Side effects of 5-Fluorouracil
[DPD Exon-14 Skipping mutation test]
This test is supported by the German health insurance companies.
Cancer patients carrying the so-called Exon 14-Skipping Mutation in the DPD-Gene are at risk of suffering serious to lethal side effects afterchemotherapy with 5-Fluorouracil. Oncoscreen has developed a test designed to identify this mutation, which should be carried out in a routine setting prior to the prescription of 5-fluorouracil.
Oncoscreen acquired a license from the Public Health Service of the United States for all molecular tests covering the DPD gene which includes the Exon 14-Skipping Mutation. The license covers the European region. Oncoscreen is the only laboratory in Germany which is legally entitled to perform the DPD test.
What is required? Scientific Background Four Case Reports Scientific Proof of the Clinical Relevance Consequences for Therapy Diagnostic Results (Numbers)
What is required?
A 5 ml-EDTA-Haemogram Monovette together with the necessary documents (see below) should be sent to the following address:
Kooperationsgemeinschaft Molekulare Labordiagnostik *
Laborarztpraxis Dr. med. Roskos
Loebstedter Str. 93
07749 Jena
Germany
* "Kooperationsgemeinschaft" is a
joint venture of Oncoscreen and the
laboratory practice.
Please enclose:
-
completed
request form
To print this document you will need Acrobat Reader (Version 4.0 or higher). -
For patients within the German public health insurance system we need the “Überweisungs- Abrechnungsschein für Laboratoriumsuntersuchungen (Nr. 10)"
Please do not forget to print the name and telephone number of the doctor treating the patient, for the purposes of our reply.
The specimen can be sent in a padded envelope without the need for cooling; however, it needs to arrive at the laboratory not later than four days after blood has been taken. Within Germany, we guarantee a reply within 4 working days after arrival of the parcel at Oncoscreen. If a mutation is diagnosed, we will immediately inform you by telephone and, if necessary, provide continued advice on individual 5-FU-pharmacokinetics.
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Scientific Background
5-Fluorouracil (5-FU) is one of the most commonly prescribed chemotherapeutical drugs in the treatment of various cancers. The 5-Fluorouracil is, however, rapidly metabolized. The enzyme Dihydropyrimidine-Dehydrogenase (DPD) plays a central role here. Several mutations have been linked to complete or partial DPD deficiencies. One of these mutations occurs particularly often and results in the so-called Exon 14-Skipping mutation. This causes a functional deficiency of the DPD enzyme. The affected patients cannot metabolize the 5-Fluorouracil in the normal way. Severe to lethal side effects occur (especially the so-called haematotoxicities) in the case of both homozygous and heterozygous mutation carriers.
Literature
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Four Case Reports of Mutation Carriers
Homozygous Exon-Skipper
A 48-year-old patient with post-menopausal breast cancer received adjuvant chemotherapy with Cyclophosphamide, Methotrexat and 5-Fluorouracil, after a R0-Resection in stage pT2, pN0, M0, G2. After one course, the patient developed an acute bone marrow aplasia. During febrile neutropenia, antibiotic broad-band therapy and administration of G-CSF was initiated. Despite these measures and close medical supervision, a rapidly progressive, therapy-resistant pneumonia appeared, with increasing cardiopulmonary failure. The patient died 12 days after completing the 1st CMF course, due to multi-organ failure.
Heterozygous Exon-Skipper
A 50-year-old patient was treated adjuvantly with 5-Fluorouracil, after an R0-Resection of a supra-anal rectal carcinoma in stage pT3 N0 M0. The treatment had to be terminated because of a strongly developed mucositis and a neutropenia of grade 4. In addition, a two-week clinical treatment including the administration of antibiotics and cytokine was necessary.
Heterozygous Exon-Skipper
After a left-sided hemicolectomy due to a colonic carcinoma in stage pT3 N1 M0, a 63-year-old patient was treated adjuvantly with 5-Fluorouracil and folinic acid over a 5day period. Ten days after the end of the chemotherapy, the patient was admitted to the emergency room with a leuco- and thrombopenia WHO-grade 4 under the clinical appearance of a sepsis with consumptive coagulopathy. In course, an uncontrollable multi-organ failure developed, causing the patient's death 4 days after being admitted to the hospital.
Heterozygous Exon-Skipper
A 75-year-old female patient was given 5-FU adjuvantly (450 mg/gm hourly infusion), calcium folinate (100mg/gm) after an R0-Resection of a colon-carcinoma. Two days after the first cycle, an emergency hospitalization was necessary because severe mucositis WHO grade 4 developed. In the course of the disease, leukopenia (WHO grade 4) substitutional thrombopenia occurred. Despite cyotkine administration, the leukopenia became protracted during the following 14 days. In addition, a sepsis occurred that was able to be treated with antibiotics.
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Scientific Proof of Clinical Relevance
The following clinical data demonstrate that pre-therapeutic diagnosis of the DPD Exon-14 mutation could have prevented approx. 630 cases annually in which patients suffer from severe to life-threatening side effects including death in Germany alone. This number corresponds to approx. one-third of the entire number of patients suffering severe side effects caused by 5-Fluorouracil. Furthermore, the data show that this specific pre-therapeutic diagnosis can reduce the health care system's expenses
1. Exon 14-Skipping Mutation and toxicity (WHO-grade 4) after 5-FU therapy, retrospective data
The following data have been gathered from international retrospective trials.
| N | Mutation carrier | Prevalence | Source |
| 60 | 17 | 28% | van Kuilenburg et al., Pharmacogenetics 12:555-8; 2002 |
| 25 | 6 | 24% | Oncoscreen/Raida et al., Clin.Canc.Res.7:2832-9; 2001 |
| 8 | 2 | 25% | Oncoscreen, unpubliziert |
| 93 | 25 | 27% | * Total |
*confidence interval (97%): 17 – 37%
R E S U L T:
One-third of all patients with a toxicity 4 after 5-FU treatment are carriers of the Exon-14 Skipper Mutation.
