According to a new study published online today in the journal The Lancet Oncology, researchers from Jonsson Comprehensive Cancer Center in Los Angeles, California, have found that palbociclib doubled progression-free survival in women with advanced breast cancer compared with those who did not receive the drug.
For the phase 2 study, researchers enrolled 165 post-menopausal women with advanced estrogen receptor-positive, human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Patients received letrozole with or without palbociclib.
Results showed that progression-free survival was 20.2 months in the letrozole plus palbociclib arm versus 10.2 months in the letrozole only arm, corresponding with a 51% decreased risk of disease progression with palbociclib.
Furthermore, over 80% of those with metastatic estrogen receptor-positive disease experienced some benefit from the addition of palbociclib. In regard to safety, palbociclib caused leukopenia, but only to a manageable extent. Palbociclib prevents cancer cell proliferation by targeting CDK4/6 proteins, which are responsible for cell growth.
Palbociclib was granted Breakthrough Therapy Designation in 2013 by the U.S. Food and Drug Administration (FDA), and researchers are currently conducting an international phase 3 study in conjunction with Pfizer of palbociclib in 660 estrogen receptor-positive, HER2-negative advanced breast cancer.
In a groundbreaking study that offers new hope for women with advanced breast cancer, researchers from UCLA’s Jonsson Comprehensive Cancer Center have published final clinical trial results that showed the amount of time patients were on treatment without their cancer worsening (called progression-free survival) was effectively doubled in women with advanced breast cancer who took the experimental drug palbociclib.