16 September 2019
The US Food and Drug Administration (FDA) has issued a safety announcement about a “rare but severe” lung inflammation that can result from the use of any of 3 breast cancer medications – palbocilcilb (Ibrance), ribociclib (Kisqali), and abemaciclib (Verzenio). These 3 medications are in a class of drugs called cyclin-dependent kinase (CDK) 4/6 inhibitors. They are used in estrogen receptor positive (ER+), Her2/neu negative metastatic (Stage 4) breast cancer, and work by interfering with cell division.
The FDA announcement states that “the overall benefit of CDK 4/6 inhibitors is still greater than the risks when used as prescribed.” Palbociclib has been FDA-approved since 2015, and ribociclib and abemaciclib hae been approved since 2017. In evaluating studies of all 3 of the CDK 4/6 inhibitors, the FDA alert noted that 1-3% of patients taking these medications developed severe lung inflammation, and less than 1% died due to the condition.
The FDA recommended that patients notify their physicians immediately if they develop difficulty or discomfort with breathing or shortness of breath while at rest or at low activity when taking any of these medications. The FDA alert notes that there no specific risk factors that have been identified to determine how likely an individual patient is to develop severe lung inflammation while taking one of the CDK 4/6 inhibitors. They recommended that physicians routinely monitor their patients for lung symptoms that could indicate the development of severe inflammation. They also recommended that any side effects be reported to the FDA MedWatch Program. The alert noted that common side effects include “nausea, vomiting, diarrhea, constipation, decreased appetite, abdominal pain, infections, low red blood cell counts, low white blood cell counts, low platelet count, headache, dizziness, hair thinning or loss, rash, tiredness, and weakness”. I will post an update as more information becomes available.