Page 160 - Genomic Medicine in Emerging Economies

Examples of Economic Evaluation and Cost-Effectiveness Analysis 149

medical intervention in different healthcare systems is the variable frequencies
of the pharmacogenomic biomarkers. As such, one should bear in mind that a
pharmacogenomics-guided medical intervention that is not cost-effective in a
certain country may be cost-effective in another country, even if no significant
cost differences exist between these two countries, but essentially because of
the higher frequency of a pharmacogenomic biomarker in the general popula-
tion. Notably, in several cases the genomic composition of a population may
be different from one geographical region to another (Mizzi et al., 2016). Indic-
atively, the Russian population clusters into several large ethnogeographical
groups, namely Slavs, Northern Caucasus populations, the Finno-Ugric people
of north European and Volga-Ural regions, the populations of South Siberia
and Central Asia, and the populations of Eastern Siberia and North Asia. For
example, the CYP2D6*7 allele frequency is significantly higher in the Maltese
population compared with the Caucasian average, and the same is true for
the CYP2C9*3 allele frequency in the Serbian population (Mizzi et al., 2016),
suggesting that there may be significant implications in the cost-effectiveness
of, for example, risperidone and warfarin treatments, respectively, in these
two countries. Another example is screening for the HLA-B*1502 allele, which
elevates patients’ risk of developing Stevens-Johnson syndrome (SJS) and
toxic epidermal necrolysis (TEN), when treated with the antiepileptic drugs
carbamazepine and phenytoin. A recent systematic review and meta-analysis
including 16 studies found considerable variation among different racial/eth-
nic populations in the relationship between HLA-B*1502 and carbamazepine-
induced SJS and TEN as illustrated by a summary odds ratio of 79.84 (95% CI,
28.45–224.06) with the following strong relationships warranting screening
for three racial/ethnic subgroups: Han Chinese 115.32 (18.17–732.13), Thais
54.43 (16.28–181.96), and Malaysians 221.00 (3.85–12,694.65) (Tangamorn-
suksan et al., 2013). Among individuals of white or Japanese race/ethnicity,
no patients with SJS or TEN were carriers of the HLA-B*1502 allele. An intra-
country example is a CEA of three ethnic groups in Singapore with different
allele frequencies of HLA-B*1502. Genotyping for HLA-B*1502 and providing
alternate antiepileptic drugs to those who test positive was found to be cost-
effective for Singaporean Chinese and Malays, but not for Singaporean Indi-
ans based on ICER ratios of US$37,030/QALY for Chinese patients, US$7,930/
QALY for Malays, and Us$136,630/QALY for Indians.

EXAMPLES OF ECONOMIC EVALUATION
AND COST-EFFECTIVENESS ANALYSIS
Anticoagulation Therapy
Warfarin is one of the most studied drugs in Europe, and one of the few drugs
in which the cost-effective data has been shared worldwide; because of this it