What Patients With Cancer Should Know About DPD Deficiency Prior to Chemo

The Food and Drug Administration (FDA) has updated the labeling for Xeloda (capecitabine) and fluorouracil (5-FU) to emphasize the risks associated with dihydropyrimidine dehydrogenase (DPD) deficiency.

In the update, the regulatory agency shares that patients with complete or partial DPD deficiency face an increased risk of severe and potentially fatal toxicities, including mucositis, diarrhea, neutropenia and neurotoxicity. The FDA advises oncologists and healthcare providers to inform patients of these risks and consider genetic testing for DPD deficiency before initiating treatment.

In an interview with CURE, Dr. Gabriel A. Brooks, an associate professor of medicine and an associate professor at The Dartmouth Institute, Dartmouth Cancer Center, The Dartmouth Institute for Health Policy and Clinical Practice, explains what DPD deficiency is and why it is important for patients receiving 5-FU or Xeloda to be aware of it. He goes on to show how patients can find out if they have DPD deficiency before starting treatment with fluorouracil or Xeloda.

Brooks is also a member of the Cancer Population Sciences Research Program, and a member of the Gastrointestinal Clinical Oncology Group, at Dartmouth Geisel School of Medicine, in Lebanon, New Hampshire.

Transcript:

DPD is the abbreviation for the enzyme that metabolizes 5-FU and Xeloda. How both of those drugs are broken down by the body is regulated by that enzyme, and deficiency of that enzyme means that the enzyme that your body has, doesn't work in a fully active or fully normal way. If you have DPD deficiency, it could lead to increased side effects from the chemotherapy.

The best way to determine if you have DPD deficiency is to do a gene test that can be done on a simple blood draw. I routinely do that test for all of my patients who are going to get 5-FU or Xeloda chemotherapy. That blood test can take about a week — sometimes a little more — to turn around.

It is important to think about this ahead of time, so that once the plan is made to do chemotherapy treatment with 5-FU or Xeloda, as soon as the decision is made, [you can send for a test]. This is the time to send this test so that it doesn't delay the start of chemotherapy. It's best to have the results back before starting chemotherapy, because if you have a significant DPD deficiency that affects the dosing of the chemotherapy, you want to know that before the first dose, ideally.

Transcript has been edited for clarity and conciseness.

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