Phase 3 Trial of Selpercatinib in Advanced RET-Mutant Medullary Thyroid Cancer

CTR-FAPI PET Enables Precision Management of Medullary Thyroid Carcinoma

Medullary thyroid carcinoma (MTC) can only be cured through the excision of all metastatic lesions, but current clinical practice fails to localize the disease in 29% to 60% of patients. Previously, we developed a fibroblast activation protein inhibitor (FAPI)-based covalent targeted radioligand (CTR) for improved detection sensitivity and accuracy. In this first-in-class clinical trial, we head-to-head compared [68Ga]Ga-CTR-FAPI PET-CT and [18F]fluorodeoxyglucose ([18F]FDG) PET-CT in 50 patients with MTC. The primary endpoint was the patient-based detection rate, with [68Ga]Ga-CTR-FAPI exhibiting higher detection than [18F]FDG (98% vs. 66%, P = 0.0002). This improved detection was attributed to increased tumor uptake (maximum standardized uptake value = 11.71 ± 9.16 vs. 2.55 ± 1.73, P < 0.0001). Diagnostic accuracy, validated on lesions with gold-standard pathology, was greater for [68Ga]Ga-CTR-FAPI compared with [18F]FDG (96.7% vs. 43.3%, P < 0.0001). Notably, the management of 32% of patients was altered following [68Ga]Ga-CTR-FAPI PET-CT, and the surgical plan was changed for 66.7% of patients. Overall, [68Ga]Ga-CTR-FAPI PET-CT provided superior detection and diagnostic accuracy compared with [18F]FDG PET-CT, enabling precision management of patients with MTC. Significance: In this first-in-class clinical trial of CTR, [68Ga]Ga-CTR-FAPI demonstrated an improved patient-based detection rate (98%), tumor uptake (maximum standardized uptake value = 11.71 ± 9.16), and pathology-validated diagnostic accuracy (96.7%) compared with the currently approved method in MTC treatment. It directly altered management in 32% of patients, enabling precision diagnosis and management of MTC. See related commentary by Witney, p. 264.

Alectinib for the treatment of papillary thyroid carcinoma harbouring STRN - ALK fusion

BACKGROUND

Anaplastic Lymphoma Kinase (ALK) rearrangement is a rare alteration in differentiated thyroid carcinomas (DTCs). Due to its low prevalence, a few evidence are available about the use of ALK inhibitors in advanced DTCs.

METHODS

We report the case of a striatin (STRN) - ALK translocated advanced thyroid carcinoma. STRN - ALK translocation was detected by NGS - RNA analysis.

RESULTS

A 74-year-old woman received first line alectinib for the treatment of a STRN - ALK translocated advanced thyroid carcinoma with symptomatic bilateral lung localizations. The dose of alectinib was progressively reduced due to the toxicity, but the treatment is still ongoing after 17 months with complete radiological response and clinical benefit.

CONCLUSION

Here we report the first case in Europe of STRN - ALK translocated advanced thyroid carcinoma successfully treated with alectinib.

Selpercatinib – a new option for a precision approach to the treatment of medullary thyroid cancer

Introduction. Multikinase inhibitors are used to treat nonresectable locally advanced and/or metastatic medullary thyroid cancer (MTC). However  they are characterized by high toxicity associated with kinase inhibition. Selective RET inhibitor selpercatinib demonstrates high selectivity and tolerance which makes it a promising agent for MTC treatment.

Aim. To evaluate selpercatinib effectiveness and tolerance in patients with metastatic MTC associated with a mutation in the RET gene.

Materials and methods. The study included 9 patients with metastatic MTC and mutation in the RET gene who received treatment with selpercatinib 160 mg 2 times a day. The drug effectiveness was evaluated every 2–3 months based on the results of multispiral computed tomography of the whole body and tumor marker (calcitonin and carcinoembryonic antigen) levels.

Results. Median duration of therapy was 29 months  overall response rate was 78 %; complete response was observed in 56 % of patients. After 12 months of therapy  progression-free survival was 100 %; after 24 months  it was 89 %. Persistent decrease in calcitonin level (by more than 90 %) was achieved in all patients. The most common adverse events were arterial hypertension and insignificant creatinine increase.

Conclusion. The results of therapy show significant improvement in the rate of objective response and progression[1]free survival which makes selpercatinib a preferential treatment choice in this category of patients.

Development of a simple high-performance liquid chromatography-ultraviolet detection method for selpercatinib determination in human plasma

Selpercatinib is a selective rearranged during transfection (RET) kinase inhibitor effective for the treatment of RET-positive non-small cell lung cancer, thyroid cancer, and other cancers. However, its clinical use requires careful management because of dose-dependent adverse effects and pharmacokinetic interactions. Given the multiple factors influencing selpercatinib blood levels, we hypothesized that establishing a therapeutic drug monitoring system for selpercatinib could help reduce adverse events and optimize efficacy. Therefore, we herein developed a high-performance liquid chromatography-ultraviolet (HPLC-UV) method for measuring selpercatinib blood levels to facilitate therapeutic drug monitoring in clinical practice. Proteins were precipitated with acetonitrile, and selpercatinib and the internal standard (gefitinib) were separated via HPLC-UV. The calibration curve was linear over 0.5-8.0 µg/mL with a coefficient of determination (r²) equaling 0.9996. Intra- and interday validation coefficients were both under 2.80%. The corresponding measurement precision ranged from - 1.50% to 12.60% and - 1.32% to 7.50%, respectively, with recoveries exceeding 94.43%. Thus, this study establishes a simple and sensitive method for quantifying selpercatinib in human plasma. Future studies will analyze plasma samples from patients treated with selpercatinib and utilize this method to explore the relationships among plasma concentration, efficacy, and adverse events to define the therapeutic concentration range.

Selpercatinib mitigates cancer cachexia independent of anti-tumor activity in the HT1080 tumor model

Anorexia is a major cause of cancer cachexia and is induced by growth differentiation factor-15 (GDF15), which activates the rearranged during transfection (RET) protein tyrosine kinase in the hindbrain through GDF family receptor α-like (GFRAL), raising the possibility of targeting RET for cancer cachexia treatment. RET-altered cancer patients treated with RET-selective kinase inhibitors gain weight, however, it is unclear whether this results from tumor regression that improves the overall health of patients. Thus, the potential of using a RET inhibitor to address cancer cachexia remains unknown. Using a RET-negative tumor model, we evaluated the activity of the RET-selective inhibitor selpercatinib (LOXO-292) against cancer cachexia. In tumor-bearing animals, selpercatinib significantly increased food consumption, skeletal muscle mass and strength, adipose tissues, and body temperature, as well as reducing body weight loss, without significantly affecting tumor growth. Transcriptomes of skeletal muscle from mock-treated tumor-bearing mice were enriched in starvation and muscle atrophy genes, whereas those from selpercatinib-treated mice were enriched in myoblast proliferation, gluconeogenesis, and insulin receptor signaling genes. In parallel, retrospective analysis of weight gain in selpercatinib-treated patients showed that weight gain was not correlated with tumor response to selpercatinib. Our data demonstrate that selpercatinib could alleviate anorexia and cancer cachexia in an animal model and that weight gain in selpercatinib-treated patients is not dependent on tumor regression. These results identify a RET inhibitor as the first protein tyrosine kinase inhibitor for mitigating cancer cachexia.

