Drug interactions with mitotane by induction of CYP3A4 metabolism in the clinical management of adrenocortical carcinoma

Cabozantinib monotherapy for advanced adrenocortical carcinoma: a single-arm, phase 2 trial

BACKGROUND

Adrenocortical carcinoma is a rare malignancy with poor response to systemic chemotherapy. Mitotane is the only approved therapy for adrenocortical carcinoma. Cabozantinib is a multikinase inhibitor approved in multiple malignancies. This is the first prospective trial to explore the anti-tumour activity, safety, and pharmacokinetic profile of cabozantinib in patients with advanced adrenocortical carcinoma.

METHODS

This investigator-initiated, single-arm, phase 2 trial in adult patients (aged ≥18 years) with advanced adrenocortical carcinoma was done at the University of Texas MD Anderson Cancer Center (Houston, TX, USA). Eligible patients had histologically confirmed adrenocortical carcinoma, were not candidates for surgery with curative intent, had measurable disease, had an estimated life expectancy of at least 3 months, and an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 with adequate organ function. Patients who had used mitotane within 6 months of study participation were required to have a serum mitotane level of less than 2 mg/L. Patients were given oral cabozantinib 60 mg daily with the option of dose reduction to manage adverse events. The primary endpoint was progression-free survival at 4 months, assessed in all patients who received at least one dose of study drug per protocol. This study is registered with ClinicalTrials.gov, NCT03370718, and is now complete.

FINDINGS

Between March 1, 2018, and May 31, 2021, we enrolled 18 patients (ten males and eight females), all of whom received at least one dose of study treatment. Of the 18 patients, eight (44%) had an ECOG performance status of 0, nine (50%) patients had a performance status of 1, and one (6%) patient had a performance status of 2. Median follow-up was 36·8 months (IQR 30·2-50·3). At 4 months, 13 (72·2%; 95% CI 46·5-90·3) of 18 patients had progression-free survival and median progression-free survival was 6 months (95% CI 4·3 to not reached). One patient remains on treatment. Treatment-related adverse events of grade 3 or worse occurred in 11 (61%) of 18 patients. The most common grade 3 adverse events were lipase elevation (three [17%] of 18 patients), elevated γ-glutamyl transferase concentrations (two [11%] patients), elevated alanine aminotransferase concentrations (two [11%] patients), hypophosphatemia (two [11%] patients), and hypertension (two [11%] patients). One (6%) of 18 patients had grade 4 hypertension. No treatment related deaths occurred on study.

INTERPRETATION

Cabozantinib in advanced adrenocortical carcinoma showed promising efficacy with a manageable and anticipated safety profile. Further prospective studies with cabozantinib alone and in combination with immune checkpoint therapy are ongoing.

FUNDING

Exelixis.

International consensus on mitotane treatment in pediatric patients with adrenal cortical tumors: indications, therapy, and management of adverse effects

OBJECTIVE

Mitotane is an important cornerstone in the treatment of pediatric adrenal cortical tumors (pACC), but experience with the drug in the pediatric age group is still limited and current practice is not guided by robust evidence. Therefore, we have compiled international consensus statements from pACC experts on mitotane indications, therapy, and management of adverse effects.

METHODS

A Delphi method with 3 rounds of questionnaires within the pACC expert consortium of the international network groups European Network for the Study of Adrenal Tumors pediatric working group (ENSAT-PACT) and International Consortium of pediatric adrenocortical tumors (ICPACT) was used to create 21 final consensus statements.

RESULTS

We divided the statements into 4 groups: environment, indications, therapy, and adverse effects. We reached a clear consensus for mitotane treatment for advanced pACC with stages III and IV and with incomplete resection/tumor spillage. For stage II patients, mitotane is not generally indicated. The timing of initiating mitotane therapy depends on the clinical condition of the patient and the setting of the planned therapy. We recommend a starting dose of 50 mg/kg/d (1500 mg/m²/d) which can be increased up to 4000 mg/m2/d. Blood levels should range between 14 and 20 mg/L. Duration of mitotane treatment depends on the clinical risk profile and tolerability. Mitotane treatment causes adrenal insufficiency in virtually all patients requiring glucocorticoid replacement shortly after beginning. As the spectrum of adverse effects of mitotane is wide-ranging and can be life-threatening, frequent clinical and neurological examinations (every 2-4 weeks), along with evaluation and assessment of laboratory values, are required.

CONCLUSIONS

The Delphi method enabled us to propose an expert consensus statement, which may guide clinicians, further adapted by local norms and the individual patient setting. In order to generate evidence, well-constructed studies should be the focus of future efforts.

Recovery of adrenal function after stopping mitotane in patients with adrenocortical carcinoma

OBJECTIVE

Mitotane is the standard therapy of adrenocortical carcinoma (ACC) due to its relative selectivity of its cytotoxic effects toward adrenocortical cells. Therefore, it virtually always leads to adrenal insufficiency. Frequency and characteristics of hypothalamic-pituitary-adrenal axis recovery after discontinuation are ill-defined.

METHODS

This was a retrospective study of patients with ACC adjuvantly treated with mitotane for ≥12 months who were disease-free at mitotane stop and had a minimum follow-up ≥1 year. Primary endpoint was adrenal recovery. Cox regression analyses were used to identify predictive factors. Moreover, mitotane plasma elimination rate and hormonal changes after mitotane stop were investigated.

RESULTS

Fifty-six patients (36 women) treated with mitotane for a median time of 25 months and an average daily dose of 2.8 g were included. Median time after discontinuation until mitotane levels dropped below 5 and 2 mg/L, and the detection limit was 152 days (interquartile range: 114-202), 280 days (192-370), and 395 days (227-546), respectively. Full adrenal recovery was documented in 32 (57%) patients after a median time of 26 months (95% confidence interval [CI] = 19.6-32.4). In 4 patients (7.1%), adrenal insufficiency persisted >5 years after discontinuation. Mitotane peak ≥ 27 mg/L significantly correlated with longer time to adrenal recovery (hazard ratio [HR] = 0.2, 95% CI = 0.1-0.8, P = .03). Twenty-seven of 38 patients (71%) followed in reference centers achieved adrenal recovery compared with only 5/18 (28%) followed up in non-reference centers (HR = 4.51, 95% CI = 1.71-11.89, P = .002). Other investigated factors were not associated with adrenal function after discontinuation.

CONCLUSIONS

Our study demonstrates that adrenal recovery occurs in most patients after stopping mitotane, particularly when followed up in specialized centers, but not in all. Elimination time of mitotane after treatment discontinuation is very long but individually quite variable.

Wnt/β-catenin signaling pathway in the tumor progression of adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is an uncommon, aggressive endocrine malignancy with a high rate of recurrence, a poor prognosis, and a propensity for metastasis. Currently, only mitotane has received certification from both the US Food and Drug Administration (FDA) and the European Medicines Agency for the therapy of advanced ACC. However, treatment in the advanced periods of the disorders is ineffective and has serious adverse consequences. Completely surgical excision is the only cure but has failed to effectively improve the survival of advanced patients. The aberrantly activated Wnt/β-catenin pathway is one of the catalysts for adrenocortical carcinogenesis. Research has concentrated on identifying methods that can prevent the stimulation of the Wnt/β-catenin pathway and are safe and advantageous for patients in view of the absence of effective treatments and the frequent alteration of the Wnt/β-catenin pathway in ACC. Comprehending the complex connection between the development of ACC and Wnt/β-catenin signaling is essential for accurate pharmacological targets. In this review, we summarize the potential targets between adrenocortical carcinoma and the Wnt/β-catenin signaling pathway. We analyze the relevant targets of drugs or inhibitors that act on the Wnt pathway. Finally, we provide new insights into how drugs or inhibitors may improve the treatment of ACC.

[Adrenocortical cancer: late diagnosis of the disease on the example of a clinical case. Case report]

Adrenocortical carcinoma (ACC) is a rare malignant tumor originating in the adrenal cortex and characterized by poor 5-year survival. It occurs with a frequency of 2-4 cases per 2 million in the population. Women are more frequently affected than men and it is mostly detected in the fourth and fifth decades. In the most of cases, the cancerogenesis occurs sporadically because of gene driver mutations in somatic adrenocortical cells, in other cases it can be found as part of a genetically determined syndrome such as Li-Fraumeni syndrome or Wermer's syndrome (multiple endocrine adenomatosis type I). ACC most frequently happens occurs without symptoms in the initial stages leading to poor diagnoses. Because of this lack of early detection, the tumor is not considered malignant reducing the benefits of further treatment. Sometimes the fact that the resected tumor is indeed adrenocortical carcinoma becomes clear only after recurrence, or after the appearance of metastases. We present a case of adrenocortical carcinoma in a 46-year-old woman who went to the doctor in 1.5 year after symptoms were manfested. This clinical case illustrates the consequences of late diagnosis of a malignant tumor. We would like to emphasize the importance of timely detection of a neoplasm, using all of the potential of laboratory-instrumental and genomic analysis. Due to low oncological awareness, our patient was slow to seek medical help, which in turn led not only to metastases, but also to complications in the cardiovascular system.

