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Table 22.1Drugs with genetic information in their labelsDrugCompanyIndicationGenotypeEffectLabelAbacavir(Ziagen)GlaxoSmithKlineHIV-1HLA-B*5701HypersensitivityScreening for the HLA-B*5701 alleleshould be done prior to initiating therapy with abacavirAzathioprine(Imuran)PrometheusRenal allografttransplantationTPMT*2, TPMT*3A,TPMT*3CSevere myelotoxicityTPMT genotyping can help identifypatients who are at an increased risk for developing Imuran toxicityCarbamazepine(Tegretol)NovartisEpilepsy, trigeminalneuralgiaHLA-B*1502Stevens-Johnsonsyndrome (toxic epidermal necrolysis)Patients in genetically at-risk populationsshould be screened for HLA-B*1502 prior to initiating treatment and those testing positive not be treated with TegretolCetuximab(Erbitux)ImcloneMetastatic colorectalcancerKRAS mutationsEfficacyUse of Erbitux is not considered effectivefor the treatment of patients colorectal cancer who have KRAS mutations in codon 12 or 13Clopidogrel(Plavix)Bristol-MyersSquibbAnti-platelet:prevents strokes and heart attacksCYP2C19*2*3EfficacyAlternative treatment should be consideredfor patients identifi ed as CYP2C19 poor metabolizersIrinotecan(Camptosar)Pfi zerMetastatic colorectalcancerUGT1A1*28Diarrhea, neutropeniaA reduction in the starting dose by at leastone level of Camptosar should be considered for patients known to be homozygous for UGT1A1*28 allelePanitumumab(Vectibix)AmgenMetastatic colorectalcancerKRAS mutationsEfficacyVectibix is ineffective in patients whosetumors have KRAS mutations© Jain PharmaBiotech22 Regulatory Aspects of Personalized Medicine