Pharmacist-Led Quality Improvement Project to Optimize Abemaciclib Dosing Within a Community Oncology Network

BACKGROUND

Dose interruption and/or dose reduction of the monarchE trial: 43.7% of patients treated with adjuvant Verzenio (abemaciclib) may be required based on individual Verzenio required dose reductions, most commonly for safety and tolerability in patients with breast cancer. In the diarrhea. Reductions were shown to effectively manage adverse events, with only 8.9% of patients discontinuing after a dose reduction; however, 52% of patients who discontinued Verzenio due to an adverse event did not have a prior dose reduction. Data have shown that the efficacy of adjuvant Verzenio is not compromised by dose reductions for patients with high-risk early breast cancer or advanced breast cancer. Timely evaluations for adverse reactions, a reduced starting dose, or dose-escalation as used in the TRADE study may allow patients to continue therapy longer and therefore maximize efficacy.

MATERIALS AND METHODS

A quality improvement project was initiated on July 1, 2025, within a community oncology network pharmacy to improve appropriate Verzenio dosing. Clinical pharmacists standardized 1) patient education for diarrhea management, 2) timeline for follow-up symptom assessments, and 3) dose-adjustment recommendations for new starts and patients experiencing diarrhea. Education was distributed to providers through the Pharmacy and Therapeutics Committee and the Pharmacy Newsletter. Success was measured by evaluating 1) the quantity of pharmacist interventions, 2) the intervention success rate (goal 80%), and 3) the percentage of patients who discontinued Verzenio without first having a prior dose reduction (goal 20%). The population evaluated included new-start Verzenio patients in both the adjuvant and metastatic settings, whose prescriptions were dispensed by the network pharmacy between July 1, 2025, and March 31, 2026. Data were collected from the dispensing software and the electronic medical record.

RESULTS

One hundred and 68 patients were started on Verzenio during the study period. Thirty-one interventions were made by the clinical pharmacists, with an 87% success rate (dose-reduced prescriptions received following intervention). Only 15% of patients who discontinued Verzenio during the study period had no dose reduction before discontinuation, vs 30% at baseline and 52% in the monarchE study. Of note, 20% of patients were started at full dose, which represented a decrease from baseline.

CONCLUSION

This quality improvement project increased the appropriate dosing of Verzenio. Data have shown that reduced starting doses and early dose reductions for toxicity do not compromise efficacy. Provider education at the start of the project and evidence-based recommendations were instrumental in achieving an 87% success rate for pharmacist interventions. We estimate that the decrease in the number of patients who discontinued Verzenio without first trialing a reduced dose translates to a longer duration of therapy and, therefore, possibly improved efficacy in this patient population.