Adrenocortical carcinoma: Diagnosis, prognostic classification and treatment of localized and advanced disease

Adrenocortical carcinoma (ACC) is a rare cancer with an estimated incidence of 0.7 to 2.0 cases per 1 million population per year in the United States. It is an aggressive cancer originating in the cortex of the adrenal gland with a poor prognosis. The 5-year survival rate is less than 15% among patients with metastatic disease. In this article, we review the epidemiology and pathogenesis of ACC, the diagnostic procedures, the prognostic classification of ACC, and the treatment options from localized and resectable forms to advanced disease detailing recent therapeutic developments such as immunotherapy and molecularly targeted therapy.

[Guidelines of the French National ENDOCAN-COMETE, Association of Endocrine Surgery, Society of Urology for the management of adrenocortical carcinoma]

The adrenocortical carcinoma (ACC) is a primary malignant tumor developed from the adrenal cortex, defined by a Weiss score≥3. Its prognosis is poor and depends mainly on the stage of the disease at diagnosis. Care is organized in France by the multidisciplinary expert centers of the national ENDOCAN-COMETE "Adrenal Cancers" network, certified by the National Cancer Institute. This document updates the guidelines for the management of ACC in adults based on the most robust data in the literature. It's divided into 11 chapters: (1) circumstances of discovery; (2) pre-therapeutic assessment; (3) diagnosis of ACC; (4) oncogenetics; (5) prognostic classifications; (6) treatment of hormonal hypersecretion; (7) treatment of localized forms; (8) treatment of relapses; (9) treatment of advanced forms; (10) follow-up; (11) the particular case of ACC and pregnancy. R0 resection of all localized ACC remains an unmet need and it must be performed in expert centers. Flow-charts for the therapeutic management of localized ACC, relapse or advanced ACC are provided. It was written by the experts from the national ENDOCAN-COMETE network and validated by all French Societies involved in the management of these patients (endocrinology, medical oncology, endocrine surgery, urology, pathology, genetics, nuclear medicine, radiology, interventional radiology).

Adrenocortical Carcinoma: Role of Adjuvant and Neoadjuvant Therapy

Adjuvant and neoadjuvant chemotherapy in the treatment of adrenocortical carcinoma (ACC) is limited by few existing trials, most of which are retrospective. The drug mitotane has been used for the treatment of ACC, although existing guidelines only support its use in high risk of recurrence. The first phase 3 trial involving systemic chemotherapy for ACC supports the use of etoposide, doxorubicin, cisplatin, and mitotane for combination therapy. No significant breakthrough has been discovered thus far in of targeted and immunotherapies. Neoadjuvant chemotherapy is only used to allow for complete surgical resection because complete excision is the definitive treatment of ACC.

Systematic analysis of the BET family in adrenocortical carcinoma: The expression, prognosis, gene regulation network, and regulation targets

BACKGROUND

Bromodomain and extracellular terminal (BET) family (including BRD2, BRD3, and BRD4) is considered to be a major driver of cancer cell growth and a new target for cancer therapy. Currently, more than 30 targeted inhibitors have shown significant inhibitory effects against various tumors in preclinical and clinical trials. However, the expression levels, gene regulatory networks, prognostic value, and target prediction of BRD2, BRD3, and BRD4 in adrenocortical carcinoma (ACC) have not been fully elucidated. Therefore, this study aimed to systematically analyze the expression, gene regulatory network, prognostic value, and target prediction of BRD2, BRD3, and BRD4 in patients with ACC, and elucidated the association between BET family expression and ACC. We also provided useful information on BRD2, BRD3, and BRD4 and potential new targets for the clinical treatment of ACC.

METHODS

We systematically analyzed the expression, prognosis, gene regulatory network, and regulatory targets of BRD2, BRD3, and BRD4 in ACC using multiple online databases, including cBioPortal, TRRUST, GeneMANIA, GEPIA, Metascape, UALCAN, LinkedOmics, and TIMER.

RESULTS

The expression levels of BRD3 and BRD4 were significantly upregulated in ACC patients at different cancer stages. Moreover, the expression of BRD4 was significantly correlated with the pathological stage of ACC. ACC patients with low BRD2, BRD3, and BRD4 expressions had longer survival than patients with high BRD2, BRD3, and BRD4 expressions. The expression of BRD2, BRD3, and BRD4 was altered by 5%, 5%, and 12% in 75 ACC patients, respectively. The frequency of gene alterations in the 50 most frequently altered BRD2, BRD3, and BRD4 neighboring genes in these ACC patients were ≥25.00%, ≥25.00%, and ≥44.44%, respectively. BRD2, BRD3, and BRD4 and their neighboring genes form a complex network of interactions mainly through co-expression, physical interactions, and shared protein domains. Molecular functions related to BRD2, BRD3, and BRD4 and their neighboring genes mainly include protein-macromolecule adaptor activity, cell adhesion molecule binding, and aromatase activity. Chemokine signaling pathway, thiamine metabolism, and olfactory transduction were found to be enriched as per the KEGG pathway analysis. SP1, NPM1, STAT3, and TP53 are key transcription factors for BRD2, BRD4, and their neighboring genes. MiR-142-3P, miR-484, and miR-519C were the main miRNA targets of BRD2, BRD3, BRD4, and their neighboring genes. We analyzed the mRNA sequencing data from 79 patients with ACC and found that ZSCAN12, DHX16, PRPF4B, EHMT1, CDK5RAP2, POMT1, WIZ, ZNF543, and AKAP8 were the top nine genes whose expression were positively associated with BRD2, BRD3, and BRD4 expression. The expression level of BRD2, BRD3, and BRD4 positively correlated with B cell and dendritic cell infiltration levels. BRD4-targeted drug PFI-1 and (BRD2, BRD3, and BRD4)-targeted drug I-BET-151 may have good inhibitory effects on the SW13 cell line.

CONCLUSIONS

The findings of this study provide a partial basis for the role of BRD2, BRD3, and BRD4 in the occurrence and development of ACC. In addition, this study also provides new potential therapeutic targets for ACC, which can serve as a reference for future basic and clinical research.

Update on Biology and Genomics of Adrenocortical Carcinomas: Rationale for Emerging Therapies

The adrenal glands are paired endocrine organs that produce steroid hormones and catecholamines required for life. Adrenocortical carcinoma (ACC) is a rare and often fatal cancer of the peripheral domain of the gland, the adrenal cortex. Recent research in adrenal development, homeostasis, and disease have refined our understanding of the cellular and molecular programs controlling cortical growth and renewal, uncovering crucial clues into how physiologic programs are hijacked in early and late stages of malignant neoplasia. Alongside these studies, genome-wide approaches to examine adrenocortical tumors have transformed our understanding of ACC biology, and revealed that ACC is composed of distinct molecular subtypes associated with favorable, intermediate, and dismal clinical outcomes. The homogeneous transcriptional and epigenetic programs prevailing in each ACC subtype suggest likely susceptibility to any of a plethora of existing and novel targeted agents, with the caveat that therapeutic response may ultimately be limited by cancer cell plasticity. Despite enormous biomedical research advances in the last decade, the only potentially curative therapy for ACC to date is primary surgical resection, and up to 75% of patients will develop metastatic disease refractory to standard-of-care adjuvant mitotane and cytotoxic chemotherapy. A comprehensive, integrated, and current bench-to-bedside understanding of our field's investigations into adrenocortical physiology and neoplasia is crucial to developing novel clinical tools and approaches to equip the one-in-a-million patient fighting this devastating disease.

Panaxytriol upregulates CYP3A4 expression based on the interaction of PXR, CAR, HSP90α, and RXRα

BACKGROUND

Cytochrome P450 3A4 (CYP3A4) is one of the most important drug-metabolizing enzymes in the human body, mainly existing in the liver, small intestine, and kidney. Panaxytriol is one of the key active components in red ginseng and Shenmai injection. Our previous study demonstrated that panaxytriol regulates CYP3A4 expression mainly by activating pregnancy X receptor (PXR). At a high concentration of panaxytriol (80 μM), the constitutive androstane receptor (CAR) is also involved in the upregulation of CYP3A4.

PURPOSE

This study investigated how the cofactors heat shock protein 90 alpha (HSP90α) and retinoid X receptor alpha (RXRα) interact with PXR and CAR to participate in the regulation of CYP3A4 by panaxytriol from the perspective of the PXR and CAR interaction.

