significantly improved progression-free survival for patients with hormone receptor positive, HER2 negative advanced breast cancer who had been previously treated with cyclin-dependent kinase 4 and 6 inhibitor plus endocrine therapy, in a new study.
The magnitude of benefit was less in the subgroup of patients with visceral metastases, Dr Kalinsky noted. Dr Regan referenced the improvement with abemaciclib in the BICR, a technique used to identify potential bias introduced by the assessment of local investigators. This can result in more favorable PFS on a treatment arm as seen in this study, but its use generally does not impact overall trial results, she said.
"I would still recommend that we check for mutations," he emphasized. The current study"is one chapter in a much larger book," and the field continues to evolve, he said."Currently, no standard second-line treatment after progression on first line CDK4/6 inhibitor plus endocrine therapy exists," Malinda T. West, MD, of the University of Wisconsin, Madison, said in an interview.