Next-Generation Sequencing in Sporadic Medullary Thyroid Cancer Patients: Mutation Profile and Disease Aggressiveness.

Context: Next-generation sequencing (NGS) analysis of sporadic medullary thyroid carcinoma (sMTC) has led to increased detection of somatic mutations, including RET M918T, which has been considered a negative prognostic indicator. Objective: This study aimed to determine the association between clinicopathologic behavior and somatic mutation identified on clinically motivated NGS. Methods: In this retrospective cohort study, patients with sMTC who underwent NGS to identify somatic mutations for treatment planning were identified. Clinicopathologic factors, time to distant metastatic disease (DMD), disease-specific survival (DSS), and overall survival (OS) were compared between somatic mutations. Results: Somatic mutations were identified in 191 sMTC tumors, including RET M918T (53.4%), other RET codons (10.5%), RAS (18.3%), somatic RET indels (8.9%), and RET/RAS wild-type (WT) status (8.9%). The median age at diagnosis was 50 years (range, 11-83); 46.1% were female. When comparing patients with RET M918T, RET-Other, and RET WT (which included RAS and RET/RAS WT), there were no differences in sex, TNM category, systemic therapy use, time to DMD, DSS, or OS. On multivariate analysis, older age at diagnosis (HR 1.05, P < .001; HR 1.06, P< .001) and M1 stage at diagnosis (HR 3.17, P = .001; HR 2.98, P = .001) were associated with decreased DSS and OS, respectively, but mutation cohort was not. When comparing RET M918T to RET indels there was no significant difference in time to DMD, DSS, or OS between the groups. Conclusion: Somatic RET mutations do not portend compromised DSS or OS in a cohort of sMTC patients who underwent clinically motivated NGS.

Adaptive Darwinian off-target resistance mechanisms to selective RET inhibition in RET driven cancer.

Patients treated with RET protein tyrosine kinase inhibitors (TKIs) selpercatinib or pralsetinib develop RET TKI resistance by secondary RET mutations or alterative oncogenes, of which alterative oncogenes pose a greater challenge for disease management because of multiple potential mechanisms and the unclear tolerability of drug combinations. A patient with metastatic medullary thyroid carcinoma (MTC) harboring a RET activation loop D898_E901del mutation was treated with selpercatinib. Molecular alterations were monitored with tissue biopsies and cfDNA during the treatment. The selpercatinib-responsive MTC progressed with an acquired ETV6::NTRK3 fusion, which was controlled by selpercatinib plus the NTRK inhibitor larotrectinib. Subsequently, tumor progressed with an acquired EML4::ALK fusion. Combination of selpercatinib with the dual NTRK/ALK inhibitor entrectinib reduced the tumor burden, which was followed by appearance of NTRK3 solvent-front G623R mutation. Preclinical experiments validated selpercatinib plus larotrectinib or entrectinib inhibited RET/NTRK3 dependent cells, whereas selpercatinib plus entrectinib was necessary to inhibit cells with RET/NTRK3/ALK triple alterations or a mixture of cell population carrying these genetic alterations. Thus, RET-altered MTC adapted to selpercatinib and larotrectinib with acquisition of ETV6::NTRK3 and EML4::ALK oncogenes can be managed by combination of selpercatinib and entrectinib providing proof-of-concept of urgency of incorporating molecular profiling in real-time and personalized N-of-1 care transcending one-size-fits-all approach.

Analytical Validation of a Telomerase Reverse Transcriptase (TERT) Promoter Mutation Assay.

