Osteonecrosis of the Jaw Risk With Verzenio (Abemaciclib)
Verzenio (abemaciclib) labeling does not list osteonecrosis of the jaw (ONJ) as a known adverse reaction or warning in the current FDA prescribing information. [1] Pharmacovigilance analyses using FDA Adverse Event Reporting System (FAERS) data have reported a disproportionality signal for ONJ with abemaciclib, which is consistent with reported cases but does not establish causality. [2], [3]
FDA Prescribing Information Position
The FDA-approved Verzenio (abemaciclib) prescribing information (revised 02/2025) does not contain text indicating ONJ or osteonecrosis of the jaw among warnings, precautions, adverse reactions, or postmarketing experience. [1]
Evidence From Pharmacovigilance Databases
A retrospective FAERS pharmacovigilance case series (reports submitted to FAERS from March 2004 through March 2024) evaluated ONJ signals for both monoclonal antibodies and small-molecule inhibitors and included abemaciclib among small-molecule inhibitors with ONJ reporting. [2] A real-world FAERS disproportionality study of CDK4/6 inhibitors reported an adverse-event signal for “osteonecrosis of the jaw” with abemaciclib. [3]
Clinical Interpretation of “Cause”
Pharmacovigilance signals indicate that ONJ was reported with abemaciclib more often than expected relative to other drugs in the database. [2], [3] Pharmacovigilance data do not prove that abemaciclib is the direct cause of ONJ because reports can be influenced by confounding cancer risk factors, concomitant medications, oral disease, and reporting bias. [2], [3]
Practical Monitoring Implications
Patients receiving abemaciclib should undergo routine dental assessment and maintenance consistent with general ONJ risk management principles used across cancer therapies that have ONJ risk signals in labeling or postmarketing reports. [2], [3] Any nonhealing oral lesion, exposed bone, jaw pain, or infection consistent with ONJ warrants prompt evaluation by an oncology team and dental/oral surgery specialists. [2], [3]
When to Escalate Risk Concern
Escalation of concern for ONJ should be applied when additional ONJ risk factors are present, including invasive dental procedures and comorbid oral/dental disease, which are common contributors to ONJ in oncology populations. [2] More intensive prevention and monitoring practices are reasonable when ONJ risk signals have been reported for the specific agent class or when multiple risk factors coexist in the same patient. [2], [3]
Sources Used for This Determination
The conclusion that ONJ is not listed in Verzenio’s FDA labeling is based on the current FDA prescribing information text. [1] The conclusion that ONJ has been reported with abemaciclib comes from FAERS pharmacovigilance signal detection studies. [2], [3]