Clinical Pharmacist–Initiated Tyrosine Kinase Inhibitor Discontinuation in Patients with Chronic Myeloid Leukemia

Presenter: Jared Freml, PharmD, BCOP, Kaiser Permanente Colorado, Denver, CO

Co-Authors: Yuliya Byakina, PharmD, BCOP, Bristol Myers Squibb, Portland, OR; Lisa A. Thompson, PharmD, BCOP, Kaiser Permanente Colorado, Denver, CO; Ekim Ekinci, PharmD, BCOP, MS, Kaiser Permanente Colorado, Denver, CO; Jasen Knudsen, PharmD, BCPS, BCOP, Kaiser Permanente Northwest, Portland, OR; Chamath Desilva, MD, Kaiser Permanente Colorado, Lafayette, CO; Soames Boyle, MD, Kaiser Permanente Northwest, Portland, OR; Thomas Delate, PhD, MS, Kaiser Permanente National Pharmacy Services, Denver, CO

BACKGROUND: Tyrosine kinase inhibitors (TKIs) are tolerated relatively well in the treatment of chronic myeloid leukemia (CML), but the wide range of adverse events and the high cost of treatment can make indefinite therapy challenging.^1-4 In recent years, data have shown that patients with CML may tolerate treatment-free remissions after prolonged deep responses to TKIs, leading to the integration of discontinuation recommendations in clinical practice guidelines.⁵ Pharmacists have demonstrated ability to assist physicians in optimizing medication management, including treatment discontinuation.^6,7 The use of pharmacists as physician extenders to identify patients with CML who may discontinue TKI therapy may provide patient and healthcare system benefits.

OBJECTIVE: To examine the clinical and financial impacts of an oncology clinical pharmacy specialist (CPS)-initiated TKI discontinuation process in a real-world population of patients with CML.

METHOD: This retrospective, descriptive analysis included adult patients from 2 integrated healthcare delivery systems who were receiving a TKI between January 1, 2019, and September 30, 2020, and had been screened under collaborative CPS/oncologist TKI discontinuation programs. Using chart data, the CPS systematically reviewed patient charts and obtained information on TKI discontinuation eligibility based on the NCCN guidelines for CML. Patients were followed until December 31, 2020, or until membership termination. The analysis outcomes included the numbers of patients who (1) were existing TKI discontinuation candidates; (2) were future TKI discontinuation candidates; (3) had a managing oncologist who agreed with the pharmacist recommendation that patients were TKI discontinuation candidates; (4) consented to TKI discontinuation; (5) discontinued TKI therapy; (6) resumed TKI therapy; and (7) avoided TKI-related costs (based on last TKI dispensed).

RESULTS: The included patients with CML (N = 133) were primarily older, male, and white and had received a TKI for >6 years. In all, 41 (30.8%) and 87 (65.4%) patients were identified as existing and future TKI discontinuation candidates, respectively. The managing oncologists agreed with the pharmacists that 36 of 41 (87.8%) patients were TKI discontinuation candidates, and of these patients, 24 (66.7%) consented to TKI discontinuation, with 23 of the 24 (95.8%) patients discontinuing TKI therapy. A total of 18 of the 23 (78.3%) patients remained off TKI therapy through follow-up. The median TKI cost avoided was $113,820 per patient. The total TKI medication cost avoided was $3,054,738.

CONCLUSION: The pharmacist-initiated TKI discontinuation programs that were analyzed were associated with systematic screening of patients with CML to formally discontinue TKI therapy and achieved TKI cost avoided. Similar pharmacist-initiated programs could be used in other healthcare settings to provide patient-centered care, reduce oncologists’ workload, and minimize financial burden on patients and the healthcare system. Future research to better characterize cost-savings, explore electronic health record tools to assist with the discontinuation of appropriate candidates, and assist with postdiscontinuation BCR-ABL1 monitoring should be considered.

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5. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines): Chronic Myeloid Leukemia. Version 3.2022. Accessed February 24, 2022.
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