Target therapy for BRAF mutated anaplastic thyroid cancer: a clinical and molecular study

Efficacy and safety of BRAF/MEK inhibitors in BRAFV600E-mutated anaplastic thyroid cancer: a systematic review and meta-analysis

PURPOSE

Approximately 45% of anaplastic thyroid cancer (ATC) patients harbor a BRAFV600E mutation and are eligible for target therapy (TT) with BRAF and MEK inhibitors (BRAFi/MEKi), nevertheless, few data advocate for this. Hence, we've conducted a systematic review and meta-analysis investigating the effectiveness and safety of BRAFi/MEKi in BRAFV600E ATC patients.

METHODS

PubMed, Embase, and the Cochrane Library were systematically searched for BRAFi/MEKi TT in BRAFV600E ATC patients. Outcomes included objective response rate (ORR), disease control rate (DCR), overall survival (OS), progression-free survival (PFS), duration of response (DOR) and adverse events (AEs).

RESULTS

Nine studies with 168 patients were included. Median follow-up ranged from 2.0 to 47.9 months. 75% of patients had stage IVc. In a pooled analysis, ORR was 68.15% (95% CI 55.31-80.99, I2 = 47%) and DCR was 85.39% (95% CI 78.10-92.68, I2 = 0), with a median DOR of 14.4 months (95% CI 4.6-14.4) and a median PFS of 6.7 months (95% CI 4.7-34.2). Moreover, 1-year OS rate was 64.97% (95% CI 48.76-81.17, I2 = 84%) and 2-years OS rate was 52.08% (95% CI 35.71-68.45, I2 = 79%). Subgroup analysis showed patients in the neoadjuvant setting had higher rates of 1 and 2-years OS and observational studies tended to report higher rates of ORR than clinical trials. No new or unexpected adverse events were found.

CONCLUSIONS

Our study demonstrated BRAFi/MEKi have a decent activity for BRAFV600E ATC patients, especially in the neoadjuvant setting, with a tolerable safety profile. However, further clinical trials are warranted to investigate these findings.

Synergistic effects of the combination of trametinib and alpelisib in anaplastic thyroid cancer with BRAF and PI3KCA co-mutations

Background

Anaplastic thyroid cancer (ATC), a rare and aggressive malignancy with a poor prognosis, has shown promise with the approved dabrafenib/trametinib combination for BRAFV600E mutation. Co-occurring PI3KCA mutations, identified as negative prognostic factors in lung cancer with BRAFV600E mutation, emphasize the need to target both pathways. Exploring trametinib and alpelisib combination becomes crucial for ATC.

Methods

A patient-derived xenograft (PDX) and primary cell line were obtained from an ATC patient with BRAF and PI3KCA co-mutation. Individual testing of targeted therapies against BRAF, MEK, and PI3KCA was followed by a combination treatment. Synergistic effects were evaluated using the combination index. Immunoblotting assessed the efficacy, with validation performed using a PDX model.

Results

In this study, the ATC0802 cell line and PDX were established from a refractory ATC patient. NGS revealed BRAF and PI3KCA co-mutations pre- and post-dabrafenib/trametinib treatment. Trametinib/alpelisib combination showed synergy, suppressing both pERK and pAKT levels, unlike monotherapies or BRAF knockdown. The combination induced apoptosis and, in the PDX model, demonstrated superior tumor growth inhibition compared to monotherapies.

Conclusions

The combination of trametinib and alpelisib showed promise as a strategy for treating ATC with co-mutations in BRAF and PI3KCA, both in vitro and in vivo. This combination offers insights into overcoming resistance to BRAF-targeted treatments in ATC with mutations in BRAF and PI3KCA.

Changes in the outcomes of patients with anaplastic thyroid carcinoma over the past two decades

OBJECTIVE

To assess the changes in survival outcomes among patients with anaplastic thyroid carcinoma in the US over the past two decades.

METHODS

Surveillance, Epidemiology, and End Results (SEER) database research data were reviewed, and patients with anaplastic thyroid carcinoma, who were diagnosed from 2004 to 2020 were evaluated. Kaplan-Meier survival estimates were conducted to examine differences in overall survival between three year-of-diagnosis groups (2004 to 2010; 2011 to 2016; and 2017 to 2020). Multivariable Cox regression analysis was then performed to explore the factors affecting overall survival.