METHODS

The mRNA and protein expressions of PXR, CAR, CYP3A4, RXRα, and HSP90α in HepG2 cells and Huh-7 cells were detected by quantitative PCR and western blot analysis, respectively. The binding levels of PXR and CAR to RXRα and HSP90α were determined by co-immunoprecipitation analysis. The nuclear translocation of PXR and RXRα into HepG2 cells and human (hCAR)-silenced HepG2 cells were measured by immunofluorescence.

RESULTS

In HepG2 cells and Huh-7 cells, panaxytriol (10-80 μM) upregulated CYP3A4 expression in a concentration-dependent manner by decreasing PXR binding to HSP90α and increasing PXR binding to RXRα. When hCAR was silenced, panaxytriol further enhanced CYP3A4 expression by strengthening PXR binding to RXRα, but it had no significant effect on the binding level of PXR and HSP90α. Additionally, at the high concentration of 80 μM panaxytriol, CAR binding to HSP90α was weakened while binding to RXRα was enhanced.

CONCLUSION

Panaxytriol can upregulate CYP3A4 expression by promoting PXR dissociation from HSP90α and enhancing PXR binding to RXRα in HepG2 cells and Huh-7 cells. At high concentrations of panaxytriol, CAR also participates in the induction of CYP3A4 through a similar mechanism. However, in general, CAR antagonizes PXR binding to RXRα, thereby attenuating the upregulation of CYP3A4 by panaxytriol.

Loco-Regional Therapies in Oligometastatic Adrenocortical Carcinoma

Objective: The recommended first-line treatment for low-tumor-burden ACC (stage IVa ACC) not amenable to radical resection is mitotane in association with loco-regional treatments (LRs). The aim of this study was to determine the patient population that would benefit the most from LR. Materials and methods: This retrospective monocentric expert center chart review study was performed from 2008 to 2021 and included stage IVa patients (≤2 tumoral organs) treated with LR (either radiotherapy, surgery, or interventional radiology). The primary endpoint was disease control (DC). Correlations between DC, time to systemic chemotherapy (TTC), overall survival (OS), and tumor characteristics were analyzed using Kaplan−Meier survival analysis and Cox’s proportional hazards regression model for multivariate analysis. Results: Thirty-four women (57%) and 26 men with a median age of 48.1 years (IQR: 38.3−59.8) were included. One hundred and nine LRs were performed, with a median of 2 (IQR: 1−3) per patient. DC was achieved in 40 out of 60 patients (66.7%). Patients with DC had a significantly longer TTC (HR: 0.27, p < 0.001) and OS (HR: 0.22, p < 0.001). Patients with less than or equal to 5 metastases (HR: 6.15 (95% CI: 1.88−20.0), p = 0.002) or a maximum metastasis diameter below 3 cm had higher rates of DC (HR: 3.78 (95% CI: 1.09−13.14), p = 0.035). Conclusion: stage IVa ACC patients with ≤5 metastases or a maximum metastasis diameter below 3 cm had favorable responses to LR. We propose the name oligometastatic ACC for this subgroup of patients.

Nuclear Receptor PXR in Drug-Induced Hypercholesterolemia

Atherosclerosis is a major global health concern. The central modifiable risk factors and causative agents of the disease are high total and low-density lipoprotein (LDL) cholesterol. To reduce morbidity and mortality, a thorough understanding of the factors that influence an individual’s cholesterol status during the decades when the arteria-narrowing arteriosclerotic plaques are forming is critical. Several drugs are known to increase cholesterol levels; however, the mechanisms are poorly understood. Activation of pregnane X receptor (PXR), the major regulator of drug metabolism and molecular mediator of clinically significant drug–drug interactions, has been shown to induce hypercholesterolemia. As a major sensor of the chemical environment, PXR may in part mediate hypercholesterolemic effects of drug treatment. This review compiles the current knowledge of PXR in cholesterol homeostasis and discusses the role of PXR in drug-induced hypercholesterolemia.

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.

Simulation-Based Interpretation of Therapeutically Monitored Cabozantinib Plasma Concentration in Advanced Adrenocortical Carcinoma with Hemodialysis

BACKGROUND

Adrenocortical carcinoma is an orphan but aggressive malignancy with limited treatment options. Cabozantinib (CAB), a tyrosine kinase inhibitor, has emerged as a new potential treatment. However, no data are available on whether and how CAB can be administered to patients undergoing hemodialysis.

METHODS

An liquid chromatography with tandem mass spectrometry detection method was developed and validated according to the European Medicines Agency and United States Food and Drug Administration guidelines for bioanalytical method validation. The samples were prepared using protein precipitation and online solid-phase extraction. The method was applied to clinical samples of an adrenocortical carcinoma patient receiving CAB treatment (80 mg daily). During the 10 days of observation, the patient received periodic hemodialysis on 7 days. Pharmacokinetic (PK) simulations were performed using Bayesian forecasting according to an existing population PK model for CAB.

RESULTS

Based on the PK simulation, a mean plasma trough concentration of 1375 ng/mL [90% prediction interval (PI), 601-2602 ng/mL] in the steady state at a daily dose of 80 mg was expected for CAB. However, an individual simulation involving the measured plasma levels of the patient resulted in a mean trough concentration of 348 ng/mL (90% PI, 278-430 ng/mL). The model based on individual PK parameters estimated accessible plasma levels of 521, 625, and 834 ng/mL by dose adjustment to 100, 120, and 160 mg, respectively.

CONCLUSIONS

After establishing an liquid chromatography with tandem mass spectrometry detection method for therapeutic drug monitoring of CAB, our analyses involving a single patient undergoing hemodialysis indicated that higher than expected doses of CAB were required to achieve reasonable plasma concentrations. Our study demonstrates the usefulness of therapeutic drug monitoring for the evaluation of "new" drugs in patients with renal impairment.

ASXL1 promotes adrenocortical carcinoma and is associated with chemoresistance to EDP regimen

Adrenocortical carcinoma (ACC) is a rare but aggressive disease that lacks definitive treatment. We aim to evaluate role of ASXL1 in ACC and exploit its therapeutic merits therein. We performed in silico reproduction of datasets of the Cancer Genome Atlas (TCGA), GDSC (Genomics of Drug Sensitivity in Cancer) and Human Protein Atlas using platforms of cBioPortal, UALCAN, NET-GE, GSEA and GEPIA. Validation in ACC was performed in tissue, in vitro and in vivo using the NCI-H295R and SW-13 cells. ASXL1 was gained in over 50% of ACC cases with its mRNA overexpressed in DNA gained cases. ASXL1 overexpression was associated with recurrence and worsened prognosis in ACC. ASXL1 gain was associated with resistance to etoposide, doxorubicin and cisplatin (EDP). ASXL1 expression was positively correlated with FSCN1 expression. Targeting ASXL1 significantly impaired fitness of ACC cells, which could be in part rescued by FSCN1 overexpression. Targeting FSCN1 however could not rescue resistance to EDP induced by ASXL1 overexpression. Targeting ASXL1 sensitized ACC cells to EDP regimen but constitutive ASXL3 overexpression in SW-13 cells could induce resistance upon prolonged treatment. Functional gain of ASXL1 was common in ACC and exerted pro-tumorigenic and chemoresistance role. Targeting ASXL1 hold promise to ACC treatment.

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.

How close are we to personalized mitotane dosing in the treatment of adrenocortical carcinoma? State of the art and future perspectives

INTRODUCTION

Mitotane is the only drug registered specifically for adrenocortical carcinoma. Finding the optimal dose for a patient is difficult due to large differences in bioavailability, toxicity and effect. We therefore look to improve personalized dosing of mitotane.

AREAS COVERED

We searched PubMed for studies related to mitotane dosing, pharmacokinetics, pharmacogenetics and combination therapy. Comparison of different dosing strategies have not resulted in an optimal advice. Several computerized pharmacokinetic models have been proposed to predict plasma levels. The current pharmacokinetic models do not explain the full variance in plasma levels. Pharmacogenetics have been proposed to find the unexplained variance. Studies on combination therapy have not yet led to a potential dose adjustment for mitotane.

EXPERT OPINION

Computerized pharmacokinetics models are promising tools to predict plasma levels, further validation is needed. Pharmacogenetics are introduced in these models, but more research is required before clinical application. We believe that in the near future, personalized mitotane dosage will be aided by a validated web-based pharmacokinetic model with good predictive ability based primarily on clinical characteristics, adjustable for actual plasma levels and dosage.