Genomics Review of Selective RET Inhibitors Sensitivity in Thyroid Cancer Clinical Trials

RET gene is a driver of thyroid cancer (TC) tumorigenesis. The incidence of TC has increased worldwide in the last few decades, both in medullary and follicular-derived subtypes. Several drugs, including multikinase and selective inhibitors, have been explored. Selpercatinib and pralsetinib are selective RET inhibitors that have shown clear clinical benefits for patients in the LIBRETTO and ARROW trials, respectively. Currently, their development and application in clinical practice are ongoing. However, its efficacy in different RET pathogenic variants has not yet been well established. Although selpercatinib and pralsetinib achieved a high ORR, no data are available regarding the differences in tumor responses of both TC groups according to RET pathogenic variants. Clinical trials and literature have analyzed the efficacy of selective RET inhibitors with a special interest in the most common variants. A review of LIBRETTO and ARROW trials was made regarding the change in tumor size depending on the pathogenic variants. M918T pathogenic variant resulted in a higher complete response rate. Patients who underwent fusion had the highest ORR (objective response rate). MKi-treated patients did not exhibit significant differences from untreated patients. Different RET pathogenic variants are not biomarkers of RETi response in TC. Selpercatinib showed a tendency to achieve a complete response. All patients with RET pathogenic variants should receive treatment with selpercatinib or pralsetinib at any moment of the therapeutic schedule owing to off-target inhibition and toxicity. Therefore, new targets for drug sensitivity and resistance should be explored.

Long-term Clinical Outcomes of Patients With Medullary Thyroid Cancer: A Single Institution, Tertiary Referral Centre Experience

AIMS

Medullary thyroid cancer (MTC) is a rare form of thyroid cancer with a variable disease course. We aimed to conduct a real-world analysis of the clinical outcomes of patients with MTC, thereby providing further insight into the prognosis and management.

MATERIALS AND METHODS

All patients with MTC whose data were available on electronic patient records since its introduction in 1992 at our institution were collected retrospectively. Data collected include patient characteristics, staging, treatment modalities and survival outcomes. The data extraction cut-off was 31st December 2022. Progression-free survival (PFS) and overall survival (OS) were analysed using Kaplan-Maier curves and log-rank test. The significance threshold was set at p value <0.05.

RESULTS

164 patients were included in this study. The median age at presentation was 44 years. Majority of patients (61%) presented with advanced disease; 41% were stage IVa, 4% IVb and 16% IVc. The 10-year OS was 92% for stage I-III disease, 77% for stage IVa/b and 38% for stage IVc. Germline rearranged during transfection (RET) mutations were detected in 21% of patients. 98% of patients received primary surgery and 24% received systemic treatment for recurrent/metastatic disease, with a high response rate seen with RET-specific inhibitors in those with RET-mutant MTC. Adjuvant radiotherapy improved locoregional control for those with locally advanced disease (p = 0.001) but failed to translate into OS benefit (p = 0.486).

CONCLUSION

Survival outcomes observed in our cohort mirror those reported in the literature and highlight the need for improved therapy options, especially in those presenting with metastatic disease. Our data reaffirmed a lack of survival benefit with adjuvant radiotherapy for MTC with a high rate of systemic relapse and future research should focus on evolving mechanisms of resistance to novel tyrosine kinase inhibitors.

Efficacy and Safety of Selective RET Inhibitors in Patients with Advanced Hereditary Medullary Thyroid Carcinoma

Background: Two selective RET inhibitors (RETis) are effective in treating REarranged during Transfection (RET)-altered medullary thyroid carcinoma (MTC), but clinical trials did not distinguish responses between hereditary MTC (hMTC) and sporadic MTC (sMTC) cases. We reviewed our single-center experience using a RETi to treat advanced hMTC. Methods: We conducted a retrospective cohort study of patients with hMTC treated with a selective RETi at a tertiary cancer center. The primary outcome was overall response rate using Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Secondary end points included overall survival (OS), progression-free survival (PFS), biochemical response rate, and safety. Results: We identified 23 evaluable patients as follows: 15 (65%) multiple endocrine neoplasia (MEN)2A and 8 (35%) MEN2B. Median age at start of RETi was 51 years (range, 15-79). All patients had distant metastases, and 52% (12/23) had received prior systemic therapy (median = 1, range, 0-3). Patients were treated with selpercatinib (n = 13) or pralsetinib (n = 10), 57% (13/23) within a clinical trial. Median duration of RETi was 25 months (range, 3-72) with 11/23 (48%) patients remaining on drug at data cutoff due to an ongoing response. Median duration of follow-up was 49 months (range, 9-72). Best radiographical response was partial response in 18 (78%) and stable disease in 5 (22%) patients. Median OS was 51 months (confidence interval, 40.5-61.3); median PFS was not reached. Most common adverse events (AEs) were increased alanine aminotransferase (ALT) (48%) and aspartate aminotransferase (26%), dry mouth (39%), QT interval prolongation (39%), fatigue (35%), and hypertension (26%). AEs led to dose reductions in eight (35%) patients. No grade 5 treatment-related AEs occurred. While the germline nature of the RET pathogenic variant in hMTC could hypothetically result in increased drug-related toxicity, the incidence of most AEs, other than grade 1-2 ALT elevation and QT interval prolongation, was comparable to published clinical trials. Conclusions: In patients with advanced hMTC, selective RETis appear safe and effective with outcomes similar to clinical trial cohorts, which mostly comprised patients with sMTC. Duration of response and AE profile was similar to sMTC, although longer follow-up and larger patient numbers are needed to confirm this.

Treatment Outcomes and Toxicities of Multiple Tyrosin Kinase Inhibitors for Metastatic Medullary Thyroid Cancer: A Case Series

Background: The current possible treatments of advanced medullary carcinoma (MTC) include different drugs belonging to the class of tyrosine kinase inhibitors (TKIs): vandetanib, cabozantinb, and selpercatinib. Although the effects of these TKIs have been well described in clinical trials, the real-practice evidence of the effectiveness and safety of these treatment is scant. This real-world case series aims to describe a niche of patients with advanced MTC treated with more than one TKI by focusing on treatment responses and any reported adverse events (AEs) and to provide additional insight on the individualized approach to the management of metastatic MTC. Methods: Five patients with a diagnosis of metastastic MTC, treated with at least two different molecules of TKIs, were retrospectively selected. Results: Three patients obtained a partial response (one with cabozantinb, one with selpercatinib, and one with vandetanib), and two patients obtained disease stability (both of them treated with all three TKIs, the first two lines discontinued for AEs). The AE profile agreed with the known clinical trials AEs except for non-neoplastic ascites related to selpercatinib and lung cavitations of non-neoplastic tissue related to cabozantinb. The latter was an AE never described so far in patients receiving TKIs. Conclusions: The best management of MTC relies on an individualized approach, keeping in mind and dealing with the potential toxicity in order to minimize the treatment withdrawal.

Assessing tolerability with the Functional Assessment of Cancer Therapy item GP5: psychometric evidence from LIBRETTO-531, a phase 3 trial of selpercatinib in medullary thyroid cancer

BACKGROUND

This psychometric analysis generated evidence to support the use of the Functional Assessment of Cancer Therapy item GP5 (GP5) as a measure of tolerability and confirms the appropriateness of categorizing "high side-effect burden" using a rating of 3 or 4 (score ranges 0-4) in patients with advanced/metastatic RET-mutant medullary thyroid cancer (MTC).

METHODOLOGY

Blinded, pooled interim data from the safety population (n=290) enrolled in the phase 3 LIBRETTO-531 trial (NCT04211337) were used. Intraclass correlation coefficients (ICC) were calculated for test-retest reliability using data from cycles 1-2 post-baseline. Construct validity was evaluated by examining the correlations of GP5 ratings with (a) symptomatic adverse events (AEs; measured by the PRO-CTCAE), and (b) functioning scores of EORTC QLQ-C30. The ability to detect change over time was examined by Cochrane-Mantel-Haenszel tests for GP5 ratings and PRO-CTCAE. The relationship of "high side-effect burden" categories with QLQ-C30 functioning scores was examined.

RESULTS

ICCs for the GP5 ratings after cycle 1 ranged between 0.80 and 0.85, indicating good reliability. Correlations between GP5 and PRO-CTCAE items ranged from 0.18 to 0.62 and ranged from -0.37 to -0.50 for QLQ-C30 functioning scores, consistent with study assumptions. Post-baseline GP5 ratings showed significant associations with PRO-CTCAE scores (p<0.001). Participants with GP5 ratings of 3 or 4 had worse physical function than those with GP5 ratings of 0 to 2 (p<0.0001).

