(HealthDay News) — The oral selective androgen receptor modulator enobosarm has antitumor activity and can yield clinical benefit in patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, according to a study published online Feb. 8 in The Lancet Oncology.
Carlo Palmieri, M.B.B.S., Ph.D., from The Clatterbridge Cancer Centre NHS Foundation Trust in Liverpool, England, and colleagues examined the activity and safety of enobosarm in women with ER-positive, HER2-negative, and androgen receptor (AR)-positive disease. Postmenopausal women with previously treated ER-positive, HER2-negative, locally advanced or metastatic breast cancer were enrolled in a randomized trial conducted at 35 centers in nine countries. Participants were randomly allocated to receive 9 mg or 18 mg of oral enobosarm daily (72 and 64 patients, respectively). The evaluable population included 50 and 52 patients, respectively).
Patients were followed for a median of 7.5 months. The researchers found that 32 and 29 percent of the patients in the 9-mg and 18-mg groups, respectively, had clinical benefit at 24 weeks. Overall, 8 and 16 percent of those receiving 9 mg and 18 mg, respectively, had grade 3 or grade 4 drug-related adverse events, most frequently increased hepatic transaminases, hypercalcemia, and fatigue.
“The data from this study provide proof-of-concept for the activity and safety of a novel selective AR modulator, enobosarm, in AR-positive, ER-positive, and HER2-negative metastatic breast cancer, thus supporting the premise that activating AR can exert antitumor effects,” the authors write.
Several authors disclosed ties to pharmaceutical companies, including Veru, which manufactures enobosarm; the study was funded by GTx, which originally developed enobosarm.