Association between statin-induced creatine kinase elevation and genetic polymorphisms in SLCO1B1, ABCB1 and ABCG2

Potential amelioration of liver function by low-dose tolvaptan in heart failure patients

Aim

This study aimed to evaluate the relationships between the pharmacokinetics of tolvaptan and its metabolites (DM-4103 and DM-4107) and liver injury in heart failure patients, using relevant laboratory test values and markers of hepatocyte injury and biliary cholestasis.

Method

The plasma concentrations of tolvaptan, DM-4103, and DM-4107 were determined using LC-MS/MS in 51 Japanese heart failure patients. The relationships between the concentrations and the N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP), AST, and ALT were assessed. K18 and glutamate dehydrogenase as a marker of liver injury and CP-I and CP-III as indicators of OATP activity were also determined.

Results

The median concentrations of tolvaptan, DM-4103, and DM-4107 were 16.2, 287, and 38.0 ng/mL, respectively. AST, ALT, and T-Bil were significantly decreased after tolvaptan administration. They were negatively correlated with tolvaptan concentration. AST was also negatively correlated with DM-4107 concentration. CP-III was positively correlated with DM-4103 concentration; however, CP-I was negatively correlated with DM-4103 concentration. K18 and glutamate dehydrogenase were not correlated with tolvaptan concentration.

Conclusion

Low-dose tolvaptan did not cause liver injury. Pharmacokinetics of tolvaptan may be associated with potential amelioration of liver function in heart failure patients.

Effect of ABCG2 c.421 C> A (rs2231142) single nucleotide polymorphisms on the lipid-modulating efficacy of rosuvastatin: a meta-analysis

BACKGROUND

To systematically evaluate the effect of ABCG2 c.421 C > A (rs2231142) single nucleotide polymorphism (SNP) on the lipid-modulating efficacy of rosuvastatin (RST).

METHODS

Searches were conducted using the Wan Fang database, Web of Science, Embase, PubMed, Cochrane Library, and China Journal Full Text Database. The time frame for the search was from the database's creation to September 1, 2024. The RevMan 5.4 software was used to conduct a meta-analysis after the literature was filtered based on the inclusion and exclusion criteria, and pertinent data was extracted following methodological quality evaluation.

RESULTS

A total of 7 studies, including 1347 patients, were included. Meta-analysis showed that in a dominant model of inheritance, RST had a significant effect on low-density lipoprotein cholesterol (LDL-C) [MD = -7.23, 95% CI (-8.71, -5.75), P < 0.05], total cholesterol (TC) [MD = -7.15, 95% CI (-8.71, -5.75), P < 0.05], and triglyceride (TG) [MD = -7.34, 95% CI (-10.88, -3.80), P < 0.05] in patients harboring an A allele decreased significantly more than CC, but there was no significant difference in the change of high-density lipoprotein cholesterol (HDL-C) [MD = -2.22, 95% CI (-19.87, 15.43), P = 0.81]. The results of the sensitivity analysis suggested that all outcome indicators were stable. However, this study's small sample size may be heterogeneous, and more large-sample, multi-center studies are needed for future validation.

CONCLUSIONS

The ABCG2 c.421 C > A (rs2231142) SNP significantly affected the lipid-modulating efficacy of RST, especially the down-regulation of LDL-C, TC, and TG.

Genetic Determinants of Response to Statins in Cardiovascular Diseases

Despite extensive efforts to identify patients with cardiovascular disease (CVD) who could most benefit from the treatment approach, patients vary in their benefit from therapy and propensity for adverse drug events. Genetic variability in individual responses to drugs (pharmacogenetics) is considered an essential determinant in responding to a drug. Thus, understanding these pharmacogenomic relationships has led to a substantial focus on mechanisms of disease and drug response. In turn, understanding the genomic and molecular bases of variables that might be involved in drug response is the main step in personalized medicine. There is a growing body of data evaluating drug-gene interactions in recent years, some of which have led to FDA recommendations and detection of markers to predict drug responses (e.g., genetic variant in VKORC1 and CYP2C9 genes for prediction of drug response in warfarin treatment). Also, statins are widely prescribed drugs for the prevention of CVD. Atorvastatin, fluvastatin, rosuvastatin, simvastatin, and lovastatin are the most common statins used to manage dyslipidemia. This review provides an overview of the current knowledge on the pharmacogenetics of statins, which are being used to treat cardiovascular diseases.

Genetic polymorphisms in ABCB1 are correlated with the increased risk of atorvastatin-induced muscle side effects: a cross-sectional study

Genetic factors are recognized as risk factors for statin-associated muscle symptoms (SAMS), which are the most common cause of statin intolerance. The aim of this study was to determine whether there is an association between polymorphisms 1236C > T, 2677G > T/A, and 3435C > T in the ABCB1 gene, encoding the efflux transporter of statins, and SAMS, as results on this topic are still controversial. A cross-sectional study was conducted on patients with or without SAMS using atorvastatin. The influence of non-genetic variables on SAMS was also evaluated. Our results show that patients with TT genotype in 1236C > T, 2677G > T/A, and 3435C > T polymorphisms had higher risk of developing SAMS, compared to wild type and heterozygous carriers together (OR 4.292 p = 0.0093, OR 5.897 p = 0.0023 and OR 3.547 p = 0.0122, respectively). Furthermore, TTT/TTT diplotype was also associated with a higher risk of SAMS, OR 9.234 (p = 0.0028). Only family history of cardiovascular disease was found to be a risk factor for SAMS, in addition to the known non-genetic variables. We believe that ABCB1 genotyping has great potential to be incorporated into clinical practice to identify high-risk patients in a timely manner.

Predictive Value of SLCO1B1 c.521T>C Polymorphism on Observed Changes in the Treatment of 1136 Statin-Users

Pharmacogenomic testing is a method to prevent adverse drug reactions. Pharmacogenomics could be relevant to optimize statin treatment, by identifying patients at high risk for adverse drug reactions. We aim to investigate the clinical validity and utility of pre-emptive pharmacogenomics screening in primary care, with SLCO1B1 c.521T>C as a risk factor for statin-induced adverse drug reactions. The focus was on changes in therapy as a proxy for adverse drug reactions observed in statin-users in a population-based Dutch cohort. In total, 1136 statin users were retrospectively genotyped for the SLCO1B1 c.521T>C polymorphism (rs4149056) and information on their statin dispensing was evaluated as cross-sectional research. Approximately half of the included participants discontinued or switched their statin treatment within three years. In our analyses, we could not confirm an association between the SLCO1B1 c.521T>C genotype and any change in statin therapy or arriving at a stable dose sooner in primary care. To be able to evaluate the predictive values of SLCO1B1 c.521T>C genotype on adverse drug reactions from statins, prospective data collection of actual adverse drug reactions and reasons to change statin treatment should be facilitated.

