Sex Differences on Mitotane Concentration and Treatment Outcome in Patients with Adrenocortical Carcinoma

Incidence, Treatment, and Survival of Adrenocortical Carcinoma in Denmark 2003-2019

Objectives

Adrenocortical carcinoma (ACC) is a malignant tumor originating from the adrenal cortex. The aim of the study was to report the incidence of ACC and survival of ACC in Denmark. The secondary objective was to describe the impact of treatment with mitotane on survival.

Design

Retrospective population study of patients diagnosed with ACC between 2003 and 2019 in Denmark.

Methods

Individuals at risk for ACC were identified in the national Danish Health registries, and diagnosis of ACC was confirmed by review of the health records. Data on demographics, presentation, treatment, recurrence, and death was evaluated.

Results

138 patients were included in the study with more females (59.4%) than males (40.6%). Incidence rate was 1.4 per million per year. The incidence rate ratio significantly increased only in females by 1.06 [95% confidence interval (CI): 1.02-1.12] per year. Overall median survival was 1.93 (95% CI: 1.24-3.00) years with no differences between males and females. The proportion of patients treated with mitotane (either as adjuvant treatment or as part of a chemotherapeutic regime) was 72.3%. Survival was significantly decreased in women not treated with mitotane compared to women treated with mitotane (either as adjuvant or as part of a chemotherapeutic regime) hazards ratio .30 (95% CI: .10-.89), adjusted for European Network for the Study of Adrenal Tumours score, age at diagnosis, and year of diagnosis, but survival was unaffected by mitotane treatment in men.

Conclusion

Incidence of ACC in Denmark was 1.4 per million per year and increased in women but not in males during the study period 2003-2019.

Sex-Based Evaluation of Lipid Profile in Postoperative Adjuvant Mitotane Treatment for Adrenocortical Carcinoma

Background: A wide interindividual variability in mitotane concentrations and treatment-related dyslipidemia have been reported. Here, we aimed to underline the sex-related differences in the lipid profile in patients that underwent radical surgery of adrenocortical carcinoma during treatment with adjuvant mitotane. Methods: A chromatographic method was used to quantify the drug in plasma collected from adult patients with complete tumor resection, also considering active metabolite o,p’-DDE. Results: We observed different lipid profiles between males and females and between pre- and post-menopausal women. Considering the mitotane-related effects on lipid levels, we observed that higher drug concentrations were correlated with higher HDL in all the considered groups (p < 0.001), with total cholesterol both in males (p = 0.005) and females (p = 0.036), with triglycerides in postmenopausal females (p = 0.002) and with LDL in male patients (p < 0.001). Increases in o,p’-DDE were positively correlated with HDL levels in all the groups (p < 0.001) and negatively with LDL in all the groups (males p = 0.008, pre- and post-menopausal females p < 0.001), with total cholesterol in pre- (p = 0.016) and post-menopausal women (p = 0.01) and with triglycerides in premenopausal females (p = 0.005). Conclusions: This is the first study designed to evaluate sex differences in lipoprotein and lipid levels during mitotane adjuvant treatment; the results suggest that a gender and personalized approach could be useful to prevent and manage alterations in the lipid profile.

The Effects of Cumulative Dose and Polymorphisms in CYP2B6 on the Mitotane Plasma Trough Concentrations in Chinese Patients With Advanced Adrenocortical Carcinoma

Mitotane is the only drug approved to treat adrenocortical carcinoma (ACC), and a relationship of pharmacokinetic/pharmacodynamic has been characterized. However, limited evidence concerning affecting factors in large interindividual variability of the pharmacokinetics of mitotane is available. To address this question, a retrospective analysis was performed on ACC Chinese patients treated with mitotane for more than 3 months. Mitotane plasma trough concentrations were detected at the steady state, and CYP2B6, CYP3A4, and pregnane X receptor (PXR) polymorphisms were genotyped. After examining homogeneous pharmacologic data, we restricted the analyses to 36 patients that received mitotane for a median (interquartile range, IQR) of 9 months (5.00–22.50) with a median dose of 2 g/day (2.00–2.50). As a result, drug exposure was significantly influenced by the cumulative dose of mitotane, and CYP2B6 516GG and CYP2B6 26570CC were at high risk to be below the therapeutic range of mitotane. No association was found between mitotane concentrations with CYP3A4 or PXR polymorphism. Our data firstly indicated that the cumulative dose of mitotane and polymorphisms of CYP2B6 516 and CYP2B6 26570 might significantly affect mitotane plasma trough concentrations in Chinese ACC patients.

Mitotane treatment in adrenocortical carcinoma: mechanisms of action and predictive markers of response to therapy

INTRODUCTION

Adrenocortical carcinoma (ACC) is a rare malignancy with a high risk of recurrence even in cases with complete surgical tumor resection. Mitotane represents the cornerstone of the adjuvant therapy as well as the first line of medical treatment in advanced cases. However, evidence on mitotane efficacy is mostly based on retrospective studies and the use of mitotane continues to represent a clinical challenge.

