July 13 (UPI) -- Research shows that a new class of drugs proving successful at treating the most common form of breast cancer is also well-tolerated by patients.
The class of oral drugs known as cyclin-dependent kinase, or CDK, inhibitors, have shown great success at treating the most common form of breast cancer known as hormone receptor-positive, or HR+ metastatic breast cancer.
The U.S. Food and Drug Administration recently approved the first CDK inhibitor palbociclib or Ibrance, in February 2015 and ribociclib or Kisqali in March 2017. A third drug, abemacicib, is currently undergoing Phase 3 trials.
"CDK inhibitors have changed the landscape of management of HR+ breast cancer," Aditya Bardia, a specialist in breast cancer at the Massachusetts General Hospital Cancer Center in Boston, said in a press release.
CDK inhibitors are so successful because the interfere with cancer cells' ability to multiply rapidly by blocking the activity of enzymes known as CDKs, particularly CDK 4 and CDK 6.
"Given the excitement with these drugs, there has been considerable uptake in clinical practice for management of patients with metastatic breast cancer," Bardia said. "However, these agents are different from endocrine therapies, and have a unique set of side effects. Therefore, we felt it was important to have a dedicated review article on clinical management of potential toxicities and drug interactions seen with the use of CDK 4/6 inhibitors and summarize practical management strategies for a medical oncologist."
For the study, published July 13 in The Oncologist, researchers reviewed all available studies on the three CDK inhibitor drugs and found the most common side effect was a low level of white blood cells, known as neutropenia, which can increase the chance of infection. The effect of neutropenia was temporary and dose-dependent.
Neutropenia was less common with abemaciclib, but side effects such as diarrhea and fatigue were more common. Nausea and alopecia are less common side effects researchers found, but they were typically mild and easily treated.