Feasibility and Activity of Megestrol Acetate in Addition to Etoposide, Doxorubicin, Cisplatin, and Mitotane as First-Line Therapy in Patients with Metastatic/Unresectable Adrenocortical Carcinoma with Low Performance Status

(1) Background: The standard first-line therapy for advanced adrenocortical carcinoma (ACC) is represented by EDP-M (etoposide, doxorubicin, cisplatin + mitotane). Progestins have shown cytotoxic activity both in vitro and in vivo on ACC; better EDP-M tolerability and efficacy have been hypnotized due to the association with progestins. (2) Methods: The feasibility and tolerability of EDP-M combined with oral megestrol acetate (EDP-MM) were tested in 24 patients (pts) affected by metastatic ACC with a low performance status (PS); the case group was compared with a 48 pts control group according to the propensity score. The secondary objectives were clinical benefit rate (CBR), progression-free survival (PFS), and overall survival (OS). (3) Results: Thirteen pts (54.2%) in the EDP-MM population experienced progestin-related toxicities; in particular, five pts experienced vaginal bleeding (20.8%); four pts experienced weight gain (16.7%); and thromboembolic events, worsening of hypertension, skin rashes, and hyperglycemia were registered in one patient each (4.2%). This led to the discontinuation of megestrol acetate in four pts (16.7%). EDP-M-related toxicities were similar in both groups. No differences in PFS and OS curves were observed; the CBR was 75.0% and 60.4%, respectively. (4) Conclusions: The association of EDP-M + megestrol acetate in ACC pts with a low PS is feasible and well tolerated; its efficacy appeared to be non-inferior to EDP-M administered to pts with a good PS.

Bridging the Scientific Gaps to Identify Effective Treatments in Adrenocortical Cancer

Adrenocortical cancer (ACC) typically presents in advanced stages of disease and has a dismal prognosis. One of the foremost reasons for this is the lack of available systemic therapies, with mitotane remaining the backbone of treatment since its discovery in the 1960s, despite underwhelming efficacy. Surgery remains the only potentially curative option, but about half of patients will recur post-operatively, often with metastatic disease. Other local treatment options have been attempted but are only used practically on a case-by-case basis. Over the past few decades there have been significant advances in understanding the molecular background of ACC, but this has not yet translated to better treatment options. Attempts at novel treatment strategies have not provided significant clinical benefit. This paper reviews our current treatment options and molecular understanding of ACC and the reasons why a successful treatment has remained elusive. Additionally, we discuss the knowledge gaps that need to be overcome to bring us closer to successful treatment and ways to bridge them.

Advances in adrenocortical carcinoma pharmacotherapy: what is the current state of the art?

INTRODUCTION

Surgery, followed or not by adjuvant mitotane, is the current mainstay of therapy for patients with early-stage adrenocortical carcinoma (ACC). Mitotane, either alone or in association with EDP (Etoposide-Doxorubicin-Cisplatin) combination chemotherapy, is the standard approach for patients with metastatic ACC.

AREAS COVERED

The activity of newer cytotoxic drugs, radioligands, targeted therapies and immunotherapy, both in preclinical and in clinical studies, will be reviewed in this paper.

EXPERT OPINION

ADIUVO trial revealed that the administration of adjuvant mitotane is not advantageous in patients with good prognosis. Future strategies are to intensify efforts in adjuvant setting in patients with high risk of relapse. In patients with advanced/metastatic disease, modern targeted therapies have shown significant cytotoxicity in preclinical studies, however, studies in ACC patients reported disappointing results so far. The absence of targeted agents specifically inhibiting the major molecular pathways of ACC growth is the main cause of the failure of these drugs. Since ACC is often antigenic but poorly immunogenic, the results of immunotherapy trials appeared inferior to those achieved in the management of patients with other malignancies. Radioligand therapy may also be a promising approach. Combination of chemotherapy plus immunotherapy could be interesting to be tested in the future.