EVIDENCE ACQUISITION

Mitotane causes selective damage to adrenocortical cells, causing an increase of cell apoptosis through a disruption of mitochondria and the induction of the endoplasmic reticulum stress. Different clinical and molecular markers predicting response to mitotane have been proposed with uncertain results. Attainment of mitotane plasma levels within the target range of 14 to 20 mg/L represent the strongest predictor of mitotane effectiveness both in adjuvant and advanced tumor setting. The occurrence of late recurrence after primary ACC diagnosis and changes in metabolic activity on FDG-PET are only weakly associated with mitotane response. Among the proposed molecular markers associated with mitotane efficacy, the investigation of the CYP2W1*6 and CYP2B6*6 single nucleotide polymorphisms appears to be currently the most promising predictive molecular markers of mitotane therapy. However, none of the evaluated markers has been validated for clinical use.

CONCLUSIONS

In the era of precision medicine, a better insight into mitotane molecular mechanisms as well as the potential use in the daily clinical practice of clinical parameters and molecular markers predicting the individual response to mitotane are urgently needed.

Management of adrenocortical carcinoma: are we making progress?

Adrenocortical carcinoma (ACC) is a rare malignancy characterized by aggressive biology and potential endocrine activity. Surgery can offer cure for localized disease but more than half of patients relapse and primary unresectable or metastasized disease is frequent. Prognosis of metastatic ACC is still limited, with less than 15% of patients alive at 5 years. Recent advances in understanding the molecular profile of ACC underline the high complexity of this disease, which is characterized by limited drugable molecular targets as well as by a complex interplay between a yet scarcely understood microenvironment and potential endocrine activity. Particularly steroid-excess further complicates therapeutic concepts such as immunotherapy, which have markedly improved outcome in other disease entities. To date, mitotane remains the only approved drug for adjuvant and palliative care in ACC. Standard chemotherapy-based protocols with cisplatin, doxorubicin and etoposide offer only marginal improvement in long-term outcome and the number of clinical trials conducted is low due to the rarity of the disease. In the current review, we summarize principles of oncological management for ACC from localized to advanced disease and discuss novel therapeutic strategies, including targeted therapies such as tyrosine kinase inhibitors and antibodies, immunotherapy with a focus on checkpoint inhibitors, individualized treatment concepts based on molecular characterization by next generation sequencing methods, the role of theranostics and evolvement of adjuvant therapy.

The Challenging Pharmacokinetics of Mitotane: An Old Drug in Need of New Packaging

Adrenocortical carcinoma (ACC) is a malignant tumor originating from the adrenal gland cortex with a heterogeneous but overall dismal prognosis in advanced stages. For more than 50 years, mitotane has remained a cornerstone for the treatment of ACC as adjuvant and palliative therapy. It has a very poor aqueous solubility of 0.1 mg/l and high partition coefficient in octanol/water (log P) value of 6. The commercially available dosage form is 500 mg tablets (Lysodren^®). Even at doses up to 6 g/day (12 tablets in divided doses) for several months, > 50% patients do not achieve therapeutic plasma concentration > 14 mg/l due to poor water solubility, large volume of distribution and inter/intra-individual variability in bioavailability. This article aims to give a concise update of the clinical challenges associated with the administration of high-dose mitotane oral therapy which encompass the issues of poor bioavailability, difficult-to-predict pharmacokinetics and associated adverse events. Moreover, we present recent efforts to improve mitotane formulations. Their success has been limited, and we therefore propose an injectable mitotane formulation instead of oral administration, which could bypass many of the main issues associated with high-dose oral mitotane therapy. A parenteral administration of mitotane could not only help to alleviate the adverse effects but also circumvent the variable oral absorption, give better control over therapeutic plasma mitotane concentration and potentially shorten the time to achieve therapeutic drug plasma concentrations considerably.

Mitotane as tablet form is currently the standard treatment for adrenocortical carcinoma. It has been used for 5 decades but suffers from highly variable responses in patients, subsequent adverse effects and overall lower response rate. This can be fundamentally linked to the exceedingly poor water solubility of mitotane itself. In terms of enhancing water solubility, a few research groups have attempted to develop better formulations of mitotane to overcome the issues associated with tablet dosage form. However, the success rate was limited, and these formulations did not make it into the clinics. In this article, we have comprehensively reviewed the properties of these formulations and discuss the reasons for their limited utility. Furthermore, we discuss a recently developed mitotane nanoformulation that led us to propose a novel approach to mitotane therapy, where intravenous delivery supplements the standard oral administration. With this article, we combine the current state of knowledge as a single piece of information about the various problems associated with the use of mitotane tablets, and herein we postulate the development of a new injectable mitotane formulation, which can potentially circumvent the major problems associated to mitotane's poor water solubility.