Pharmacists help apply pharmacogenomics tests in gastro settings

Pharmacogenomics (PGx) testing may help clinicians avoid toxicities in patients with colorectal cancer (CRC), researchers said at the 2018 ASCO Gastrointestinal Cancers Symposium.

Pharmacogenomics (PGx) testing may help clinicians avoid toxicities in patients with colorectal cancer (CRC), researchers said at the 2018 ASCO Gastrointestinal Cancers Symposium. "Our pilot study also showed that when we have the right players involved, including pharmacist experts who can offer patient-specific recommendations and follow-up, we make more meaningful use of the comprehensive test results," said Pashtoon M. Kasi, MD, an assistant professor of oncology and medicine at Mayo Clinic in Jackson, FL. He said getting test results back before administering chemotherapy can help clinicians tailor genotype-driven dosing to reduce the risk of toxicities. Observing that certain CRC patients undergoing irinotecan and/or 5-FU chemotherapy were experiencing higher rates of toxicity than expected, researchers started using a 23-gene PGx comprehensive test to detect dihydropyrimidine dehydrogenase <i>(DPYD)</i> and <i>UGT1A1</i> mutations, which are known to increase the risk for adverse effects with 5-FU chemotherapy and irinotecan, respectively. Researchers found that 67% of the 80 patients had some variation in <i>DPYD</i>, <i>UGT1A1</i>, or both, which would explain the higher rate of toxicities. "Past studies have focused on two genes, but we now have platforms that allow us to test for 23 genes, which can help guide us not just in administering drugs for cancer treatment but also for supportive care medications," he said.