CONCLUSIONS

This analysis generated evidence supportive of the psychometric properties of the GP5 as a fit-for-purpose measure to assess treatment tolerability in patients with advanced/metastatic MTC. The definition of "high side-effect burden" was associated with the clinical feature of tolerability.

Fovea-Involved Outer Retinal Abnormality Induced by a Novel RET Inhibitor

This case report describes an outer retinal abnormality associated with taking a RET inhibitor during a clinical trial in a 52-year-old patient with right lung adenocarcinoma and a RET gene fusion.

Long-term safety of selpercatinib for Rearranged during transfection (RET)-activated advanced solid tumors in LIBRETTO-001: differing patterns of adverse events over time

BACKGROUND

Selpercatinib is a selective RET inhibitor approved for treatment of RET-activated cancers. Adverse events (AEs) are manageable with dose modifications. This post hoc analysis characterized selpercatinib's clinical safety profile after long-term follow-up in the safety population of LIBRETTO-001.

PATIENTS AND METHODS

LIBRETTO-001 is an ongoing phase I/II, single-arm, open-label trial (NCT03157128). Eligible patients were ≥18 years old with diagnosis of advanced/metastatic RET fusion-positive solid tumor, RET-mutant medullary thyroid cancer, or other RET-activated tumors. In phase I, patients received selpercatinib 20 mg QD or 20-240 mg BID; patients in phase II received 160 mg BID. The analyzed population comprised all patients who received ≥1 selpercatinib dose and were followed up until data cutoff (January 13, 2023).

RESULTS

For the 837 patients, median follow-up was 45.4 months (95% CI, 44.5-46.6); median time on treatment was 30.1 months (range 0.1-66.8). Grade ≥3 treatment-emergent AEs (TEAEs) were reported in 76.2% of patients; most common events were hypertension (19.7%), ALT increased (11.8%), and hyponatremia (9.2%). Serious TEAEs were reported in 51.4% of patients. Most frequently reported any-grade AEs at <6 months of treatment were fatigue (36.6%), dry mouth (32.8%), and ALT increased (30.5%); at ≥24 months of treatment, these were edema (63.2%), diarrhea (60.7%), and fatigue (53.0%). Selpercatinib-related TEAEs leading to reduced dosage were reported in 39.3%, those leading to treatment interruption were reported in 47.1%, and those leading to discontinuation were reported in 4.3% of patients.

CONCLUSION

Long-term treatment with selpercatinib is feasible. AEs are manageable with dose modifications, allowing most patients to continue safely on therapy.

Adverse event profiles of selpercatinib: a real-world pharmacovigilance analysis based on FAERS database

BACKGROUND

Selpercatinib, a highly selective tyrosine kinase inhibitor, has emerged as an excellent treatment option for patients with rearranged during transfection-altered cancer. However, there is limited comprehensive safety information available for selpercatinib through large-scale post-marketing monitoring.

METHODS

This study conducted a comprehensive analysis of selpercatinib-related adverse events (AEs) using the FDA Adverse Event Reporting System database. Four disproportionality methods were employed to identify potential AEs associated with selpercatinib. Specifically, this study investigated the differences in AEs of selpercatinib with respect to reporter continent, indication, sex, age, weight, dose, frequency, and onset time.

RESULTS

A total of 464 reports and 1,007 selpercatinib-related AEs were identified. Three new significant AEs were discovered, including dysphagia, pericardial effusion, and hemiparesis. Notably, Asia reported hepatic function abnormal more frequently, especially in patient administered doses exceeding 160 mg. Furthermore, hypersensitivity was reported more frequently by Asia and in individuals weighing less than 50 kg.

CONCLUSIONS

It is paramount to stay vigilant concerning the potential emergence of three newly identified AEs. Significant differences were found in selpercatinib-related AEs concerning reporter continent, sex, weight, dose, frequency, and onset time, which deserved clinical attention. These findings contribute to a broader understanding of the AE profiles of selpercatinib.

Biodistribution and Radiation Dosimetry for 68 Ga-DOTA-CCK-66, a Novel CCK 2 R-Targeting Compound for Imaging of Medullary Thyroid Cancer

ABSTRACT

Cholecystokinin 2 receptor (CCK 2 R) is a promising target for imaging and treatment of medullary thyroid cancer due to its overexpression in over 90% of tumor cells. 68 Ga-DOTA-CCK-66 is a recently introduced PET tracer selective for CCK 2 R, which has shown favorable pharmacokinetics in vivo in preclinical experiments. In order to further investigate safety and suitability of this tracer in the human setting, whole-body distribution and radiation dosimetry were evaluated.

PATIENTS AND METHODS

Six patients with a history of medullary thyroid cancer were injected intravenously with 169 ± 19 MBq of 68 Ga-DOTA-CCK-66. Whole-body PET/CT scans were acquired at 10 minutes, 1 hour, 2 hours, and 4 hours after tracer injection. Time-activity curves per organ were determined, and mean organ-absorbed doses and effective doses were calculated using OLINDA/EXM.

RESULTS

Injection of a standard activity of 150 MBq of 68 Ga-DOTA-CCK-66 results in an effective dose of 4.5 ± 0.9 mSv. The highest absorbed organ doses were observed in the urinary bladder wall (40 mGy) and the stomach (15 mGy), followed by the kidneys (6 mGy), as well as the liver and the spleen (3 mGy each). CCK 2 R-expressing tumor manifestations could be detected in 2 of the 6 patients, including lymph node, bone, and liver metastases.

CONCLUSIONS

68 Ga-DOTA-CCK-66 exhibits a favorable dosimetry. Beyond physiologic receptor expression of the stomach, no other relevant tracer accumulation could be observed, rendering this organ at risk in case of subsequent radioligand therapy using 177 Lu-DOTA-CCK-66.

Is peptide receptor radionuclide therapy still a promising option for medullary thyroid carcinoma?

Medullary thyroid carcinoma (MTC) is a rare cancer that originates from germline RET proto-oncogene mutations in all hereditary forms and from somatic RET mutations in most sporadic cases. Currently, highly selective RET inhibitors have been approved for clinical use in patients with RET mutations with persistent, recurrent or metastatic disease. This therapy has proven efficacy, low toxicity, and a limited impact on patients' quality of life. However, for recurrent or metastatic RET-negative disease, few systemic therapies are available. Multikinase inhibitors are used; however, tumour cells frequently develop resistance mechanisms, or treatment must be discontinued due to the high incidence of side effects. In this context, peptide receptor radionuclide therapy (PRRT) may be a treatment option, but its clinical utility remains under investigation. The aim of this review is to evaluate the evidence of PRRT in MTC and discuss its limitations in the RET inhibitor era.

Real-World Outcomes of Selective RET Inhibitor Selpercatinib in the United States: Descriptive, Retrospective Findings from Two Databases

OBJECTIVES

This study described real-world patient characteristics and outcomes among selpercatinib-treated patients in the United States, using the Flatiron Health electronic health record-derived deidentified database (FHD) for advanced/metastatic non-small cell lung cancer (a/mNSCLC) and Optum's de-identified Clinformatics® Data Mart Database (CDM).

METHODS

Patients initiating selpercatinib treatment between 08MAY2020 and 30JUN2023 were included. We evaluated real-world time to selpercatinib treatment discontinuation or death (rwTTDd) and time to next treatment or death (rwTTNTd) using Kaplan-Meier analyses. Medication possession ratio (MPR) was estimated as a measure of medication adherence in CDM patients.