2. Exon 14-Skipping Mutation and toxicity after 5-FU therapy, prospective data
The first prospective data were published by Bokemeyer/Eichelbaum during a workshop at the Margarete-Fischer-Bosch Institute in September 2003. Carriers of the Exon 14-Skipping Mutation were identified within a multi-centric clinical trial and treated with 5-FU. The results are presented in the following table:
|
toxicity grading according to WHO |
Number of Mutation carriers (heterozygous) | Prevalence |
| 4 | 4 | 30,8% |
| 3 | 2 | 15,4% |
| 2 | 3 | 23,1% |
| 0-1 | 2 | 30,8% |
| 13 | 100% |
R E S U L T:
Even these prospective data show that Exon 14-Skipping Mutation carriers suffer an increased risk of toxicity.
3. Prevalence
bislang liegen aus international veröffentlichten retrospektiven Untersuchungen folgende Daten vor:
| N | Heterozygous | Prevalence | Source |
| 851 | 8 | 0,94% | Raida et al., Clin. Canc. Res. 7, 2832-9, 2001 |
| 1357 | 24 | 1,77% | van Kuilenburg et al., Clin. Canc. Res. 7, 1149-53, 2001 |
| 685 | 13 | 1,90% | Bokemeyer/Eichelbaum/Schwab 09/2003 |
| 1455 | 15 | 1,03% | Oncoscreen/FSU University, Jena, preliminary data, 01/03 |
| 4348 | 60 | 1,38%* | *Total |
*confidence interval (97%): 1,0%-1,8%
In Germany doctors initiate treatment with 5-Fluorouracil for approx.100,000 patients annually. This means that approx. 1,380 heterozygous and about 3 homozygous mutation carriers are treated each year. Of those, approx. 45 % or 600 patients suffer severe to life-threatening side effects, including death. The 5-Fluorouracil treatment is life threatening for homozygous mutation carriers. These cases could be avoided if patients were tested pre-therapeutically.
Literature4. Pharma-economical aspects
As the above-mentioned numbers indicate, approx. 160 patients have to be tested to save one patient from severe side effects after 5-Fluorouracil treatment, because of the DPD mutation. In Germany, one test costs approx. 150 euros and the combined testing of 160 patients costs approx. 24,000 euros. With our best knowledge, the costs of the treatment of a WHO grade 4 toxicity patient can be as high as 30,000 to 100,000 euros. Even if we take the lowest number (30,000 euros) the DPD Exon-14 pre-therapeutic testing can save more than 3.6 million euros per year (6,000 euros savings X 600 patients). These calculations demonstrate that general testing of the DPD Exon 14-Skipping Mutation could substantially decrease health care expenses.
5. Prospective Investigations
A study involving 1455 patients initiated by Oncoscreen and the Clinic for Internal Medicine of the Friedrich Schiller University, Jena, is finished and the data are currently being analyzed. This should quantify with greater precision the relationship between the genotype and phenotype of the mutation carrier. Clear confidence for the treating doctor is only possible, however, when an investigation into the individual pharmaco-kinetics is carried out if a positive test for the Exon 14-Skipping Mutation occurs.
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Consequences of Treatment
Patients who are heterozygous carriers can be shown to be at risk of suffering severe to lethal side effects after a 5- Fluorouracil chemotherapy treatment. In Germany approx. 1350 heterozygous mutation carriers per annum are treated with 5-Fluorouracil. In the case of mutation carriers, alternative substances should be considered, or the patient should undergo a pharmaco-kinetic test. A test of this kind can be carried out in the laboratory of Prof. Schalhorn in the university clinics of Munich-Großhadern in Germany. We are more than happy to arrange appropriate contacts.
The cells of homozygous mutation carriers have no significant DPD-activity, so that in general, massive side effects of the 5-Fluorouracil can be expected. Recently (Clin. Canc. Res. 5 [1999] 2006-2011), the case of a patient was described who after just a topical application of Efudex ointment to the scalp, developed a life-threatening bone marrow depression.
A 5-Fluorouracil therapy is contra-indicated for these patients.
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Diagnostic Results (Numbers)
Among 12,000 patients Oncoscreen has tested 5 homozygous and 187 heterozygous mutation carriers were discovered. 43 of the mutation carriers were identified before the treatment with Fluorouracil; unfortunately, 68 of the mutation carriers were only identified retrospectively, after strong side effects of the Fluorouracil had appeared. Eleven of these patients died as a result of the side effects. Two mutation carriers were identified after severe toxicities (WHO grade 4) following a treatment with Capecitabine/Xeloda. This example shows that mutation carriers are at risk of severe toxicities even when 5-FU is administered as a pro-drug.
Thus, Oncoscreen has identified more carriers of the Exon 14-Skipping Mutation than any other laboratory in the world.
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Oncoscreen®
Loebstedter Str. 93
07749 Jena
Germany
Phone: +49 (0) 3641 / 5074-0