RESULTS

A total of 1804 patients with anaplastic thyroid carcinoma were included. Using Kaplan-Meier survival estimates, overall survival was better among patients diagnosed from 2017 to 2020 versus those diagnosed at earlier periods (P < 0.001). One-year survival estimates were 25% among patients diagnosed from 2017 to 2020 versus 15% for patients diagnosed from 2011 to 2016, and 19%, for patients diagnosed from 2004 to 2010. Using the multivariable Cox regression model, an earlier year of diagnosis was associated with worse overall survival compared to the diagnosis year 2017 to 2020 (HR for diagnosis 2004 to 2010 versus diagnosis 2017 to 2020: 1.170; 95% CI: 1.029 to 1.331, and HR for diagnosis 2011 to 2016 versus diagnosis 2017 to 2020: 1.251; 95% CI: 1.103 to 1.419).

CONCLUSIONS

While anaplastic thyroid carcinoma remains a deadly cancer, survival seems to be improving for the last few years compared to earlier years. There is still additional work to be done to improve the outcomes of those patients.

The role of targeted therapy and/or immunotherapy therapy in anaplastic thyroid carcinoma

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is a highly invasive malignant tumor with a poor prognosis. Traditional treatment methods have not been effective. However, advancements in targeted therapy and immunotherapy in recent years have shed new light on the management of ATC. The aim of this study was to examine the treatment plan and prognostic factors of ATC.

METHODS

This study conducted a retrospective analysis of ATC patients who received treatment at our institution between 2000 and 2023 to evaluate the clinical characteristics, treatment methods, and factors influencing survival. Survival analysis was performed by the Kaplan‒Meier method and log-rank test, and multivariate analysis was performed using the Cox proportional hazard model.

RESULTS

The 6-month and 1-year disease-specific OS rates were 49% and 29%, respectively. The presence of clinical symptoms and the timing of treatment significantly impacted patient prognosis (P < 0.05). Compared with surgery + radiotherapy/chemotherapy and only surgery, targeted therapy and targeted + immunotherapy represented an improved overall survival, The 6-month/1-year survival rates of which were 81%/61% and 91%/73% (P < 0.05), respectively. Multivariate analysis indicated that the symptoms at initial diagnosis, year of presentation, performance status and treatment plan were independent factors affecting the prognosis. The year of presentation (P = 0.048) and the treatment plan (P = 0.038) were significantly meaningful in predicting prognosis.

CONCLUSION

Targeted therapy and targeted+immune therapy can effectively prolong the survival period of ATC patients. Symptoms at initial diagnosis and treatment plan have a significant impact on the prognosis.

CDK4 phosphorylation status and rational use for combining CDK4/6 and BRAF/MEK inhibition in advanced thyroid carcinomas

Background

CDK4/6 inhibitors (CDK4/6i) have been established as standard treatment against advanced Estrogen Receptor-positive breast cancers. These drugs are being tested against several cancers, including in combinations with other therapies. We identified the T172-phosphorylation of CDK4 as the step determining its activity, retinoblastoma protein (RB) inactivation, cell cycle commitment and sensitivity to CDK4/6i. Poorly differentiated (PDTC) and anaplastic (ATC) thyroid carcinomas, the latter considered one of the most lethal human malignancies, represent major clinical challenges. Several molecular evidence suggest that CDK4/6i could be considered for treating these advanced thyroid cancers.

Methods

We analyzed by two-dimensional gel electrophoresis the CDK4 modification profile and the presence of T172-phosphorylated CDK4 in a collection of 98 fresh-frozen tissues and in 21 cell lines. A sub-cohort of samples was characterized by RNA sequencing and immunohistochemistry. Sensitivity to CDK4/6i (palbociclib and abemaciclib) was assessed by BrdU incorporation/viability assays. Treatment of cell lines with CDK4/6i and combination with BRAF/MEK inhibitors (dabrafenib/trametinib) was comprehensively evaluated by western blot, characterization of immunoprecipitated CDK4 and CDK2 complexes and clonogenic assays.

Results

CDK4 phosphorylation was detected in all well-differentiated thyroid carcinomas (n=29), 19/20 PDTC, 16/23 ATC and 18/21 thyroid cancer cell lines, including 11 ATC-derived ones. Tumors and cell lines without phosphorylated CDK4 presented very high p16CDKN2A levels, which were associated with proliferative activity. Absence of CDK4 phosphorylation in cell lines was associated with CDK4/6i insensitivity. RB1 defects (the primary cause of intrinsic CDK4/6i resistance) were not found in 5/7 tumors without detectable phosphorylated CDK4. A previously developed 11-gene expression signature identified the likely unresponsive tumors, lacking CDK4 phosphorylation. In cell lines, palbociclib synergized with dabrafenib/trametinib by completely and permanently arresting proliferation. These combinations prevented resistance mechanisms induced by palbociclib, most notably Cyclin E1-CDK2 activation and a paradoxical stabilization of phosphorylated CDK4 complexes.