Angiogenesis in the Normal Adrenal Fetal Cortex and Adrenocortical Tumors

Angiogenesis plays an important role in several physiological and pathological processes. Pharmacological angiogenesis modulation has been robustly demonstrated to achieve clinical benefits in several cancers. Adrenocortical carcinomas (ACC) are rare tumors that often have a poor prognosis. In addition, therapeutic options for ACC are limited. Understanding the mechanisms that regulate adrenocortical angiogenesis along the embryonic development and in ACC could provide important clues on how these processes could be pharmacologically modulated for ACC treatment. In this report, we performed an integrative review on adrenal cortex angiogenesis regulation in physiological conditions and ACC. During embryonic development, adrenal angiogenesis is regulated by both VEGF and Ang-Tie signaling pathways. In ACC, early research efforts were focused on VEGF signaling and this pathway was identified as a good prognostic factor and thus a promising therapeutic target. However, every clinical trial so far conducted in ACC using VEGF pathway- targeting drugs, alone or in combination, yielded disappointing results. In contrast, although the Ang-Tie pathway has been pointed out as an important regulator of fetal adrenocortical angiogenesis, its role is yet to be explored in ACC. In the future, further research on the role and efficacy of modulating both Ang-Tie and VEGF pathways in ACC is needed.

Metabolic and hormonal side effects of mitotane treatment for adrenocortical carcinoma: A retrospective study in 50 Danish patients

OBJECTIVE

Mitotane is used in the treatment of adrenocortical carcinoma (ACC). Metabolic and hormonal side effects of mitotane, the effect of subsequent treatment with statins and hormones and the effects of discontinuation of mitotane were assessed.

PATIENTS AND METHODS

Fifty patients were included. Lipid profiles, thyroid hormones, sex hormones and adrenal function from first year of mitotane treatment and after cessation were evaluated.

RESULTS

After 6 months of mitotane treatment total cholesterol increased from (median) 5.1 (IQR 4.3 to 5.8) to 7.4 (6.2-9.0) mmol/L, p < .001. LDL, HDL and triglyceride also increased, all p ≤ .03. Three months of treatment with statins decreased total and LDL-cholesterol, and cessation of mitotane led to further reduction in lipids. Plasma thyroxine decreased from 90 (78-111) to 57 (47-63) nmol/L and free thyroxine from 16.0 (13.0-18.3) to 11.7 (10.5-12.6) pmol/L on mitotane, both p < .001, while TSH remained unchanged. Treatment with thyroxin significantly increased plasma thyroxine and free thyroxine and decreased TSH. Cessation of mitotane increased total T4 (p < .001). Mitotane increased plasma SHBG from 36 (22-51) to 189 (85-259) nmol/L and LH from 4.6 (1.6-8.1) to 20.0 (10.0-34.9) IU/L, both p < .001. In males the changes were accompanied by an increase in testosterone from 9.8 (7.2-14.5) to 27.0 (15.3-34.8) nmol/L, p < .03. Fifteen of 24 tested patients regained normal adrenal function 6 (3-16) months after cessation of mitotane.

CONCLUSIONS

Mitotane treatment exerts multiple severe side effects involving both the metabolic and endocrine systems that may require treatment, but the effect appears to be partially reversible.

Updates in adrenal steroidogenesis inhibitors for Cushing's syndrome - A practical guide

Medical therapy is essential in the management of patients with Cushing's syndrome (CS) when curative surgery has failed, surgery is not feasible, when awaiting radiation effect, and in recurrent cases of CS. Steroidogenesis inhibitors have a rapid onset of action and are effective in reducing hypercortisolism, however, adverse effects, including adrenal insufficiency require very close patient monitoring. Osilodrostat is the only steroidogenesis inhibitor to have been assessed in prospective randomized controlled trials and approved for Cushing's disease (CD) by the US Food and Drug Administration and for CS by the European Medical Agency (EMA). Osilodrostat has been shown to be highly effective at maintaining normal urinary free cortisol in patients with CD. Drugs such as metyrapone, ketoconazole (both EMA approved), and etomidate lack prospective evaluation(s). There is, however, considerable clinical experience and retrospective data that show a very wide efficacy range in treating patients with CS. In the absence of head-to-head comparative clinical trials, therapy choice is determined by the specific clinical setting, risk of adverse events, cost, availability, and other factors. In this review practical points to help clinicians who are managing patients with CS being treated with steroidogenesis inhibitors are presented.

Adrenally Directed Medical Therapies for Cushing Syndrome

CONTEXT

Endogenous Cushing syndrome (CS) is characterized by excess cortisol secretion, which is driven by tumorous secretion of corticotropin in the majority of patients. Untreated, CS results in substantial morbidity and mortality. Tumor-directed surgery is generally the first-line therapy for CS. However, hypercortisolism may persist or recur postoperatively; in other cases, the underlying tumor may not be resectable or its location may not be known. Yet other patients may be acutely ill and require stabilization before definitive surgery. In all these cases, additional interventions are needed, including adrenally directed medical therapies.

EVIDENCE ACQUISITION

Electronic literature searches were performed to identify studies pertaining to adrenally acting agents used for CS. Data were abstracted and used to compile this review article.

EVIDENCE SYNTHESIS

Adrenally directed medical therapies inhibit one or several enzymes involved in adrenal steroidogenesis. Several adrenally acting medical therapies for CS are currently available, including ketoconazole, metyrapone, osilodrostat, mitotane, and etomidate. Additional agents are under investigation. Drugs differ with regards to details of their mechanism of action, time course of pharmacologic effect, safety and tolerability, potential for drug-drug interactions, and route of administration. All agents require careful dose titration and patient monitoring to ensure safety and effectiveness, while avoiding hypoadrenalism.

CONCLUSIONS

These medications have an important role in the management of CS, particularly among patients with persistent or recurrent hypercortisolism postoperatively or those who cannot undergo tumor-directed surgery. Use of these drugs mandates adequate patient instruction and close monitoring to ensure treatment goals are being met while untoward adverse effects are minimized.

Medical management of adrenocortical carcinoma: Current recommendations, new therapeutic options and future perspectives

Adrenocortical carcinoma is a rare malignant tumor of poor prognosis, frequently requiring additional treatments after initial surgery. Due to its adrenolytic action, mitotane has become the first-line medical treatment in patients with aggressive adrenocortical carcinoma. Over the last 2years, apart from the classical chemotherapy based on etoposide and platinum salts, several studies reported the use of drugs such as temozolomide, tyrosine kinase inhibitors or immunotherapy, with more or less convincing results. The aim of this review is to give further insights in the use of these drugs, and to describe potential therapeutic perspectives based on recent pangenomic studies, for the future management of these still difficult to treat tumors.

Operative intervention for recurrence of adrenocortical carcinoma: A single-center experience

INTRODUCTION

Adrenocortical carcinoma is a rare endocrine malignancy with a high recurrence rate. The aim of this study was to evaluate the role of surgery for patients with local or distant recurrent adrenocortical carcinoma and to attempt to identify prognostic features related to survival benefit in patients undergoing resection of recurrence.

METHODS

The data of 47 patients with recurrent adrenocortical carcinoma in West China Hospital, Sichuan, China, between 2009 and 2019 were retrospectively collected. These patients were divided into 2 groups according to whether resection of recurrence was performed. The correlation between overall survival after recurrence and reoperation was evaluated. Kaplan-Meier and univariate/multivariate Cox regression methods were used to identify any prognostic factors.

RESULTS

Included in our study were 21 patients who underwent reoperation and 26 patients who underwent nonoperative treatments were. The operation group had a better median overall survival after recurrence than the nonoperation group (19 months versus 6.5 months; P = .007). In the operated group, disease-free interval >12 months (P = .002), complete resection of recurrent adrenocortical carcinoma (P = .041), and R0 resection of the primary tumor (P = .005) were associated with prolonged survival after recurrence.

CONCLUSIONS

Reoperation plays an important role in the management of selected patients with recurrent adrenocortical carcinoma. Disease-free interval, preoperative evaluation for complete resection, and R0 resection of the primary tumor are important prognostic characteristics for the resection of recurrent adrenocortical carcinoma. The overall survival after recurrence was significantly improved for patients who had a disease-free interval >12 months, and initial R0 resection or complete resection of recurrent adrenocortical carcinoma is feasible.

Medical Approaches in Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) represents one of the most aggressive endocrine tumors. In spite of a correct therapeutic strategy based on a multidisciplinary approach between endocrinologist, surgeon and oncologist, the prognosis is often poor. Surgery is the mainstay treatment in ACC. Mitotane, a dichloro-diphenyl-trichloro-ethane derivate, represents the main medical treatment of ACC in consideration of its adrenocytolitic activity and it is mainly employed as adjuvant treatment after complete surgical resection and for the treatment of advanced ACC. However, the use of mitotane as adjuvant therapy is still controversial, also in consideration of the retrospective nature of several studies. The recurrence of disease is frequent, especially in advanced disease at the diagnosis. Therefore, in these contexts, conventional chemotherapy must be considered in association with mitotane, being the combination etoposide, doxorubicin and cisplatin (EDP) the standard of care in this setting. A more modern therapeutic approach, based on the need of a salvage therapy for advanced ACC that progresses through first-line EDP, is focused on molecular-targeted therapies. However, robust clinical trials are necessary to assess the real efficacy of these treatments.

