The company’s lead product candidate, enobosarm, is also being evaluated in a separate Phase II clinical trial to treat estrogen receptor positive (ER+), AR+ breast cancer.
The open-label, multi-center, multinational Phase II trial is designed to assess the efficacy and safety of orally administered enobosarm in up to 55 women with advanced, AR+ TNBC.
In the trial, patients will receive 18mg of enobosarm once daily for up to 12 months and the initial stage will be evaluated among the first 21 evaluable patients.
According to the company, if at least two of 21 patients achieve clinical benefit at week 16, then the trial will proceed to the second stage of enrollment of up to a total of 41 evaluable patients.
GTx executive chairman Robert Wills said: "Most women with triple negative breast cancer have extremely limited treatment options and poor prognoses.
"Based on our preclinical research and positive data from patient-derived and cell line-derived xenografts of TNBC, we are hopeful that enobosarm, by targeting the androgen receptor, may offer another treatment option to women with this disease."
Being conducted under the leadership of Dr Hope Rugo from the University of California at San Francisco, the trial will include investigators from more than 40 clinical trial sites in the US and abroad.
Recently, enobosarm 9mg has been assessed in a proof of concept Phase II clinical trial of 22 postmenopausal women with ER+ metastatic breast cancer who have previously responded to endocrine therapy.
The trial showed that 17 of the 22 patients were confirmed to be AR+ and six of these 17 patients showed clinical benefit at six months.