SLCO1B1 gene variability influences lipid-lowering efficacy on simvastatin therapy in Southern Brazilians.

BACKGROUND: Variants in uptake and efflux transporters can influence diverse statin pharmacokinetics in different populations. This study aimed to investigate the influence of SLCO1B1 gene polymorphism on simvastatin treatment efficacy in a Brazilian population of European ancestry. METHODS: Two hundred and sixteen hypercholesterolemic patients were treated with 20 mg/day simvastatin for 6 months. Plasma lipid and lipoprotein levels were measured at baseline and after 2 and 6 months of treatment. The single nucleotide polymorphisms (SNPs) c.388A>G, c.463C>A and c.521T>C at SLCO1B1 gene were determined by allelic discrimination with TaqMan 5'-nuclease assays. The 388G allele was observed in 160 patients, the 521 C allele was observed in 64 individuals, whereas 61 subjects were 463 A allele carriers. RESULTS: Carriers of the SLCO1B1 388G allele had a greater reduction of total cholesterol and LDL cholesterol with simvastatin treatment, when compared with 56 388A homozygotes (-28.8% vs. -15.8%, p=0.005 and -39.0% vs. -30.6%, p=0.003; respectively). The c.463C>A and c.521T>C SNPs were not associated with simvastatin treatment. The SLCO1B1 haplotypes showed no statistically significant differences in mean percentage reductions in lipid and lipoprotein levels after simvastatin treatment. CONCLUSIONS: The present study suggests that the SLCO1B1 c.388A>G polymorphism could play a role in the inter-individual variation of clinical response to simvastatin in Brazilians. These results add to those that suggest that the effects of SLCO1B1 variants may be statin specific.

The role of common variants of ABCB1, CYP3A4, and CYP3A5 genes in lipid-lowering efficacy and safety of simvastatin treatment.

OBJECTIVE: Our objective was to investigate the interactions between common polymorphisms in ABCB1, CYP3A4, and CYP3A5 genes and the lipid-lowering efficacy and safety of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor simvastatin. METHODS: One hundred sixteen hypercholesterolemic patients were prospectively screened by physical examination, medical history, and clinical laboratory evaluation and were included in this study. Subjects entering the study were treated with 20 mg/d simvastatin. Plasma lipid and lipoprotein levels were measured before treatment, after 2 months of treatment, and after 6 months of treatment. Ninety-nine patients completed the 6-month follow-up and were included in the association analysis for treatment efficacy. Seventeen subjects who had adverse drug reactions (ADRs) to simvastatin (ADR group) could not complete the 6-month follow-up and were included in the association analyses for safety. Myalgia was observed in 15 of 17 subjects and was the only ADR included in the association analyses, but other common ADRs were also observed. Myalgia was defined as proximal or diffuse muscle pain, tenderness, or weakness, or both pain and weakness, with normal or slightly increased serum creatine phosphokinase levels. ABCB1 (1236C>T, 2677G>A/T, and 3435C>T), CYP3A4 (-392A>G), and CYP3A5 (6986A>G) allele variants were determined by polymerase chain reaction and restriction mapping. RESULTS: After adjustment for covariates, carriers of the ABCB1 1236T variant allele had a greater reduction in total cholesterol and low-density lipoprotein cholesterol with simvastatin treatment, as compared with homozygotes with the wild-type allele (-29.0% [95% confidence interval (CI), -25.9 to -32.5] versus -24.2% [95% CI, -19.0 to -29.3] [P = .042] and -39.6% [95% CI, -35.8 to -44.0] versus -33.8% [95% CI, -27.4 to -40.2] [P = .042], respectively). Similar results were observed for the 2677G>A/T polymorphism and haplotype data. The 1236T, 2677non-G, and 3435T alleles were less frequent in ADR cases than in the non-ADR group (P < .05 for all single-nucleotide polymorphisms). Haplotype analyses also demonstrated a reduction of the T-non-G-T haplotype frequency (20%) in patients in whom myalgia developed during simvastatin treatment, as compared with the non-ADR group (41.4%) (P = .03). No significant associations were observed between the CYP3A4 -392A>G and CYP3A5*3 allele variants and the efficacy or tolerability of simvastatin. CONCLUSIONS: Our data suggest an association of ABCB1 gene polymorphisms and the efficacy and safety of simvastatin.

Pharmacogenetic study of apolipoprotein E, cholesteryl ester transfer protein and hepatic lipase genes and simvastatin therapy in Brazilian subjects.

BACKGROUND: In recent years, one of the focuses of genetic investigation in cardiology has been to identify the genetic factors associated with variable response to statin treatment. Polymorphisms in apolipoprotein E (APOE), cholesteryl ester transfer protein (CETP) and hepatic lipase (LIPC), proteins with major roles in lipid metabolism and homeostasis have been shown associated with lipid-lowering drugs response. METHODS: One hundred forty-six hypercholesterolemic patients of European descent were prospectively enrolled and treated with simvastatin 20 mg per day for over 6 months. Ninety-nine subjects completed the 6-month follow-up. Plasma lipids and lipoproteins were measured before and throughout the study. APOE (E*2, E*3 and E*4), LIPC-250A > G and CETP TaqIB genotypes were determined by PCR and restriction mapping. RESULTS: After a 6-month follow-up, no differences among genotypes in the percentage variation in lipid and lipoprotein concentrations for APOE and LIPC SNPs were observed. After adjustment for covariates, CETP B2B2 homozygotes showed a greater HDL-cholesterol increase compared to B1B2 and B1B1 subjects (14.1% vs. 1.7% and 1.3%, P < 0.05, respectively). CONCLUSION: Our study demonstrates that individual plasma HDL-cholesterol response to simvastatin is mediated, in part, by the CETP gene locus, with the B2 homozygotes having more benefit in HDL-C improvement than carriers of B1 allele.