COMPARISON BETWEEN A POINT-OF-CARE AND A LABORATORY-BASED CYP2C19*2 GENOTYPING ASSAY
FOR PHARMACIST-LED PERSONALISATION OF ANTIPLATELET THERAPY
DEPARTMENT OF PHARM
ACY
UNIVERSI
TY OF MA
LTA
Francesca Wirth*, Graziella Zahra**, Robert G. Xuereb***, Christopher Barbara**, Albert Fenech***, Lilian M. Azzopardi*
*Department of Pharmacy, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
** Molecular Diagnostics Unit, Department of Pathology, Mater Dei Hospital, Msida, Malta
***Cardiac Catheterisation Suite, Department of Cardiology, Mater Dei Hospital, Msida, Malta
Department of Pharmacy University of Malta
Email: francesca.wirth@um.edu.mt
INTRODUCTION
METHOD
RESULTS
The novel point-of-care (POC) Spartan™ RX
 After obtaining written informed consent, patients undergoing PCI with stent
 The patient cohort consisted of 34 patients.
Twenty-five patients were male and 9 were
female, mean age was 66 years (range 49-75
years) and all patients were Caucasian.
has not been previously compared to
deployment for acute coronary syndrome or stable angina and who were
candidates for dual antiplatelet therapy, were recruited by non-probability
sampling from the catheterisation laboratory at Mater Dei Hospital (MDH).
Exclusion criteria were patients age < 18 years and > 75 years, body weight
< 60 kg, history of stroke or transient ischaemic attack, active bleeding,
coagulation or platelet disorders, and/or chronic liver disease.
laboratory-based CYP2C19*2 genotyping
 A buccal swab and EDTA-whole blood sample were obtained for CYP2C19*2
CYP2C19
genotyping
assay
rapidly
identifies presence of the CYP2C19 loss-offunction ‘*2’ variant allele and can be
applied to personalise antiplatelet therapy
at the start of treatment.
1-3
This POC assay
using reverse dot-blot (RDB) hybridisation.
AIMS
To apply the Spartan™ RX assay for
pharmacist-led CYP2C19*2 genotyping to
personalise antiplatelet therapy in
patients undergoing percutaneous
coronary intervention (PCI) and compare
it to a laboratory-based CYP2C19*2
genotyping assay which uses a robust and
accurate RDB hybridisation technique.
genotyping with the POC Spartan™ RX CYP2C19 assay (Spartan Bioscience)
and with the laboratory-based GenID® RDB hybridisation 2070/1X assay
(Autoimmun Diagnostika AID GmbH) respectively.
 Each patient was genotyped as a non-carrier of CYP2C19*2 (*1/*1), a carrier
of one *2 allele (*1/*2), or a carrier of two *2 alleles (*2/*2).
 Genotypes requiring alternative antiplatelet therapy to clopidogrel (*1/*2,
4
*2/*2) were verbally communicated to the cardiologist and treatment
decision was taken by the cardiologist. All processes were led by a clinical
 With
the POC Spartan™ RX assay,
21 patients were genotyped as non-carriers
of the CYP2C19 *2 allele, 12 patients as
carriers of one *2 allele and 1 patient as a
carrier of two *2 alleles.
 With the GenID® assay, the same 21
patients were genotyped as non-carriers of
the CYP2C19 *2 allele, however 13 patients
were genotyped as carriers of one *2 allele
and no patients were identified as carriers of
two *2 alleles.
 Agreement in genotype results was 97%
Type of test system
Polymerase chain
reaction-based
Sample type for
genomic DNA
Technique
Approximate timefor-result (hours)
User-friendliness
of test procedure
Sample
batching
Interpretation
of results
Assay
storage
Controls
Estimated cost
(€) per test
(consumables only)
Spartan™ RX
assay
Point-of-care
Yes
GenID® RDB
assay
Laboratory-based
Yes with reverse
hybridisation
Buccal swab
EDTA-whole blood
Non-invasive
Invasive
1
6
Simple procedure
Laborious
with no laborious
procedure with
preparation and
extensive training
very minimal
required
training required
Not required
Not required
however may be
more practical
Very user-friendly Very user-friendly
Strict requirement
Fridge 2-8 °C and
for manual defrost
any type of freezer
freezer at –20 °C
at –20°C or below
or below
Internal
Internal
225
23
Table 1: Qualitative comparison of assays used
(κ=0.939).
pharmacist researcher.
 Comparison between genotype results obtained with the two assays was
carried out using percentage agreement and Cohen’s kappa (κ) statistic.
CONCLUSION
The POC Spartan™ RX assay is accurate and reliable (97% agreement in genotype results). The single mismatched result does not
4
impact personalisation of antiplatelet therapy since an alternative to clopidogrel is recommended for both carriers of one and
two CYP2C19 LoF *2 alleles (13 patients in the cohort studied). The POC assay provides much faster results, requires minimal
training to perform the test and is non-invasive, however the tests are more expensive.
References
1. Roberts JD et al. Point-of-care genetic testing for personalisation of antiplatelet treatment (RAPID GENE): A prospective, randomised,
proof-of-concept trial. Lancet 2012; 379 (9827): 1705-11.
2. Stimpfle F et al. Impact of point-of-care testing for CYP2C19 on platelet inhibition in patients with acute coronary syndrome and early
dual antiplatelet therapy in the emergency setting. Thromb Res 2014; 134(1):105-10.
3. So DY al. A prospective randomized evaluation of a pharmacogenomic approach to antiplatelet therapy among patients with
ST-elevation myocardial infarction: The RAPID STEMI study. Pharmacogenomics J 2015 [Epub ahead of print].
4. Scott et al. Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for CYP2C19 genotype and clopidogrel therapy:
2013 update. Clin Pharmacol Ther 2013; 94 (3): 317-23.
Acknowledgements
This research was carried out in collaboration with all the consultant cardiologists, doctors, nurses and staff at the Department of Cardiology, MDH.
Financial Support: University of Malta Faculty of Medicine and Surgery Dean’s Initiative, Technoline Ltd., Scientech Ltd., Malta Heart Foundation,
Autoimmun Diagnostika AID GmbH, Orme Scientific Ltd., LEVO Laboratory Services Ltd.