Intermittent Dosing of Dabrafenib and Trametinib in Metastatic BRAFV600E Mutated Papillary Thyroid Cancer: Two Case Reports

Clinical Pharmacy Initiatives Contribute to the Excellent Efficacy of the Dabrafenib/Trametinib Combination for Iodine-Refractory Thyroid Carcinoma: A Case Report

A 76-year-old female patient presented with an iodine-refractory papillary thyroid carcinoma (PTC), diagnosed eight years earlier, with several lymph node recurrences requiring successive surgeries. Fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) imaging revealed a new unresectable loco-regional recurrence. The patient was diagnosed with a somatic BRAF V600E mutation. Therefore, dabrafenib and trametinib combination therapy was introduced and closely monitored by a dedicated multidisciplinary team, involving pharmaceutical consultations. As early as six weeks after treatment initiation, the patient reported multiple adverse events (AEs) to the clinical pharmacy team, who provided advice on resolving AEs or improving tolerance. Close interprofessional collaboration among healthcare workers involved in the care pathway allowed for the identification of the most opportune times for temporary suspension of treatment (four suspensions over seven months) or dose reduction (two reductions over 3.5 months). This resulted in a total treatment duration (one year) longer than the average times reported in the literature. The patient showed a rapid and excellent response to treatment immediately after initiation, culminating in a complete metabolic response assessed by [18F]FDG PET/CT imaging at nine months. Twenty-five months after treatment discontinuation, the disease remained controlled. Overall, dabrafenib and trametinib combination could offer excellent outcomes in selected patients with refractory BRAF-mutated PTC, with additional clinical pharmacy initiatives allowing for the optimized management of AEs and prolonged treatment periods.

A phase I trial of the pan-ERBB inhibitor neratinib combined with the MEK inhibitor trametinib in patients with advanced cancer with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation or KRAS mutation

PURPOSE

Aberrant alterations of ERBB receptor tyrosine kinases lead to tumorigenesis. Single agent therapy targeting EGFR or HER2 has shown clinical successes, but drug resistance often develops due to aberrant or compensatory mechanisms. Herein, we sought to determine the feasibility and safety of neratinib and trametinib in patients with EGFR mutation/amplification, HER2 mutation/amplification, HER3/4 mutation and KRAS mutation.

METHODS

Patients with actionable somatic mutations or amplifications in ERBB genes or actionable KRAS mutations were enrolled to receive neratinib and trametinib in this phase I dose escalation trial. The primary endpoint was determination of the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT). Secondary endpoints included pharmacokinetic analysis and preliminary anti-tumor efficacy.

RESULTS

Twenty patients were enrolled with a median age of 50.5 years and a median of 3 lines of prior therapy. Grade 3 treatment-related toxicities included: diarrhea (25%), vomiting (10%), nausea (5%), fatigue (5%) and malaise (5%). The MTD was dose level (DL) minus 1 (neratinib 160 mg daily with trametinib 1 mg, 5 days on and 2 days off) given 2 DLTs of grade 3 diarrhea in DL1 (neratinib 160 mg daily with trametinib 1 mg daily). The treatment-related toxicities of DL1 included: diarrhea (100%), nausea (55.6%) and rash (55.6%). Pharmacokinetic data showed trametinib clearance was significantly reduced leading to high drug exposures of trametinib. Two patients achieved stable disease (SD) ≥ 4 months.

CONCLUSION

Neratinib and trametinib combination was toxic and had limited clinical efficacy. This may be due to suboptimal drug dosing given drug-drug interactions.

TRIAL REGISTRATION ID

NCT03065387.

Case report: Visibly curative effect of dabrafenib and trametinib on advanced thyroid carcinoma in 2 patients

Background

Differentiated thyroid cancer accounts for the majority of thyroid cancers and has a good prognosis after standard treatment. However, there are still some complex and refractory thyroid cancers, including locally advanced differentiated thyroid carcinoma and medullary carcinoma (MTC), poorly differentiated thyroid carcinoma (PDTC), and anaplastic thyroid carcinoma (ATC). Here, we report the therapeutic response of 2 advanced thyroid carcinoma patients treated with dabrafenib and trametinib.

Case presentation

Two elderly females presented to the clinic with neck masses, dyspnea, and dysphagia. Signs of the trachea and esophageal compression were markedly visible in computed tomography (CT) scan and ultrasonography. Pathologic diagnoses of PDTC were confirmed for both patients through ultrasound-guided fine-needle aspiration (US-FNA). Both patients were significantly relieved from dyspnea and dysphagia after a course of treatment with dabrafenib and trametinib, and their tumors gradually shrank during the follow-up period.

Conclusion

Overall, this treatment modality is rare, but effective. By sharing these 2 case reports, we hope to provide a reference for the treatment of clinically similar patients with advanced thyroid carcinoma.

