Palbociclib added to anti-HER2 and endocrine therapies in advanced breast cancer. Results from the PATINA study

Data from the PATINA study, recently published in The New England Journal of Medicine, show that adding the CD4/6 inhibitor palbociclib to a standard therapy with anti-HER2 and endocrine agents improves progression-free survival in patients with hormone receptor-positive and HER2-positive metastatic breast cancer. In Italy, the study was coordinated by Fondazione Michelangelo, acting as the cooperative group delegated by the sponsor, which selected and monitored the Italian centers participating in the research project.

The PATINA study, an open-label randomised trial, involved a total of 518 patients with hormone receptor-positive and HER2-positive metastatic breast cancer who did not have disease progression after four to eight cycles of chemotherapy plus HER2-targeted therapy; patients received a maintenance standard therapy with or without palbociclib. After a median follow-up of 53.5 months, progression-free survival was 44.3 months in the group treated with palbociclib and 29.1 months in control group; grade 3 and 4 adverse events (mainly neutropenia) occurred in 79.7% and 10.1% of patients, respectively. As authors conclude, «Palbociclib in combination with anti-HER2 and endocrine therapy is an effective first-line strategy for patients with HR-positive, HER2-positive metastatic breast cancer. The observed benefit probably reflects the biologic convergence of HER2, endocrine receptors and CDK4/6 signaling and hence the effect of their combined inhibition. These findings provide a compelling rationale for concurrent inhibition of HER2, endocrine receptors and the cell cycle through CDK4/6 inhibition to improve disease control and potentially survival outcomes in this setting».