DPYD-guided fluoropyrimidine dose adjustment for patients with one DPYD gene variant

DPYD Pharmacogenomics and Fluoropyrimidine (FP) Dose-Adjustment

PHASE4 · Rutgers, The State University of New Jersey · NCT07158164

This trial will test whether giving lower doses of fluoropyrimidine chemotherapy based on a patient's DPYD gene result reduces severe (Grade 3–4) side effects in people with colorectal, breast, or head and neck cancers who carry one DPYD variant.

Quick facts

PhasePHASE4
Study typeInterventional
Enrollment100 (estimated)
Ages18 Years and up
SexAll
SponsorRutgers, The State University of New Jersey (other)
Drugs / interventionschemotherapy
Locations12 sites (Belleville, New Jersey and 11 other locations)
Trial IDNCT07158164 on ClinicalTrials.gov

What this trial studies

This is a prospective, phase 4, multi-center comparison of DPYD-guided dose reduction versus standard dosing for patients starting 5‑FU or capecitabine. Patients with a single (heterozygous) DPYD variant are assigned to reduced fluoropyrimidine dosing and compared with patients with wild-type DPYD receiving standard doses, with severe (Grade 3–4) FP-related toxicities as the primary outcome. The trial enrolls adults in adjuvant or metastatic settings and accepts both measurable and non-measurable disease, using real-world clinical workflows and CLIA-certified DPYD testing before treatment. Participating sites are regional cancer centers affiliated with Rutgers and RWJBarnabas Health in New Jersey.

Who should consider this trial

Good fit: Ideal candidates are adults with colorectal, breast, head and neck, or related gastrointestinal cancers who need initial therapy with 5‑FU or capecitabine, have CLIA-certified DPYD testing showing one DPYD variant (heterozygote), and have ECOG performance status 0–2.

Not a fit: Patients without DPYD variants (wild-type), those with contraindications to 5‑FU or capecitabine, or people with homozygous/complete DPD deficiency are unlikely to benefit from the specific dose-reduction strategy tested here.

Why it matters

Potential benefit: If successful, this approach could reduce severe, potentially life-threatening chemotherapy toxicities and make fluoropyrimidine treatment safer for patients with a DPYD variant.

How similar studies have performed: Prior pharmacogenomic research and guideline recommendations have shown that DPYD-guided dose adjustments can reduce fluoropyrimidine toxicity, but prospective real-world comparative data remain limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Diagnosis of cancer in either the adjuvant or metastatic setting requiring initial therapy with 5-FU or Capecitabine.
* DPYD testing performed by a CLIA-certified laboratory (i.e., Guardant 360 or Caris blood testing for genomic profiling, DPYD testing by the Mayo Clinic or other certified laboratory) with results available before starting chemotherapy.
* DPYD testing results falling into one of the following cohorts for first-line therapy with a fluoropyridine:
* Study Cohort: Patients with one DPYD variant in one gene (heterozygotes).
* Control Arm: Patients with normal or wild-type DPYD genes, for comparison, will be treated at the usual 100% dose.

  --FOLFOX regimen (N=50)
* ECOG Performance Status 0-2.
* Measurable disease or non-measurable disease allowed, including adjuvant 5-FU-based regimens.

Exclusion Criteria:

* Patients for whom 5-FU or Capecitabine therapy is contraindicated or not deemed appropriate in the judgment of the treating physician.
* Patients with two DPYD variants (homozygous deletions or non-functional genetic variants, or double heterozygotes with two different abnormalities) should not receive 5-FU or Capecitabine and are therefore excluded from the study.
* Pregnant Women and Children

Where this trial is running

Belleville, New Jersey and 11 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Colorectal Neoplasms, Breast Neoplasms, Head and Neck Neoplasms, Gastro-Intestinal Intraepithelial Neoplasia, colorectal cancer, breast cancer, head and neck cancer, Gastro-Intestinal cancer

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.