Targeted Therapy for Adrenocortical Carcinoma: A Genomic-Based Search for Available and Emerging Options

In rare diseases such as adrenocortical carcinoma (ACC), in silico analysis can help select promising therapy options. We screened all drugs approved by the FDA and those in current clinical studies to identify drugs that target genomic alterations, also known to be present in patients with ACC. We identified FDA-approved drugs in the My Cancer Genome and National Cancer Institute databases and identified genetic alterations that could predict drug response. In total, 155 FDA-approved drugs and 905 drugs in clinical trials were identified and linked to 375 genes of 89 TCGA patients. The most frequent potentially targetable genetic alterations included TP53 (20%), BRD9 (13%), TERT (13%), CTNNB1 (13%), CDK4 (7%), FLT4 (7%), and MDM2 (7%). We identified TP53-modulating drugs to be possibly effective in 20-26% of patients, followed by the Wnt signaling pathway inhibitors (15%), Telomelysin and INO5401 (13%), FHD-609 (13%), etc. According to our data, 67% of ACC patients exhibited genomic alterations that might be targeted by FDA-approved drugs or drugs being tested in current clinical trials. Although there are not many current therapy options directly targeting reported ACC alterations, this study identifies emerging options that could be tested in clinical trials.

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.

Emerging drugs for the treatment of adrenocortical carcinoma

Introduction: Adrenocortical cancer (ACC) is a rare and aggressive disease with a median survival of 14-17 months and 5-year survival of around 20% for advanced disease. Emerging evidence of sub-groups of ACC with specific molecular drivers indicate ACC may be amenable to inhibition of receptor tyrosine kinases involved in growth and angiogenic signaling. A significant subset of patients may also be responsive to immune strategies.Areas covered: This review outlines approaches of targeting upregulated growth pathways including Insulin-like Growth Factor, Vascular Endothelial Growth Factor, Fibroblast Growth Factor and Epidermal Growth Factor Receptor in ACC. Data of immune checkpoint blockade with nivolumab, ipilimumab, pembrolizumab and avelumab is explored in detail. Genomic studies indicate that up to 40% of ACC are driven by dysregulated WNT and glucocorticoid signaling, special focus is placed on emerging drugs in these pathways.Expert opinion: Progress in the treatment of ACC has faced challenges stemming from the rarity of the disease. Given recent advances in the understanding of the molecular pathogenesis of ACC, a window of opportunity has now opened to make significant progress in developing therapeutic options that target key pathways such as excessive glucocorticoid signaling, WNT signaling, cell cycle and immune checkpoints.

Adrenocortical Carcinoma in Eight Children: A Report and Literature Review

Objective

This study aimed to summarize the clinical characteristics, comprehensive treatment, and prognosis of adrenocortical carcinoma (ACC) in children.

Methods

The clinical data of eight children with definite diagnoses of ACC were retrospectively analyzed, and statistical methods were used to analyze the clinical characteristics, comprehensive treatment mode, and prognosis of these patients.

Results

(1) Clinical characteristics: two were males and six were females with the median age of onset was six-years old were involved. Four patients had a rash and precocious puberty as the symptoms of onset. European Network for the Study of Adrenal Tumors (ENSAT) staging: stage II, two patients; stage IV, six patients. (2) Comprehensive treatment: all eight patients underwent surgical treatment and received six cycles of chemotherapy: the regimen was “etoposide + pirarubicin + cisplatin + mitotane.” (3) Prognosis analysis: among these eight patients, two patients died, two patients achieved complete remission, the disease was stable in four patients, and the overall five-year survival rate was 75%. Prognosis analyzed according to ENSAT staging (stage II versus stage IV) revealed that two-year survival rates of the two groups were 100% versus 65%, respectively, without statistical significant (χ² = 1.066, P = 0.302). Prognosis analyzed according to Weiss score (Weiss score was <6, five patients;≥6, three patients) revealed That survival time of the two groups was 50±9.52 months versus 6±1.70 months, the two-year survival rates of the two groups were 100% versus 35%, and the difference in survival rates between these two groups was statistically significant (χ² = 4.091, P = 0.043).

Conclusion

The Weiss score is an important prognostic factor for ACC. The chemotherapy regimen “mitotane + etoposide + adriamycin + cisplatin” is recommended.

Management of adrenocortical carcinoma in Western Australia: a perspective over 14 years

BACKGROUND

Adrenocortical carcinoma is a rare but aggressive form of endocrine neoplasm that confers a poor prognosis. To date, the only Australian data published is from New South Wales. This paper describes our experience in Western Australia with a focus on surgical approach and outcomes.

METHODS

A retrospective study of patients treated for adrenocortical carcinoma in Western Australia over 14 years was performed.

