A high-pressure liquid chromatographic method for measuring mitotane [1,1-(o,p'-Dichlorodiphenyl)-2,2-dichloroethane] and its metabolite 1,1-(o,p'-Dichlorodiphenyl)-2,2-dichloroethene in plasma

A simplified method for therapeutic drug monitoring of mitotane by gas chromatography-electron ionization-mass spectrometry

Mitotane is a key drug for the treatment of adrenal cortical carcinoma. Due to its narrow therapeutic window, 14–20 μg/mL, monitoring its concentration is crucially important. In this study, a simplified method for measuring mitotane in plasma using gas chromatography‐electron ionization‐mass spectrometry (GC‐EI‐MS) was developed. Through deproteination and liquid–liquid extraction, mitotane and an internal standard (IS) were extracted from plasma samples. GC‐EI‐MS yielded retention times of 8.2 and 8.7 min, for mitotane and the IS, respectively, with a total run time of 12 min. Selectivity and intra‐/inter‐batch accuracy and precision analyses provided a lower limit of quantification of 0.25 μg/mL, and a calibration curve between 0.25 and 40 μg/mL had good linearity (coefficient of determination = 0.992). The matrix effect factor and percent recovery of the method had good precision. Additionally, long‐term sample stability was observed below 4°C. In a clinical setting, mitotane levels in plasma from an adrenal cortical carcinoma patient were within calibration range. Therefore, this simplified method can be applied to routine therapeutic drug monitoring of mitotane, which may contribute to improved treatment of adrenal cortical carcinoma.

Pediatric adrenocortical tumors: diagnosis, management and advancements in the understanding of the genetic basis and therapeutic implications

Adrenocortical tumors (ACTs) may be sporadic or related to inherited genetic syndromes. Uncovering the molecular defects underlying these genetic syndromes has revealed key signaling pathways involved in adrenocortical tumorigenesis. Although the understanding of ACT biology has improved, to date, very few potential prognostic molecular markers of childhood ACTs have been identified. In this review, we summarize the current knowledge of the epidemiology, clinical presentation, diagnosis, prognosis and treatment options for pediatric patients with ACTs. A review of the genetic basis of adrenocortical tumorigenesis is presented, focusing on the main molecular abnormalities involved in the tumorigenic process and potential novel therapy targets that have been generated, or are being generated, with the discovery of these molecular defects.

Mitotane associated with cisplatin, etoposide, and doxorubicin in advanced childhood adrenocortical carcinoma: mitotane monitoring and tumor regression

PURPOSE

To define a mitotane dose for pediatric patients with adrenocortical cancer (ACC) that maintains therapeutic plasma levels (TL) between 14 and 20 microg/mL and to verify its antitumor efficacy in association with 8 cycles of cisplatin, etoposide, and doxorubicin (CED).

METHODS

Powdered mitotane was dissolved in a medium chain triglyceride oil and administered to 11 children with ACC (2.4 to 15.4 y of age); an initial low dose was increased to 4 g/m2/d. Ten of the 11 children had a germline TP53 R337H mutation. Mitotane plasma levels were determined using high-performance liquid chromatography.

RESULTS

The mitotane dose to maintain TL in 7 patients ranged from 1.0 to 5.3 g/m2/d. Six children reached mitotane levels of 10 microg/mL in 3.6 months (1.5 to 5.0 mo), whereas 5 children took 8 months (6.5 to 12.5 mo). Minor to partial tumor remission was found in 5 patients (<1 y) and complete remission was found in 2 patients. Of the 3 patients who are alive at the time of report, 1 patient has been without disease for 16 months, and 2 patients have progressive disease. All patients had recurrent metastatic disease (2 to 9 times). Mitotane toxic effects were nausea, diarrhea, vomiting, neurologic alterations, gynecomastia, a rare case of hypertensive encephalopathy, and CED-related hematologic toxic effects.

CONCLUSIONS

Mitotane daily dose to maintain TL is variable and monitoring should start 1.5 months after the beginning of treatment. CED combined with mitotane is the best available pharmacologic treatment for ACC, but further studies are required to characterize different profiles of therapeutic response.

Tratamento do tumor do córtex adrenal na infância

O tumor do córtex adrenal (TCA) na infância é raro. Entretanto, no Paraná sua incidência é 15 vezes maior do que a observada em outros países. A mutação germinativa R337H TP53, presente em mais de 95% dos nossos pacientes, provavelmente está relacionada à maior incidência. Cento e vinte e cinco pacientes foram tratados no período de 1966 a 2003. A cirurgia é o único tratamento curativo. Em nossa experiência, tumores no estádio I, ausência de spillage durante a cirurgia e ausência de trombo são parâmetros relacionados à maior sobrevida. Dados preliminares mostram que a associação de etoposídeo, doxorrubicina, cisplatina e mitotano produziu remissão completa do tumor e/ou das metástases em alguns pacientes. Os efeitos colaterais destas drogas são comuns e pode ocorrer insuficiência adrenocortical. As doses de reposição de glicocorticóides e mineralocorticóides devem ser 2 a 3 vezes maiores que as doses fisiológicas.

Tumores do córtex adrenal na infância

O tumor do córtex adrenal (TCA) na infância é raro. Entretanto, no Paraná sua incidência é 15 vezes maior do que a observada em outros países. Descrevemos as características clínicas, laboratoriais, tratamento e evolução de 125 pacientes atendidos em uma única instituição no Paraná. A média de idade ao diagnóstico foi de 4,3 anos, com uma relação feminino:masculino de 2,6:1. As formas clínicas mais comuns foram virilização isolada (51,2%) e virilização e síndrome de Cushing (42%). Em 4,8% dos casos, os tumores foram não-funcionantes. Dois pacientes (1,6%) apresentaram síndrome de Cushing isolado e 1 (0,8%) síndrome de Conn. Hipertensão arterial ocorreu em 56% dos pacientes. O único tratamento curativo é a cirurgia. Os dados da nossa casuística mostram que estádio clínico 1 do TCA, ausência de trombo intra-venoso e ausência de spillage durante a cirurgia estão associados a uma maior sobrevida.

Determination of mitotane (o,p-DDD) and its metabolites o,p-DDA and o,p-DDE in plasma by high-performance liquid chromatography

The adrenolytic agent mitotane (o,p'-DDD or 1,1-(o,p'-dichlorodiphenyl)-2,2-dichoroethane) is believed to be metabolically activated, resulting in the generation of reactive intermediates or the formation of o,p'-DDA. A new high-performance liquid chromatographic (HPLC) method for measurement of mitotane and two of its metabolites, o,p'-DDA (1,1-(o,p'-dichlorodiphenyl) acetic acid) and o,p'-DDE (1,1-(o,p'-dichlorodiphenyl)-2,2 dichloroethene), in plasma has been developed. Sample preparation involves precipitation of plasma proteins with acetone before chromatographic separation under isocratic conditions on a silica-based diphenyl column. Mitotane and metabolites are quantified by ultraviolet detection at 218 nm. Recoveries for the three compounds range between 99% and 110%, with between-day and within-day coefficients of variation <6% within the therapeutic range. Limits of detection are 0.5 microM and the assay is linear up to at least 800 microM for o,p'-DDA and 100 microM for mitotane and o,p'-DDE. The method has been evaluated using samples from three patients on mitotane therapy, revealing o,p'-DDA levels in plasma 3 to 10 times higher than the levels of the parent compound.