Open-label phase II clinical trial of orteronel (TAK-700) in metastatic or advanced non-resectable granulosa cell ovarian tumors: the Greko II study (GETHI2013-01)

Background: Granulosa cell ovarian tumors (GCTs) are a rare neoplasia characterized by a pathognomonic mutation in the FOXL2 gene. In vitro studies have demonstrated an overactivation of hormone activity due to this alteration. Thus, we aimed to determine the activity of orteronel, a CYP17 inhibitor, in advanced disease.

Methods: We designed a multicentric open-label phase II clinical trial. Eligible patients were adult woman with advanced or unresectable GCTs. Primary objective was clinical benefit rate, defined as the average of patients with radiological response plus stable disease longer than 6 months.

Results: From October 1, 2014 to May 20, 2016, ten patients were included in six participating institutions members of the GETTHI group. The study was terminated early due to a low recruitment rate. Up to 40% (CI 95% [9.6-70.4%]) cases presented a disease stabilization longer than 6 months and two of them, longer than 12 months. One patient continued on treatment at database closure 29 months after inclusion in the trial. No patient reached partial or complete response by RECIST criteria on the independent radiological review. The drug was well tolerated with nausea as the only grade 3 adverse event in one case.

Conclusion: Low accrual led to an early interruption of the study. However, orteronel achieved a promising clinical benefit rate that supports further development of new hormonotherapies in this tumor.

Gov identifier: NCT02101684.