Adaptive therapy to circumvent drug resistance to tyrosine kinase inhibitors in cancer: is it clinically relevant?

INTRODUCTION

Cancer is highly adaptable and is constantly evolving against current targeted therapies such as tyrosine kinase inhibitors. Despite advances in recent decades, the emergence of drug resistance to tyrosine kinase inhibitors constantly hampers therapeutic efficacy of cancer treatment. Continuous therapy versus intermittent clinical regimen has been a debate in drug administration of cancer patients. An ecologically-inspired shift in cancer treatment known as 'adaptive therapy' intends to improve the drug administration of drugs to cancer patients that can delay emergence of drug resistance.

AREAS COVERED

We discuss improved understanding of the concept of drug resistance, the basis of continuous therapy, intermittent clinical regimens, and adaptive therapy will be reviewed. In addition, we discuss how adaptive therapy provides guidance for future cancer treatment.

EXPERT OPINION

The current understanding of drug resistance in cancer leads to poor prognosis and limited treatment options in patients. Fighting drug resistance mutants is constantly followed by new forms of resistance. In most reported cases, continuous therapy leads to drug resistance and an intermittent clinical regimen vaguely delays it. However, adaptive therapy, conceptually, exploits multiple parameters that can suppress the growth of drug resistance and provides safe treatment for cancer patients in the future.

Sendeng-4 Suppressed Melanoma Growth by Induction of Autophagy and Apoptosis

Sendeng-4 is a traditional Chinese medicine that has been successfully applied to anti-inflammatory diseases in clinical practice. Monomers within Sendeng-4 showed promising antitumor activity against lung cancer, colon cancer, and cutaneous cancer. However, potency of Sendeng-4 in melanoma has not been explored. This study aims to explore the potential application of Sendeng-4 in melanoma treatment. In the present study, we systemically investigate the possibility of Sendeng-4 for treatment of melanoma cancer in vitro by proliferation assay, colony formation, flow cell cytometry, RNA-seq, western blot, and fluorescence-based assay. Our data demonstrated that Sendeng-4 suppresses the proliferation and colony formation capacity of melanoma cells and induces cell cycle block at G2/M phase and eventually cell death. Mechanistically, transcriptome sequencing demonstrates that the PI3K-AKT pathway was significantly inactivated upon Sendeng-4 exposure, which was confirmed by western blot showing decreased phosphorylation of AKT. In addition, decreased BCL-2 expression and increased BAX expression were observed, suggesting programmed cell death via apoptosis. Moreover, LC3-II production as well as autophagosomes formation was observed as demonstrated by western blot and immunofluorescence, indicating elevated autophagy network by Sendeng-4 stimulation. Collectively, we concluded that Sendeng-4 might be used as an anticancer drug for melanoma.

Canadian consensus statement on the management of radioactive iodine-resistant differentiated thyroid cancer

Radioactive iodine-resistant differentiated thyroid cancer (RAIRTC) is an aggressive form of thyroid cancer that is uncommon and heterogeneous in its clinical behavior. With the emergence of more effective systemic therapy, the need for guidance in decision-making was recognized and a consensus committee of national experts was assembled. The consensus committee consisted of 13 clinicians involved in treating RAIRTC from across Canada and included endocrinologists, nuclear medicine physicians, surgeons, and radiation and medical oncologists. Domains of interest were identified by consensus, and evidence gathered using systematic reviews. Consensus recommendations for the diagnosis and management of RAIRTC were developed. It was recognized that the rarity of RAIRTC in practice and heterogeneous patterns of thyroid cancer care could limit access to effective therapy for some RAIRTC patients. This document offers guidance to manage RAIRTC patients in a multidisciplinary manner.

The role of molecular genetics in the presurgical management of thyroid nodules

INTRODUCTION

Fine-needle aspiration (FNA) is an important diagnostic tool for the evaluation of thyroid nodules. However, in almost ¼ of all nodules submitted to FNA cytology is indeterminate. Since the majority of genetic alterations in thyroid cancer have been identified, the use of molecular testing platforms has been endorsed by American Thyroid Association for management of indeterminate nodules.

EVIDENCE ACQUISITION

Several commercial tests were based on mRNA expression of FNA samples (Afirma®, Veracyte, South San Francisco, CA, USA) while others detect DNA alterations (ThyroSeq, UPMC, Pittsburgh, PA, USA). Noncommercial tests detect limited number of point mutations or re-arrangements (gene panels). Literature study included a Pubmed research for adult original studies from 2003 to 2020, focusing on terms such as "molecular tests," "nodules with indeterminate AUS/FLUS and FN/SFN cytology."

