Breast cancer is the most common cancer among women worldwide. According to JAMA there has been a small increase in the incidence of advanced stage breast cancer among women 25 to 39 years old. Survival rates for patients with advanced or metastatic breast cancer remain low even though there are numerous treatment options.
According to Pfizer:
"Palbociclib is an investigational, oral and selective inhibitor of cyclin dependent kinases (CDK) 4 and 6. CDK 4 and 6 are two closely related kinases that enable tumor cell progression during phase G1 to phase S in the cell cycle. This progression is necessary for DNA replication and cell division."The company said:
"We appreciate the opportunity that Breakthrough Therapy designation provides to work closely with the FDA on the development of palbociclib."
"Breakthrough Therapy" designation was developed to speed up the review and development of potential new medicines for life-threatening conditions.
According to the FDA 012 FDA Safety and Innovation Act (FDASIA), Breakthrough Therapy is "intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints."
Dr Mace Rothenberg, senior vice president of clinical development and medical affairs for Pfizer's Oncology business unit, said:
"We appreciate the opportunity that Breakthrough Therapy designation provides to work closely with the FDA on the development of palbociclib. Palbociclib is one example of Pfizer's commitment to identifying and translating innovative science into meaningful new treatment options for cancer patients."
A double-blind study evaluated the efficacy of palbociclib in combination with letrozole for treating post-menopausal breast cancer patients.
Women who received a combination of palbciclib and letrozole experienced better overall median progression free survival (PFS) than those solely on letrozole.
Results from the preliminary Phase 2 trial drove the FDA's decision to carry out the breakthrough therapy designation.