ASSOCIATION OF SOLUTE CARRIER ORGANIC ANION TRANSPORTER 1B1 GENE POLYMORPHISM WITH RESPONSE TO ATORVASTATIN AND ASSOCIATED MYOPATHY IN IRAQI DYSLIPIDEMIA PATIENTS

OBJECTIVE

Aim: The study aims to investigate the effect of solute carriers organic anions transporters 1B1 (SLCO1B1) gene polymorphisms rs4149056, rs2306283, rs55901008, and rs729559745 in a sample of patients with dyslipidemia, and relate it to atorvastatin response and associated myopathy.

PATIENTS AND METHODS

Materials and Methods: A cross sectional enrolled 200 patients both males and females of Arabic race, Iraqi nationality aged between 30-65 years. The patients were divided into two groups: Group 1 (Atorvastatin responders and tolerant), Group 2 (Atorvastatin non responder and intolerant). Blood samples collected from the patients for biochemical studies and analyzed statistically by Student T-test and Chi-square, and DNA extracted for polymerase chains reactions (PCR).

RESULTS

Results: The results showed insignificant association P≥0.05 between the demographic characteristics of the study population with different genotypes, and significant difference P<0.05 in the biochemical parameters regarding (T-cholesterol, triglycerides, low density lipoproteins, and Creatine kinase-MM) when comparing the two groups. Odds ratio (OR) with confidence intervals CI (95%) used to evaluate the risk association to develop myopathy and poor response to atorvastatin therapy show relevant association for CC and CT genotype of rs4149056, while rs2306283 GG genotype show low association, also rs55901008 show low association for CC genotype, and moderate association for rs72559745 genotypes GG, AG.

CONCLUSION

Conclusions: The mutant allele's genotypes of rs4149056, rs55901008, and rs72559745, and the wild allele genotype of rs2306283 show significant association with the development of poor response to atorvastatin and elevated the level of CK-MM plasma concentration.

Association between high-dose methotrexate-induced toxicity and polymorphisms within methotrexate pathway genes in acute lymphoblastic leukemia

Methotrexate (MTX) is a folic acid antagonist, the mechanism of action is to inhibit DNA synthesis, repair and cell proliferation by decreasing the activities of several folate-dependent enzymes. It is widely used as a chemotherapy drug for children and adults with malignant tumors. High-dose methotrexate (HD-MTX) is an effective treatment for extramedullary infiltration and systemic consolidation in children with acute lymphoblastic leukemia (ALL). However, significant toxicity results in most patients treated with HD-MTX, which limits its use. HD-MTX-induced toxicity is heterogeneous, and this heterogeneity may be related to gene polymorphisms in related enzymes of the MTX intracellular metabolic pathway. To gain a deeper understanding of the differences in toxicity induced by HD-MTX in individuals, the present review examines the correlation between HD-MTX-induced toxicity and the gene polymorphisms of related enzymes in the MTX metabolic pathway in ALL. In this review, we conclude that only the association of SLCO1B1 and ARID5B gene polymorphisms with plasma levels of MTX and MTX-related toxicity is clearly described. These results suggest that SLCO1B1 and ARID5B gene polymorphisms should be evaluated before HD-MTX treatment. In addition, considering factors such as age and race, the other exact predictor of MTX induced toxicity in ALL needs to be further determined.

Pharmacogenomics of lipid-lowering agents: the impact on efficacy and safety

Hyperlipidemia is a significant risk factor for cardiovascular disease morbidity and mortality. The lipid-lowering drugs are considered the cornerstone of primary and secondary prevention of atherosclerotic cardiovascular disease. Unfortunately, the lack of efficacy and associated adverse effects, ranging from mild-to-moderate to potentially life-threatening, lead to therapy discontinuation. Numerous reports support the role of gene polymorphisms in drugs' pharmacokinetic parameters and their associated adverse reactions. Therefore, this study aims to understand the pharmacogenomics of lipid-lowering drugs and the impact of genetic variants of key genes on the drugs' efficacy and toxicity. Indeed, genetically guided lipid-lowering therapy enhances overall safety, improves drug adherence and achieves long-term therapy.

Loss of function polymorphisms in SLCO1B1 (c.521T>C, rs4149056) and ABCG2 (c.421C>A, rs2231142) genes are associated with adverse events of rosuvastatin: a case-control study

PURPOSE

The study aims to evaluate relationship between polymorphisms associated with a reduced function of two transporter proteins resulting in increased exposure to rosuvastatin - organic anion transporter 1B1 (OATP1B1) (SLCO1B1 c.521T>C) and ATP binding cassette subfamily G member 2 (ABCG2) (ABCG2 c.421C>A) and occurrence of rosuvastatin related myotoxicity/hepatotoxicity.

METHODS

In a case-control study, cases (rosuvastatin treated patients developing myotoxicity or hepatotoxicity) and controls (concurrent rosuvastatin treated patients free of adverse events) were prospectively recruited over a 2 year period in a single tertiary center specialized in treatment of metabolic disorders. Subjects were evaluated for clinical, comorbidity, and comedication characteristics and for genotype predicted metabolizing phenotypes regarding cytochrome P450 enzymes CYP2C9 and CYP2C19. Standard regression analysis and analysis in matched sets of cases and controls (optimal full matching) were undertaken by fitting frequentist and Bayesian models (covariates/matching variables: age, sex, diabetes, liver/renal disease, hypertension, CYP2C9 and C19 phenotype, use of CYP or transporter inhibitors, non evaluated transporter genotype).

RESULTS

A total of 88 cases (81 with myotoxicity, 6 with hepatotoxicity, 1 with both) and 129 controls were recruited. Odds of variant SLCO1B1 c.521T>C allele were 2.2-2.5 times higher in cases than in controls (OR = 2.45, 95% CI 1.34-4.48; Bayesian OR = 2.59, 95% CrI 1.42-4.90 in regression analysis; OR = 2.20, 1.10-4.42; Bayesian OR = 2.26, 1.28-4.41 in matched analysis). Odds of variant ABCG2 c.421C>A allele were 2.1-2.3 times higher in cases than in controls (OR = 2.24, 1.04-4.83; Bayesian OR = 2.35, 1.09-4.31 in regression analysis; OR = 2.10, 0.83-5.31; Bayesian OR = 2.17, 1.07-4.35 in matched analysis).