RESULTS

In a/mNSCLC patients from the FHD (N = 68), the median rwTTDd and rwTTNTd were 22.4 [95%CI: 13.3-NR] and 21.0 [95%CI: 11.6-NR] months, respectively. In CDM, these durations were 12.1 [95%CI: 9.6-NR] and 16.2 [95%CI: 9.6-NR] months for lung cancer (n = 43), while these were not reached for thyroid cancer (n = 24) patients. The median MPR was 0.98 [IQR: 0.84-1.00] among all patients in the CDM (N = 75), with 77.3% of patients adhering (MPR ≥ 0.80) to selpercatinib.

CONCLUSIONS

Real-world outcomes in this older and frailer patient cohort align with phase 3 trial results, further supporting selpercatinib as the standard of care for patients with RET-altered cancers. Early testing for the detection of RET alterations remains essential.

DLK1 Is Associated with Stemness Phenotype in Medullary Thyroid Carcinoma Cell Lines

Medullary thyroid carcinoma (MTC) is a rare and aggressive tumor, often requiring systemic treatment in advanced or metastatic stages, where drug resistance presents a significant challenge. Given the role of cancer stem cells (CSCs) in cancer recurrence and drug resistance, we aimed to identify CSC subpopulations within two MTC cell lines harboring pathogenic variants in the two most common MEN2-associated codons. We analyzed 15 stemness-associated markers, along with well-established thyroid stem cell markers (CD133, CD44, and ALDH1), a novel candidate (DLK1), and multidrug resistance proteins (MRP1 and MRP3). The ability to efflux the fluorescent dye Hoechst 3342 and form spheroids, representing CSC behavior, was also assessed. MZ-CRC-1 cells (p.M918T) displayed higher expressions of canonical markers, DLK1, and MRP proteins than TT cells (p.C634W). MZ-CRC-1 cells also formed more spheroids and showed less dye accumulation (p < 0.0001). Finally, we observed that DLK1+ cells (those expressing DLK1) in both cell lines exhibited significantly higher levels of stemness markers compared to DLK1- cells (those lacking DLK1 expression). These findings underscore DLK1's role in enhancing the stemness phenotype, providing valuable insights into MTC progression and resistance and suggesting potential therapeutic implications.

First-in-human, phase 1 dose-escalation and dose-expansion study of a RET inhibitor SY-5007 in patients with advanced RET-altered solid tumors

Oncogenic RET alteration is an important, tissue-agnostic therapeutic target across diverse cancers. We conducted a first-in-human phase 1 study on SY-5007, a potent and selective RET inhibitor, in patients with RET-altered solid tumors. Primary endpoints were safety, maximum tolerated dose (MTD), and recommended phase 2 dose (RP2D). Secondary endpoints included pharmacokinetics and preliminary anti-tumor activity. A total of 122 patients were enrolled (17 in dose-escalation phase and 105 in dose-expansion phase), including 91 with non-small cell lung cancer, 23 with medullary thyroid cancer, 7 with papillary thyroid cancer and 1 with gastric cancer. Treatment-related adverse events (TRAEs) were reported in 96.7% of patients, with the most common grade ≥ 3 TRAEs being hypertension (22.1%), diarrhea (16.4%), hypertriglyceridemia (6.6%), and neutropenia (6.6%). The exposure to SY-5007 was dose proportional. Among the 116 efficacy-evaluable patients, the overall objective response rate (ORR) was 57.8%, with 70.0% in treatment-naïve patients and 51.3% in previously treated patients. The median progression-free survival (PFS) was 21.1 months. Efficacy was observed regardless of tumor types and previous therapies. Biomarker analysis of 61 patients with circulating tumor DNA (ctDNA)-detectable RET alterations showed an ORR of 57.4% and median PFS of 13.8 months. Rapid ctDNA clearance of RET alteration correlated with faster responses and improved outcomes. In relapsed patients, off-target induced resistance was observed in 57.1% (12/21), with no on-target RET alterations identified. In conclusion, SY-5007 was well-tolerated and showed promising efficacy in patients with RET-altered solid tumors. Serial ctDNA monitoring may unveil treatment response and potential resistance mechanisms (NCT05278364).

MIG6 loss increased RET inhibitor tolerant persister cells in RET-rearranged non-small cell lung cancer

Recently approved RET tyrosine kinase inhibitors (TKIs) have shown promising therapeutic effects against RET-rearranged non-small cell lung cancer (NSCLC) or RET-mutated thyroid cancer. However, resistance develops, limiting long-term efficacy. Although many RET-TKI resistance mechanisms, such as secondary mutations in RET or activation of bypass pathways, are known, some primary or acquired resistance mechanisms are unclear. Here, human genome-wide CRISPR/Cas9 screening was performed to identify genes related to drug-tolerant persister cells. Patient-derived cells with RET-fusion were introduced genome-wide sgRNA library and treated with RET-TKI for 9 days, resulting in the discovery of several candidate genes. Knockout of MED12 or MIG6 significantly increased residual drug-tolerant persister cells under RET-TKI treatment. MIG6 loss induced significant EGFR activation even with low concentrations of EGFR ligands and led to resistance to RET-TKIs. EGFR inhibition with afatinib or cetuximab in combination with RET TKIs was effective in addressing drug persistence. By contrast, a KIF5B-RET positive cells established from a RET-rearranged NSCLC patient, showed significant resistance to RET-TKIs and high dependence on EGFR bypass signaling. Consistently, knocking out EGFR or RET led to high sensitivity to RET or EGFR inhibitor respectively. Here, we have provided a comprehensive analysis of adaptive and acquired resistance against RET-rearranged NSCLC.

SEOM-GETNE-TTCC Clinical guideline thyroid cancer (2023)

Thyroid cancer (TC) represents 3% of global cancer incidence. Recent changes have optimized treatment decisions based on risk assessment, molecular profiling, and imaging assessment, leading the development of targeted agents that have modified the natural history of this disease. This increasing complexity on treatment options requires careful assessment at the different stages of the disease to provide the most suitable approach from diagnosis to long-term follow-up. This guideline aims to offer a comprehensive and practical overview on the current status and last updates of TC management.

Endogenous EWSR1-FLI1 degron alleles enable control of fusion oncoprotein expression in tumor cell lines and xenografts

Pediatric malignancies frequently harbor chromosomal translocations that induce expression of fusion oncoproteins. The EWSR1-FLI1 fusion oncoprotein acts as a neomorphic transcription factor and is the dominant genetic driver of Ewing's sarcoma. Interrogation of the mechanisms by which EWSR1-FLI1 drives tumorigenesis has been limited by a lack of model systems to precisely and selectively control its expression in patient-derived cell lines and xenografts. Here, we report the generation of a panel of patient-derived EWS cell lines in which inducible protein degrons were engineered into the endogenous EWSR1-FLI1 locus. These alleles enabled rapid and efficient depletion of EWSR1-FLI1. Complete suppression of EWSR1-FLI1 induced a reversible cell cycle arrest at the G 1 -S checkpoint, and we identified a core set of transcripts downstream of EWSR1-FLI1 across multiple cell lines and degron systems. Additionally, depletion of EWSR1-FLI1 potently suppressed tumor growth in xenograft models validating efforts to directly target EWSR1-FLI1 in Ewing's sarcoma.

Unveiling new chapters in medullary thyroid carcinoma therapy: advances in molecular genetics and targeted treatment strategies

Medullary Thyroid Carcinoma (MTC), a neuroendocrine malignancy that arises from the calcitonin-secreting parafollicular C-cells of the thyroid, constitutes a minor yet impactful fraction of thyroid malignancies. Distinguished by its propensity for aggressive growth and a pronounced tendency for metastasis, MTC poses formidable obstacles to the early diagnosis and therapeutic intervention. The molecular genetics of MTC, particularly the role of the RET gene and the RAS gene family, have been extensively studied, offering insights into the pathogenesis of the disease and revealing potential therapeutic targets. This comprehensive review synthesizes the latest advancements in the molecular genetics of MTC, the evolution of precision therapies, and the identification of novel biomarkers. We also discuss the implications of these findings for clinical practice and the future direction of MTC research.

