Abemaciclib and Mobocertinib: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Mobocertinib
Abemaciclib
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Here's what's going on. Abemaciclib (Verzenio) is a cancer medicine that your body breaks down using a liver enzyme called CYP3A. Mobocertinib (Exkivity) can speed that enzyme up. When the enzyme works faster, your body may clear abemaciclib more quickly, which can lower the amount in your blood. The concern is that abemaciclib could become less effective at fighting the cancer.
This is based on how these drugs are expected to behave rather than firm studies, so please don't be alarmed. The most important thing is not to stop or change either medicine on your own. Your cancer care team can manage this by adjusting your dose or watching you more closely.
Effect: Mobocertinib may induce CYP3A-mediated metabolism of abemaciclib, a CYP3A substrate, lowering abemaciclib exposure (AUC/Cmax) and risking reduced efficacy (potential therapeutic failure).
- Direction: Reduced abemaciclib effect (enzyme induction; neither drug is a prodrug requiring activation).
- Magnitude: Not quantified for abemaciclib; midazolam AUC fell ~16 to 32% as a probe.
- Onset: Unspecified.
- Evidence: Theoretical.
Management: Avoid concomitant use where small concentration changes may cause treatment failure. If unavoidable, increase the abemaciclib dose per labeling and monitor response/tolerability closely.
What happens
Decreased plasma concentrations of the CYP3A substrate, which may result in serious therapeutic failure
Interaction Deep Dive
Because mobocertinib acts as a CYP3A inhibitor, its use alongside a CYP3A substrate that has a narrow therapeutic index should be avoided, as it lowers the substrate's plasma levels, and even small shifts in concentration can produce serious therapeutic failures. When mobocertinib was given together with midazolam (a CYP3A substrate), the midazolam AUC fell by 32% and 16%, respectively1.
Why it happens (mechanism)
Induction of the metabolism of CYP3A substrates by mobocertinib
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your oncology team tells you otherwise. This is something your care team can plan for.
- Your team may avoid using these two together when possible, since abemaciclib's effect could be weakened.
- If both are needed, your abemaciclib dose may be increased and individualized by your prescriber as recommended.
- Your team may monitor you more closely to make sure the cancer treatment keeps working.
Ask your pharmacist or oncologist before starting, stopping, or changing either drug, and mention any new medicines you begin.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) When mobocertinib 160 mg once daily was given together with midazolam (a CYP3A substrate) by the oral or IV route, the AUC of midazolam fell by 32% and 16%, respectively1.
Common questions
Can I take Abemaciclib and Mobocertinib together?
Mobocertinib may lower abemaciclib levels and make it less effective, so this combination is best avoided; if both are needed, your oncology team can adjust the abemaciclib dose and monitor you closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Mobocertinib interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Abemaciclib and Mobocertinib interaction managed?
Keep taking both medicines exactly as prescribed unless your oncology team tells you otherwise. This is something your care team can plan for. Your team may avoid using these two together when possible, since abemaciclib's effect could be weakened. If both are needed, your abemaciclib dose may be increased and individualized by your prescriber as recommended. Your team may monitor you more closely… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Abemaciclib or Mobocertinib need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: EXKIVITY(TM) oral capsules, mobocertinib oral capsules. Takeda Pharmaceuticals America Inc (per FDA), Lexington, MA, 2021.
Keep reading about Mobocertinib
Keep reading about Abemaciclib
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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