Abstract 3425
Background
Genetic variants of dihydropyrimidine dehydrogenase (DPYD) gene can result in varied enzymatic activity and potential toxicity when receiving 5-FU chemotherapy including treatment related death in up to 1% patients. Current international guidelines suggest an international rate of 3-5% albeit routine prospective pharmacogenomic testing is not currently recommended. However, in a genetically homogenous population such as Ireland, DPYD variant enrichment may support routine testing.
Methods
All patients receiving 5-FU based chemotherapy in South & South-West region of Ireland were prospectively tested from 01/09/2018 to present. The Viapath DPYD genotyping panel which interrogates for 5 variants was used. Toxicity type and grade for all patients were recorded (CTCAE v5.0).
Results
To date, 139 patients have been tested,50.4% male and 49.6% female, median age 63 years. The majority(59%) were being treated for colorectal cancer. Sixteen patients were found to be heterozygous carriers of a DYPD variant with one compound heterozygous variant identified i.e. an overall prevalence of 12 %. No homozygous carriers were identified. Grade ≥3 was observed in 33% DPYD variant carriers compared to 19% in DPYD wild type patients i.e. relative risk of grade ≥3 toxicity is 1.7, p = 0.17.Table:
648P
DPYD Variants | Prevalence % n = 139 | % Rate of ≥ G3 toxicity |
---|---|---|
7(5.0%) | 42% | |
c. 2846A>T | 1(0.7%) | n/a* |
c. 1905 + 1G>A | 3(2.2%) | 100% |
c. 1679T>G | 0 (0%) | n/a* |
c. 1601GA | 5 (3.6%) | 0% |
c. 1905 + 1G>A+c;1236G>A/Hapb3 compound heterozygous | 1(0.7%) | n/a* |
TOTAL:17 (12.2%) |
Conclusions
The study shows a higher than expected prevalence of DPYD variants of 12.2% compared to internationally reported 3-5%. Patients with DPYD variants c.1236G>A and c.1905+1G>A were particularly likely to develop Grade ≥ 3 toxicity. Prospective testing continues to assess the clinical relevance of individual variants in our population.
Legal entity responsible for the study: The authors.
Clinical trial identification
Editorial acknowledgement
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
3059 - Intraoperative chemotherapy with 5-FU for colorectal cancer patients receiving curative resection (IOCCRC): A randomized, multicenter, prospective, phase III trial
Presenter: Rongxin Zhang
Session: Poster Display session 2
Resources:
Abstract
3082 - Prognostic and predictive role of body mass index (BMI) in metastatic colorectal cancer (mCRC): a pooled analisys of TRIBE and TRIBE-2 studies by GONO
Presenter: Emanuela Dell'Aquila
Session: Poster Display session 2
Resources:
Abstract
3618 - Drug holidays and overall survival in patients treated for metastatic colorectal cancer
Presenter: Silvio Ken Garattini
Session: Poster Display session 2
Resources:
Abstract
6111 - Quality of life during 1st-line FOLFOXIRI+/- panitumumab in RAS wild-type metastatic colorectal cancer: Results from the randomized VOLFI trial (AIO KRK-0109)
Presenter: Michael Geissler
Session: Poster Display session 2
Resources:
Abstract
1042 - A biomarker combination indicating resistance to FOLFOX plus bevacizumab in metastastic colorectal cancer : results of phase I of the PERMAD trial
Presenter: Thomas Seufferlein
Session: Poster Display session 2
Resources:
Abstract
3291 - Microsatellite Instability (MSI) status and prognosis in colorectal cancer: meta-analysis
Presenter: James Toh
Session: Poster Display session 2
Resources:
Abstract
2046 - Choosing the right strategy based on individualized treatment effect predictions: Combination versus sequential chemotherapy in patients with metastatic colorectal cancer.
Presenter: Miriam Koopman
Session: Poster Display session 2
Resources:
Abstract
2589 - Noninferiority on overall survival of every-2-weeks vs weekly schedule of cetuximab for first-line treatment of RAS wild-type metastatic colorectal cancer
Presenter: Stefan Kasper
Session: Poster Display session 2
Resources:
Abstract
4944 - POLAF study: Efficacy and safety of FOLFIRI/aflibercept in a phase II trial in patients with metastatic colorectal cancer: Results of plasmatic prognostic and predictive markers
Presenter: Maria Elena Elez Fernandez
Session: Poster Display session 2
Resources:
Abstract
2042 - The accuracy of the clinical PCI score in patients with peritoneal carcinomatosis of colorectal cancer
Presenter: Nadine De Boer
Session: Poster Display session 2
Resources:
Abstract