La prise en charge des cancers médullaires de la thyroïde en 2024

MANAGING MEDULLARY THYROID CARCINOMA IN 2024: Medullary thyroid carcinoma is a rare neuroendocrine thyroid cancer with a heterogeneous prognosis which has the particularity of being associated with a RET gene mutation, germline in 20-25% of cases in the context of multiple endocrine neoplasia type 2 (NEM2), and somatic in 70% of sporadic cases. It is often diagnosed on a thyroid nodule or in the context of genetic screening. Calcitonin is a biological marker, used for diagnosis, monitoring of therapeutic response and prognostic evaluation. The only curative treatment is surgery for localized disease. The extent must be carefully assessed, particularly in terms of calcitonin levels and imaging, and carried out by an expert surgeon. The prognosis of locally advanced or metastatic disease is highly heterogeneous. Histological factors, such as high grade, or biological factors, such as calcitonin doubling time, can help assess prognosis. The development of multi-kinase inhibitors cabonzantinib and vandetanib, and RET-targeted inhibitors selpercatinib, has completely changed the therapeutic arsenal for advanced disease, but their prescription is reserved to progressive disease with high tumor volume or to symptomatic disease inaccessible to local treatment in expert centers from the ENDOCAN-TUTHYREF network. Active surveillance is the alternative of choice for slowly progressing disease.

Primary resistance to selpercatinib in a patient with advanced medullary thyroid cancer

Selpercatinib, a selective RET kinase inhibitor, has demonstrated remarkable efficacy in treating patients with advanced medullary (MTC) and differentiated thyroid cancer with RET alterations. Primary resistance to selpercatinib is a very uncommon situation, and its underlying mechanisms are poorly understood. We report the case of a 42-year-old female with advanced MTC harboring a somatic M918T RET mutation who exhibited a primary resistance to selpercatinib. Despite prompt treatment initiation after the diagnosis of progressive disease, the patient continued experiencing rapid spread of disease, characterized by the appearance of new metastatic lesions and increased tumor burden. Genomic analysis revealed no additional mutations associated with on-target or off-target resistance. This case highlights a rare clinical scenario of primary resistance to selpercatinib in advanced MTC. While secondary resistance mechanisms have been well-documented, primary resistance remains poorly understood. Possible explanations include tumor heterogeneity and activation of alternative signaling pathways that stills need to be elucidated. Emerging therapies targeting resistance mechanisms and next-generation RET inhibitors offer promising avenues for further investigation.

Nouveautés en pathologie thyroïdienne : classification OMS 2022, système Bethesda 2023, biologie moléculaire et testing moléculaire

ADVANCES IN THYROID PATHOLOGY

WHO CLASSIFICATION 2022, BETHESDA SYSTEM 2023, MOLECULAR BIOLOGY AND MOLECULAR TESTING: Thyroid pathology has experienced significant advances with the publication of the 5th edition of the World Health Organization classification of endocrine tumors in 2022 and the third edition of the Bethesda system for thyroid cytopathology in 2023. At the same time, the availability of next-generation sequencing data coupled with numerous translational research projects have considerably increased our knowledge of the genomics and mechanics of thyroid cancers, enabling us to refine prognosis and propose new targeted therapies. In this review, we will take up the main new features of the WHO 2022 and Bethesda 2023 classifications, as well as molecular biology findings, with an emphasis on the practical implications for clinicians.

Molecular genetics, therapeutics and RET inhibitor resistance for medullary thyroid carcinoma and future perspectives

Medullary thyroid carcinoma (MTC) is a rare type of thyroid malignancy that accounts for approximately 1-2% of all thyroid cancers (TCs). MTC include hereditary and sporadic cases, the former derived from a germline mutation of rearrangement during transfection (RET) proto-oncogene, whereas somatic RET mutations are frequently present in the latter. Surgery is the standard treatment for early stage MTC, and the 10-year survival rate of early MTC is over 80%. While for metastatic MTC, chemotherapy showing low response rate, and there was a lack of effective systemic therapies in the past. Due to the high risk (ca. 15-20%) of distant metastasis and limited systemic therapies, the 10-year survival rate of patients with advanced MTC was only 10-40% from the time of first metastasis. Over the past decade, targeted therapy for RET has developed rapidly, bringing hopes to patients with advanced and progressive MTC. Two multi-kinase inhibitors (MKIs) including Cabozantinib and Vandetanib have been shown to increase progression-free survival (PFS) for patients with metastatic MTC and have been approved as choices of first-line treatment. However, these MKIs have not prolonged overall survival (OS) and their utility is limited due to high rates of off-target toxicities. Recently, new generation TKIs, including Selpercatinib and Pralsetinib, have demonstrated highly selective efficacy against RET and more favorable side effect profiles, and gained approval as second-line treatment options. Despite the ongoing development of RET inhibitors, the management of advanced and progressive MTC remains challenging, drug resistance remains the main reason for treatment failure, and the mechanisms are still unclear. Besides, new promising therapeutic approaches, such as novel drug combinations and next generation RET inhibitors are under development. Herein, we overview the pathogenesis, molecular genetics and current management approaches of MTC, and focus on the recent advances of RET inhibitors, summarize the current situation and unmet needs of these RET inhibitors in MTC, and provide an overview of novel strategies for optimizing therapeutic effects.

Adverse event profile differences between pralsetinib and selpercatinib: a real-world study based on the FDA adverse events reporting system

Aims

The objective of this study is to compare the adverse events (AEs) associated with pralsetinib and selpercatinib.

Methods

To evaluate the imbalance of AEs linked to pralsetinib and selpercatinib in real-world data, the reporting odds ratio (ROR) was utilized to detect potential signals of AEs. Stratified analysis was conducted to examine the differences in AEs occurring among different genders and age groups taking pralsetinib and selpercatinib.

Results

FAERS received 891 reports for pralsetinib and 569 reports for selpercatinib. Our analysis confirmed expected AEs like hypertension, fatigue, and elevated transaminase levels. Unexpected AEs such as rhabdomyolysis, myocardial injury and cognitive disorder were associated with pralsetinib, while selpercatinib was linked with pulmonary embolism, deep vein thrombosis, and pericardial effusion. The risk of AEs such as decreased platelet count, anemia, decreased white blood cell count, pneumonitis, asthenia, and edema caused by pralsetinib is significantly higher than that of selpercatinib. In contrast, the risk of AEs such as ascites, elevated alanine aminotransferase, and elevated aspartate aminotransferase caused by selpercatinib is significantly higher than that of pralsetinib. Women treated with pralsetinib experience higher rates of hypertension, pulmonary embolism, and blurred vision than men, who are more susceptible to rhabdomyolysis. Adults between 18 and 65 years are more likely to experience taste disorder, edema, and pulmonary embolism than individuals older than 65, who are particularly vulnerable to hypertension. For patients treated with selpercatinib, males demonstrate a significantly higher incidence of QT prolongation, urinary tract infection, and dysphagia. Individuals aged 18 to 65 are more likely to experience pyrexia and pleural effusion than those older than 65, who are more prone to hypersensitivity.

Conclusion

In the clinical administration of pralsetinib and selpercatinib, it is crucial to monitor the effects of gender and age on AEs and to be vigilant for unlisted AEs.

