Oncology Pharmacists Can Improve TKI Adherence in CML

An oncology pharmacist–managed program significantly increased adherence to tyrosine kinase inhibitor (TKI) therapy among patients with chronic myeloid leukemia (CML), according to a new study.

TKIs including imatinib, dasatinib, and others have greatly increased the overall survival of CML patients in recent years. “Though the efficacy of TKIs in CML has been well documented, treatment failure in this patient population is still prevalent,” wrote study authors led by Masha S. H. Lam, PharmD, of Kaiser Permanente in Antioch, California. “The reported medication adherence rates to imatinib in CML patients ranged from 54% to 74%,” and non-adherence is a major contributor to treatment failure.

The researchers looked into whether an oncology pharmacist–managed oral anticancer therapy program could improve adherence rates for these agents. The study included 56 total CML patients, 45 of whom were treated with imatinib. The results were published online ahead of print in the Journal of Oncology Pharmacy Practice.

The study was retrospective, and involved reviews of electronic refill history and medical records of patients over a 6-year period, which were compared to a cohort of usual care patients not treated by oncology pharmacists. TKI adherence was defined as a medication possession ratio (MPR) of at least 90%; the MPR is the supply of drug dispensed divided by the number of days studied.

The adherence rate in the oncology pharmacist group was 88.6%, compared with 65.8% in the comparison group (P = .0046). The mean MPR among the oncology pharmacist patients was 94%, compared with 88% in the 225-patient comparison cohort.

The researchers tested for correlations between other variables and adherence rate among the oncology pharmacist–group patients, but found none; this included the number of total medications taken (including the TKI), Charlson comorbidity index, and the frequency of pharmacist encounters per month.

The study included a total of 3,432 pharmacist encounters in the main group, and 567 interventions were necessary; these included side effect monitoring or management, drug interaction detection, TKI dose adjustments, among others. There was a mean of 10.1 interventions per patient.

“As a number of oral anticancer drugs have been approved in the past few years, cancer patients are given more treatment options by self-administration, at home,” Lam said in an email. “This provides a great opportunity for pharmacists to play a significant role in educating and monitoring patients to ensure dosing accuracy, side effects, drug interactions, and drug adherence to maximize treatment outcomes.”

The authors noted that regular follow-up with a pharmacist at least monthly should be maintained even among patients who had to that point been adherent to TKI therapy, as it can prolong that adherence.