(081) Evaluation and Implementation of a Standardized DPYD Testing Protocol for Patients Receiving Fluoropyrimidine-based Chemotherapy in the Medical Oncology Setting

Poster Abstract:

Background: Pharmacogenomics (PGx) is being increasingly utilized in healthcare to optimize treatment outcomes. Patients receiving fluoropyrimidine chemotherapy benefit from PGx testing given the potential for severe, even fatal, side effects associated with dihydropyrimidine dehydrogenase (DPYD) deficiency. Despite these risks, PGx testing prior to initiation of fluoropyrimidine chemotherapy is not yet considered standard of care in the United States, and the ideal implementation of PGx testing for DPYD into clinical workflow remains uncertain.

St. Elizabeth Healthcare (SEH) is a multi-site system operating 6 hospital facilities and 4 ambulatory cancer centers across Northern Kentucky and Southeast Indiana. Since 2022, SEH has maintained an internal policy recommending pre-treatment DPYD testing. The goal of this multi-site, mixed-methods study was to evaluate clinician perceptions and adherence to this policy, and to identify barriers/facilitators to implementing standardized PGx testing.

Methods: Between June and December 2023, 217 patients received 5-fluorouracil (n=114) or capecitabine (n=103) and were retrospectively reviewed to evaluate policy adherence. Cohorts were cross-referenced with the SEH Precision Medicine PGx registry to evaluate the percentage of patients with a DPYD PGx test. A semi-structured interview to assess clinician perceptions was developed using the Consolidated Framework for Implementation Research (CFIR). We invited 28 clinicians to interview as a representative sample of the multidisciplinary medical oncology team providing services across different SEH sites in both inpatient and ambulatory settings.

Results: The overall percentage of DPYD testing in the retrospective 5-fluorouracil and capecitabine cohorts was determined to be 86% and 84%, respectively. For the qualitative portion of the study, 24 of 28 invited clinicians responded, including 4 physicians, 6 clinic nurses, 7 APRNs, and 7 pharmacists. Clinician perceptions were incongruent with objective DPYD testing calculations as 37% (n=9) of respondents perceived percentages to approximate 100%. All respondents had positive perceptions of DPYD testing, but several implementation barriers were identified, including inconsistent PGx ordering practices (71%, n=17), difficulty accessing results (66%, n=16), test turn-around time (50%, n=12), and inadequate PGx education (37%, n=9). Only 50% (n=12) reported being satisfied with the current process.

Conclusions: While clinicians have a positive perception of the value of DPYD testing, there are opportunities to optimize PGx testing in the medical oncology setting. Specifically, more education of team members around PGx, standardizing test workflows, minimizing result turn-around time, and streamlining result access can facilitate and improve adherence to standardized PGx processes. A revised workflow incorporating these findings is being operationalized with results forthcoming.

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