Pharmacist-Led Management of Vorasidenib in Patients With Isocitrate Dehydrogenase Mutation–Positive Gliomas

Presenting Authors: Marie Noelle Bate Baiyee, PharmD; Mary Hilliger, PharmD; Bilge Parlakkilic, PharmD, Tufts Medical Center, Boston, MA

BACKGROUND: Vorasidenib was recently approved for the treatment of low-grade isocitrate dehydrogenase (IDH) 1 and IDH2 mutation–positive gliomas, demonstrating higher central nervous system penetration compared with ivosidenib.¹ Increasing use of antidepressants and antiepileptic drugs has been seen in patients with low-grade gliomas.^2,3 The vorasidenib prescribing information recommends avoiding concomitant administration of cytochrome (CY) P450 1A2 inhibitors and inducers, as well as CYP3A4 substrates,⁴ which presents a challenge when starting patients on vorasidenib. Pharmacists play a critical role in initiating and monitoring patients receiving oral oncology medications^5,6; however, no established medication therapy management model exists for patients starting treatment with vorasidenib.

OBJECTIVES: To evaluate the impact of pharmacist-led interventions and characterize the types of interventions implemented in the management of patients with low-grade IDH2 mutation–positive gliomas treated with vorasidenib.

METHODS: This single-center, retrospective study included patients with low-grade gliomas who were initiated on vorasidenib between August 2024 and October 2025. All prescriptions were held in a multistep order transmission (MSOT) queue, enabling pharmacists to perform a comprehensive medication and chart review, including assessment of drug-drug interactions (DDIs), medication reconciliation, and benefits investigations. Providers were notified of any clinically significant DDIs requiring therapy change before initiating vorasidenib. Patient education, either in person or via telephone, was completed before starting treatment. Follow-up assessments were completed every 30 days for the first 3 months and then annually. Refill prescriptions were routed through the MSOT queue, allowing pharmacists to review laboratory results, fill history, and new medications to ensure there were no new DDIs with vorasidenib. Follow-up assessments included medication reconciliations, adverse event (AE) monitoring, and adherence evaluations using the proportion of days covered (PDC) method and an adapted questionnaire.⁷

RESULTS: In all, 16 patients were screened, and 11 met the inclusion criteria. Clinically significant DDIs were identified and resolved in 82% of patients, with 55% requiring a change or discontinuation of ≥1 medication prior to initiating vorasidenib. A total of 21 medication therapy problems were identified. Of those problems, 16 were DDI checks resulting in 9 clinically significant DDIs; 3 were consultative interventions, including AE management, contraceptive counseling, and excursion data clarification. In addition, 1 was a medication access issue requiring an appeal, and 1 was a laboratory test order request. Finally, we found that 80% of patients had a PDC of >90%.

CONCLUSION: Close monitoring of patients with low-grade gliomas is vital to ensure safe, efficacious, and comprehensive care. The findings from this study highlight the critical role of pharmacist-led interventions in optimizing medication therapy management in this complex patient population.

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