Durability of Response With Selpercatinib in Patients With RET-Activated Thyroid Cancer: Long-Term Safety and Efficacy From LIBRETTO-001

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.LIBRETTO-001 is a registrational phase I/II, single-arm, open-label study of selpercatinib in patients with RET (REarranged during Transfection)-activated cancers (ClinicalTrials.gov identifier: NCT03157128). We present long-term safety and efficacy from LIBRETTO-001 in patients with RET-mutant medullary thyroid cancer (MTC; n = 324) and RET fusion-positive thyroid cancer encompassing different histological subtypes (TC; n = 66). At the data cutoff of January 2023, the objective response rate was 82.5% among patients with cabozantinib/vandetanib-naïve MTC and 95.8% among patients with treatment-naïve TC. At a median follow-up time of 42.4 and 44.0 months in patients with cabozantinib/vandetanib-naïve and pretreated MTC, the median progression-free survival (PFS) was not reached and 41.4 months, respectively. At a median follow-up time of 24.9 and 30.4 months in patients with treatment-naïve and pretreated TC, the median PFS was not reached and 27.4 months, respectively. Three-year PFS rates were 75.2% and 87.3% among patients with cabozantinib/vandetanib-naïve MTC and treatment-naïve TC, respectively. Median PFS was similar to median duration of response for each patient group. The safety profile of selpercatinib was consistent with previous reports. With an additional follow-up of 37 months and 228 more patients from the last disclosure, selpercatinib continued to provide durable and robust responses in treatment-naïve and previously treated patients with RET-mutant MTC and RET fusion-positive TC.

Recent advances in the use of tyrosine kinase inhibitors against thyroid cancer

INTRODUCTION

Oncogenic tyrosine kinases (TK) are enzymes that play a key role in cell growth and proliferation and their mutations can lead to uncontrolled cell growth and development of aggressive cancer. This knowledge has led to the development of new classes of drugs, Tyrosine kinase inhibitors (TKI). They target oncogenic kinases who are associated with advanced radioactive iodine (RAI) refractory TC, which is not able to uptake RAI anymore and/or still grows between consecutive treatments with Iodine 131 (I131).

AREAS COVERED

Since Lenvatinib and Sorafenib approval, several other molecular inhibitors have been studied and then introduced for the treatment of aggressive and refractory thyroid cancer (TC), and, although the development of adverse effects or tumor resistance mechanisms, more and more compounds are still under investigation. The literature search was executed in PubMed and ClinicalTrials.gov to identify relevant articles and clinical trials published until December 2023.

EXPERT OPINION

In the context of clinical trials, driven by the presence of specific molecular mutations or even in the absence of both conditions, systemic therapy TKIs are valuable weapons to be used in patients affected by aggressive forms of TC, waiting for further expansion of the treatment landscape with more efficacious and safer drugs.

Paraneoplastic Diarrhea From Medullary Thyroid Carcinoma Resolved With Yttrium-90 Radioembolization of Liver Metastases

Medullary thyroid carcinoma (MTC) can often have an indolent course despite distant metastatic disease. Additionally, given that metastatic MTC is incurable and systemic therapies have non-negligeable toxicities, localized treatments are often favored in presence of oligo-progressive disease. Transarterial radioembolization (TARE) with yttrium-90 (Y90) has emerged as a safe and efficacious treatment for nonresectable primary and metastatic liver tumors, yet data supporting its use in metastatic MTC are limited. We present the case of a patient with hereditary MTC and large bilobar liver metastases who demonstrated tumor response and resolution of their paraneoplastic diarrhea following TARE with Y90 microspheres.

Rapid response to selpercatinib in RET fusion positive pancreatic neuroendocrine carcinoma confirmed by smartwatch

This case report describes the efficacy of selpercatinib, a selective RET inhibitor, in an unusual case of large-cell neuroendocrine pancreatic carcinoma (LCNEPAC) harboring a CCDC6::RET fusion. A 56-year-old male with a history of multiple lines of systemic therapies exhibited marked clinical amelioration shortly after initiating selpercatinib within the LOXO-RET-17001 study (ClinicalTrials.gov ID: NCT03157128, first posted: 2017-05-17). Data from the patient's smartwatch suggested early efficacy before conventional methods, such as serum tumor markers and CT imaging confirmed the antitumor activity. This case not only underscores the efficacy of selpercatinib in treating RET fusion-positive rare tumors but also highlights the potential of wearable technology in cancer care. In conclusion, the standard readings from commercially available wearable devices can be useful for the monitoring of treatment response to targeted therapy and may serve as digital biomarkers in clinical trials. This approach marks a significant advancement in patient-centric healthcare, leveraging technology to enhance the effectiveness and precision of treatment evaluation.

The neurotransmitter calcitonin gene-related peptide shapes an immunosuppressive microenvironment in medullary thyroid cancer

Neurotransmitters are key modulators in neuro-immune circuits and have been linked to tumor progression. Medullary thyroid cancer (MTC), an aggressive neuroendocrine tumor, expresses neurotransmitter calcitonin gene-related peptide (CGRP), is insensitive to chemo- and radiotherapies, and the effectiveness of immunotherapies remains unknown. Thus, a comprehensive analysis of the tumor microenvironment would facilitate effective therapies and provide evidence on CGRP's function outside the nervous system. Here, we compare the single-cell landscape of MTC and papillary thyroid cancer (PTC) and find that expression of CGRP in MTC is associated with dendritic cell (DC) abnormal development characterized by activation of cAMP related pathways and high levels of Kruppel Like Factor 2 (KLF2), correlated with an impaired activity of tumor infiltrating T cells. A CGRP receptor antagonist could offset CGRP detrimental impact on DC development in vitro. Our study provides insights of the MTC immunosuppressive microenvironment, and proposes CGRP receptor as a potential therapeutic target.

Multidisciplinary Management of Advanced Thyroid Cancer

Bruce, Glazer, and Kimple discuss advances in the management of advanced thyroid carcinoma and the role of surgery and radiation to provide context to the review by Yun and Cohen focused on systemic therapy.

An Era of Advances in Systemic Therapies for Advanced Thyroid Cancer

Thyroid carcinomas comprise distinct pathologic subtypes. However, advancements in characterizing the molecular tumorigenesis of thyroid cancers have changed the treatment paradigm in the past decade. Genetic profiling has become an integral component of personalizing cancer care. Oral kinase inhibitors are currently standard-of-care therapies for progressive, radioactive iodine (RAI)-refractory differentiated thyroid carcinomas (DTCs) and medullary thyroid carcinomas (MTCs). Sorafenib, lenvatinib, and cabozantinib are multikinase inhibitors approved for patients with metastatic RAI-refractory DTC, whereas vandetanib and cabozantinib are approved for patients with MTC. Management of thyroid carcinomas has evolved such that targeted therapies have become therapeutic options for patients with BRAF, RET, NTRK, ALK, and ROS1 alterations and even have reported efficacy in anaplastic thyroid carcinomas. In this article, we review the advances made over the years in the treatment of metastatic thyroid carcinoma and focus on the systemic therapies that have recently transformed the treatment landscape of advanced disease.

Recommendations for the use of next-generation sequencing (NGS) for patients with advanced cancer in 2024: a report from the ESMO Precision Medicine Working Group

BACKGROUND

Advancements in the field of precision medicine have prompted the European Society for Medical Oncology (ESMO) Precision Medicine Working Group to update the recommendations for the use of tumour next-generation sequencing (NGS) for patients with advanced cancers in routine practice.

METHODS

The group discussed the clinical impact of tumour NGS in guiding treatment decision using the ESMO Scale for Clinical Actionability of molecular Targets (ESCAT) considering cost-effectiveness and accessibility.

RESULTS

As for 2020 recommendations, ESMO recommends running tumour NGS in advanced non-squamous non-small-cell lung cancer, prostate cancer, colorectal cancer, cholangiocarcinoma, and ovarian cancer. Moreover, it is recommended to carry out tumour NGS in clinical research centres and under specific circumstances discussed with patients. In this updated report, the consensus within the group has led to an expansion of the recommendations to encompass patients with advanced breast cancer and rare tumours such as gastrointestinal stromal tumours, sarcoma, thyroid cancer, and cancer of unknown primary. Finally, ESMO recommends carrying out tumour NGS to detect tumour-agnostic alterations in patients with metastatic cancers where access to matched therapies is available.

CONCLUSION

Tumour NGS is increasingly expanding its scope and application within oncology with the aim of enhancing the efficacy of precision medicine for patients with cancer.