Unwanted Hormonal and Metabolic Effects of Postoperative Adjuvant Mitotane Treatment for Adrenocortical Cancer

Simple Summary

Mitotane is the only drug approved for treatment of adrenocortical cancer. Although mitotane is a derivative of the pesticide dichlorodiphenyltrichloroethane (DDT), limited data are available on its toxicity. Herein, we reported on the type and frequency of mitotane adverse events and on supportive therapies used to deal with toxicity in 74 mitotane-treated patients. Beyond the expected glucocorticoid insufficiency, a significant number of patients had a deficit of mineralocorticoid hormones, hypothyroid state and impaired testicular function, while fertile women frequently developed ovarian cysts during mitotane treatment. Multiple hormone replacement therapies were needed in >30% of patients. Statins were used in 50% of patients for significant hypercholesterolemia. Supportive therapies were able to revert the biochemical alterations, although higher doses were frequently used due to pharmacokinetic interactions with mitotane. Our study underlines the need of a careful and global approach to manage mitotane toxicity, to make adjuvant therapy safer and easier for patients.

Abstract

Mitotane is widely used for the treatment of adrenocortical cancer (ACC), although the drug-related toxicity complicates its use. The aim of this study is to assess comprehensively the different endocrine and metabolic unwanted effects of the drug, and to provide data on the supportive therapies. We retrospectively analyzed 74 ACC patients adjuvantly treated with mitotane for ≥12 months. During the treatment period (40 months, 12–195), 32.4% of patients needed replacement therapy for mineralocorticoid deficit, 36.2% for hypothyroidism and 34.3% for male hypogonadism. In fertile women, hypogonadism was uncommon, while 65.4% of women developed ovarian cysts. Although no significant change in low-density lipoprotein (LDL) was observed, statins were started in 50% of patients for a significant increase in total cholesterol and triglycerides. Dyslipidemia occurred early, after a median time of 6 months from mitotane start. Conversely, testosterone replacement was usually started after >2 years. In many cases, ranging from 29.4% to 50% according to the side effect, toxicity occurred well before the achievement of the target mitotane concentrations. Supportive therapies were able to revert the biochemical alterations induced by mitotane, although higher doses were needed for a likely pharmacokinetic interaction of exogenous steroids and statins with mitotane. In conclusion, adjuvant mitotane therapy is associated with a spectrum of unwanted effects encompassing the function of different endocrine glands and requires a careful clinical and biochemical assessment associated with the therapeutic drug monitoring.

Objective Response and Prolonged Disease Control of Advanced Adrenocortical Carcinoma with Cabozantinib

BACKGROUND

Objective response of advanced adrenocortical carcinoma (ACC) to mitotane and cytotoxic chemotherapy regimen is only ~20% and early tumor progression is frequent. Previous clinical trials with oral multikinase inhibitors were negative, which has been attributed in part to inadvertent drug interaction with mitotane. Cabozantinib (CABO) is an inhibitor of c-MET, vascular endothelial growth factor receptor 2, AXL, and RET and approved for advanced kidney cancer, liver carcinoma after previous sorafenib, and medullary thyroid carcinoma.

OBJECTIVE

To investigate the clinical efficacy and safety of CABO monotherapy in ACC patients.

DESIGN

Retrospective cohort study.

SETTING

Three referral centers for ACC (Germany, United States).

RESULTS

Sixteen patients (13 female) with progressive ACC received CABO after previous mitotane in 15/16 and 3 (median, range 0-8) further systemic treatments. Prior CABO therapy, mitotane was discontinued in all patients. Mitotane plasma concentration was <2 mg/L in 7/16 patients and discontinued >12 months in 6 additional patients before CABO use. In 4/5 cases with available plasma samples, CABO concentration was in the expected steady-state range. Adverse events of grade 1/2 and 3 were observed in 13 and 3 patients, respectively, and consistent with the known safety profile of CABO. Best response was partial response in 3, stable disease in 5, and progressive disease in 8 patients. Median progression-free and overall survival was 16 and 58 weeks, respectively.

CONCLUSION

CABO monotherapy appears to be safe and effective as a monotherapy in advanced ACC after failing prior treatments. Therefore, prospective investigation of CABO in ACC patients is warranted.

Next-generation therapies for adrenocortical carcinoma

Almost one decade ago, etoposide, doxorubicin, cisplatin and mitotane (EDP-M) has been established as first-line systemic therapy of metastatic adrenocortical carcinoma (ACC). Although heterogeneous, the prognosis of advanced stage ACC is still poor and novel treatments are urgently needed. This article provides a short summary of current systemic ACC treatment and provides a comprehensive overview of new therapeutic approaches that have been investigated in the past years, including drugs targeting the IGF pathway, tyrosine kinase inhibitors, radionuclide treatment, and immunotherapy. The results of most of these trials were disappointing and we will discuss possible reasons why these drugs failed (e.g. drug interactions with mitotane, disease heterogeneity with exceptional responses in very few patients, and resistance mechanisms to immunotherapy). We then will present potential new drug targets that have emerged from many molecular studies (e.g. wnt/β-catenin, cyclin-dependent kinases, PARP1) that may be the foundation of next-generation therapies of ACC.

Advanced Adrenocortical Carcinoma (ACC): a Review with Focus on Second-Line Therapies

Advanced adrenocortical cancer (ACC) is a rare, highly aggressive malignancy, which typically has a poor prognosis. In advanced ACC, the overall trend is toward a short PFS interval following first-line systemic therapy, highlighting a clear need for improved second-/third-line treatment strategies. We conducted a review of the literature and relevant scientific guidelines related to systemic therapy for advanced ACC. Public indexes including PubMed/MEDLINE were searched. Treatment selection in the second-line setting is based on small phase 2 trials, case reports, and pre-clinical evidence. The best data available for initial second-line therapy selection supports the use of gemcitabine and capecitabine (G + C) or streptozotocin (S), both with or without mitotane. G + C is becoming increasingly recommended based on phase 2 clinical trial data in patients of good PS, due to the inferred superior PFS and OS from non-comparative trials. Alternatively, streptozotocin was better tolerated than EDP + M in the FIRM-ACT study and remains an option when warranted. Beyond this, further treatment approaches should be tailored to individual patient characteristics, utilizing a mixture of systemic therapies, local therapies, and enrolment in clinical trials where available. Additionally, the role of molecular stratification, predictive biomarkers, and immune checkpoint inhibitors in specific individuals, such as Lynch syndrome, is evolving and may become increasingly utilized in clinical practice. Advanced ACC necessitates a multidisciplinary approach and is best managed in a specialist center. Although there is no one definitive second-line treatment strategy, there are some favorable approaches, which require further validation in larger clinical trials.

The effects of mitotane and 1α,25-dihydroxyvitamin D3 on Wnt/beta-catenin signaling in human adrenocortical carcinoma cells

PURPOSE

Mitotane is the only chemotherapeutic agent available for the treatment of adrenocortical carcinoma (ACC), however, the anti-neoplastic efficacy is limited due to several side-effects in vivo. There is, therefore, a need of exploring for new anti-tumoral agents which can be used either alone or in combination with mitotane. The active vitamin D metabolite 1α,25-dihydroxyvitamin D₃ (1α,25(OH)₂D₃) acts as an anti-proliferative agent in human cancer by inhibiting the Wnt/beta-catenin pathway through the vitamin D receptor (VDR). The aim of this study was to study the effects of mitotane and 1α,25(OH)₂D₃, individually or in combination, in an in vitro model with H295R ACC cells, and to elucidate the molecular events behind their effects involving the Wnt/beta-catenin signaling.

METHODS AND RESULTS

Multiple concentrations of mitotane and 1α,25(OH)₂D₃, individually or in combination, were tested on H295R cells for 24-96 h, and the effects analysed by MTT. A reduction in cell growth was observed in a dose/time-dependent manner for both mitotane and 1α,25(OH)₂D₃. In addition, a combination of clinically sub-therapeutic concentrations of mitotane with 1α,25(OH)₂D₃, had an additive anti-proliferative effect (Combination Index = 1.02). In a wound healing assay, individual treatments of both mitotane and 1α,25(OH)₂D₃ reduced the migration ability of H295R cells, with the effect further enhanced on combining both the agents. Western blotting and qRT-PCR analysis showed a modulation of the Wnt/beta-catenin and VDR signaling pathways.