CONCLUSION

Loss of function polymorphisms in SLCO1B1 c.521T>C and ABCG2 c.421C>A genes are associated with the presence of rosuvastatin related myotoxicity and/or hepatotoxicity.

A systematic review and meta-analysis of genotype-based and individualized data analysis of SLCO1B1 gene and statin-induced myopathy

This meta-analysis was conducted to determine the genotypic effects of rs4149056 and rs2306283 polymorphism in SLCO1B1 gene on myopathy in patients with statin. Studies were searched using multiple databases and selected following inclusion criteria. Two reviewers independently performed data extraction and assessments for risk of bias. Fixed-or-random-effect was applied to pool allele frequency/effects. Mixed-effect logit model was used to pool genotypic effects using individual patient data. Heterogeneity and publication bias were explored. Fourteen studies were pooled for rs4149056; the minor C allele frequency were 15% in Caucasians and 14% in Asians. Six studies were pooled for rs2306283; the minor G allele frequency was 34% in Caucasian and 75% in Asians. Genotypic effects of rs4149056 polymorphism in Caucasians indicated that statin users who carried CC and TC genotypes had a significantly higher risk of myopathy than those who carried TT genotype, with a pooled odds ratio (OR) of 2.9 (95% confidence interval, 1.59, 5.34) and 1.6 (1.20, 2.16), respectively. For subgroup analysis, CC and TC genotypes also suggested a higher risk of myopathy in simvastatin users [OR = 2.8 (1.17, 6.77) and OR = 1.8 (1.15, 2.77), respectively] and in atorvastatin users [OR = 4.0 (1.23, 12.63) and OR = 2.0 (1.11, 3.52), respectively] than those who carried TT genotype. There was no significant association between rs2306283 polymorphism and myopathy in Caucasians and Asians. There was no evidence of publication bias for both polymorphisms.

Correlation between single-nucleotide polymorphisms and statin-induced myopathy: a mixed-effects model meta-analysis

PURPOSE

A meta-analysis was performed to evaluate the correlation between single-nucleotide polymorphisms (SNPs) and risk of statin-induced myopathy (SIM).

METHODS

We retrieved the studies published on SIM until April 2019 from the PubMed, Embase, and Cochrane Library databases. We collected data from 32 studies that analyzed 10 SNPs in five genes and included 21,692 individuals and nine statins.

RESULTS

The analysis of the heterozygous (p = 0.017), homozygous (p = 0.002), dominant (p = 0.005), and recessive models (p = 0.009) of SLCO1B1 rs4149056 showed that this SNP increases the risk of SIM. Conversely, heterozygous (p = 0.048) and dominant models (p = 0.030) of SLCO1B1 rs4363657 demonstrated that this SNP is associated with a reduced risk of SIM. Moreover, an increased risk of SIM was predicted for carriers of the rs4149056 C allele among simvastatin-treated patients, whereas carriers of the GATM rs9806699 A allele among rosuvastatin-treated patients had a lower risk of SIM.

CONCLUSION

The meta-analysis revealed that the rs4149056 and rs4363657 SNPs in SLCO1B1 and the rs9806699 SNP in GATM are correlated with the risk of SIM.

Pharmacogenetics of Statin-Induced Myotoxicity

Statins, a class of lipid-lowering medications, have been a keystone treatment in cardiovascular health. However, adverse effects associated with statin use impact patient adherence, leading to statin discontinuation. Statin-induced myotoxicity (SIM) is one of the most common adverse effects, prevalent across all ages, genders, and ethnicities. Although certain demographic cohorts carry a higher risk, the impaired quality of life attributed to SIM is significant. The pathogenesis of SIM remains to be fully elucidated, but it is clear that SIM is multifactorial. These factors include drug-drug interactions, renal or liver dysfunction, and genetics. Genetic-inferred risk for SIM was first reported by a landmark genome-wide association study, which reported a higher risk of SIM with a polymorphism in the SLCO1B1 gene. Since then, research associating genetic factors with SIM has expanded widely and has become one of the foci in the field of pharmacogenomics. This review provides an update on the genetic risk factors associated with SIM.

Statin-Related Myotoxicity: A Comprehensive Review of Pharmacokinetic, Pharmacogenomic and Muscle Components

Statins are a cornerstone in the pharmacological prevention of cardiovascular disease. Although generally well tolerated, a small subset of patients experience statin-related myotoxicity (SRM). SRM is heterogeneous in presentation; phenotypes include the relatively more common myalgias, infrequent myopathies, and rare rhabdomyolysis. Very rarely, statins induce an anti-HMGCR positive immune-mediated necrotizing myopathy. Diagnosing SRM in clinical practice can be challenging, particularly for mild SRM that is frequently due to alternative aetiologies and the nocebo effect. Nevertheless, SRM can directly harm patients and lead to statin discontinuation/non-adherence, which increases the risk of cardiovascular events. Several factors increase systemic statin exposure and predispose to SRM, including advanced age, concomitant medications, and the nonsynonymous variant, rs4149056, in SLCO1B1, which encodes the hepatic sinusoidal transporter, OATP1B1. Increased exposure of skeletal muscle to statins increases the risk of mitochondrial dysfunction, calcium signalling disruption, reduced prenylation, atrogin-1 mediated atrophy and pro-apoptotic signalling. Rare variants in several metabolic myopathy genes including CACNA1S, CPT2, LPIN1, PYGM and RYR1 increase myopathy/rhabdomyolysis risk following statin exposure. The immune system is implicated in both conventional statin intolerance/myotoxicity via LILRB5 rs12975366, and a strong association exists between HLA-DRB1*11:01 and anti-HMGCR positive myopathy. Epigenetic factors (miR-499-5p, miR-145) have also been implicated in statin myotoxicity. SRM remains a challenge to the safe and effective use of statins, although consensus strategies to manage SRM have been proposed. Further research is required, including stringent phenotyping of mild SRM through N-of-1 trials coupled to systems pharmacology omics- approaches to identify novel risk factors and provide mechanistic insight.

Drug-drug-gene interactions and adverse drug reactions

The economic and health burden caused by adverse drug reactions has increased dramatically in the last few years. This is likely to be mediated by increasing polypharmacy, which increases the likelihood for drug–drug interactions. Tools utilized by healthcare practitioners to flag potential adverse drug reactions secondary to drug–drug interactions ignore individual genetic variation, which has the potential to markedly alter the severity of these interactions. To date there have been limited published studies on impact of genetic variation on drug–drug interactions. In this review, we establish a detailed classification for pharmacokinetic drug–drug–gene interactions, and give examples from the literature that support this approach. The increasing availability of real-world drug outcome data linked to genetic bioresources is likely to enable the discovery of previously unrecognized, clinically important drug–drug–gene interactions.