RESULTS

Over the 14-year period, a total of 33 patients underwent surgery for adrenocortical carcinoma. Resection outcomes were superior in an open en bloc approach with an 85% R0 margin (P = 0.007). Local recurrence rates were lowest in an open en bloc approach (11%) compared to laparoscopic (75%). Multivariate analysis showed that an en bloc resection is highly correlated with an R0 resection (P < 0.05) and significantly associated with lower (odds ratio = 0.06) local recurrence (P = 0.009). Higher volume surgeons (>5 cases) had lower operative times and blood loss. Compliance with mitotane was significantly improved with close monitoring of levels. The European Network for the Study of Adrenal Tumours (ENSAT) stage at presentation was most predictive of long-term survival with 100% of stage I patients alive compared to 53% of stage II, 25% of stage III and 17% of stage IV patients at the end of the follow-up period.

CONCLUSION

An open en bloc approach with a low threshold for multi-visceral resection performed by high volume surgeons have improved outcomes in local recurrence, operative times and blood loss.

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.

microRNA-431 as a Chemosensitizer and Potentiator of Drug Activity in Adrenocortical Carcinoma

BACKGROUND

Adrenocortical carcinoma (ACC) is a rare endocrine cancer with treatments limited in efficacy for metastatic disease. New molecular targeted therapies have yet to improve patient outcomes. In contrast, established treatment regimens of adrenolytics and chemotherapy have demonstrated treatment benefit, although admittedly in a minority of patients. Identification of microRNAs (miRNAs) in patients responsive to adjuvant therapy may offer a means to sensitize patients with progressive disease to existing adjuvant regimens.

MATERIALS AND METHODS

Samples from primary ACC tumors of 10 Stage IV patients were examined for differentially expressed miRNAs between a "sensitive" and "resistant" cohort. Candidate microRNAs were restored via transfection in two functional ACC cell lines. Gain of function and effects on apoptosis and cell cycle were assessed.

RESULTS

microRNA-431 (miR-431) was underexpressed in patients with ACC with progressive disease undergoing adjuvant therapy. Restoration of miR-431 in vitro decreased the half maximal inhibitory concentrations of doxorubicin and mitotane, with markedly increased apoptosis. We found that a reversal of epithelial-mesenchymal transition underlies the action of miR-431 with doxorubicin treatment, with Zinc Finger E-Box Binding Homeobox 1 implicated as the molecular target of miR-431 in ACC.

CONCLUSION

This is the first report of the potential of miRNA therapy to sensitize ACC to current established adjuvant therapy regimens, which may mitigate the resistance underlying treatment failure in patients with advanced ACC. Effective and well-studied methods of targeted miRNA delivery in existence hints at the imminent translatability of these findings.

IMPLICATIONS FOR PRACTICE

Adrenocortical carcinoma (ACC) is a rare endocrine cancer with outcomes not improving despite extensive research and new targeted therapies. Mitotane and etoposide/doxorubicin/cisplatin chemotherapy is trial validated for improved recurrence-free survival. However, a minority of patients experience sustained benefit. Significant side effects exist for this regimen, with patients often unable to attain target drug doses shown to give survival benefit. This preclinical study examines the role of microRNAs in sensitizing ACC to doxorubicin or mitotane. This study offers an important bridge between new and existing cancer treatments, offering an imminently translatable approach to the treatment of adrenocortical carcinoma.

Efficacy of oral metformin in a patient with metastatic adrenocortical carcinoma: Examination of mechanisms and therapeutic implications

Although rare, adrenocortical carcinoma is among the most common tumors found in children with Li-Fraumeni syndrome and Li-Fraumeni-like syndrome, associated with germ-line mutations in the TP53 gene. In southern Brazil, one form of Li-Fraumeni syndrome, associated with childhood adrenocortical carcinoma, is caused by a mutation in the R337H TP53 tetramerisation domain and is attributed to a familial founder effect. Adrenocortical carcinoma is considered an aggressive neoplasm, usually of poor prognosis and is generally unresponsive to systemic chemotherapy. Optimal treatment regimens remain to be established. We report the case of a young woman with metastatic adrenocortical carcinoma, who achieved stable disease with mitotane, cisplatin, doxorubicin, and etoposide as first-line therapy, but then had an objective response to oral metformin that lasted 9 months. The presence of the R337H TP53 mutation suggests a mechanism for the observed response to metformin.

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.