CONCLUSION

Our results show an additive effect of mitotane and 1α,25(OH)₂D₃ on the inhibition of H295R ACC cell growth and viability, and suggest that molecular mechanisms of their effects involve a functional link between VDR and Wnt/beta-catenin pathways.

A Micellar Mitotane Formulation with High Drug-Loading and Solubility: Physico-Chemical Characterization and Cytotoxicity Studies in 2D and 3D In Vitro Tumor Models

Adrenocortical carcinoma (ACC) is a rare tumor and prognosis is overall poor but heterogeneous. Mitotane (MT) has been used for treatment of ACC for decades, either alone or in combination with cytotoxic chemotherapy. Even at doses up to 6 g per day, more than half of the patients do not achieve targeted plasma concentration (14-20 mg L^-1 ) even after many months of treatment due to low water solubility, bioavailability, and unfavorable pharmacokinetic profile. Here a novel MT nanoformulation with very high MT concentrations in physiological aqueous media is reported. The MT-loaded nanoformulations are characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffraction which confirms the amorphous nature of the drug. The polymer itself does not show any cytotoxicity in adrenal and liver cell lines. By using the ACC model cell line NCI-H295 both in monolayers and tumor cell spheroids, micellar MT is demonstrated to exhibit comparable efficacy to its ethanol solution. It is postulated that this formulation will be suitable for i.v. application and rapid attainment of therapeutic plasma concentrations. In conclusion, the micellar formulation is considered a promising tool to alleviate major drawbacks of current MT treatment while retaining bioactivity toward ACC in vitro.

Prognostic Role of Ki-67 in Adrenocortical Carcinoma After Primary Resection: A Retrospective Mono-Institutional Study

INTRODUCTION

Adrenocortical carcinoma (ACC) is a rare malignancy with poor prognosis. It is vitally important to predict prognosis and restrict unnecessary adjuvant treatments for patients with ACC. This study aims to confirm the prognostic value of Ki-67 and provide a prognostic evaluation on ACC after primary surgery.

METHODS

A total of 66 patients satisfied the inclusion criteria and their complete data were collected and reviewed. The correlation between Ki-67 index and clinicopathologic variables was analyzed using chi-square tests and Pearson's or Spearman's test. Survival curves were generated by Kaplan-Meier analysis and compared with the log-rank test. The Cox regression model was performed to estimate hazard ratios for univariate and multivariate analyses.

RESULTS

Of the 66 patients, recurrence was observed in 30 patients (45.5%) and 26 patients (39.4%) died of progressive ACC. The evaluated median overall survival (OS) of the entire study population was 16.5 (range 1-104) months and recurrence-free survival (RFS) was 9.0 (range 0-104) months. Increased Ki-67 expression (> 20% and > 3%) was negatively correlated with OS and RFS (chi-square, P = 0.006 and 0.044, respectively). In multivariate analysis, the Ki-67 index with 20% and 3% cutoff as an independent prognostic factor for OS and RFS was validated [hazard ratio (HR) 3.289; 95% CI 1.345-8.042; P = 0.009 and HR 4.471; 95% CI 1.086-18.410; P = 0.038, respectively].

CONCLUSIONS

Ki-67 is a reliable, convenient, and independent prognostic marker for ACC. Additionally, as an indicator with a divergent prognostic role at different cutoff values (20% and 3%), Ki-67 could be used for stratifying patients with a high risk of death or rapid recurrence.

Adrenocortical carcinoma - towards genomics guided clinical care

Adrenocortical carcinoma (ACC) is an aggressive and rare neoplasm that originates in the cortex of the adrenal gland. The disease is associated with heterogeneous but mostly poor outcomes and lacks effective pharmaceutical treatment options. Multi-omics studies have defined the landscape of molecular alterations in ACC. Specific molecular signatures can be detected in body fluids, potentially enabling improved diagnostic applications for patients with adrenal tumours. Importantly, pan-molecular data sets further reveal a spectrum within ACC, with three major subgroups that have different disease outcomes. These new subgroups have value as prognostic biomarkers. Research has revealed that the p53-RB and the WNT-β-catenin pathways are common disease drivers in ACC. However, these pathways remain difficult to target by therapeutic interventions. Instead, a unique characteristic of ACC is steroidogenic differentiation, which has emerged as a potential treatment target, with several agents undergoing preclinical or clinical investigations. Finally, a large proportion of ACC tumours have genetic profiles that are associated with promising therapeutic responsiveness in other cancers. All these opportunities now await translation from the laboratory into the clinical setting, thereby offering a real potential of improved survival outcomes and increased quality of life for patients with this serious condition.

A phase II study of the orally administered negative enantiomer of gossypol (AT-101), a BH3 mimetic, in patients with advanced adrenal cortical carcinoma

Background Adrenal cortical carcinoma (ACC) is a rare cancer with treatment options of limited efficacy, and poor prognosis if metastatic. AT-101 is a more potent inhibitor of B cell lymphoma 2 family apoptosis-related proteins than its racemic form, gossypol, which showed preliminary clinical activity in ACC. We thus evaluated the efficacy of AT-101 in patients with advanced ACC. Methods Patients with histologically confirmed metastatic, recurrent, or primarily unresectable ACC were treated with AT-101 (20 mg/day orally, 21 days out of 28-day cycles) until disease progression and/or prohibitive toxicity. The primary endpoint was objective response rate, wherein a Response Evaluation Criteria In Solid Tumors (RECIST) partial response rate of 25% would be considered promising and 10% not, with a Type I error of 10% and 90% power. In a 2-stage design, 2 responses were required of the first 21 assessable subjects to warrant complete accrual of 44 patients. Secondary endpoints included safety, progression-free survival and overall survival. Results This study accrued 29 patients between 2009 and 2011; median number of cycles was 2. Seven percent experienced grade 4 toxicity including cardiac troponin elevations and hypokalemia. None of the first 21 patients attained RECIST partial response; accordingly, study therapy was deemed ineffective and the trial was permanently closed. Conclusions AT-101 had no meaningful clinical activity in this study in patients with advanced ACC, but demonstrated feasibility of prospective therapeutic clinical trials in this rare cancer.

Pharmacokinetic interaction between mitotane and etoposide in adrenal carcinoma: a pilot study

Background The combination of mitotane and platinum-etoposide chemotherapy is a front-line treatment in metastatic adrenocortical carcinoma (ACC), although this regimen shows limited efficacy. Pharmacokinetic drug-drug interaction between mitotane, a strong CYP3A4 inducer, and etoposide, which is a substrate of CYP3A4, may contribute to chemoresistance. The aim of this pilot study was to assess the pharmacokinetic interaction between mitotane and etoposide in ACC patients. Methods Five consecutive ACC patients treated with platinum etoposide (120-150 mg/m2 day 1-2-3 at cycle 1), with or without concomitant mitotane, were included. In the absence of limiting toxicity, a dose escalation of etoposide was proposed since cycle 2. Plasma etoposide concentrations were measured using liquid chromatography at 0, 4 and 24 h after each infusion. Clearance and area under the curve (AUC) of etoposide were determined at each cycle. Results Patients received two to six chemotherapy cycles, in association with mitotane (N = 4) or after mitotane discontinuation (N = 1). Etoposide clearance was two-fold higher with concomitant mitotane (4.95 L/h) than after mitotane discontinuation (2.53 L/h, P = 0.014), and 2.5-fold higher than that in reference population not treated with mitotane (1.81 L/h). Etoposide dose escalation was performed in four patients under mitotane, resulting in two minor tumor responses and one severe toxicity (febrile aplasia) at dose of 300 mg/m2/day. Tumor response was associated with higher etoposide AUC (267.3 vs 188.8 mg.h/L, P = 0.04). Conclusion A drug-drug interaction between mitotane and etoposide may contribute to the low efficacy of platinum-etoposide chemotherapy. This pilot study suggests further a potential benefit of increasing etoposide dose in ACC patients receiving mitotane.