Pharmacogenetics of statins treatment: Efficacy and safety

WHAT IS KNOWN AND OBJECTIVE

Statins are widely used worldwide in the prevention and treatment of coronary atherosclerotic heart disease and ischaemic stroke. However, in clinical application, statins have shown great individual differences in terms of the efficacy and safety, some of which are related to genetic factors. The purpose of this article was to summarize the recent advances about the correlation between gene polymorphisms and the efficacy/safety of statins.

METHODS

We searched the databases including PharmGKB and PubMed (published before June 2019) using the keywords such as 'statin', 'gene polymorphism' and 'SNP' and obtained more than 100 articles. In this review, we described the clinical studies of genetic variants associated with both the efficacy and adverse reactions of statins. We also clarified the importance of taking pharmacogenetic variation into account to improve the clinical application of statins.

RESULTS AND DISCUSSION

The available data were collected and analysed to present the polymorphisms of candidate genes encoding the most promising proteins including SLCO1B1 (encoding uptake transporters); ABCB1, ABCC2, ABCG2 (encoding effluent transporter); APOE, APOA5 (encoding apolipoprotein); genes encoding cytochrome P450 enzyme system; KIF6, HMGCR, LDLR, LPA, PCSK9, COQ2, CETP, etc These genes were proved to be related to the pharmacodynamics and pharmacokinetics of statins, thus affecting the efficacy and safety.

WHAT IS NEW AND CONCLUSION

In this paper, the correlation between gene polymorphisms and the efficacy/safety of statins was summarized. The authors reached a consensus that the variants of the genes encoding uptake and effluent transporters have the most effect on the efficacy/safety of statins. It pointed out that it is desirable to do genetic testing of these transporter genes to reduce the incidence of myopathy or to achieve better outcomes before patients use statins, especially in the regions with high frequency of risk allele.

Effects of SLCO1B1 and GATM gene variants on rosuvastatin-induced myopathy are unrelated to high plasma exposure of rosuvastatin and its metabolites

Myotoxicity is a significant factor contributing to the poor adherence and reduced effectiveness in the treatment of statins. Genetic variations and high drug plasma exposure are considered as critique causes for statin-induced myopathy (SIM). This study aims to explore the sequential influences of rosuvastatin (RST) pharmacokinetic and myopathy-related single-nucleotide polymorphisms (SNPs) on the plasma exposure to RST and its metabolites: rosuvastatin lactone (RSTL) and N-desmethyl rosuvastatin (DM-RST), and further on RST-induced myopathy. A total of 758 Chinese patients with coronary artery disease were enrolled and followed up SIM incidents for 2 years. The plasma concentrations of RST and its metabolites were determined through a validated ultra-performance liquid chromatography mass spectrometry method. Nine SNPs in six genes were genotyped by using the Sequenom MassArray iPlex platform. Results revealed that ABCG2 rs2231142 variations were highly associated with the plasma concentrations of RST, RSTL, and DM-RST (P_adj < 0.01, FDR < 0.05). CYP2C9 rs1057910 significantly affected the DM-RST concentration (P_adj < 0.01, FDR < 0.05). SLCO1B1 rs4149056 variant allele was significantly associated with high SIM risk (OR: 1.741, 95% CI: 1.180-2.568, P = 0.0052, FDR = 0.0468). Glycine amidinotransferase (GATM) rs9806699 was marginally associated with SIM incidents (OR: 0.617, 95% CI: 0.406-0.939, P = 0.0240, FDR = 0.0960). The plasma concentrations of RST and its metabolites were not significantly different between the SIM (n = 51) and control groups (n = 707) (all P > 0.05). In conclusion, SLCO1B1 and GATM genetic variants are potential biomarkers for predicting RST-induced myopathy, and their effects on SIM are unrelated to the high plasma exposure of RST and its metabolites.

Precision Medicine and Personalized Management of Lipoprotein and Lipid Disorders in Chronic and End-Stage Kidney Disease

Precision medicine is an emerging field that calls for individualization of treatment strategies based on characteristics unique to each patient. In lipid management, current guidelines are driven mainly by clinical trial results that presently indicate that patients with non-dialysis-dependent chronic kidney disease (CKD) should be treated with a β-hydroxy β-methylglutaryl-CoA reductase inhibitor, also known as statin therapy. For patients with end-stage kidney disease (ESKD) being treated with hemodialysis, statin therapy has not been shown to successfully reduce poor outcomes in trials and therefore is not recommended. The two major guidelines dissent on whether statin therapy should be of moderate or high intensity in non-dialysis-dependent CKD patients, but often leave the prescribing clinician to make that decision. These decisions often are complicated by the increased concerns for adverse events such as myopathies in patients with advanced kidney disease and ESKD. In the future, there may be an opportunity to further identify CKD and ESKD patients who are more likely to benefit from lipid-modifying therapy as opposed to those who likely will suffer from its side effects using precision medicine tools. For now, data from genetics studies and subgroup analyses may provide insight for future research directions in this field and we review some of the work that has been published in this regard.

Associations of the SLCO1B1 Polymorphisms With Hepatic Function, Baseline Lipid Levels, and Lipid-lowering Response to Simvastatin in Patients With Hyperlipidemia

Our goal was to examine the associations of the 388A>G and 521T>C polymorphisms in the solute carrier organic anion transporter 1B1 (SLCO1B1) gene with hepatic function, baseline lipid levels, and the lipid-lowering efficiency of simvastatin. We recruited 542 patients with hyperlipidemia. The 388A>G and 521T>C polymorphisms were genotyped. Serum alanine aminotransferase (ALT) and aspartate transaminase (AST), Serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels were measured before and after an oral 20-mg dose of simvastatin. Individuals with the 388AA genotype had higher ALT and AST levels than those with the 388AG or 388GG genotypes (P = .037 and P = .002, respectively). Individuals with both the 388AA and the 521TT genotypes had the highest levels of ALT and AST (P = .001 and P = .001, respectively). Moreover, we divided all patients into normal and abnormal subgroups based on elevated ALT and AST values (≥ 40 U/L), participants in the abnormal subgroup had a higher frequency of the 388A/521T haplotype and a lower frequency of the 388G/521T haplotype compared to those in the normal subgroup.  In addition, compared to 388G allele and 521C allele carriers, individuals with the 388G allele and 521TT genotype carriers had greater TC and LDL-C reduction in response to simvastatin after 4 weeks of treatment. Our conclusion suggests that the interaction between the SLCO1B1 388A>G and 521T>C polymorphisms could be an important genetic determinant of hepatic function and the therapeutic efficiency of simvastatin in Chinese patients with hyperlipidemia.

