| Ch 11 | Page 13 / 16 | |
| Cancer other treatments |
EGFR inhibitors | |
Two molecules are now in clinical use.
ZD 1839 (Iressa™) and OSI-774 (Tarceva™) are selective inhibitors of the tyrosine kinase of the Epidermal Growth Factor Receptor. They block signal transduction and thus cell multiplication. They are administered orally.
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| Iressa is given orally at a common continuous dosage of 500 mg/m2 | Tarceva is given at various dosages from 25 to 200 mg/day orally. |
The facility to detect the HER-2 receptor has enabled the development of a specific antibody (trastuzumab). However, to date, we cannot assay the overexpression of EGFR with a precise and reproducible method. Thus, it is difficult to predict which type of tumour and, within a given type which tumour, will respond to treatment.
Various methods were used:
local dosage of EGFR by analytical or immunoenzyme methods
dosage of the serum protein,
fixation methods of EGF at the tumour surface,
transcription RNA level.
The expression of EGFR generally signifies poor prognosis with a poor response to chemotherapy.
EGFR are very ubiquitous. EGFR abnormalities can be more severe than their overexpression would suggest.
In France, no such EGFR small molecule inhibitor has been accepted by the health authority and trials are still underway.
The main tumours for which these products seems to be interesting are :
- Non-small cell lung cancer, for which bright but generally short responses have been observed
Generally they are easy to monitor but may handicap the patient, since they are generally long term treatments:
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