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

CONTEXT: 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 which inform clinical decision making. OBJECTIVE: 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 percent 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 intra-run, inter-run and inter-laboratory 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 7ng DNA input with > 95% sensitivity. Both NPA and PPA were 100% against the reference primer pair. The test remains accurate in 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 NGS-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 GSC 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.

Review article: new treatments for advanced differentiated thyroid cancers and potential mechanisms of drug resistance.

The treatment of advanced, radioiodine refractory, differentiated thyroid cancers (RR-DTCs) has undergone major advancements in the last decade, causing a paradigm shift in the management and prognosis of these patients. Better understanding of the molecular drivers of tumorigenesis and access to next generation sequencing of tumors have led to the development and Food and Drug Administration (FDA)-approval of numerous targeted therapies for RR-DTCs, including antiangiogenic multikinase inhibitors, and more recently, fusion-specific kinase inhibitors such as RET inhibitors and NTRK inhibitors. BRAF + MEK inhibitors have also been approved for BRAF-mutated solid tumors and are routinely used in RR-DTCs in many centers. However, none of the currently available treatments are curative, and most patients will ultimately show progression. Current research efforts are therefore focused on identifying resistance mechanisms to tyrosine kinase inhibitors and ways to overcome them. Various novel treatment strategies are under investigation, including immunotherapy, redifferentiation therapy, and second-generation kinase inhibitors. In this review, we will discuss currently available drugs for advanced RR-DTCs, potential mechanisms of drug resistance and future therapeutic avenues.

Clinical outcomes of immune checkpoint inhibitor diabetes mellitus at a comprehensive cancer center.

Introduction: Immune checkpoint inhibitor-associated diabetes mellitus (ICI-DM) is a rare adverse event. In this study, we characterize clinical outcomes of patients with ICI-DM and evaluate survival impact of this complication on melanoma patients. Research design & methods: We conducted a retrospective review of 76 patients diagnosed with ICI-DM from April 2014 to December 2020. Results: 68% of patients presented in diabetic ketoacidosis, 16% had readmissions for hyperglycemia, and hypoglycemia occurred in 70% of patients after diagnosis. Development of ICI-DM did not impact overall survival or progression-free survival in melanoma patients. Conclusion: Development of ICI-DM is associated with long-term insulin dependence and pancreatic atrophy; the use of diabetes technology in this patient population can help improve glycemic control.

Cancer treatment with immune checkpoint inhibitors can cause irreversible side effects. In this study, we describe the clinical presentations of 76 patients who developed immune checkpoint inhibitor diabetes mellitus, a rare complication of checkpoint inhibitor therapy that requires lifelong treatment with insulin therapy. Most patients presented with a life-threatening hyperglycemic emergency and had experienced weight loss and hyperglycemia several weeks prior to diagnosis. After diagnosis, these patients are at risk for high and low blood sugars, but the use of glucose monitoring devices and insulin pumps can help improve blood sugar control. In our study, the development of this complication did not affect survival for melanoma patients. We need to improve awareness of this rare complication to ensure timely treatment for patients.

Immune checkpoint inhibitor related hypophysitis: diagnostic criteria and recovery patterns.

Data on the diagnosis, natural course and management of immune checkpoint inhibitor (ICI)-related hypophysitis (irH) are limited. We propose this study to validate the diagnostic criteria, describe characteristics and hormonal recovery and investigate factors associated with the occurrence and recovery of irH. A retrospective study including patients with suspected irH at the University of Texas MD Anderson Cancer Center from 5/2003 to 8/2017 was conducted. IrH was defined as: (1) ACTH or TSH deficiency plus MRI changes or (2) ACTH and TSH deficiencies plus headache/fatigue in the absence of MRI findings. We found that of 83 patients followed for a median of 1.75 years (range 0.6-3), the proposed criteria used at initial evaluation accurately identified 61/62 (98%) irH cases. In the irH group (n = 62), the most common presentation was headache (60%), fatigue (66%), central hypothyroidism (94%), central adrenal insufficiency (69%) and MRI changes (77%). Compared with non-ipilimumab (ipi) regimens, ipi has a stronger association with irH occurrence (P = 0.004) and a shorter time to irH development (P < 0.01). Thyroid, gonadal and adrenal axis recovery occurred in 24, 58 and 0% patients, respectively. High-dose steroids (HDS) or ICI discontinuation was not associated with hormonal recovery. In the non-irH group (n = 19), one patient had isolated central hypothyroidism and six had isolated central adrenal insufficiency. All remained on hormone therapy at the last follow-up. We propose a strict definition of irH that identifies the vast majority of patients. HDS and ICI discontinuation is not always beneficial. Long-term follow-up to assess recovery is needed.