Interactions Between ABCB1 Genotype and Preoperative Statin Use Impact Clinical Outcomes Among Breast Cancer Patients

Multiple clinical trials investigate statins' effects in breast cancer. The ABCB1 genotype appears to influence statin response and toxicity in the cardiovascular setting. This exploratory study aimed to investigate the interplay between preoperative statin use, ABCB1 genotype, and tumor-specific expression of the statin target 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in breast cancer. Preoperative statin use, ABCB1 C3435T genotype, and HMGCR expression in relation to outcome were analyzed in 985 primary breast cancer patients from a population-based prospective cohort in Sweden from 2002 to 2012. Preoperative statin use (n = 80) was not associated with ABCB1 C3435T genotype (n = 576), HMGCR expression (n = 848), or clinical outcomes. ABCB1 C3435T TT-carriers had lower risk of breast cancer events than any C-carriers (adjusted hazard ratio (HR_adj) 0.74; 95%CI 0.49, 1.12), but only in non-statin users (P_interaction = 0.042). Statin users with TT genotype had higher risk of distant metastasis (HR_adj 4.37; 95%CI 1.20, 15.91; P_interaction = 0.009) and shorter overall survival than other patients (HR_adj 3.77; 95%CI 1.37, 10.39; P_interaction = 0.019). In conclusion, there were nominally significant interactions between ABCB1 genotype and preoperative statin use on clinical outcomes, while preoperative statin use was not associated with outcomes. Since this is an exploratory study of the impact of the ABCB1 genotype in relation to statin use and clinical outcomes in the breast cancer setting, the results should be interpreted with caution and warrant replication in an independent cohort, preferably in a randomized setting. Since statin use is common in breast cancer patients, it would be of interest to further elucidate the clinical impact of the ABCB1 genotype in breast cancer.

Familial Hypercholesterolemia: New Horizons for Diagnosis and Effective Management

Familial hypercholesterolemia (FH) is a common genetic cause of premature cardiovascular disease (CVD). The reported prevalence rates for both heterozygous FH (HeFH) and homozygous FH (HoFH) vary significantly, and this can be attributed, at least in part, to the variable diagnostic criteria used across different populations. Due to lack of consistent data, new global registries and unified guidelines are being formed, which are expected to advance current knowledge and improve the care of FH patients. This review presents a comprehensive overview of the pathophysiology, epidemiology, manifestations, and pharmacological treatment of FH, whilst summarizing the up-to-date relevant recommendations and guidelines. Ongoing research in FH seems promising and novel therapies are expected to be introduced in clinical practice in order to compliment or even substitute current treatment options, aiming for better lipid-lowering effects, fewer side effects, and improved clinical outcomes.

Rosuvastatin-Induced Rhabdomyolysis - Possible Role of Ticagrelor and Patients' Pharmacogenetic Profile

Up to the beginning of 2018, a total of eight cases describing rare but clinically important drug interactions between rosuvastatin and ticagrelor which resulted in rhabdomyolysis have been noted in the Global World Health Organization (WHO) adverse drug reaction (ADR) database (VigiBase) as well as in available literature. There are several possible factors which could contribute to the onset of rhabdomyolysis: old age, initially excessive rosuvastatin dose, drug-drug interactions (DDI) on metabolic enzymes (CYPs and UGTs) and drug transporter levels (ABCB1, ABCG2, OATP1B1) and pharmacogenetic predisposition. We reviewed all available cases plus the case of an 87-year-old female Croatian/Caucasian patient who developed rhabdomyolysis following concomitant treatment with rosuvastatin and ticagrelor. The results of the pharmacogenetic analysis indicated that the patient was a carrier of inactivating alleles CYP2C9*1/*3, CYP3A4*1/*22, CYP3A5*3/*3, CYP2D6*1/*4, UGT1A1*28/*28, UGT2B7 -161C/T, ABCB1 3435C/T and ABCB1 1237C/T which could have added to the interactions not only between ticagrelor and rosuvastatin but also other concomitantly prescribed medicines, such as amiodarone and proton pump inhibitors. In this case report, the possible multifactorial causes for rhabdomyolysis following concomitant use of rosuvastatin and ticagrelor such as old age, polypharmacy, renal impairment, along with pharmacogenetics will be discussed.

Effect modification by region in the associations of LEP G2548A and LEPR Q223R polymorphisms with statin-induced CK elevation

We investigated the associations of LEP G2548A and LEPR Q223R polymorphisms with statin-induced creatine kinase (CK) elevation among Chinese patients with hyperlipidemia. A total of587 enrolled individuals were treated with 20 mg/d oral simvastatin for 8 consecutive weeks. Genotyping of LEP G2548A and LEPR Q223R were conducted using PCR-RFLP. Multiple regression analyses showed that, in the Dongzhi region only, patients carrying the LEP AA genotype had a significantly greater increase in CK levels compared to those carrying the AG+GG genotypes after four weeks (P = 0.004) and eight weeks (P < 0.001) consecutive simvastatin treatment. Patients were further divided into three groups based on the tertiles of the CK distribution. Compared to subjects in the lowest tertile of CK elevation, the adjusted relative odds of having the AG+GG genotypes among subjects in the highest tertile was 0.5 (95% CI, 0.3 to 0.7) and 0.4 (95% CI, 0.2 to 0.6) after the fourth and eighth weeks, respectively. The interaction terms between the Beijing or Dongzhi region and the LEP GA+AA genotypes were marginally significant for CK elevation at the fourth week (P = 0.057) and significant for CK elevation at the eighth week (P = 0.002). The adverse effect of the LEP G2548A polymorphism on increasing CK levels may be dependent on the environmental milieu. It suggests that lifestyle interventions might offset the side effects of simvastatin therapy among those with genetic susceptibility. Further research is needed to identify specific individual-level factors for clinical practice that modify the effect of genotype.

