Cardiotoxicity in metastatic melanoma patients treated with BRAF and MEK inhibitors in a real-world setting

Cellular and Molecular Mechanisms of MEK1 Inhibitor-Induced Cardiotoxicity

Background

Trametinib is a MEK1 (mitogen-activated extracellular signal-related kinase kinase 1) inhibitor used in the treatment of BRAF (rapid accelerated fibrosarcoma B-type)-mutated metastatic melanoma. Roughly 11% of patients develop cardiomyopathy following long-term trametinib exposure. Although described clinically, the molecular landscape of trametinib cardiotoxicity has not been characterized.

Objectives

The aim of this study was to test the hypothesis that trametinib promotes widespread transcriptomic and cellular changes consistent with oxidative stress and impairs cardiac function.

Methods

Mice were treated with trametinib (1 mg/kg/d). Echocardiography was performed pre- and post-treatment. Gross, histopathologic, and biochemical assessments were performed to probe for molecular and cellular changes. Human cardiac organoids were used as an in vitro measurement of cardiotoxicity and recovery.

Results

Long-term administration of trametinib was associated with significant reductions in survival and left ventricular ejection fraction. Histologic analyses of the heart revealed myocardial vacuolization and calcification in 28% of animals. Bulk RNA sequencing identified 435 differentially expressed genes and 116 differential signaling pathways following trametinib treatment. Upstream gene analysis predicted interleukin-6 as a regulator of 17 relevant differentially expressed genes, suggestive of PI3K/AKT and JAK/STAT activation, which was subsequently validated. Trametinib hearts displayed elevated markers of oxidative stress, myofibrillar degeneration, an 11-fold down-regulation of the apelin receptor, and connexin-43 mislocalization. To confirm the direct cardiotoxic effects of trametinib, human cardiac organoids were treated for 6 days, followed by a 6-day media-only recovery. Trametinib-treated organoids exhibited reductions in diameter and contractility, followed by partial recovery with removal of treatment.

Conclusions

These data describe pathologic changes observed in trametinib cardiotoxicity, supporting the exploration of drug holidays and alternative pharmacologic strategies for disease prevention.

Real-life incidence of cardiotoxicity and associated risk factors in sarcoma patients receiving doxorubicin

BACKGROUND

Anthracycline induced cardiotoxicity is well recognized but only few data exist in sarcoma patients. This study retrospectively aimed to analyze sequential Cadmium Zinc Telluride (CZT)-multigated equilibrium radionuclide angiography (ERNA) for monitoring left ventricular ejection fraction (LVEF) and to assess the real-life incidence of cardiotoxicity in sarcoma patients receiving doxorubicin based chemotherapy.

MATERIALS AND METHODS

A retrospective analysis was performed on all sarcoma patients referred to Herlev University Hospital between 2012 and 2015. Cardiotoxicity was defined as a decline in LVEF of > 10% percentage point to a LVEF < 50% as compared to baseline. Early cardiotoxicity was defined as < 1 year and late cardiotoxicity as ≥ 1 year. Recovery of cardiotoxicity was defined as a LVEF ≥ 50%.

RESULTS

A total of 149 patients were referred, 75 (50%) sarcoma patients were included. The main reason for exclusion was that only one CZT-ERNA had been performed in 50 (68%) of the patients. Twenty-three (31%) of the patients experienced cardiotoxicity, 11 (48%) were female, mean age was 56.9 years. Early cardiotoxicity was observed in 16 (70%) of the patients and 11 (48%) experienced clinical symptoms of cardiotoxicity at diagnosis. Recovery of LVEF was seen in 12 (55%) of the patients and persistent recovery in 10 (45%). The diastolic blood pressure at baseline was positively and significantly associated with a higher risk of developing cardiotoxicity (Relative Risk (RR): 1.039 (95% CI= 1.001 - 1.079; p = 0.042)). The median survival was 1.4 years (range 0.5 - 2.2 years) for patients with metastatic disease versus 3.9 years (range 1.5 - 6.4 years) (p = 0.009) for localized disease at baseline.

CONCLUSION

Cardiotoxicity is a relative frequent complication in sarcoma patients treated with doxorubicin based chemotherapy and the diastolic blood pressure at baseline was significantly associated with a higher risk of developing cardiotoxicity.