Implementing Preemptive Pharmacogenomic Testing for Colorectal Cancer Patients in a Community Oncology Clinic

The goal of personalized medicine is to tailor therapies to an individual patient with a goal of maximizing benefit and minimizing treatment related side effects. Inter-individual variability in metabolic enzymes can have a significant impact on cancer therapies. Pharmacogenomics (PGx) studies the interactions between drugs and genes, and pharmacogenomic screening tests can assess for genetic variations among individuals to personalize medicine. PGx testing identifies genes within an individual that may affect treatment, efficacy, and toxicity of drugs. PGx screening prior to chemotherapy would help identify patients with genetic polymorphisms that are at increased risk for drug toxicity and would benefit from genetic-guided dosing, resulting in decreased risk of adverse events (AEs) related to the chemotherapy. PGx testing is not routinely used in community-based oncology practices. The cost of testing as well as lengthy waits for results have limited routine use of this testing. Advances in testing have reached the point where routine preemptive testing could benefit patients with newly diagnosed cancer.

PGx testing evaluating a large number of metabolic enzymes is now commercially available. OneOme RightMed® is a privately owned company developed by doctors and scientists at Mayo Clinic with a mission "to provide the most cost-effective, comprehensive, personalized, pharmacogenomics analysis integrated into everyday clinical care." OneOme RightMed® currently tests for 22 genes that impact over 340 drugs used in multiple fields of medicine, including oncology. The drugs tested for by OneOme RightMed® were generated from practice guidelines and the FDA's guidelines for genotyping, and drugs with published, clinical evidence supporting genotyping. With developments in sequencing technology, comprehensive PGx testing can now be completed for a modest cost. Testing is done using a prepackaged OneOme RightMed® kit to collect a buccal swab. OneOme RightMed® PGx test uses a DNA Genotek ORAcollect OC-100 buccal swab kit to extract DNA, which is then analyzed through polymerase chain reaction (PCR). The results are available in 10 or less calendar days to the provider and/or pharmacist. The report provides "genotype-derived recommendations" with additional quick references for medication dosing guidance.

Despite clear clinical implications, incorporation of PGx testing has historically been challenging due to potential delay in initiation of therapy and uncertainty of clinical and economic benefits. However, in the past decades, clinically actionable gene-drug interactions, such as the polymorphisms discussed above, have been identified. Additionally, the availability of high-quality genotyping in a timely manner with lower costs makes PGx testing feasible. Pilot studies implementing PGx testing have been conducted at academic centers.10,13-15 Though the knowledge gained from those studies enhanced their ability to implement PGx testing, pilot studies implementing PGx testing in a community-based health care setting in oncology treatment have not been conducted, to the best of our knowledge. Therefore, our pilot study would evaluate the feasibility of implementing PGx testing in routine oncology treatment at a community-based health care center. CRC is a common cancer and the drugs used in treating CRC are affected by PGx. Thus, CRC represents an ideal situation to evaluate the feasibility of routine preemptive PGx testing. While this study represents an initial pilot feasibility study, our ultimate goal is to evaluate the benefits of PGx in the community setting in regards to reduction of toxicity, improved cancer outcomes, and cost savings.

Primary Objective

1. To determine if preemptive PGx testing is feasible in a community oncology clinic.