Review of the Reported Measures of Clinical Validity and Clinical Utility as Arguments for the Implementation of Pharmacogenetic Testing: A Case Study of Statin-Induced Muscle Toxicity

Advances from pharmacogenetics (PGx) have not been implemented into health care to the expected extent. One gap that will be addressed in this study is a lack of reporting on clinical validity and clinical utility of PGx-tests. A systematic review of current reporting in scientific literature was conducted on publications addressing PGx in the context of statins and muscle toxicity. Eighty-nine publications were included and information was selected on reported measures of effect, arguments, and accompanying conclusions. Most authors report associations to quantify the relationship between a genetic variation an outcome, such as adverse drug responses. Conclusions on the implementation of a PGx-test are generally based on these associations, without explicit mention of other measures relevant to evaluate the test's clinical validity and clinical utility. To gain insight in the clinical impact and select useful tests, additional outcomes are needed to estimate the clinical validity and utility, such as cost-effectiveness.

Recent developments and future directions for the use of pharmacogenomics in cardiovascular disease treatments

INTRODUCTION

Cardiovascular disease is still the leading cause of death worldwide. There are many environmental and genetic factors that play a role in the development of cardiovascular disease. The treatment of cardiovascular disease is beginning to move in the direction of personalized medicine by using biomarkers from the patient's genome to design more effective treatment plans. Pharmacogenomics have already uncovered many links between genetic variation and response of many different drugs. Areas covered: This article will focus on the main polymorphisms that impact the risk of adverse effects and response efficacy of statins, clopidogrel, aspirin, β-blockers, warfarin dalcetrapib and vitamin E. The genes discussed include SLCO1B1, ABCB1, CYP3A4, CYP3A5, CYP2C19, PTGS1, PTGS2, ADRB1, ADCY9, CYP2C19, PON1, CES1, PEAR1, GPIIIa, CYP2D6, CKORC1, CYP2C9 and Hp. Expert opinion: Although there are some convincing results that have already been incorporated in the labelling treatment guidelines, most gene-drug relationships have been inconsistent. A better understanding of the relationships between genetic factors and drug response will provide more opportunities for personalized diagnosis and treatment of cardiovascular disease.

Association of genetic variations with pharmacokinetics and lipid-lowering response to atorvastatin in healthy Korean subjects

BACKGROUND

Statins are effective agents in the primary and secondary prevention of cardiovascular disease, but treatment response to statins varies among individuals. We analyzed multiple genetic polymorphisms and assessed pharmacokinetic and lipid-lowering responses after atorvastatin 80 mg treatment in healthy Korean individuals.

METHODS

Atorvastatin 80 mg was given to 50 healthy Korean male volunteers. Blood samples were collected to measure plasma atorvastatin and lipid concentrations up to 48 hours after atorvastatin administration. Subjects were genotyped for 1,936 drug metabolism and transporter genetic polymorphisms using the Affymetrix DMET plus array.

RESULTS

The pharmacokinetics and lipid-lowering effect of atorvastatin showed remarkable interindividual variation. Three polymorphisms in the SLCO1B1, SLCO1B3, and ABCC2 genes were associated with either the maximum concentration (Cmax) of atorvastatin or changes in total cholesterol or low-density lipoprotein cholesterol (LDL-C). Minor homozygotes (76.5 ng/mL) of SLCO1B1 c.-910G>A showed higher Cmax than heterozygotes (34.0 ng/mL) and major homozygotes (33.5 ng/mL, false discovery rate P=0.040). Cmax and the area under the plasma concentration curve from hour 0 to infinity (AUC∞) were higher in carriers of the SLCO1B1*17 haplotype that included c.-910G>A than in noncarriers (46.1 vs 32.8 ng/mL for Cmax; 221.5 vs 154.2 ng/mL for AUC∞). SLCO1B3 c.334G>T homozygotes (63.0 ng/mL) also showed higher Cmax than heterozygotes (34.7 ng/mL) and major homozygotes (31.4 ng/mL, FDR P=0.037). A nonsynonymous ABCC2 c.1249G>A was associated with small total cholesterol and LDL-C responses (0.23% and -0.70% for G/A vs -11.9% and -17.4% for G/G). The Cmax tended to increase according to the increase in the number of minor allele of SLCO1B1 c. -910G>A and SLCO1B3 c.334G>T.

CONCLUSION

Genetic polymorphisms in transporter genes, including SLCO1B1, SLCO1B3, and ABCC2, may influence the pharmacokinetics and lipid-lowering response to atorvastatin administration.

Chronic hepatitis B: a critical discussion

Telbivudine (LdT) is an antiviral agent currently used in the treatment of chronic hepatitis B virus, which was first approved by the US FDA in 2006. The safety of LdT is of great importance for patients that receive long-term treatment for this condition. It has been confirmed that patients treated with LdT have significantly elevated creatine kinase levels. However, the mechanism responsible for this adverse reaction is unclear. This review summarizes the current literature of the adverse reactions of LdT and the possible mechanisms that are involved in chronic hepatitis B infection. Thus, we aim to provide guidance on best practices in using LdT and to provide evidence of the possible mechanisms of LdT-associated adverse reactions.

Impact of New Genomic Technologies on Understanding Adverse Drug Reactions

It is well established that variations in genes can alter the pharmacokinetic and pharmacodynamic profile of a drug and immunological responses to it. Early advances in pharmacogenetics were made with traditional genetic techniques such as functional cloning of genes using knowledge gained from purified proteins, and candidate gene analysis. Over the past decade, techniques for analysing the human genome have accelerated greatly as knowledge and technological capabilities have grown. These techniques were initially focussed on understanding genetic factors of disease, but increasingly they are helping to clarify the genetic basis of variable drug responses and adverse drug reactions (ADRs). We examine genetic methods that have been applied to the understanding of ADRs, review the current state of knowledge of genetic factors that influence ADR development, and discuss how the application of genome-wide association studies and next-generation sequencing approaches is supporting and extending existing knowledge of pharmacogenetic processes leading to ADRs. Such approaches have identified single genes that are major contributing genetic risk factors for an ADR, (such as flucloxacillin and drug-induced liver disease), making pre-treatment testing a possibility. They have contributed to the identification of multiple genetic determinants of a single ADR, some involving both pharmacologic and immunological processes (such as phenytoin and severe cutaneous adverse reactions). They have indicated that rare genetic variants, often not previously reported, are likely to have more influence on the phenotype than common variants that have been traditionally tested for. The problem of genotype/phenotype discordance affecting the interpretation of pharmacogenetic screening and the future of genome-based testing applied to ADRs are also discussed.