Systemic Therapy in Locally Advanced or Metastatic Adrenal Cancers: A Critical Appraisal and Clinical Trial Update

Mitotane and chemotherapy with etoposide, doxorubicin, and cisplatin plus mitotane (EDP-M) are the only therapies with demonstrated efficacy in advanced adrenocortical carcinoma. Prognostic and predictive factors are needed to identify patients who could obtain the best benefit from these treatments. Despite the strong rationale for their use, clinical trials on molecular targeted therapies have failed to demonstrate that these drugs are efficacious in the management of this extremely rare disease.

Adrenocortical carcinoma

Recent developments in the treatment of adrenocortical carcinoma (ACC) include diagnostic and prognostic risk stratification algorithms, increasing evidence of the impact of historical therapies on overall survival, and emerging targets from integrated epigenomic and genomic analyses. Advances include proper clinical and molecular characterization of all patients with ACC, standardization of proliferative index analyses, referral of these patients to large cancer referral centers at the time of first surgery, and development of new trials in patients with well-characterized ACC. Networking and progress in the molecular characterization of ACC constitute the basis for significant future therapeutic breakthroughs.

Emerging therapy for adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a very rare and aggressive tumor with dismal outcomes. Best current treatments include complete surgical resection for localized resectable disease and systemic therapy with mitotane alone or in combination for advanced ACC. Advances in molecular genetic profiling of ACC have created multiple new targets for potential treatment options in ACC. This article reviews the current treatment options available for ACC and discusses the potential new targets identified through molecular profiling.

Management of adrenal cancer: a 2013 update

Adrenocortical carcinoma (ACC) is a devastating tumor for either patients or their families because of short life expectancy and severe impact on quality of life. Due to the rarity of ACC, with a reported annual incidence of 0.5-2 cases per million population, progress in the development of treatment options beyond surgery has been limited. Up to now, no personalized approach of ACC therapy has emerged, apart from plasma level-guided mitotane therapy, and no simple targetable molecular event has been identified from preclinical studies. Complete surgical removal of ACC is the only potentially curative approach and has the most important impact on patient’s prognosis. Despite the limits of the available evidence, adjuvant mitotane therapy is currently recommended in many expert centers whenever the patients present an elevated risk of recurrence. The management of patients with recurrent and metastatic disease is challenging and the prognosis is often poor. Mitotane monotherapy is indicated in the management of patients with a low tumor burden and/or more indolent disease while patients whose disease show an aggressive behavior need cytotoxic chemotherapy. The treatment of patients with advanced ACC may include loco-regional approaches such as surgery and radiofrequency ablation in addition to systemic therapies. The present review provides an updated overview of the management of ACC patients following surgery and of the management of ACC patients with advanced disease.

Molecular markers and targeted therapies for adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a lethal disease with poor prognosis and lack of effective therapeutic options. Systemic treatment is often employed to treat patients with advanced ACC, but outcomes are disappointing. During the last decade, some of the causative genetic mutations in sporadic ACCs have been identified. Molecular analysis has had a significant impact on the understanding of the pathogenetic mechanism of ACC development and the evaluation of prognostic and predictive markers. Preclinical investigations and clinical trials of tyrosine kinase inhibitors and anti-angiogenic compounds have been initiated to seek target therapy of ACCs. This review summarizes the current view of molecular alterations involved in the pathophysiology of adrenocortical carcinogenesis. The rationale for testing targeted therapies of ACC is also presented.

Update in adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is an orphan malignancy that has attracted increasing attention during the last decade. Here we provide an update on advances in the field since our last review published in this journal in 2006. The Wnt/β-catenin pathway and IGF-2 signaling have been confirmed as frequently altered signaling pathways in ACC, but recent data suggest that they are probably not sufficient for malignant transformation. Thus, major players in the pathogenesis are still unknown. For diagnostic workup, comprehensive hormonal assessment and detailed imaging are required because in most ACCs, evidence for autonomous steroid secretion can be found and computed tomography or magnetic resonance imaging (if necessary, combined with functional imaging) can differentiate benign from malignant adrenocortical tumors. Surgery is potentially curative in localized tumors. Thus, we recommend a complete resection including lymphadenectomy by an expert surgeon. The pathology report should demonstrate the adrenocortical origin of the lesion (eg, by steroidogenic factor 1 staining) and provide Weiss score, resection status, and quantitation of the proliferation marker Ki67 to guide further treatment. Even after complete surgery, recurrence is frequent and adjuvant mitotane treatment improves outcome, but uncertainty exists as to whether all patients benefit from this therapy. In advanced ACC, mitotane is still the standard of care. Based on the FIRM-ACT trial, mitotane plus etoposide, doxorubicin, and cisplatin is now the established first-line cytotoxic therapy. However, most patients will experience progress and require salvage therapies. Thus, new treatment concepts are urgently needed. The ongoing international efforts including comprehensive "-omic approaches" and next-generation sequencing will improve our understanding of the pathogenesis and hopefully lead to better therapies.