Immune-Related Thyroiditis with Immune Checkpoint Inhibitors.

BACKGROUND: Although immune-related thyroiditis (irT) with immune checkpoint inhibitors (ICI) is a common consequence, its natural course and management recommendations are not well characterized in existing guidelines. This study sought to investigate the evolution of irT and describe its course and sequelae. METHODS: This was a retrospective study of cancer patients treated with ICI between November 2014 and July 2016 at MD Anderson Cancer Center and referred for endocrinology evaluation for suspected irT. Patients included had normal baseline thyroid function tests prior to starting ICI and developed thyrotoxicosis due to irT. RESULTS: Of 657 patients treated with ICI during the study period, 43(6.5%) met the inclusion criteria. ICI included: ipilimumab + nivolumab (40%), nivolumab (33%), pembrolizumab (21%), and other (7%). Cancer diagnoses observed were melanoma (23%), renal-cell carcinoma (21%), lung cancer (19%), bladder cancer (12%), colon cancer (9%), and other cancers (15%). Median time from ICI start to thyrotoxicosis was 5.3 weeks (range 0.6-19.6 weeks). Clinically, patients presented with painless thyroiditis, and 67% were asymptomatic during the thyrotoxicosis phase. Thyrotoxicosis lasted a median of six weeks (range 2.6-39.7 weeks). Hypothyroidism developed in 37 (84%) patients at a median of 10.4 weeks (range 3.4-48.7 weeks) after starting ICI. These patients remained on levothyroxine and ICI at a median follow-up of 57.4 weeks (range 1-156.7 weeks) from hypothyroidism onset. Four patients recovered without initiating levothyroxine and remained euthyroid at a median follow-up of 11.35 months (range 4.43-14.43 months). Subgroup analysis of ipilimumab + nivolumab versus nivolumab alone showed a median time to thyrotoxicosis of two weeks [confidence interval (CI) 3.5-8.4] versus six weeks ([CI 1.2-2.8]; p = 0.26) and time to hypothyroidism of 10 weeks [CI 8.1-11.9] versus 17 weeks ([CI 8.8-25.2]; p = 0.029) after starting ICI. Thyroid peroxidase and thyroglobulin antibodies were present in 45% and 33% at the time of irT diagnosis. CONCLUSIONS: IrT manifests as an early onset of thyrotoxicosis, which is largely asymptomatic, followed by rapid transition to hypothyroidism requiring long-term levothyroxine substitution. The evolution of irT is more rapid with combination ICI. Frequent monitoring of thyroid function tests during ICI is warranted. Future guidelines need to recognize this entity and incorporate their management.

Salvage pembrolizumab added to kinase inhibitor therapy for the treatment of anaplastic thyroid carcinoma.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is a rare but deadly form of thyroid cancer. Kinase inhibitors kinase inhibitors have shown clinical efficacy in the management of ATC, however, eventually these tumors acquire resistance to KI and patients succumb to their disease. Salvage therapy in this setting is limited. As ATC tumors diffusely express the programmed cell death protein ligand (PD-L1), anti- programmed cell death protein (PD-1) drugs such as pembrolizumab offer therapeutic potential. We sought to explore the efficacy of adding pembrolizumab to kinase inhibitors at progression in ATC. METHODS: We retrospectively reviewed the charts of ATC patients initiated on pembrolizumab in combination with KI at the time of progression on kinase inhibitors at MD Anderson Cancer Center between August 2016 and August 2017. Efficacy was evaluated with best overall response (BOR) using RECISTv1.1 criteria. Progression free survival (PFS) from the start of pembrolizumab and overall survival (OS) from the start of kinase inhibitors, as well as from the time of addition of pembrolizumab were calculated. RESULTS: Twelve patients were treated with combination kinase inhibitors plus pembrolizumab at the time of progression on their KI therapy. Median age at initiation of pembrolizumab was 60 years (range 47-84 years). BOR was as follows: 5/12 (42%) had partial response, 4/12 (33%) had stable disease and 3/12 (25%) had progressive disease. Median OS from the start of kinase inhibitor was 10.43 months (95% CI = 6.02, 14.83, range 5.4-40 months). Median OS and PFS from the addition of pembrolizumab were 6.93 months (95% CI = 1.7, 12.15, range 3-15.9 months) and 2.96 months (95% CI = 2.2, 3.7, range 0.57-13.14 months), respectively. Fatigue, anemia and hypertension were the most common AEs encountered on these combinations. Therapy had to be discontinued in 2 patients due to drug induced rash and altered mental status likely from progression of disease. CONCLUSION: In a subset of ATC patients, pembrolizumab may be an effective salvage therapy added to kinase inhibitors at the time of progression on these drugs. However, better treatment strategies aimed at incorporating immunotherapy in patients with ATC should be explored. Frontline combination of KI with immunotherapy should be studied in prospective clinical trials.

