[AmpliChip CYP450: Cytochrome P450 genotyping in psychiatric patients]

Cuadros Celorrio M, Villegas Portero R
Record ID 32010001470
Authors' recommendations: Pharmacogenetics may offer enormous potential in providing clinical benefits to patients (personalised medicine), as well as clear financial advantages for Healthcare Services.However, unless the variants under study are relatively common among the population (prevalence > 30%) and there is a clear effect in terms of response to medication, large-scale population studies will be required to determine whether genetic variants alter patient prognosis.Among the most interesting allelic gene variants of cytochrome P450 which define the main phenotypes – i.e. poor, intermediate, extensive and ultra rapid – (1), are those that identify poor metabolisers which are associated with a greater incidence of adverse drug reactions (ADRs) and costly treatments as a result of prolonged hospitalisation (2).In theory, genotyping tests should identify most genetic variants functionally capable of modifying the expression or function of the proteins responsible for drug metabolism, transportation and/or reception. To choose the best suited method requires knowledge on the main mutations or polymorphisms to be studied, along with the sensitivity/specificity of the procedure, sample requirements and cost.The AmpliChip CYP450® test is heralded as one of the most practical and comprehensive methods for analysing a large number of the genetic variants of genes CYP2D6 and CYP2C19 and for identifying pharmacogenetic profiles in psychiatric patients (3). However, before this technology is introduced in the National Health Service prospective studies must be conducted on the AmpliChip CYP450® test in order to address crucial issues such as genotype veracity, correct patient identification, benefits derived from any treatment changes suggested by outcomes, presence of other genetic and environmental factors that may influence metabolism, the usefulness of the intervention in patients treated with drugs that are metabolised by CYP450 and, finally, how the data compiled may be applied to the prescription of drug therapy.In addition, structures, professional training and education will need to be adapted as well as decision-making with regard to candidate drugs for pharmacogenetic testing to ensure the successful introduction of pharmacogenetics in clinical practice; both cost-effectiveness studies and laboratory monitoring must be conducted by pharmaceuticals and specialists in the field, while possible ethical and legal issues also need to be fully addressed.Existing evidence on the sensitivity/specificity of the AmpliChip CYP450® test in determining CYP2D6 and CYP2C19 genotypes is poor. The only study that we were able to assess was conducted by industry, although research on CYP450 microarrays and the experience of research groups warrant the consistency of the genotypes obtained using AmpliChip CYP450®.There are some indications that microarrays – including AmpliChip CYP450®) – are sometimes a good alternative to sequencing although there are more requirements to be met in obtaining pharmacogenetic profiles for psychiatric patients.
Project Status: Completed
Year Published: 2007
English language abstract: An English language summary is available
Publication Type: Not Assigned
Country: Spain
MeSH Terms
  • Cytochrome P-450 CYP2D6
  • Genotype
Organisation Name: Andalusian Health Technology Assessment Area
Contact Address: Area de Evaluacion de Tecnologias Sanitarias Sanitarias de Andalucia (AETSA) Avda. Innovación, s/n Edificio Arena 1. Sevilla (Spain) Tel. +34 955 006 309
Contact Name: aetsa.csalud@juntadeandalucia.es
Contact Email: aetsa.csalud@juntadeandalucia.es
Copyright: Andalusian Agency for Health Technology Assessment (AETSA)
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