Conclusion

Our study supports further clinical evaluation of CDK4/6i and their combination with anti-BRAF/MEK therapies as a novel effective treatment against advanced thyroid tumors. Moreover, the complementary use of our 11 genes predictor with p16/KI67 evaluation could represent a prompt tool for recognizing the intrinsically CDK4/6i insensitive patients, who are potentially better candidates to immediate chemotherapy.

Recent advances in anaplastic thyroid cancer management

PURPOSE OF REVIEW

To summarize recent developments in the diagnosis and management of patients with anaplastic thyroid cancer (ATC).

RECENT FINDINGS

An updated edition of the Classification of Endocrine and Neuroendocrine Tumors was released by the World Health Organization (WHO), in which squamous cell carcinoma of the thyroid are now a subtype of ATC. Broader access to next generation sequencing has allowed better understanding of the molecular mechanisms driving ATC and improved prognostication. BRAF-targeted therapies revolutionized the treatment of advanced/metastatic BRAFV600E -mutated ATC, offering significant clinical benefit and allowing better locoregional control of disease through the neoadjuvant approach. However, inevitable development of resistance mechanisms represents a major challenge. Addition of immunotherapy to BRAF/MEK inhibition has shown very promising results and significant improvement in survival outcomes.

SUMMARY

Major advancements took place in the characterization and management of ATC in recent years, especially in patients with a BRAF V600E mutation. Still, no curative treatment is available, and options are limited once resistance to currently available BRAF-targeted therapies develops. Additionally, there is still a need for more effective treatments for patients without a BRAF mutation.

SPRY4 as a Potential Mediator of the Anti-Tumoral Role of Macrophages in Anaplastic Thyroid Cancer Cells

Anaplastic thyroid carcinoma (ATC) is the most lethal subtype of thyroid cancer, with high invasive and metastatic potential, not responding to conventional treatments. Its aggressiveness may be influenced by macrophages, which are abundant cells in the tumor microenvironment. To investigate the role of macrophages in ATC aggressiveness, indirect co-cultures were established between ATC cell lines and THP-1-derived macrophages. Macrophages significantly increased both the migration and invasion of T235 cells (p < 0.01; p < 0.01), contrasting with a decrease in C3948 (p < 0.001; p < 0.05), with mild effects in T238 migration (p < 0.01) and C643 invasion (p < 0.05). Flow cytometry showed upregulation of CD80 (pro-inflammatory, anti-tumoral) and downregulation of CD163 (anti-inflammatory, pro-tumoral) in macrophages from co-culture with T235 (p < 0.05) and C3948 (p < 0.05), respectively. Accordingly, we found an upregulation of secreted pro-inflammatory mediators (e.g., GM-CSF, IL-1α; p < 0.05) in C3948-macrophage co-cultures. Proteomic analysis showed the upregulation of SPRY4, an inhibitor of the MAPK pathway, in C3948 cells from co-culture. SPRY4 silencing promoted cancer cell invasion, reverting the reduced invasion of C3948 caused by macrophages. Our findings support that macrophages play a role in ATC cell aggressiveness. SPRY4 is a possible modulator of macrophage-ATC cell communication, with a tumor suppressor role relevant for therapeutic purposes.

Association of DNA Promoter Methylation and BRAF Mutation in Thyroid Cancer

The BRAF V600E mutation and DNA promoter methylation play important roles in the pathogenesis of thyroid cancer (TC). However, the association of these genetic and epigenetic alterations is not clear. In this study, using paired tumor and surrounding normal tissue from the same patients, on a genome-wide scale we tried to identify (a) any association between BRAF mutation and DNA promoter methylation, and (b) if the molecular findings may provide a basis for therapeutic intervention. We included 40 patients with TC (female = 28, male = 12) without distant metastasis. BRAF mutation was present in 18 cases. We identified groups of differentially methylated loci (DML) that are found in (a) both BRAF mutant and wild type, (b) only in BRAF mutant tumors, and (c) only in BRAF wild type. BRAF mutation-specific promoter loci were more frequently hypomethylated, whereas BRAF wild-type-specific loci were more frequently hypermethylated. Common DML were enriched in cancer-related pathways, including the mismatch repair pathway and Wnt-signaling pathway. Wild-type-specific DML were enriched in RAS signaling. Methylation status of checkpoint signaling genes, as well as the T-cell inflamed genes, indicated an opportunity for the potential use of PDL1 inhibitors in BRAF mutant TC. Our study shows an association between BRAF mutation and methylation in TC that may have biological significance.