DPD Deficiency

About DPD Deficiency

Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme that clears fluoropyrimidines - 5-fluorouracil (5-FU), capecitabine and tegafur - among the most widely used chemotherapy agents in colorectal, breast and head-and-neck cancers. When DPD activity is reduced, these drugs accumulate to toxic levels: around 1 treated patient in 5 experiences severe toxicity, and complete deficiency can be fatal. A partial deficiency affects 3-5% of patients, a complete deficiency 0.01-0.5%.

The cause is genetic. Loss-of-function variants in the DPYD gene reduce or abolish enzyme activity, and identifying carriers before the first dose enables genotype-guided dosing - the single most effective way to prevent early, avoidable toxicity. This is now standard of care, increasingly mandated:

• EMA (2020) recommends DPD testing before fluorouracil, capecitabine and tegafur; patients who completely lack DPD must not receive them.
• France has required pre-treatment DPD screening since 2019 — the result conditions prescription and dispensing.
• UK (NHS England) mandates DPYD genotyping before fluoropyrimidine therapy; ESMO and CPIC endorse genotype-guided dosing.
• US FDA has added a Boxed Warning to capecitabine and fluorouracil labeling advising DPYD testing prior to treatment.

Our DPYD testing range

LaCAR offers a modular DPYD portfolio buiit on a single LAMP workflow - directly from EDTA whole blood, no DNA extraction, actionable results in under an hour. Start with the guideline-aligned multiplex panel, then extend coverage to rarer or population-specific alleles as your lab requires.