Breast cancer is the second most commonly identified cancer in women in the United States after skin cancer.
The past few years have seen a substantial increase in breast cancer awareness campaigns and active research in fields of
diagnosis and targeted therapy. These factors have led to a better mechanistic understanding of the disease, detection at
earlier stages and more personalized approach to treatment, ultimately causing a crucial increase in the survival rates after
detection. However, with the advances in treatment, cases of patients developing primary resistance and acquired resistance
are increasing. Most of the breast cancers which develop resistance to therapy are ER+ and are typically treated with
tamoxifen and fulvestrant. These drugs either lower the levels of estrogen or inhibit the receptors for estrogen and prevent
the tumor from spreading. Around one third of women treated with these drugs develop resistance to them, lowering their
chances of survival. This has directed to the search of newer drug therapies to target advanced breast cancer and resistance.
One of these efforts has resulted in the development of Palbociclib, a first in class inhibitor of cyclin dependent kinases 4
and 6 (CDK4 and CDK6), which was granted accelerated approval from FDA for combination therapy in postmenopausal
women with ER+, HER2- metastatic breast cancer. This review is focused on the various aspects of “Palbociclib” including
its synthesis, molecular modeling studies and efficacy and safety profile with clinical trials data.