Although aromatase inhibitors can be effective against breast cancer, many patients discontinue the therapy because of side effects. A study presented at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting tested 3 dosing schedules of the aromatase inhibitor exemestane to determine whether less frequent dosing could be as effective as the current standard of daily dosing.
The multicenter, double-blind, phase IIb study randomized 173 eligible, evaluable patients who were awaiting surgery for estrogen receptor (ER)–positive breast cancer. Each patient received one of 3 exemestane dosing schedules for 4 to 6 weeks before surgery: 25 mg per day (QD) (n = 56), 25 mg three times a week (TIW) (n = 57), or 25 mg once a week (QW) (n = 60).
The researchers collected blood and tissue biomarkers at baseline and the patient’s final visit. They found that the median percentage change in estradiol level was the same between the QD and TIQ arms, but it was lower in the QW arm. In addition, the QD and TIW groups had similar levels of estrone, total estrone, and estrone sulfate. Ki-67 and progesterone receptors were reduced in all arms, slightly more so in the QD group. Sex hormone-binding globulin and high-density lipoprotein cholesterol were more favorable in the TIW group.
All groups had similar adverse events and menopausal symptoms, but the authors cautioned that this similarity should be viewed with caution because of the short duration of treatment.
The authors said the comparable activity between QD and TIW dosing can help guide further research and provide a treatment option in certain patients. “This new schedule should be further assessed in prevention studies and in women on adjuvant treatment who do not tolerate the daily dose,” wrote the authors, led by Andrea De Censi, of EO Ospedali Galliera in Genoa, Italy.