A Multicenter, Open-label, Phase II Study to Evaluate the Efficacy and Safety of Cabozantinib in Advanced (Unresectable or Metastatic) Adrenocortical Carcinoma

Adrenocortical carcinoma is an orphan malignant disease that has a dismal prognosis in advanced stages. Mitotane is the only approved treatment but is limited by severe toxicity. Efficacy of mitotane is unsatisfactory with an objective response rate of ≈20% in monotherapy in selected patients (Megerle et al., JCEM 2018). Cytotoxic chemotherapy with etoposide, doxorubin and cisplatin (EDP) or streptozotocin (Sz) in addition to mitotane (Fassnacht et al., N Engl J Med 2012) succeeded in a progression-free survival of 5.6 months and 2.2 months, respectively in patients with advanced ACC. Objective response rates were 23 and 9%. EDP plus mitotane is therefore considered as standard treatment of ACC. Results by Phan et al. (Cancer Research 2015) demonstrated expression of c-MET and its ligand HGF in ACC and provide a rationale to therapeutically target c-MET in ACC. In a case series of 16 patients with advanced ACC refractory to mitotane (with the exception of one case) and 3 (median, range 0-8)further lines of therapy, single agent treatment with cabozantinib off label resulted in three partial responses and five additional cases of disease stabilization for four months or longer (Kroiss et al., J Clin Endocrinol Metab 2020).