Pharmacogenomics of statins: understanding susceptibility to adverse effects

Statins are a cornerstone of the pharmacologic treatment and prevention of atherosclerotic cardiovascular disease. Atherosclerotic disease is a predominant cause of mortality and morbidity worldwide. Statins are among the most commonly prescribed classes of medications, and their prescribing indications and target patient populations have been significantly expanded in the official guidelines recently published by the American and European expert panels. Adverse effects of statin pharmacotherapy, however, result in significant cost and morbidity and can lead to nonadherence and discontinuation of therapy. Statin-associated muscle symptoms occur in ~10% of patients on statins and constitute the most commonly reported adverse effect associated with statin pharmacotherapy. Substantial clinical and nonclinical research effort has been dedicated to determining whether genetics can provide meaningful insight regarding an individual patient’s risk of statin adverse effects. This contemporary review of the relevant clinical research on polymorphisms in several key genes that affect statin pharmacokinetics (eg, transporters and metabolizing enzymes), statin efficacy (eg, drug targets and pathways), and end-organ toxicity (eg, myopathy pathways) highlights several promising pharmacogenomic candidates. However, SLCO1B1 521C is currently the only clinically relevant pharmacogenetic test regarding statin toxicity, and its relevance is limited to simvastatin myopathy.

A possible role for HLA-DRB1*04:06 in statin-related myopathy in Japanese patients

Statin-related myopathy (SRM) is a clinically important adverse reaction. Recent pharmacogenetic research, mainly in non-Asian populations, have indicated clinical relevance of some of genetic biomarkers to SRM, but predictive markers for SRM in Asian populations including Japanese has not yet been established. This study was aimed to identify clinically important genetic markers associated with SRM in Japanese patients. Allele frequencies of the three reported candidate markers - SLCO1B1 rs4149056, RYR2 rs2819742, and GATM rs9806699 - and carrier frequencies of HLA types were compared between patients with SRM patients (n = 52) and healthy Japanese subjects (n = 2878 or 86 (for rs9806699) as controls). No significant association of RYR2, SLCO1B1, and GATM variants with SRM were observed in our Japanese patients, but a significant association was detected for HLA-DRB1*04:06 with SRM (odds ratio: 3.19; 95% confidence interval: 1.53-6.66). This study suggested that HLA-DRB1*04:06 might be associated with SRM onset in a Japanese population. Further studies are required to validate these results.

Impact of CYP2D6, CYP3A5, CYP2C19, CYP2A6, SLCO1B1, ABCB1, and ABCG2 gene polymorphisms on the pharmacokinetics of simvastatin and simvastatin acid

OBJECTIVE

The effects of various polymorphisms in cytochrome P450 (CYP) enzyme and transporter genes on the pharmacokinetics (PK) of simvastatin were evaluated in healthy Korean men.

METHODS

Plasma concentration data for simvastatin and simvastatin acid were pooled from four phase I studies comprising 133 participants. The polymorphisms CYP2D6*4, CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, CYP2C19*2, CYP2C19*3, CYP2A6*7, and CYP2A6*9; SLCO1B1 rs4149056, rs2306283, and rs4149015; ABCB1 rs1128503, rs2032582, and rs1045642; and ABCG2 rs2231142 were evaluated in each participant. Noncompartmental PK results were compared by genotype.

RESULTS

CYP2D6*5 and CYP2D6*14 were found to be associated with a higher area under the curve (AUC) for simvastatin, whereas the AUC of simvastatin acid was significantly increased in patients with the SLCO1B1 rs4149056, ABCG2 rs2231142, and CYP2D6*41 allele variants. Patients with the CYP2D6*41 variant showed a higher peak serum concentration (Cmax) of both simvastatin and simvastatin acid. The SLCO1B1 rs4149056 and rs4149015 polymorphisms were associated with an increased AUC ratio (i.e. ratio of simvastatin acid to simvastatin), whereas the SLCO1B1 rs4149056 and CYP2D6*5 variants were related to a higher Cmax ratio.

CONCLUSION

The CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, SLCO1B1 rs4149056 and rs4149015, and ABCG2 rs2231142 genetic polymorphisms are associated with the PK of both simvastatin and simvastatin acid. This could potentially be used as a basis for individualized simvastatin therapy by predicting the clinical outcomes of this treatment.

Polymorphisms of dopamine receptor genes and risk of visual hallucinations in Parkinson's patients

BACKGROUND

Visual hallucinations (VHs) are frequent non-motor complication of Parkinson's disease (PD), associated to a negative prognosis. Previous studies showed an association between dopamine receptor (DR) gene (DR) variants and psychosis in Alzheimer's disease, addictions, schizophrenia, and bipolar disorder. However, there are only a few studies on DR variants and VHs in PD, which did not provide conclusive results.

OBJECTIVES

The present study aimed to determine whether genetic differences of DR are associated with visual hallucinations (VHs) in a cohort of Parkinson's disease (PD) patients.

METHODS

A case-control study of 84 PD subjects, 42 with and 42 without VHs,that were matched for age, gender, disease duration, and dopaminergic medication was conducted. Polymerase chain reaction for SNPs in both D1-like (DRD1A-48G [rs4532] and C62T [rs686], DRD5T798C [rs6283]) and D2-like DR (DRD2G2137A [rs1800497] and C957T [rs6277], DRD3G25A [rs6280] and G712C [rs1800828], DRD4C616G [rs747302] and nR VNTR 48bp) analyzed genomic DNA.

RESULTS

Patients carrying allele T at DRD1C62T had an increased risk of VHs, expressed as OR (95 % CI, p value), of 10.7 (2.9-40, p = 0.0001). Moreover, patients with DRD1-48 GG and 62TT genotype displayed shorter time to VHs, whereas a longer time to VHs was found in subjects carrying the DRD4 CG alleles.

CONCLUSIONS

PD patients with VHs display higher frequency of DR SNPs associated with increased D1-like activity and decreased D2-like activity. Our data are in line with associations reported in other neurodegenerative and psychiatric conditions. Results likely provide valuable information for personalizing pharmacological therapy in PD patients.

Molecular mechanisms of statin intolerance

Statins reduce cardiovascular morbidity and mortality in primary and secondary prevention. Despite their efficacy, many persons are unable to tolerate statins due to adverse events such as hepatotoxicity and myalgia/myopathy. In the case of most patients, it seems that mild-to-moderate abnormalities in liver and muscle enzymes are not serious adverse effects and do not outweigh the benefits of coronary heart disease risk reduction. The risk for mortality or permanent organ damage ascribed to statin use is very small and limited to cases of myopathy and rhabdomyolysis. Statin-induced muscle-related adverse events comprise a highly heterogeneous clinical disorder with numerous, complex etiologies and a variety of genetic backgrounds. Every patient who presents with statin-related side effects cannot undergo the type of exhaustive molecular characterization that would include all of these mechanisms. Frequently the only solution is to either discontinue statin therapy/reduce the dose or attempt intermittent dosing strategies at a low dose.