CONTEXT: Telomerase reverse transcriptase (TERT) promoter-mutated thyroid cancers are associated with a decreased rate of disease-free and disease-specific survival. High-quality analytical validation of a diagnostic test promotes confidence in the results that inform clinical decision-making. OBJECTIVE: This work aimed to demonstrate the analytical validation of the Afirma TERT promoter mutation assay. METHODS: TERT promoter C228T and C250T variant detection in genomic DNA (gDNA) was analyzed by assessing variable DNA input and the limit of detection (LOD) of variant allele frequency (VAF). The negative and positive percentage agreement (NPA and PPA) of the Afirma TERT test was examined against a reference primer pair as was the analytical specificity from potential interfering substances (RNA and blood gDNA). Further, the intrarun, interrun, and interlaboratory reproducibility of the assay were tested. RESULTS: The Afirma TERT test is tolerant to variation in DNA input amount (7-13 ng) and can detect expected positive TERT promoter variants down to 5% VAF LOD at 7 ng DNA input with greater than 95% sensitivity. Both NPA and PPA were 100% against the reference primer pair. The test remains accurate in the presence of 20% RNA or 80% blood gDNA for an average patient sample that typically has 30% VAF. The test also demonstrated a 100% confirmation rate when compared with an external next-generation sequencing-based reference assay executed in a non-Veracyte laboratory. CONCLUSION: The analytical robustness and reproducibility of the Afirma TERT test support its routine clinical use among thyroid nodules with indeterminate cytology that are Afirma Genomic Sequencing Classifier suspicious or among Bethesda V/VI nodules.

Checkpoint Inhibition in Addition to Dabrafenib/Trametinib for BRAFV600E-Mutated Anaplastic Thyroid Carcinoma.

Background: The dabrafenib plus trametinib combination (DT) has revolutionized the treatment of BRAFV600E-mutated anaplastic thyroid carcinoma (BRAFm-ATC). However, patients eventually develop resistance and progress. Single-agent anti-PD-1 inhibitor spartalizumab has shown a median overall survival (mOS) of 5.9 months. Combination of immunotherapy with BRAF/MEK inhibitors (BRAF/MEKi) seems to improve outcomes compared with BRAF/MEKi alone, although no direct comparison is available. BRAF-targeted therapy before surgery (neoadjuvant approach) has also shown improvement in survival. We studied the efficacy and safety of DT plus pembrolizumab (DTP) compared with current standard-of-care DT alone as an initial treatment, as well as in the neoadjuvant setting. Methods: Retrospective single-center study of patients with BRAFm-ATC treated with first-line BRAF-directed therapy between January 2014 and March 2023. Three groups were evaluated: DT, DTP (pembrolizumab added upfront or at progression), and neoadjuvant (DT before surgery, and pembrolizumab added before or after surgery). The primary endpoint was mOS between DT and DTP. Secondary endpoints included median progression-free survival (mPFS) and response rate with DT versus DTP as initial treatments, and the exploratory endpoint was mOS in the neoadjuvant group. Results: Seventy-one patients were included in the primary analysis: n = 23 in DT and n = 48 in DTP. Baseline demographics were similar between groups, including the presence of metastatic disease at start of treatment (p = 0.427) and prior treatments with surgery (p = 0.864) and radiation (p = 0.678). mOS was significantly longer with DTP (17.0 months [confidence interval CI, 11.9-22.1]) compared with DT alone (9.0 months [CI, 4.5-13.5]), p = 0.037. mPFS was also significantly improved with DTP as the initial treatment (11.0 months [CI, 7.0-15.0]) compared with DT alone (4.0 months [CI, 0.7-7.3]), p = 0.049. Twenty-three patients were in the exploratory neoadjuvant group, where mOS was the longest (63.0 months [CI, 15.5-110.5]). No grade 5 adverse events (AEs) occurred in all three cohorts, and 32.4% had immune-related AEs, most frequently hepatitis and colitis. Conclusions: Our results show that in BRAFm-ATC, addition of pembrolizumab to dabrafenib/trametinib may significantly prolong survival. Surgical resection of the primary tumor after initial BRAF-targeted therapy in selected patients may provide further survival benefit. However, conclusions are limited by the retrospective nature of the study. Additional prospective data are needed to confirm this observation.