EVIDENCE SYNTHESIS

Gene expression profile tests serve as "rule out" tests due to their high negative predictive value and perform better in a setting of low cancer pretest probability. Genetic alteration platforms display high positive predictive value and serve as rather "rule in" tests but their diagnostic accuracy is hampered either because a small proportion of nodules does not harbor any of these alterations targeted (gene panels) or because commonly identified RAS mutations can also be found in benign nodules.

CONCLUSIONS

Next generation sequencing development and incorporation of other genetic markers such as miRNA can improve diagnostic accuracy of molecular tests.

Upregulation of OIP5-AS1 Predicts Poor Prognosis and Contributes to Thyroid Cancer Cell Proliferation and Migration

As a common malignancy, thyroid cancer mainly occurs in the endocrine system. There have been accumulating studies on therapeutic methods of thyroid cancer, but its internal molecular mechanism is still not fully understood. Long noncoding RNA (lncRNA) OIP5-AS1 was confirmed as an oncogene and related to poor prognosis in various cancers. Nevertheless, its role and underlying mechanism remain unclear in thyroid cancer. Here, we observed a significant upregulation of OIP5-AS1 in thyroid cancer tissues and cells, and upregulated OIP5-AS1 was correlated with poor prognosis in thyroid cancer. Moreover, OIP5-AS1 knockdown resulted in the inhibited cell proliferation and migration, while overexpressed OIP5-AS1 exhibited the reverse function in thyroid cancer. Besides, OIP5-AS1 was found to positively regulate Wnt/β-catenin signaling pathway. Through mechanism exploration, OIP5-AS1 was discovered to activate Wnt/β-catenin signaling pathway via FXR1/YY1/CTNNB1 axis. Finally, rescue assays indicated that the inhibitive role of silenced OIP5-AS1 in thyroid cancer cell growth and Wnt/β-catenin signaling pathway could be rescued by overexpression of CTNNB1 or addition of lithium chloride (LiCl). In conclusion, upregulation of OIP5-AS1 predicted unfavorable prognosis and enhanced thyroid cancer cell growth by activating Wnt/β-catenin signaling pathway.

First-Line Treatment of Widely Metastatic BRAF-Mutated Salivary Duct Carcinoma With Combined BRAF and MEK Inhibition

Salivary duct carcinoma (SDC) is a rare and aggressive malignancy for which limited data exist to guide treatment decisions. With the advent of advanced molecular testing and tumor genomic profiling, clinicians now have the ability to identify potential therapeutic targets in difficult-to-treat cancers such as SDC. This report presents a male patient with widely metastatic SDC found on targeted next-generation sequencing to have a BRAF p.V600E mutation. He experienced a prolonged and robust response to first-line systemic chemotherapy with dabrafenib and trametinib. During his response interval, new data emerged to justify subsequent treatment with both an immune checkpoint inhibitor and androgen blockade after his disease progressed. To our knowledge, this is the first report of frontline BRAF-directed therapy eliciting a response in metastatic SDC.

Novel Drug Treatments of Progressive Radioiodine-Refractory Differentiated Thyroid Cancer

Systemic therapy options have emerged for treatment of progressive, radioiodine-refractory differentiated thyroid carcinoma. Approved therapies that target tumor angiogenesis, lenvatinib and sorafenib, improve progression-free survival and, in an older subset, lenvatinib can prolong overall survival. Treatments based on targeting specific somatic genetic alterations are also available, which potentially also may prolong progression-free survival but are not yet approved for use by the Food and Drug Administration for this specific disease. More novel approaches that may benefit select patients include resensitization therapies that allow further radioiodine utilization and new immunotherapy concepts.

Radioactive Iodine-Refractory Differentiated Thyroid Cancer in the Elderly

Most common thyroid cancers are differentiated thyroid cancers (DTCs) and have papillary, follicular, or Hürthle cell morphology. Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland. The incidence of DTC increases with age. While most of the patients with DTC have an excellent prognosis, the outcome can be poor when diagnosed in elderly patients.

PURPOSE OF REVIEW

Current treatment approach for DTC includes surgery, thyroid-stimulating hormone (TSH) suppression, radioactive iodine, external beam radiotherapy, or systemic treatments such as kinase inhibitors. Radioactive iodine therapy (RAI) is the primary first-line systemic treatment for advanced DTC. However, during the course of treatment, the tumor may become refractory to RAI. Elderly patients are more likely to be diagnosed with advanced disease that can be refractory to RAI.

RECENT FINDINGS

The advent of TKIs (tyrosine kinase inhibitors) and their usage in RAI refractory disease has shown improved progression-free survival. These agents are, however, associated with increased toxicity. The variable nature of disease and toxicity associated with the systemic therapy makes it important to have an individualized approach to management, especially in the elderly population who can be more susceptible to toxicities.