Overview

• The Penn Medicine trial recruited 517 gastrointestinal cancer patients across three University of Pennsylvania Health System sites to assess pre-treatment genotyping for DPYD and UGT1A1
• Among patients carrying high-risk variants, genotype-guided dose reductions cut serious adverse event rates from 65% in untested individuals to 38% in those receiving tailored dosing
• A one-week turnaround for genetic results enabled oncologists to adjust fluoropyrimidine and irinotecan doses before patients began their first chemotherapy cycle
• Variable laboratory workflows, electronic health record integration challenges and clinician uncertainty are limiting the implementation of pharmacogenetic testing in routine U.S. oncology practice
• Researchers recommend deploying automated testing alerts, streamlining lab processes and enhancing clinician education to expand precision dosing strategies