Insulin growth factor receptor (IGF-1R) antibody cixutumumab combined with the mTOR inhibitor temsirolimus in patients with metastatic adrenocortical carcinoma

Background:

Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine malignancy without an available effective systemic chemotherapy. Insulin growth factor 2 (IGF-2) overexpression leading to the activation of the IGF-1 receptor (IGF-1R)/mammalian target of rapamycin (mTOR) pathway is well described in ACC. Cixutumumab, a fully human IgG1 monoclonal antibody directed at IGF-1R was combined with temsirolimus on the basis of preclinical data.

Methods:

Patients received cixutumumab, 3–6 mg kg⁻¹ intravenously (IV) weekly, and temsirolimus, 25–37.5 mg IV weekly (4-week cycles), with restaging after 8 weeks.

Results:

Twenty-six patients were enrolled (13 (50%) men); median age, 47 years; median number of prior therapies, 4. Five patients previously received an IGF-1R inhibitor and one, temsirolimus. The most frequent toxicities, at least possibly drug related, were grade 1–2 thrombocytopenia (38%), mucositis (58%), hypercholesterolaemia (31%), hypertriglyceridemia (35%), and hyperglycaemia (31%). In all, 11 of 26 patients (42%) achieved stable disease (SD) >6 months (duration range=6–21 months) with 3 of the 11 having received a prior IGF-1R inhibitor.

Conclusion:

Cixutumumab combined with temsirolimus was well tolerated and >40% of patients achieved prolonged SD.

The next generation of therapies for adrenocortical cancers

Adrenocortical carcinoma (ACC) is a rare cancer for which few treatment options have been available. Currently, the best available treatment involves combination chemotherapy with the adrenolytic drug mitotane, although the response rate remains modest. Over the past 10 years there has been renewed interest in the field owing to the recognition that targeted therapies may provide new avenues for effective treatment of this deadly disease. Molecular analyses have revealed specific signaling alterations in ACC, and advances in drug development have generated the tools to block these pathways. Although convincing evidence for the effectiveness of targeted therapies is not currently available, these studies are in progress and should shift the prognosis of this disease in the years to come.

Targeted therapies for adrenocortical carcinoma: IGF and beyond

Standard chemotherapy for adrenocortical cancer currently is under evaluation in the context of the recently completed FIRM-ACT evaluating the combination of mitotane with either streptozocin or etoposide, cisplatin, and doxorubicin. New agents are eagerly sought by the ACC community that hopes to make progress against this deadly disease. Investigators have begun to dissect the molecular and genomic context of ACC with a goal of identifying potential novel therapeutic agents. One gene consistently overexpressed in ACC is insulin growth factor type 2. Targeting its receptor IGF1R has shown encouraging results in ACC cell lines and against murine xenografts. As a result, clinical trials to evaluate agents targeting the IGF1R have been done including mitotane and IMC-A12 (a monoclonal antibody) and the GALACCTIC trial that has just completed accrual to evaluate OSI-906, a small molecule IGF1R antagonist. On the horizon are other agents targeting other tyrosine kinases, including EGF and FGF, and novel strategies such as individualized tumor analysis to select treatment.

[131I]iodometomidate for targeted radionuclide therapy of advanced adrenocortical carcinoma

CONTEXT

In advanced adrenocortical carcinoma (ACC), many patients have progressive disease despite standard treatment, indicating a need for new treatment options. We have shown high and specific retention of [123I]metomidate ([123I]IMTO) in ACC lesions, suggesting that labeling of metomidate with 131I offers targeted radionuclide therapy for advanced ACC.

OBJECTIVE

Safety and efficacy of radionuclide therapy with [131I]IMTO in advanced ACC.

DESIGN/SETTING

This monocentric case series comprised 19 treatments in 11 patients with nonresectable ACC.

PATIENTS AND INTERVENTION

Between 2007 and 2010, patients with advanced ACC not amenable to radical surgery and exhibiting high uptake of [123I]IMTO in their tumor lesions were offered treatment with [131I]IMTO (1.6-20 GBq in one to three cycles of [131I]IMTO).