[Thyroid carcinomas: the role of systemic therapies in internal medicine]

The molecular pathogenesis of thyroid carcinoma is well studied and of importance for the treatment of advanced stages. Differentiated, poorly differentiated and anaplastic carcinomas originate in the follicular cells, while medullary carcinomas derive from the C‑cells. The prognosis of differentiated thyroid carcinoma is generally very favourable after surgery and radioiodine therapy. Where tumours progress and lose the ability to enrich iodine, curative treatment is usually not possible. A strategy of watchful waiting is often appropriate. Activating mutations in BRAF or gene fusions of RET and NTRK provide opportunities for targeted therapies. These may be applied with the aim of restoring iodine uptake (redifferentiation). In the absence of molecular therapy targets, multityrosine kinase inhibitors (MKI) are the therapy of choice. If anaplastic thyroid carcinoma is suspected, rapid diagnostic workup including molecular pathology is warranted. Surgery where possible and radiochemotherapy are essential components of therapy. In the presence of a BRAF mutation, inhibition of BRAF and MEK is effective, even if it is not approved in Germany. Where molecular targets are lacking, combination therapy with the MKI lenvatinib and immune checkpoint inhibition is highly effective. Mutations in RET are present in the vast majority of cases of medullary thyroid carcinoma. In aggressive advanced disease, selective RET inhibition has recently been approved as first-line therapy and often leads to an objective response and long-lasting disease stabilisation. In summary, thyroid carcinomas are among the tumour entities for which molecularly targeted therapies can be used most frequently. The involvement of specialised centres is advisable.

Safety and efficacy of nintedanib as second-line therapy for patients with differentiated or medullary thyroid cancer progressing after first-line therapy. A randomized phase II study of the EORTC Endocrine Task Force (protocol 1209-EnTF)

Background

Nintedanib is a triple-angiokinase inhibitor with potential activity in patients with advanced thyroid cancers, as radioiodine refractory differentiated thyroid cancer (RAIR DTC) and medullary thyroid cancer (MTC).

Design

EORTC-1209 (NCT01788982) was a double-blind randomized (2:1 ratio) placebo-controlled phase II, multi-cohort study exploring the efficacy and safety of nintedanib in patients with progressive, locally advanced, and/or metastatic RAIR DTC and MTC. The primary endpoint was progression-free survival (PFS) in the per-protocol (PP) population for both cohorts. Secondary endpoints included response rate, duration of response, overall survival (OS), and safety.

Results

RAIR DTC cohort: Seventy out of the 75 planned patients with RAIR DTC (median age, 66 years; 39 women) who had progressed after one (76%) or two lines (24%) of previous systemic therapy were randomized to receive either nintedanib (N = 45) or placebo (N = 25). Of these, 69 patients started treatment and 56 met all inclusion criteria (PP). At data cutoff, the median duration of follow-up was 26.3 months in the nintedanib arm and 19.8 months in the placebo arm. In the PP population, the median PFS was 3.7 months [80% confidence interval (CI), 1.9-6.5] in the nintedanib arm and 2.9 months (80% CI, 2.0-5.6) in the placebo arm (HR = 0.65; 80% CI, 0.42-0.99; one-sided log-rank test P = 0.0947). No objective response was observed. The median OS was 29.6 months [80% CI, 15.2-not reached (NR)] in the nintedanib arm and not reached in the placebo arm. Grade 3-4 adverse events of any attribution occurred in 50% of patients receiving nintedanib and in 36% of patients receiving placebo. MTC cohort: Thirty-one out of the 67 planned patients with MTC (median age, 57 years; eight women) who had progressed after one (68%) or two (32%) lines of previous systemic therapy were randomized to receive either nintedanib (N = 22) or placebo (N = 9). Of these, 20 patients (15 in the nintedanib arm and five in the placebo arm) started treatment and met all inclusion criteria (PP). The median PFS was 7.0 months (80% CI, 1.9-8.7) in the nintedanib arm and 3.9 months (80% CI, 3.0-5.5) in the placebo arm (HR = 0.49; 95% CI, 0.16-1.53). No objective response was reported. The median OS was 16.4 months (80% CI, 12.1-24.9) in the nintedanib arm and 12.3 months (80% CI, 7.1-NR) in the placebo arm. Grade 3-4 adverse events of any attribution during the blinded period occurred in 59.1% of patients receiving nintedanib and in 33.3% of patients receiving placebo.

Conclusion

This study did not suggest a clinically significant improvement of PFS with nintedanib over placebo in patients with pretreated RAIR DTC and MTC.

Medullary Thyroid Cancer: Molecular Drivers and Immune Cellular Milieu of the Tumour Microenvironment-Implications for Systemic Treatment

In this review, we explore the underlying molecular biology of medullary thyroid carcinoma (MTC) and its interplay with the host immune system. MTC is consistently driven by a small number of specific pathogenic variants, beyond which few additional genetic events are required for tumorigenesis. This explains the exceedingly low tumour mutational burden seen in most MTC, in contrast to other cancers. However, because of the low tumour mutational burden (TMB), there is a correspondingly low level of tumour-associated neoantigens that are presented to the host immune system. This reduces tumour visibility and vigour of the anti-tumour immune response and suggests the efficacy of immunotherapy in MTC is likely to be poor, acknowledging this inference is largely based on the extrapolation of data from other tumour types. The dominance of specific RET (REarranged during Transfection) pathogenic variants in MTC tumorigenesis rationalizes the observed efficacy of the targeted RET-specific tyrosine kinase inhibitors (TKIs) in comparison to multi-kinase inhibitors (MKIs). Therapeutic durability of pathway inhibitors is an ongoing research focus. It may be limited by the selection pressure TKI treatment creates, promoting survival of resistant tumour cell clones that can escape pathway inhibition through binding-site mutations, activation of alternate pathways, and modulation of the cellular and cytokine milieu of the tumour microenvironment (TME).

Pyrazolopyridine-based kinase inhibitors for anti-cancer targeted therapy

The need for effective cancer treatments continues to be a challenge for the biomedical research community. In this case, the advent of targeted therapy has significantly improved therapeutic outcomes. Drug discovery and development efforts targeting kinases have resulted in the approval of several small-molecule anti-cancer drugs based on ATP-mimicking heterocyclic cores. Pyrazolopyridines are a group of privileged heterocyclic cores in kinase drug discovery, which are present in several inhibitors that have been developed against various cancers. Notably, selpercatinib, glumetinib, camonsertib and olverembatinib have either received approval or are in late-phase clinical studies. This review presents the success stories employing pyrazolopyridine scaffolds as hinge-binding cores to address various challenges in kinase-targeted drug discovery research.

Drug repositioning in thyroid cancer: from point mutations to gene fusions

The diagnosis of thyroid cancer (TC) has increased dramatically in recent years. Papillary TC is the most frequent type and has shown a good prognosis. Conventional treatments for TC are surgery, hormonal therapy, radioactive iodine, chemotherapy, and targeted therapy. However, resistance to treatments is well documented in almost 20% of all cases. Genomic sequencing has provided valuable information to help identify variants that hinder the success of chemotherapy as well as to determine which of those represent potentially druggable targets. There is a plethora of targeted therapies for cancer, most of them directed toward point mutations; however, chromosomal rearrangements that generate fusion genes are becoming relevant in cancer but have been less explored in TC. Therefore, it is relevant to identify new potential inhibitors for genes that are recurrent in the formation of gene fusions. In this review, we focus on describing potentially druggable variants and propose both point variants and fusion genes as targets for drug repositioning in TC.

Patient-reported outcomes with selpercatinib treatment in patients with RET-driven cancers in the phase I/II LIBRETTO-001 trial

BACKGROUND

This post-hoc retrospective study describes long-term patient-reported outcomes (PROs) for REarranged during Transfection (RET)-altered non-small-cell lung cancer (NSCLC), medullary thyroid cancer (MTC), non-MTC thyroid cancer (TC), and tumor agnostic (TA) patients (Data cut-off: January 2023) from the LIBRETTO-001 trial.

