Palbociclib May Prove Effective Across Variety of Cancer Drugs

Palbociclib has been found effective inhibiting the mobilization of enzymes that contribute to the rapid division of tumor cells.

Although the oral drug palbociclib is currently prescribed for the treatment of breast cancer, recent studies have shown it has the potential to fight other cancers when combined with different therapies, a recent study indicates.

Palbociclib has been found to hinder the mobilization of the CDK4 and CDK6 enzymes, which contribute to the rapid division of cells in tumors. These enzymes are also found in other cancers.

Since palbociclib is able to halt the natural process of cell division, it has the ability to be relevant in other types of cancer, such as lymphoma, sarcoma, and teratoma, according to a study published in JAMA Oncology.

“Pairing palbociclib with other anti-cancer therapies such as endocrine therapy, chemotherapy, and targeted therapy can create a powerful combinatorial effect with real promise for addressing a variety of cancers,” said lead author Amy S. Clark, MD, assistant professor of Hematology/Oncology at Penn’s Perelman School of Medicine.

During a phase 2 of a trial of the drug in mantle-cell lymphoma, researchers found 1 complete response and 2 partial responses among 17 patients enrolled. Five patients showed progression-free survival longer than a year, while the median progression-free survival was 4 months.

An additional phase 2 trial that treated 29 sarcoma patients with palbociclib showed progression-free survival of 66% at 12 weeks.

Although palbociclib was found to be safe during trials, it does have 1 main side effect, reversible neutropenia, which leaves patients much more susceptible to infectious diseases.

"This drug has minor effects on normal cells other than neutrophils (white blood cells)," said study senior author Peter J. O'Dwyer, MD, a professor of Hematology/Oncology at Penn. "In tumors, it can cause shrinkage, or more commonly, arrest of growth. As we discover new functions for the CDK4/6 target of this medicine, we are likely to use it in combinations to make other anti-cancer agents work better."