MAIN OUTCOME MEASURE

Tumor response was assessed according to response evaluation criteria in solid tumors (RECIST version 1.1) criteria, and side effects were assessed by Common Toxicity Criteria (version 4.0).

RESULTS

Best response was classified as partial response in one case with a change in target lesions of -51% from baseline, as stable disease in five patients, and as progressive disease in four patients. One patient died 11 d after treatment with [131I]IMTO unrelated to radionuclide therapy. In patients responding to treatment, median progression-free survival was 14 months (range, 5-33) with ongoing disease stabilization in three patients at last follow-up. Treatment was well tolerated, but transient bone marrow depression was observed. Adrenal insufficiency developed in two patients.

CONCLUSIONS

Radionuclide therapy with [131I]IMTO is a promising treatment option for selected patients with ACC, deserving evaluation in prospective clinical trials.

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

Mitotane [1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2-dichloroethane, (o,p'-DDD)] is the only drug approved for the treatment for adrenocortical carcinoma (ACC) and has also been used for various forms of glucocorticoid excess. Through still largely unknown mechanisms, mitotane inhibits adrenal steroid synthesis and adrenocortical cell proliferation. Mitotane increases hepatic metabolism of cortisol, and an increased replacement dose of glucocorticoids is standard of care during mitotane treatment. Recently, sunitinib, a multityrosine kinase inhibitor (TKI), has been found to be rapidly metabolized by CYP3A4 during mitotane treatment, indicating clinically relevant drug interactions with mitotane. We here summarize the current evidence concerning mitotane-induced changes in hepatic monooxygenase expression, list drugs potentially affected by mitotane-related CYP3A4 induction and suggest alternatives. For example, using standard doses of macrolide antibiotics is unlikely to reach sufficient plasma levels, making fluoroquinolones in many cases a superior choice. Similarly, statins such as simvastatin are metabolized by CYP3A4, whereas others like pravastatin are not. Importantly, in the past, several clinical trials using cytotoxic drugs but also targeted therapies in ACC yielded disappointing results. This lack of antineoplastic activity may be explained in part by insufficient drug exposure owing to enhanced drug metabolism induced by mitotane. Thus, induction of CYP3A4 by mitotane needs to be considered in the design of future clinical trials in ACC.

Current and emerging therapies for advanced adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare but aggressive malignancy with a poor prognosis. Complete surgical resection offers the only potential for cure; however, even after apparently successful excision, local or metastatic recurrence is frequent. Treatment options for advanced ACC are severely limited. Mitotane is the only recognized adrenolytic therapy available; however, response rates are modest and unpredictable whereas systemic toxicities are significant. Reported responses to conventional cytotoxic chemotherapy have also been disappointing, and the rarity of ACC had hampered the ability to undertake randomized clinical studies until the establishment of the First International Randomized Trial in Locally Advanced and Metastatic Adrenocortical Carcinoma. This yet-to-be reported study seeks to identify the most effective first- and second-line cytotoxic regimens. The past decade has also seen increasing research into the molecular pathogenesis of ACCs, with particular interest in the insulin-like growth factor signaling pathway. The widespread development of small molecule tyrosine kinase inhibitors in broader oncological practice is now allowing for the rational selection of targeted therapies to study in ACC. In this review, we discuss the currently available therapeutic options for patients with advanced ACC and detail the molecular rationale behind, and clinical evidence for, novel and emerging therapies.

Clinical management of adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare and heterogeneous malignancy, and most of the diagnostic and therapeutic strategies are not fully established according to criteria of evidence-based medicine. However, recently collaborative efforts (e.g. International Consensus Conference 2003 and networks like the European Network for the Study of Adrenal Tumours (ENSAT)) have significantly advanced the field. This article summarizes current standards in the management of ACC. In patients with suspected ACC a thorough endocrine and imaging work-up is followed by complete (Ro) resection of the tumour by an expert surgeon and initiation of adjuvant mitotane. In advanced disease not amenable to radical resection, cytotoxic drugs will be added to mitotane. The most promising regimens (etoposide, doxorubicin, cisplatin plus mitotane and streptozotocin plus mitotane) are currently compared in an international phase-III trial. Several targeted therapies are under investigation (e.g. IGF-1 inhibitors, sunitinib, sorafenib) and may lead to new treatment options.