PATIENTS AND METHODS

Patients completed the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30). Patients with MTC also completed a modified version of the Systemic Therapy-Induced Diarrhea Assessment Tool (mSTIDAT). The proportion of patients with improved, stable, or worsened status after baseline was reported. PROs were summarized at 3 years (cycle 37) post-baseline for the NSCLC and MTC cohorts, and at 2 years (cycle 25) post-baseline for the TC and TA cohorts. Time-to-event outcomes (time to first improvement or worsening and duration of improvement) were reported.

RESULTS

The baseline assessment was completed by 200 (63.3%), 209 (70.8%), 50 (76.9%), and 38 (73.1%) patients in the NSCLC, MTC, TC, and TA cohorts, respectively. The total compliance rate was 80%, 82%, 70%, and 85%, respectively. Approximately 75% (NSCLC), 81% (MTC), 75% (TC), and 40% (TA) of patients across all cohorts reported improved or stable QLQ-C30 scores at year 3 (NSCLC and MTC) or year 2 (TC and TA) with continuous selpercatinib use. Across cohorts, the median time to first improvement ranged from 2.0 to 19.4 months, the median duration of improvement ranged from 1.9 to 28.2 months, and the median time to first worsening ranged from 5.6 to 44.2 months. The total compliance rate for the mSTIDAT was 83.7% and the proportion of patients with MTC who reported diarrhea on the mSTIDAT was reduced from 80.8% at baseline to 35.6% at year 3.

CONCLUSIONS

A majority of patients with RET-driven cancers improved or remained stable on most QLQ-C30 domains, demonstrating favorable health-related quality of life as measured by the QLQ-C30 during long-term treatment with selpercatinib.

Timing and Ideal Patient for an Appropriate Search for Somatic RET Mutation in Medullary Thyroid Cancer

RET somatic mutation analysis in sporadic MTC should be guided by postoperative evaluation results.

Selpercatinib for treating recurrent mixed medullary and follicular cell-derived thyroid carcinoma: a case report

BACKGROUND

Mixed medullary and follicular cell-derived thyroid carcinoma (MMFCC) is characterized by the coexistence of follicular and C cell-derived tumour cell populations within the same lesion. Due to its rarity, its etiology and clinical course remain unclear, and treatment for advanced or recurrent cases has not been established.

CASE PRESENTATION

We report a case of MMFCC treated with selpercatinib. The patient was a 69-year-old male presenting with tumors in the right thyroid lobe and in the upper mediastinum. Fine-needle aspiration (FNA) cytology of the right thyroid lobe tumor revealed a medullary carcinoma; germline RET mutations were not detected. After resection of the right thyroid lobe with central node dissection, rapid intraoperative diagnosis of the mediastinal mass confirmed malignancy, leading to total thyroidectomy with excision of the upper mediastinal tumor. Histologically, the tumor in the right thyroid lobe and the pretracheal lymph node revealed a mixture of medullary and follicular carcinoma components, diagnosed as MMFCC. The mediastinal lymph node exhibited only medullary carcinoma components. At 11 months postoperatively, computed tomography scans showed enlargement of the right supraclavicular and upper mediastinal lymph nodes. FNA cytology of the right supraclavicular lymph node suggested the recurrence of medullary thyroid carcinoma. The gene panel testing (The Oncomine Dx Target Test Multi-CDx system®, Thermo Fisher SCIENTIFIC) of metastatic lymph node revealed RET somatic mutation (M918T). Treatment with selpercatinib was initiated, and both the cervical and mediastinal lymph nodes showed a reduction in size.

CONCLUSIONS

We report a rare case of selpercatinib use for MMFCC. Since RET mutations may occur frequently in MMFCC, selpercatinib could be effective in treating MMFCC.

RET kinase inhibitors for the treatment of RET-altered thyroid cancers: Current knowledge and future directions

RET gain-of-function mutations are the most common drivers in medullary thyroid carcinoma, while RET fusions are identified in 5-10% of papillary thyroid carcinomas. Thus, RET plays a major role in the tumorigenesis of thyroid neoplasia, making it a valuable therapeutic target. Over a decade ago, multikinase inhibitors (MKIs) were first shown to have variable degrees of anti-RET activity. Despite some clinical efficacy in RET-altered thyroid cancers, significant off-target activity of MKIs led to marked toxicities limiting their use. More recently, two potent, highly selective RET inhibitors, selpercatinib and pralsetinib, were shown to have notable efficacy in RET-altered cancers, associated with more tolerable side effect profiles than those of MKIs. However, these treatments are non-curative, and emerging evidence suggests that patients who progress on therapy acquire mutations conferring drug resistance. Thus, the quest for a more definitive treatment for advanced, RET-altered thyroid cancers continues. This year we celebrate the 30th anniversary of the association of germline mutations of the RET proto-oncogene with the multiple endocrine neoplasia (MEN) type 2 syndromes. In this timely review, we summarize the current state-of-the-art treatment strategies for RET-altered thyroid cancers, their limitations, as well as future therapeutic avenues.

Enhancer-activated RET confers protection against oxidative stress to KMT2A-rearranged acute myeloid leukemia

Ectopic activation of rearranged during transfection (RET) has been reported to facilitate lineage differentiation and cell proliferation in different cytogenetic subtypes of acute myeloid leukemia (AML). Herein, we demonstrate that RET is significantly (p < 0.01) upregulated in AML subtypes containing rearrangements of the lysine methyltransferase 2A gene (KMT2A), commonly referred to as KMT2A-rearranged (KMT2A-r) AML. Integrating multi-epigenomics data, we show that the KMT2A-MLLT3 fusion induces the development of CCCTC-binding (CTCF)-guided de novo extrusion enhancer loop to upregulate RET expression in KMT2A-r AML. Based on the finding that RET expression is tightly correlated with the selective chromatin remodeler and mediator (MED) proteins, we used a small-molecule inhibitor having dual inhibition against RET and MED12-associated cyclin-dependent kinase 8 (CDK8) in KMT2A-r AML cells. Dual inhibition of RET and CDK8 restricted cell proliferation by producing multimodal oxidative stress responses in treated cells. Our data suggest that epigenetically enhanced RET protects KMT2A-r AML cells from oxidative stresses, which could be exploited as a potential therapeutic strategy.

[Precision medicine in endocrinology exemplified by medullary thyroid cancer]

Medullary thyroid cancer (MTC) is a prime example for precision medicine in endocrinology and underlines the immediate benefits of basic, translational and healthcare research for patients with a rare disease in clinical . A mutation in the rearranged during transfection (RET) proto-oncogene that codes for a transmembrane receptor protein tyrosine kinase, leads to constitutive activation of the kinase, which is the decisive pathomechanism for the disease. The MTC occurs in a sporadic (somatic RET mutation) or hereditary form (RET germline mutation, multiple endocrine neoplasia types 2 and 3). For germline mutation carriers the timing of preventive thyroidectomy depends on the RET genotype. For advanced metastasized RET-mutant MTC, selective RET kinase inhibitors are available, which are currently considered to be game changers in the treatment. Based on the specific tumor marker calcitonin, MTC can be identified at an early stage during the differential diagnosis of thyroid nodules. The preoperative calcitonin level even enables statements on the degree of dissemination of the disease and on the probability of a cure through surgery. A new development is the consideration of desmoplasia as a histopathological biomarker for the metastatic potential of a MTC, which could possibly modify the operative approach as well as the future MTC nomenclature. Furthermore, the postoperative calcitonin level and the calcitonin doubling time are highly valid prognostic markers for tumor burden and biological aggressiveness of MTC and therefore decisive for patient follow-up. Biochemical, molecular and histological markers enable a risk-adapted surgical treatment and together with new targeted systemic treatments have contributed to a paradigm shift in the diagnostics, prognosis and treatment of MTC in recent years. Endocrine precision medicine for MTC therefore enabled a change from the previous purely symptom-oriented to a modern preventive and individualized treatment.