Unveiling Discrepant and Rare Dihydropyrimidine Dehydrogenase (DPYD) Results Using an In-House Genotyping Test: A Case Series.

Fluoropyrimidine chemotherapy is a primary component of many solid tumor treatment regimens, particularly those for gastrointestinal malignancies. Approximately one-third of patients receiving fluoropyrimidine-based chemotherapies experience serious adverse effects. This risk is substantially higher in patients carrying DPYD genetic variants, which cause reduced fluoropyrimidine metabolism and inactivation (ie, dihydropyridine dehydrogenase [DPD] deficiency). Despite the known relationship between DPD deficiency and severe toxicity risk, including drug-related fatalities, pretreatment DPYD testing is not standard of care in the United States. We developed an in-house DPYD genotyping test that detects 5 clinically actionable variants associated with DPD deficiency, and genotyped 827 patients receiving fluoropyrimidines, of which 49 (6%) were identified as heterozygous carriers. We highlight 3 unique cases: (1) a patient with a false-negative result from a commercial laboratory that only tested for the c.1905 + 1G>A (*2A) variant, (2) a White patient in whom the c.557A>G variant (typically observed in people of African ancestry) was detected, and (3) a patient with the rare c.1679T>G (*13) variant. Lastly, we evaluated which DPYD variants are detected by commercial laboratories offering DPYD genotyping in the United States and found 6 of 13 (46%) did not test for all 5 variants included on our panel. We estimated that 20.4% to 81.6% of DPYD heterozygous carriers identified on our panel would have had a false-negative result if tested by 1 of these 6 laboratories. The sensitivity and negative predictive value of the diagnostic tests from these laboratories ranged from 18.4% to 79.6% and 95.1% to 98.7%, respectively. These cases underscore the importance of comprehensive DPYD genotyping to accurately identify patients with DPD deficiency who may require lower fluoropyrimidine doses to mitigate severe toxicities and hospitalizations. Clinicians should be aware of test limitations and variability in variant detection by commercial laboratories, and seek assistance by pharmacogenetic experts or available resources for test selection and result interpretation.

Addressing barriers to increased adoption of DPYD genotyping at a large multisite cancer center.

PURPOSE: To describe the implementation of an in-house genotyping program to detect genetic variants linked to impaired dihydropyrimidine dehydrogenase (DPD) metabolism at a large multisite cancer center, including barriers to implementation and mechanisms to overcome barriers to facilitate test adoption. SUMMARY: Fluoropyrimidines, including fluorouracil and capecitabine, are commonly used chemotherapy agents in the treatment of solid tumors, such as gastrointestinal cancers. DPD is encoded by the DPYD gene, and individuals classified as DPYD intermediate and poor metabolizers due to certain genetic variations in DPYD can experience reduced fluoropyrimidine clearance and an increased risk of fluoropyrimidine-related adverse events. Although pharmacogenomic guidelines provide evidence-based recommendations for DPYD genotype-guided dosing, testing has not been widely adopted in the United States for numerous reasons, including limited education/awareness of clinical utility, lack of testing recommendations by oncology professional organizations, testing cost, lack of accessibility to a comprehensive in-house test and service, and prolonged test turnaround time. Based on stakeholder feedback regarding barriers to testing, we developed an in-house DPYD test and workflow to facilitate testing in multiple clinic locations at Levine Cancer Institute. Across 2 gastrointestinal oncology clinics from March 2020 through June 2022, 137 patients were genotyped, and 13 (9.5%) of those patients were heterozygous for a variant and identified as DPYD intermediate metabolizers. CONCLUSION: Implementation of DPYD genotyping at a multisite cancer center was feasible due to operationalization of workflows to overcome traditional barriers to testing and engagement from all stakeholders, including physicians, pharmacists, nurses, and laboratory personnel. Future directions to scale and sustain testing in all patients receiving a fluoropyrimidine across all Levine Cancer Institute locations include electronic medical record integration (eg, interruptive alerts), establishment of a billing infrastructure, and further refinement of workflows to improve the rate of pretreatment testing.

Molecules to minds: grand challenges for the 21st century.

The Institute of Medicine's Forum on Neuroscience and Nervous System Disorders established a "Grand Challenges Initiative." The goal is to help frame a broad, integrated research program that would attract substantial funding and generate additional resources to support large-scale efforts to tackle some of the most daunting but important neuroscience questions.

Autism and the environment: challenges and opportunities for research.

Autism spectrum disorder is a complex developmental disorder that dramatically affects the lives of patients and their families and the broader community. The causes of autism are unknown; however, evidence increasingly suggests that a complex interplay among environmental stressors, genetic mutations, and other biological factors likely plays a significant role in the development and/or progression of autism spectrum disorder. On April 18 and 19, 2007, the Institute of Medicine's Forum on Neuroscience and Nervous System Disorders hosted a workshop to provide a venue to bring together scientists; major sponsors of autism-related research; and members of the autism patient, family, and advocacy community to discuss the most promising and urgent scientific questions and opportunities. Broad participation by the autism community enriched the meeting significantly by contributing a valuable and personal perspective that is often missing from scientific meetings. It also began a much improved public-private partnership in which all stakeholders are represented. On the basis of the presentations and the discussions that followed, an array of important scientific opportunities were identified in 5 general categories: (1) opportunities to advance clinical research; (2) opportunities to enhance epidemiologic studies; (3) opportunities to improve the understanding of autism's pathology and etiology; (4) tools and infrastructure needs; and (5) opportunities for public-private partnerships. This workshop demonstrated that full public engagement can greatly enhance activities such as this workshop and its outcomes. Furthermore, we expect that this listing of scientific challenges, needs, and opportunities will help to frame a more comprehensive research agenda.