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

(1) Background: In clinical settings, data regarding sex are rarely investigated. In women, factors such as body size and composition, hormonal variations, metabolism, and access to care systems and therapy could strongly influence the pharmacological management and the outcome of the therapy. To underline this sex-related difference, we retrospectively collected data from adrenocortical carcinoma patients treated with mitotane, and then evaluated sex-related pharmacokinetics parameters. (2) Methods: A fully validated chromatographic method was used to quantify mitotane concentration in plasma collected from adult patients, also considering the active metabolite ortho,para,dichlorodiphenylethene (o,p′-DDE). Statistical analyses were used to evaluate the sex influence on drugs pharmacokinetics. (3) Results: We found that sex resulted as predictive factor of plasma mitotane and o,p′-DDE concentrations and significantly influenced the attainment of the therapeutic target of mitotane, implying that female sex could be a risk factor of treatment failure. (4) Conclusions: These results suggest that mitotane therapy should be modulated according to patient sex. Furthermore, the proposed approach could contribute to facilitating and disseminating sex-specific pharmacology.