Pharmacogenomics Advocacy for the Cancer Patient

What does pharmacogenomics (PGx) in the oncology landscape look like today? Physicians and pharmacists are at the forefront of advancing the utilization of PGx testing in oncology.[i],[ii] There are two areas of interest in cancer PGx, germline and somatic.iii The focus of this article will be germline mutations, which can be inherited versus somatic mutations which are not.[iii], [iv] According to the CDC, 1,603,844 new cancer cases were reported in 2020.[v]

We are at a time where field experts are advocating to policy makers about the importance of having certain PGx information prior to specific oncology treatment. For example, the European Medicines Agency (EMA), in 2020, recommended pre-treatment DPD deficiency testing via two methods, including genotyping for risk variant alleles in DPYD as one method.[vi], [vii]

PGx in the oncology space provides a method for personalized medicine that can potentially help in minimizing adverse effects for certain cancer treatments.[viii] An example is DPYD which encodes for the dihydropyrimidine dehydrogenase (DPD) enzyme that metabolizes fluoropyrimidines such as 5-fluorouracil (5-FU) and capecitabine.i, [ix] Certain DPYD variants are associated with grade ≥3 toxicity during fluoropyrimidine chemotherapy.[x] The Clinical Pharmacogenetics Implementation Consortium (CPIC) provides guidelines for Dihydropyrimidine Dehydrogenase genotype and fluoropyridine dosing.ix In the case of 5-FU, some may have DPYD variants that may lead to partial or full DPD deficiency resulting in toxic buildup/potential side effects.viii Taking it a step further and looking at the patient wholistically to assess the need for PGx supportive care is another area of focus.[xi] Patients with cancer may be on other medications for chemotherapy-induced nausea and vomiting, pain, or depression for example.xi

Policy and legislative movements are stepping forward. For example, in Minnesota, HF 4899: requirement for health plans to provide coverage for biomarker testing was passed.[xii] Another example is the Medi-Cal program in California where a bill was signed outlining pharmacogenetic testing coverage.[xiii]  Furthermore, the American Cancer Society Cancer Action Network provided a public policy issue of PGx Consensus Recommendations that is endorsed by 12 organizations outlines key action items to enhance PGx implementation.viii

These policies are only the beginning. We are at crossroads where we need more forward thinking thought leaders, including physicians, pharmacists, and payers to come together with an aligned action plan that includes the patient’s best interest.

Ghada Elnashar, PharmD, MS is a clinical and managed care pharmacist leader and is currently the Associate Director of Medical Affairs at OneOme LLC, a med tech company in Minneapolis, MN. OneOme offers additional information and PGx education which can be found at or you may reach out to


[i] Hertz DL, Smith DM, Scott SA, Patel JN, Hicks JK. Response to the FDA Decision Regarding DPYD Testing Prior to Fluoropyrimidine Chemotherapy. Clin Pharmacol Ther. 2023 Oct;114(4):768-779. doi: 10.1002/cpt.2978. Epub 2023 Jul 11. PMID: 37350752.

[ii] Innocenti F, Mills SC, Sanoff H, Ciccolini J, Lenz HJ, Milano G. All You Need to Know About DPYD Genetic Testing for Patients Treated With Fluorouracil and Capecitabine: A Practitioner-Friendly Guide. JCO Oncol Pract. 2020 Dec;16(12):793-798. doi: 10.1200/OP.20.00553. Epub 2020 Nov 16. PMID: 33197222; PMCID: PMC8462561.

[iii] Patel JN. Cancer pharmacogenomics, challenges in implementation, and patient-focused perspectives. Pharmgenomics Pers Med. 2016 Jul 12;9:65-77. doi: 10.2147/PGPM.S62918. PMID: 27471406; PMCID: PMC4948716.

[iv] Somatic & Germline Mutations. Cleveland Clinic [online]. Available at:–germline-mutations Accessed October 13, 2023

[v] CDC. Cancer Data and Statistics. [Online] Accessed October 11, 2023

[vi] de With M, Sadlon A, Cecchin E, Haufroid V, Thomas F, Joerger M, van Schaik RHN, Mathijssen RHJ, Largiadèr CR; ‘The Working Group on the Implementation of DPD-deficiency Testing in Europe’. Implementation of dihydropyrimidine dehydrogenase deficiency testing in Europe. ESMO Open. 2023 Apr;8(2):101197. doi: 10.1016/j.esmoop.2023.101197. Epub 2023 Mar 28. PMID: 36989883; PMCID: PMC10163157.

[vii] European Medicines Agency (EMA). EMA recommendations on DPD testing prior to treatment with fluorouracil, capecitabine, tegafur and flucytosine. 2020. Available at: Accessed October 11, 2023

[viii] American Cancer Society Cancer Action Network. Pharmacogenomics (PGx) Consensus Recommendations. Equitable Discovery and Implementation of Pharmacogenomics (PGx) Testing in Cancer Care: Recommendations [Online] Accessed October 11, 2023

[ix] Amstutz, Ursula, et al. “Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for dihydropyrimidine dehydrogenase genotype and fluoropyrimidine dosing: 2017 update.” Clinical Pharmacology & Therapeutics 103.2 (2018): 210-216.

[x] Sharma BB, Rai K, Blunt H, Zhao W, Tosteson TD, Brooks GA. Pathogenic DPYD Variants and Treatment-Related Mortality in Patients Receiving Fluoropyrimidine Chemotherapy: A Systematic Review and Meta-Analysis. Oncologist. 2021 Dec;26(12):1008-1016. doi: 10.1002/onco.13967. Epub 2021 Sep 29. PMID: 34506675; PMCID: PMC8649021.

[xi] Patel JN, Wiebe LA, Dunnenberger HM, McLeod HL. Value of Supportive Care Pharmacogenomics in Oncology Practice. Oncologist. 2018 Aug;23(8):956-964. doi: 10.1634/theoncologist.2017-0599. Epub 2018 Apr 5. PMID: 29622698; PMCID: PMC6156181.

[xii] Minnesota Department of Commerce. Evaluation of HF 4899: Requirement for Health Plans to Provide Coverage for Biomarker Testing Report to the Minnesota Legislature Pursuant to Minn. Stat. § 62J.26. JANUARY 2023. [Online] Accessed October 11, 2023

[xiii] California Assembly Bill 425. Medi-Cal: pharmacogenomic testing. [Online]. Accessed October 11, 2023.