Formal discussant of the LY2835219 trial reported at the American Association for Cancer Research Annual Meeting, Gary Schwartz, MD, of Columbia University School of Medicine, New York, said the drug had “dramatic effects” in estrogen receptor–positive patients.

“This drug is highly active in luminal estrogen receptor–positive breast cancer. If we could identify a predictive biomarker [other than estrogen receptor positivity], that would facilitate drug development. These [cyclin-dependent kinase–4/6 inhibitors] are new breakthrough drugs. It is an exciting time in oncology,” Dr. Schwartz said. ■

Disclosure: Dr. Schwartz reported no potential conflicts of interest.