Real-World Experience with Targeted Therapy for the Treatment of Anaplastic Thyroid Carcinoma.

BACKGROUND: Patients with anaplastic thyroid cancer (ATC) have a dismal prognosis, despite systemic cytotoxic chemotherapy. The objective of this study was to investigate the efficacy and safety of targeted therapy in ATC patients when used outside of a clinical trial. METHODS: This is a retrospective review from April 2015 to May 2016 at a single academic institution where 16 ATC patients receiving targeted therapy outside of a clinical trial were studied. Ten patients (eight BRAF wild type and two BRAFV600E mutant tumors) were started on lenvatinib, and six with BRAFV600E-mutated tumors received a combination of dabrafenib plus trametinib. Best response evaluated by RECIST v1.1, progression-free survival, and overall survival were determined. Adverse events were evaluated for safety. RESULTS: The majority of patients (63%) were men, and all had distant metastases or radiation-resistant primary disease at the time of treatment. In the entire cohort, 6/16 (38%) had a partial response, 6/16 (38%) had stable disease, and 2/16 (12%) had progressive disease. Two (12%) patients died before restaging. Median follow-up time was 11.8 months. Median progression-free survival was 3.7 months [confidence interval 1.8-7.6] in the entire cohort, 2.7 months for lenvatinib, and 5.2 months for dabrafenib plus trametinib. Median OS was 6.3 months [confidence interval 1.8-7.6] for the entire cohort, 3.9 months for lenvatinib, and 9.3 months for dabrafenib plus trametinib. Adverse events were as expected and manageable. CONCLUSIONS: Targeted therapies, lenvatinib, and dabrafenib plus trametinib (for BRAFV600E mutants) may provide clinical benefit in ATC patients who are unable to participate in clinical trials, and toxicities are manageable.

Circulating BRAF V600E Cell-Free DNA as a Biomarker in the Management of Anaplastic Thyroid Carcinoma.

Purpose: Anaplastic thyroid cancer (ATC) is a deadly form of thyroid cancer. BRAF V600E is the only actionable mutation for which there is a Food and Drug Administration-approved drug combination. Rapid detection of BRAF V600E and initiation of therapy is critical. We explored the ability of droplet digital polymerase chain reaction (ddPCR) to identify this mutation in circulating cell-free DNA (cfDNA) in plasma. Materials and Methods: The ddPCR assay was evaluated for its sensitivity, specificity for detection of BRAF V600E cfDNA, and concordance with tumor tissue. The assay also was used to evaluate its potential role as a biomarker of response. Results: Forty-four patients with ATC who were tested for the BRAF mutation by tumor tissue DNA sequencing or immunohistochemistry were included. Sixteen BRAF V600E-positive patients had treatment samples to evaluate cfDNA levels as a biomarker of response in correlation with restaging scans. Concordance of ddPCR with tumor tissue was 93%, with a sensitivity of 85% and specificity of 100%. Area under the curve by Wilcoxon rank sum test was 0.9 (95% CI, 0.80 to 0.99; P < .001). As a biomarker of response to treatment, 94% of ddPCR samples were concordant with tumor shrinkage in restaging scans, and 47% were concordant with tumor growth (Fisher's exact test P = .0061). In addition, cfDNA levels by ddPCR were predictive of treatment response in 71% of samples. Conclusion: cfDNA detection by ddPCR is highly sensitive, specific, and concordant with mutation status on ATC tumors. ddPCR also can be used for monitoring cfDNA levels in conjunction with imaging scans in patients with ATC.