A review of Cushing's disease treatment by the Department of Neuroendocrinology of the Brazilian Society of Endocrinology and Metabolism

Evaluation of ketoconazole as a treatment for Cushing's disease in a retrospective cohort

OBJECTIVE

The first-line treatment for Cushing's disease is transsphenoidal surgery, after which the rates of remission are 60 to 80%, with long-term recurrence of 20 to 30%, even in those with real initial remission. Drug therapies are indicated for patients without initial remission or with surgical contraindications or recurrence, and ketoconazole is one of the main available therapies. The objective of this study was to evaluate the safety profile of and the treatment response to ketoconazole in Cushing's disease patients followed up at the endocrinology outpatient clinic of a Brazilian university hospital.

PATIENTS AND METHODS

This was a retrospective cohort of Cushing's disease patients with active hypercortisolism who used ketoconazole at any stage of follow-up. Patients who were followed up for less than 7 days, who did not adhere to treatment, or who were lost to follow-up were excluded.

RESULTS

Of the 172 Cushing's disease patients who were followed up between 2004 and 2020, 38 received ketoconazole. However, complete data was only available for 33 of these patients. Of these, 26 (78%) underwent transsphenoidal surgery prior to using ketoconazole, five of whom (15%) had also undergone radiotherapy; seven used ketoconazole as a primary treatment. Ketoconazole use ranged from 14 days to 14.5 years. A total of 22 patients had a complete response (66%), three patients had a partial response (9%), and eight patients had no response to treatment (24%), including those who underwent radiotherapy while using ketoconazole. Patients whose hypercortisolism was controlled or partially controlled with ketoconazole had lower baseline 24-h urinary free cortisol levels than the uncontrolled group [times above the upper limit of normal: 0.62 (SD, 0.41) vs. 5.3 (SD, 8.21); p < 0.005, respectively] in addition to more frequent previous transsphenoidal surgery (p < 0.04). The prevalence of uncontrolled patients remained stable over time (approximately 30%) despite ketoconazole dose adjustments or association with other drugs, which had no significant effect. One patient received adjuvant cabergoline from the beginning of the follow-up, and it was prescribed to nine others due to clinical non-response to ketoconazole alone. Ten patients (30%) reported mild adverse effects, such as nausea, vomiting, dizziness, and loss of appetite. Only four patients had serious adverse effects that warranted discontinuation. There were 20 confirmed episodes of hypokalemia among 10/33 patients (30%).

CONCLUSION

Ketoconazole effectively controlled hypercortisolism in 66% of Cushing's disease patients, being a relatively safe drug for those without remission after transsphenoidal surgery or whose symptoms must be controlled until a new definitive therapy is carried out. Hypokalemia is a frequent metabolic effect not yet described in other series, which should be monitored during treatment.

Medical therapy in severe hypercortisolism

Severe hypercortisolism is characterized as a life-threatening endocrine condition in patients with Cushing syndrome, usually related to the concomitant onset of one or more comorbidities, requiring rapid normalization of cortisol concentrations and aggressive treatment of associated complications. It is mainly, but not exclusively, caused by ectopic ACTH syndrome, and the diagnosis of severity is more accurate when is based on simultaneous evaluation of the clinical course and manifestations of the disease, cortisol levels and systematic search of comorbidities. Once the severity and imminent risk to life are established, urgent therapeutic measures must be taken and etiological investigation postponed until the patient is stabilized. Adrenal steroidogenesis inhibitors (mainly etomidate, ketoconazole, and metyrapone), alone or in combined therapy, are commonly the first-line treatment for severe hypercortisolemia due to their rapid action, good efficacy and safety profile. The new drug osilodrostat is a future potential candidate to be included in the list. The glucocorticoid receptor antagonist mifepristone has also a rapid action, but its use has been limited due to difficulties to monitor its efficacy and safety. Other slow-acting cortisol-lowering drugs (mainly mitotane, cabergoline, and pasireotide) might be included in the therapeutic scheme to synergize and overcome a possible escape phenomenon frequently observed with the fast-acting drugs in the prolonged follow-up. When medical therapies fail, are unavailable or contra-indicated, bilateral adrenalectomy should be indicated as a life-saving measure. Adrenal arterial embolization is rarely encountered in routine clinical practice, being a last alternative in specialized centers when all other options fail or are contra-indicated.

Cushing's disease due to somatic USP8 mutations: a systematic review and meta-analysis

PURPOSE

Cushing's disease (CD) is a severe illness generally caused by microcorticotropinomas (MICs) and in approximately 7-20% of patients by macrocorticotropinomas (MACs). USP8-mutations have been identified as a major genetic cause of CD (~ 50%). Few studies have reported the distribution between MICs-MACs related to USP8-mutations and their genotype-phenotype correlations. Therefore, we aimed to evaluate USP8-mutations in a cohort of MICs-MACs from a unique center and to perform a systematic review and meta-analysis.

METHODS

DNA-tumor-tissues from 47 corticotropinomas (16 MICs and 31 MACs) were sequenced. Clinical-biochemical data, radiological imaging data and remission/recurrence rates were evaluated. In addition, we performed a meta-analysis of nine published series (n = 630).

RESULTS

We identified four different USP8-mutations previously described, in 11 out of 47 (23.4%) corticotropinomas; 8 out of 11 were MACs. The urinary cortisol levels of our patients with corticotrophin USP8-mutated-alleles were lower than those of patients with wild-type (WT) alleles (p ≤ 0.017). The frequency of USP8-mutated-alleles among the series was approximately 30% with a higher prevalence in female-patients (p < 0.1 × 10^-4). Among the 5 series, the remission rates were higher in patients with USP8-mutated-alleles than in those with the USP8-WT-alleles (p < 0.1 × 10^-4).

CONCLUSION

Our data, as well as the retrospective review of CD series associated with USP8-mutated alleles, show heterogeneous findings among the series. Several drawbacks included the lack of a systematic protocol to evaluate these patients before surgery and follow-up. Further prospective studies using a systematic protocol will provide more consistent information about the influence of the corticotropinomas with USP8-mutated alleles on the phenotype, responses to treatment and outcome of patients with CD.