Présenté au congrès hiv therapy

Evaluation of assays for anti-HIV drugs in serum in France :
preliminary results of a quality control survey.
C. Palette1,2, A.M. Taburet3, P. Marquet4, B. Diquet5, G. Peytavin6, A. Vassault1,7.
1 : ASQUALAB Hôpital Corentin Celton - 92130 Issy les Moulineaux, 2 : Hôpital A. Mignot (Biochimie-Pharmacologie) - 78157 Le Chesnay, 3 : Hôpital Bicêtre (Pharmacie) - 94270 Le Kremlin Bicêtre, Hôpital Dupuytren (Pharmacologie) - 87042 Limoges, 5 : Hôpital Pitié-Salpétrière (Pharmacologie)- 75013 Paris, 6 : Hôpital Bichat (Pharmacie) - 75018 Paris, Hôpital Necker (Biochimie) - 75015 Paris.
INTRODUCTION
The recent development of new HIV treatment combining various protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTI)
has emphasised the necessity for drug determination in serum for therapeutic drug monitoring (TDM). The need for inter-laboratory quality control
survey has been first raised by the members of the pharmacology group of the French Research Agency against AIDS (ANRS). ASQUALAB,
organiser of QC survey in the field of TDM, has been in charge of the development, design and organisation of this survey.
The aim of this study is to list and evaluate the assays current used for the different HIV drugs through the results of an external quality control. This exercise is intended to lead to improvement of the analytical methods used and possibly to the development of standard techniques.
MATERIALS, DESIGN AND METHODS
Human serum pool was spiked with the five VIH-protease inhibitors (Amprenavir, Indinavir, Nelfinavir, Table 2 : Number of participants for each drug
Ritonavir and Saquinavir) and two non-nucleoside Number of labs not performing Number of unreported results Efavirenz), then lyophilised (Randox). Twelve samples were shipped to 27 laboratories during February 2 000. The theoretical concentration ranges for the first survey Some of laboratories sent no result.
Table 3 : Characteristics of the methods used
Table 1 : Drugs targed concentrations
H.P.L.C. has been used by all the participants.
Table 4 : Mean, SD and CV for each drug
This first two samples had to be assayed before end of Consensus mean determination : data were computed
Amprenavir
according the usual procedure of QCs. Outliers, identified by a statistical treatment, were omitted from Indinavir
Nelfinavir
Ritonavir
DISCUSSION
Saquinavir
Protease inhibitors are the most often determined drugs Nevirapine
because of their short half-life, drug interactions and Efavirenz
high inter-individual variability in metabolism in human. May be NNRTIs are seldom assayed because of lessinter-individual variability and difficulty in obtaining pure standards.
For Ritonavir V02, Saquinavir V01, Nevirapine V01, CONCLUSION
Efavirenz V01, a limited number of laboratories were The inter-laboratory variability illustrates the difficulties encountered by the able to participate : the concentrations were found minus laboratories in the implementation of new HPLC methods when no internal nor than the limit of quantification for most of the other external QC are available. This first exercise demonstrates the need for development laboratories. Limits differs widely from one laboratory of standard methods and will help improve assay quality. The spiked concentrations were chosen to include both the therapeutic range of the anti-HIV drugs and the In this first round-robin, the criterium for quality lowest concentrations found in pharmaceutical studies. This is a useful tool for assessment was to be within ± 20% of the increasing inter-laboratory consistency of the results and consequently to improve interlaboratory mean for the two levels. ASQUALAB : Assurance de Qualité des Laboratoires

Source: http://www.asqualab.com/documents/publications/articles_et_posters/posters/poster_anti_HIV_drugs.pdf