European Society of Endocrinology Clinical Practice Guidelines on the management of adrenocortical carcinoma in adults, in collaboration with the European Network for the Study of Adrenal Tumors

Adrenocortical carcinoma (ACC) is a rare and in most cases steroid hormone-producing tumor with variable prognosis. The purpose of these guidelines is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with ACC based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions, which we judged as particularly important for the management of ACC patients and performed systematic literature searches: (A) What is needed to diagnose an ACC by histopathology? (B) Which are the best prognostic markers in ACC? (C) Is adjuvant therapy able to prevent recurrent disease or reduce mortality after radical resection? (D) What is the best treatment option for macroscopically incompletely resected, recurrent or metastatic disease? Other relevant questions were discussed within the group. Selected Recommendations: (i) We recommend that all patients with suspected and proven ACC are discussed in a multidisciplinary expert team meeting. (ii) We recommend that every patient with (suspected) ACC should undergo careful clinical assessment, detailed endocrine work-up to identify autonomous hormone excess and adrenal-focused imaging. (iii) We recommend that adrenal surgery for (suspected) ACC should be performed only by surgeons experienced in adrenal and oncological surgery aiming at a complete en bloc resection (including resection of oligo-metastatic disease). (iv) We suggest that all suspected ACC should be reviewed by an expert adrenal pathologist using the Weiss score and providing Ki67 index. (v) We suggest adjuvant mitotane treatment in patients after radical surgery that have a perceived high risk of recurrence (ENSAT stage III, or R1 resection, or Ki67 >10%). (vi) For advanced ACC not amenable to complete surgical resection, local therapeutic measures (e.g. radiation therapy, radiofrequency ablation, chemoembolization) are of particular value. However, we suggest against the routine use of adrenal surgery in case of widespread metastatic disease. In these patients, we recommend either mitotane monotherapy or mitotane, etoposide, doxorubicin and cisplatin depending on prognostic parameters. In selected patients with a good response, surgery may be subsequently considered. (vii) In patients with recurrent disease and a disease-free interval of at least 12 months, in whom a complete resection/ablation seems feasible, we recommend surgery or alternatively other local therapies. Furthermore, we offer detailed recommendations about the management of mitotane treatment and other supportive therapies. Finally, we suggest directions for future research.

Treating canine Cushing's syndrome: Current options and future prospects

Naturally occurring hypercortisolism, also known as Cushing's syndrome, is a common endocrine disorder in dogs that can be caused by an adenocorticotrophic hormone (ACTH)-producing pituitary adenoma (pituitary-dependent hypercortisolism, PDH; 80-85% of cases), or by an adrenocortical tumor (ACT; 15-20% of cases). To determine the optimal treatment strategy, differentiating between these two main causes is essential. Good treatment options are surgical removal of the causal tumor, i.e. hypophysectomy for PDH and adrenalectomy for an ACT, or radiotherapy in cases with PDH. Because these options are not without risks, not widely available and not suitable for every patient, pharmacotherapy is often used. In cases with PDH, the steroidogenesis inhibitor trilostane is most often used. In cases with an ACT, either trilostane or the adrenocorticolytic drug mitotane can be used. Although mostly effective, both treatments have disadvantages. This review discusses the current treatment options for canine hypercortisolism, and considers their mechanism of action, efficacy, adverse effects, and effect on survival. In addition, developments in both adrenal-targeting and pituitary-targeting drugs that have the potential to become future treatment options are discussed, as a more selective and preferably also tumor-targeted approach could have many advantages for both PDH and ACTs.

Role of Mitotane in Adrenocortical Carcinoma - Review and State of the art

Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine tumour deriving from the adrenal cortex. A correct therapeutic strategy requires a multidisciplinary approach between endocrinologist, surgeon and oncologist. Surgery is the mainstay treatment in ACC while mitotane, deriving from the insecticide dichloro-diphenyl-trichloro-ethane, is the main base of the medical treatment of ACC in consideration of its adrenocytolitic activity. However, the use of mitotane as adjuvant therapy is still controversial, also in consideration of the retrospective nature of several studies. A prospective randomised trial (ADIUVO), recruiting patients with low-intermediate risk of recurrence, is evaluating the utility of adjuvant treatment with mitotane in this setting. The therapeutic response is observed with plasma levels of mitotane >14 mg/L. However, the major difficulty in the management of mitotane treatment is related to side effects and to the risk of toxicity, which is related to plasmatic levels >20 mg/L, that is considered the upper limit of the therapeutic window. Mitotane therapy results in adrenal insufficiency, and glucocorticoid replacement therapy has to be administered at higher doses than those used in other aetiologies of primary adrenal insufficiency. Furthermore, other endocrine side effects related to mitotane should be considered, in particular on thyroid hormone and testosterone metabolism. Waiting for new medical strategies on molecular targets, it will be mandatory to optimise the current knowledge by prospective trials and, in consideration of the rarity of the disease, collaborative studies between endocrinologists and oncologists are necessary.

Adrenocortical Carcinoma with Hypercortisolism

Adrenocortical carcinoma (ACC) is a rare and aggressive tumor. ACC may be associated with different syndromes of hormone excess, most frequently Cushing's syndrome with or without hypersecretion of androgens. Recent data suggest that cortisol excess is a negative prognostic factor in advanced and localized ACC. Surgery with radical intent, when feasible, is the most effective treatment for ACC with hypercortisolism. Mitotane is the medical treatment of choice, both postoperatively and in inoperable or metastatic cases. Because of its slow onset of action, combination with other antisecretory agents (ie, metyrapone) is helpful to achieve more rapid and effective control of hypercortisolism.

Proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitor use in the management of resistant hypercholesterolemia induced by mitotane treatment for adrenocortical cancer

We report the case of a patient with probable heterozygous familial hypercholesterolemia and mitotane-induced resistant hypercholesterolemia, despite combination therapy with rosuvastatin and ezetimibe. The patient was managed with the addition of evolocumab. Use of a proprotein convertase subtilisin-kexin type 9 inhibitor, should be considered in patients who develop mitotane-related hypercholesterolemia that cannot be managed with conventional lipid-lowering treatment.

Tissue Expression and Pharmacological In Vitro Analyses of mTOR and SSTR Pathways in Adrenocortical Carcinoma

New therapies for advanced adrenocortical carcinoma (ACC) are urgently needed, as the majority of the patients experience a rapid and inexorable progression despite surgery and adjuvant mitotane. In vitro data suggest that somatostatin receptors (SSTRs) and mTOR pathway might represent reasonable targets for novel therapies, being involved in functionality and growth of ACC cells. However, in vitro analysis of combination treatments targeting both mTOR and SSTR as compared to mitotane are poorly explored in ACC. This study aimed to investigate in vitro the effects on cell growth of pasireotide, everolimus, and mitotane, alone or combined, in the two ACC cell lines H295R and SW13 (mitotane sensitive and resistant, respectively). Moreover, the tissue expression of mTOR pathway molecules and SSTR (types 1-5) was assessed in 58 ACCs. In both cell lines, only everolimus induced a significant inhibition of cell growth. Conversely, the combinations among mitotane, pasireotide, and everolimus produced antagonistic effects on mitotane-induced growth inhibition on H295R cell line. A heterogeneous profile of mTOR-related molecules and SSTR expression was observed in ACC samples, being the mTOR pathway found activated in approximately 30% of cases. In conclusion, our data suggest caution in designing combinations of mitotane with other drugs potentially active in ACC, such as mTOR inhibitors or somatostatin analogs.

Overexpression of cytochrome P450 2A6 in adrenocortical carcinoma

BACKGROUND

Cytochrome P450-mediated metabolism of chemotherapeutic agents contributes to chemotherapy resistance in multiple malignancies. Adrenocortical carcinoma is known to have a poor response to adjuvant therapies; however, the mechanism remains unknown. Recent comprehensive genetic analyses of adrenocortical carcinomas demonstrated recurrent copy number gains in multiple cytochrome P450 genes prompting investigation into whether cytochrome P450 overexpression potentiates adrenocortical carcinoma chemoresistance.

METHODS

We determined the expression patterns of 6 cytochrome P450 genes (CYP2A6, CYP2A7, CYP2A13, CYP2B6, CYP2S1, and CYP4F2) predicted to be amplified in adrenocortical carcinoma (n = 29) relative to normal adrenal cortex (n = 10). Gene copy numbers were determined with the TaqMan copy number assay. Gene silencing was performed via small interfering RNA (siRNA) in the adrenocortical carcinoma cell line NCI-H295R and treated with mitotane and cisplatin.

RESULTS

Of the 6 cytochrome P450 genes tested, CYP2A6 was overexpressed with a 55-fold mean increase compared to normal adrenal samples (P < .05). Immunohistochemical analysis confirmed protein overexpression. Copy gains of CYP2A6 were found in 26% (7/27) of adrenocortical carcinoma specimens. Silencing of CYP2A6 in NCI-H295R cells resulted in decreased cell viability and increased chemosensitivity (P < .05).

CONCLUSION

Frequent upregulation in adrenocortical carcinomas and the reversal of chemoresistance in adrenocortical carcinoma cells via enforced silencing suggest a role for CYP2A6 in adrenocortical malignancy.

Immediate versus modified release hydrocortisone in mitotane-treated patients with adrenocortical cancer

OBJECTIVE

Mitotane induces hepatic CYP3A4 activity, resulting in accelerated cortisol inactivation, and also increases cortisol binding globulin (CBG). Therefore, higher hydrocortisone doses are required in patients with adrenocortical cancer (ACC) on mitotane treatment. Modified release hydrocortisone has not been used in mitotane-treated ACC patients yet.

