A New Standard of Care Announced by the FDA on October 3Rd, 2025.

“Serious adverse reactions or death may occur in patients with complete DPD deficiency. Test patients for genetic variants of DPYD prior to initiating Xeloda unless immediate treatment is necessary. Avoid use in patients with certain homozygous or compound heterozygous DPYD variants that result in complete DPD deficiency.”
Source: Box Warnings of 5FU and Xeloda (Capecitabine)

“Serious adverse reactions or death may occur in patients with complete DPD deficiency. Test patients for genetic variants of DPYD prior to initiating Xeloda unless immediate treatment is necessary. Avoid use in patients with certain homozygous or compound heterozygous DPYD variants that result in complete DPD deficiency.”
Source: Box Warnings of 5FU and Xeloda (Capecitabine)

DPYD Testing Before 5FU or Capecitabine Chemotherapy: A Critical Patient Safety Step

Recent US Guidance on Use of 5FU/Capecitabine:

  • FDA’s Black Box Warning recommends testing for DPYD variants before treatment
  • NCCN & ASCO similarly recommend pre-screening

Why Testing is Important:

  • The DPD enzyme regulates the active drug to limit damage to healthy cells
  • Variants in the DPYD gene identify patients at risk of low DPD enzyme activity (1 in 20 patients)
  • DPD deficient patients are at significantly greater risk of severe toxicity and possibly death

Patient Toolkit:

  • These drugs are used to treat solid tumor cancer types such as GI, breast, head/neck cancers
  • Be aware that the guidance to test is new and compliance is not universal so ask your doctor about this
  • If your doctor does not recommend testing, ask why?
  • It may cost you but Medicare and many insurance companies now cover test costs

Clinician Resources:

What you need to know:

  • Fluorouracil (5-FU) and Xeloda (Capecitabine) are used to treat tumors typically found in gastrointestinal, breast, and head/neck cancer patients.
  • The DPD enzyme plays an essential role in removing 5-FU from the body; when DPD enzyme activity is diminished, standard 5-FU results in 50-88% risk of severe toxicity (hospitalization/treatment delays) and 10% fatalities.
  • The death rate in the US is estimated at 700 to 1,400 annually.
  • Genetic variants of the DPYD gene have been shown to lead to compromised DPD enzyme activity as first reported in 1988 by Dr. Robert Diasio. These variants are present in 5-8% of European and 5% of African American descendants.
  • Tests are available to detect DPD deficiency and have been demonstrated to be life-saving and cost effective.
  • In most cases, patients with DPD deficiency are asymptomatic prior to receiving 5-FU or Xeloda which is why pre-screening is the best means to ensure safe treatment.
  • The European Medicines Agency has recommended pre-screening and therapeutic dose management since 2020.

  • A number of NCCN member institutes and other leading cancer centers in the US are now pre-screening patients and the number grows as institutes see the value in achieving better patient outcomes

  • The FDA drug label for Xeloda/capecitabine now indicates patients should be tested for DPD deficiency prior to treatment unless immediate treatment is necessary.” This is no longer a suggestion, it is the new standard of care that will save lives. A similar recommendation to test is expected in the near future for the fluorouracil (5-FU) drug label.

  • The National Comprehensive Cancer Network (NCCN) colon/rectal/anal panel guideline suggests physicians discuss testing with patients prior to starting treatment. Following the FDA’s issuing the box warning that recommends testing, we should expect each of the NCCN cancer panel guidelines to recommend pre-screening as well.

Why Test?

Approximately 5-7% of patients carry genetic DPYD variants that can lead to much greater risk of severe toxic reactions or death.

Treatment Warning Signs

If you think that you are having a moderate to severe reaction on your first or second round of chemotherapy, you should contact your healthcare provider immediately.

Initiatives

Learn about the steps we are taking and how you can get involved.

Our Mission

To improve the standard of care in the United States for cancer patients undergoing fluoropyrimidine chemotherapy (5-FU and/or Capecitabine), through advocacy, education and research.

“A tragic story can be rewritten with a simple test”

— Glenn P, who lost his wife, Kerrie, after a single dose of 5FU.

Working with your oncologist

Working with Your Oncologist

Working with Your Oncologist

You will need to initiate discussion of testing for DPD/DPYD deficiency with your oncologist because it is NOT the standard of care in the US.

Contact Us

We’re here to help. Please let us know how we can help you.

Consult your oncologist to order tests to ensure your safety.

Minimize risk with DPD testing and adjusting dosage

Consult your oncologist to order DPD/DPYD tests to ensure your safety.