Matthew Goetz, MD
FDA approvals of 3 CDK4/6 inhibitors have added important treatment options to the armamentarium for patients with hormone receptor (HR)–positive breast cancer, but the future will focus on defining mechanisms of acquired and de novo resistance to these agents, said Matthew P. Goetz, MD.
Palbociclib (Ibrance) received an accelerated approval from the FDA in 2015 for use in combination with letrozole as a frontline treatment for postmenopausal women with estrogen receptor (ER)-positive, HER2-negative metastatic breast cancer. A full approval was granted by the FDA in March 2017. This CDK4/6 inhibitor is now also indicated for use in combination with fulvestrant or an aromatase inhibitor (AI) in this setting.
Additionally, frontline ribociclib (Kisqali) was approved by the FDA in July 2018 for use in combination with an AI for the treatment of pre-, peri-, or postmenopausal women with HR-positive/HER2-negative advanced or metastatic breast cancer, and for use in combination with fulvestrant for the treatment of postmenopausal women with this subtype of advanced or metastatic breast cancer, in the frontline setting or after disease progression on endocrine therapy. This regulatory decision follows ribociclib’s initial approval in March 2017 for treatment of postmenopausal women with HR-positive, HER2-negative advanced or metastatic breast cancer in combination with an AI as initial endocrine therapy.
Third, the FDA approved abemaciclib (Verzenio) in combination with fulvestrant in September 2017 for patients with HR-positive, HER2-negative advanced breast cancer with disease progression following endocrine therapy. At this time, it was also approved as a single agent for those who previously received endocrine therapy and chemotherapy. In February 2018, this CDK4/6 inhibitor was approved in combination with an AI as initial endocrine-based therapy for postmenopausal women with HR-positive, HER2-negative advanced or metastatic breast disease.