AIM

Case series to compare serum cortisol, calculated free serum cortisol and ACTH levels in ACC patients on mitotane treatment with immediate and modified release hydrocortisone.

DESIGN

Pharmacokinetics of immediate and modified release hydrocortisone, each administered at a dose of 40-20-0 mg, in nine patients with ACC and adjuvant mitotane treatment. For comparison, ten patients with secondary adrenal insufficiency (SAI) on three different hydrocortisone regimens and ten healthy males were included.

METHODS

Serum cortisol and plasma ACTH were measured by chemiluminescent enzyme immunoassay, and CBG by RIA, followed by calculation of free cortisol.

RESULTS

Calculated free serum cortisol levels after 40 mg immediate release hydrocortisone in ACC patients (46 ± 14 nmol/l) were similar to those after 10 mg immediate release hydrocortisone intake in men with SAI (64 ± 16 nmol/l) or to the physiological morning free cortisol levels in healthy subjects (31 ± 5 nmol/l). Compared to immediate release hydrocortisone, free cortisol levels after 40 mg modified release hydrocortisone in ACC patients were significantly lower (12 ± 3 nmol/l; P = 0·03) resulting in a generally lower AUC (98 ± 21 vs 149 ± 37 nmol h/l; P = 0·02).

CONCLUSIONS

40-20-0 mg immediate release, but not modified release hydrocortisone, resulted in sufficient glucocorticoid coverage in patients with ACC receiving mitotane treatment. The use of equivalent doses of modified release hydrocortisone preparation should be avoided in patients on mitotane treatment.

New insights and future perspectives in the therapeutic strategy of adrenocortical carcinoma (Review)

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with an incidence ranging from 0.7 to 2.0 cases/million people per year. Hypercortisolism represents the most common clinical presentation in many patients although, less frequently, some ACC secreting androgens and estrogens are even more pathognomonic compared to cortisol secretion. Currently, radical surgery, when feasible, is still the only curative therapy. Mitotane, an adrenolytic drug, is used in the adjuvant setting and in combination with chemotherapy drugs in metastatic disease. The use of radiotherapy remains controversial, being indicated only in selected cases. New targeted therapies, such as insulin growth factor-1 (IGF-1), mammalian-target of rapamycin (m-TOR), vascular endothelial growth factor (VEGF) inhibitors and others, have recently been investigated with disappointing clinical results. The partial effectiveness of current treatments mandates the need for new therapeutic strategies against this tumor.

Therapeutic Strategies for the Treatment of Severe Cushing's Syndrome

Severe Cushing's syndrome presents an acute emergency and is defined by massively elevated random serum cortisol [more than 36 μg/dL (1000 nmol/L)] at any time or a 24-h urinary free cortisol more than fourfold the upper limit of normal and/or severe hypokalaemia (<3.0 mmol/L), along with the recent onset of one or more of the following: sepsis, opportunistic infection, intractable hypokalaemia, uncontrolled hypertension, heart failure, gastrointestinal haemorrhage, glucocorticoid-induced acute psychosis, progressive debilitating myopathy, thromboembolism or uncontrolled hyperglycaemia and ketocacidosis. Treatment focuses on the management of the severe metabolic disturbances followed by rapid resolution of the hypercortisolaemia, and subsequent confirmation of the cause. Emergency lowering of the elevated serum cortisol is most rapidly achieved with oral metyrapone and/or ketoconazole; if parenteral therapy is required then intravenous etomidate is rapidly effective in almost all cases, but all measures require careful supervision. The optimal order and combination of drugs to treat severe hypercortisolaemia-mostly in the context of ectopic ACTH-secreting syndrome, adrenocortical carcinoma or an ACTH-secreting pituitary adenoma (mainly macroadenomas)-is not yet established. Combination therapy may be useful not only to rapidly control cortisol excess but also to lower individual drug dosages and consequently the possibility of adverse effects. If medical treatments fail, bilateral adrenalectomy should be performed in the shortest possible time span to prevent the debilitating complications of uncontrolled hypercortisolaemia.

Inhibition of Human Adrenocortical Cancer Cell Growth by Temozolomide in Vitro and the Role of the MGMT Gene

CONTEXT

Treatment of patients with adrenocortical carcinomas (ACC) with mitotane and/or chemotherapy is often associated with toxicity and poor tumor response. New therapeutic options are urgently needed.

OBJECTIVE

The objectives of the study were to evaluate the therapeutic possibilities of temozolomide (TMZ) in ACC cells and to assess the potential predictive role of the DNA repair gene O6-Methylguanine-DNA methyltransferase (MGMT) in adrenocortical tumors.

METHODS

Three human ACC cell lines and eight primary ACC cultures were used to assess effects of TMZ in vitro. In the cell lines, 11 normal adrenals, 16 adrenocortical adenomas, and 29 ACC, MGMT promoter methylation and expression were determined.

RESULTS

IC₅₀ values of TMZ on cell growth were 39 μM, 38 μM, and 44 μM for H295R, HAC15, and SW13, respectively. TMZ induced apoptosis and provoked cytotoxic and cytostatic effects by reducing the surviving fraction of ACC colonies and the colony size. TMZ thereby induced cell cycle arrests in ACC cell lines. TMZ and mitotane both inhibited growth of ACC cells cultured as three-dimensional spheroids. TMZ inhibited cell amount in five of eight primary ACC cultures and induced apoptosis in seven of eight primary ACC cultures. In ACC cell lines and adrenal tissues, MGMT promoter methylation was low. In ACCs, methylation was inversely correlated with MGMT mRNA expression. MGMT protein expression was not correlated with MGMT methylation.

CONCLUSIONS

For the first time, we show the therapeutic potential of temozolomide for ACC, offering an urgently needed potential alternative for patients not responding to mitotane alone or with etoposide, doxorubicin, and cisplatin. (Pre-)clinical studies are warranted to assess efficacy in vivo.

Drug Synergism of Proteasome Inhibitors and Mitotane by Complementary Activation of ER Stress in Adrenocortical Carcinoma Cells

Mitotane is the only drug approved for treatment of the orphan disease adrenocortical carcinoma (ACC) and was recently shown to be the first clinically used drug acting through endoplasmic reticulum (ER)-stress induced by toxic lipids. Since mitotane has limited clinical activity as monotherapy, we here study the potential of activating ER-stress through alternative pathways. The single reliable NCI-H295 cell culture model for ACC was used to study the impact MG132, bortezomib (BTZ) and carfilzomib (CFZ) on mRNA and protein expression of ER-stress markers, cell viability and steroid hormone secretion. We found all proteasome inhibitors alone to trigger expression of mRNA (spliced X-box protein 1, XBP1) and protein markers indicative of the inositol-requiring enzyme 1 (IRE1) dependent pathway of ER-stress but not phosphorylation of eukaryotic initiation factor 2α (eIF2α), a marker of the PRKR-like endoplasmic reticulum kinase (PERK)-dependent pathway. Whereas mitotane alone activated both pathways, combination of BTZ and CFZ with low-dose mitotane blocked mitotane-induced eIF2α phosphorylation but increased XBP1-mRNA splicing indicating that proteasome inhibitors can commit signalling towards a single ER-stress pathway in ACC cells. By applying the median effect model of drug combinations using cell viability as a read out, we determined significant drug synergism between mitotane and both BTZ and CFZ. In conclusion, combination of mitotane with activators of ER-stress through the unfolded protein response is synergistic in an ACC cell culture model. Since proteasome inhibitors are readily available clinically, they are attractive candidates to study for ACC treatment in clinical trials in combination with mitotane.

The adrenal specific toxicant mitotane directly interacts with lipid membranes and alters membrane properties depending on lipid composition

Mitotane (o,p'.-DDD) is an orphan drug approved for the treatment of adrenocortical carcinoma. The mechanisms, which are responsible for this activity of the drug, are not completely understood. It can be hypothesized that an impact of mitotane is mediated by the interaction with cellular membranes. However, an interaction of mitotane with (lipid) membranes has not yet been investigated in detail. Here, we characterized the interaction of mitotane and its main metabolite o,p'-dichlorodiphenyldichloroacetic acid (o,p'-DDA) with lipid membranes by applying a variety of biophysical approaches of nuclear magnetic resonance, electron spin resonance, and fluorescence spectroscopy. We found that mitotane and o,p'-DDA bind to lipid membranes by inserting into the lipid-water interface of the bilayer. Mitotane but not o,p'-DDA directly causes a disturbance of bilayer structure leading to an increased permeability of the membrane for polar molecules. Mitotane induced alterations of the membrane integrity required the presence of phosphatidylethanolamine and/or cholesterol. Collectively, our data for the first time characterize the impact of mitotane on the lipid membrane structure and dynamics, which may contribute to a better understanding of specific mitotane effects and side effects.