Programmed Cell Death Genes Are Linked to Elevated Creatine Kinase Levels in Unhealthy Male Nonagenarians

Declining health in the oldest-old takes an energy toll for the simple maintenance of body functions. The underlying mechanisms, however, differ in males and females. In females, the declines are explained by loss of muscle mass; but this is not the case in males, in whom they are associated with increased levels of circulating creatine kinase. This relationship raises the possibility that muscle damage rather than muscle loss is the cause of the increased energy demands of unhealthy aging in males. We have now examined factors that contribute to the increase in creatine kinase. Much of it (60%) can be explained by a history of cardiac problems and lower kidney function, while being mitigated by moderate physical activity, reinforcing the notion that tissue damage is a likely source. In a search for genetic risk factors associated with elevated creatine kinase, the Ku70 gene XRCC6 and the ceramide synthase gene LASS1 were investigated because of their roles in telomere length and longevity and healthy aging, respectively. Single nucleotide polymorphisms in these two genes were independently associated with creatine kinase levels. The XRCC6 variant was epistatic to one of the LASS1 variants but not to the other. These gene variants have potential regulatory activity. Ku70 is an inhibitor of the proapoptotic Bax, while the product of Lass1, ceramide, operates in both caspase-dependent and -independent pathways of programmed cell death, providing a potential cellular mechanism for the effects of these genes on tissue damage and circulating creatine kinase.

ABCB1 C3435T polymorphism and the lipid-lowering response in hypercholesterolemic patients on statins: a meta-analysis

BACKGROUND

A number of researches have evaluated the association between the ABCB1 polymorphism and the lipid-lowering response of statins, but the results have been inconclusive. To examine the lipid-lowering efficacy and safety associated with the ABCB1 C3435T polymorphism in hypercholesterolemic patients receiving statin, all available studies were included in this meta-analysis.

METHODS

A systematic search for eligible studies in the Cochrane library database, Scopus and PubMed was performed. Articles meeting the inclusion criteria were comprehensively reviewed, and the available data were accumulated by the meta-analysis.

RESULTS

The results indicated that the comparisons of CC+CT vs. TT were associated with a significant elevation of the serum HDL-C levels after statin treatment (CC+CT vs. TT: MD, 2.46; 95 % CI, 0.36 to 4.55; P = 0.02), and the ABCB1 C3435T variant in homozygotes was correlated with decreases in LDL-C (CC vs. TT: MD, 2.29; 95 % CI, 0.37 to 4.20; P = 0.02) as well as TC (CC vs. TT: MD, 3.05; 95 % CI, 0.58 to 5.53; P = 0.02) in patients treated with statin. However, we did not observe a significant association in the TG group or an association between other genetic models serum lipid parameters. In addition, statin treatment more than 5 months led to a higher risk of muscle toxicity.

CONCLUSIONS

The evidence from the meta-analysis demonstrated that the ABCB1 C3435T polymorphism may represent a pharmacogenomic biomarker for predicting treatment outcomes in patients on statins and that statin treatment for more than 5 months can increase the risk of myopathy.

Association Between SLCO1B1 Gene T521C Polymorphism and Statin-Related Myopathy Risk: A Meta-Analysis of Case-Control Studies

Statin-related myopathy is an important adverse effect of statin which is classically unpredictable. The evidence of association between solute carrier organic anion transporter 1B1 (SLCO1B1) gene T521C polymorphism and statin-related myopathy risk remained controversial. This study aimed to investigate this genetic association. Databases of PubMed, EMBASE, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database, and Wanfang Data were searched till June 17, 2015. Case-control studies investigating the association between SLCO1B1 gene T521C polymorphism and statin-related myopathy risk were included. The Newcastle-Ottawa Scale (NOS) was used for assessing the quality of included studies. Data were pooled by odds ratios (ORs) and their 95% confidence intervals (CIs). Nine studies with 1360 cases and 3082 controls were included. Cases of statin-related myopathy were found to be significantly associated with the variant C allele (TC + CC vs TT: OR = 2.09, 95% CI = 1.27-3.43, P = 0.003; C vs T: OR = 2.10, 95% CI = 1.43-3.09, P < 0.001), especially when statin-related myopathy was defined as an elevation of creatine kinase (CK) >10 times the upper limit of normal (ULN) or rhabdomyolysis (TC + CC vs TT: OR = 3.83, 95% CI = 1.41-10.39, P = 0.008; C vs T: OR = 2.94, 95% CI = 1.47-5.89, P = 0.002). When stratified by statin type, the association was significant in individuals receiving simvastatin (TC + CC vs TT: OR = 3.09, 95% CI = 1.64-5.85, P = 0.001; C vs T: OR = 3.00, 95% CI = 1.38-6.49, P = 0.005), but not in those receiving atorvastatin (TC + CC vs TT: OR = 1.31, 95% CI = 0.74-2.30, P = 0.35; C vs T: OR = 1.33, 95% CI = 0.57-3.12, P = 0.52). The available evidence suggests that SLCO1B1 gene T521C polymorphism is associated with an increased risk of statin-related myopathy, especially in individuals receiving simvastatin. Thus, a genetic test before initiation of statins may be meaningful for personalizing the treatment.

ABCG2 gene polymorphisms as risk factors for atorvastatin adverse reactions: a case-control study

AIM

To explore the association between dose-related adverse drug reactions (ADRs) of atorvastatin and polymorphisms of ABCG2, taking into account the influence of CYP3A4 and SLCO1B1 genes.

MATERIALS & METHODS

Sixty patients who experienced atorvastatin dose-related ADRs and 90 matched patients without ADRs were enrolled in the study. Genotyping for ABCG2 421C > A, CYP3A4*22, SLCO1B1 388A > G, SLCO1B1 521T > C variants was performed by real-time PCR.

RESULTS

Patients with ABCG2 421CA or AA genotypes had 2.9 times greater odds of developing atorvastatin dose-dependent ADRs (OR: 2.91; 95% CI: 1.22-6.95; p = 0.016) than those with ABCG2 421CC genotype. After adjustments for clinical and genetic risk factors, ABCG2 remained a statistically significant predictor of adverse drug reactions (OR: 2.75; 95% CI: 1.1-6.87; p = 0.03;). Also, carriers of SLCO1B1 521 TC or CC genotypes had 2.3 greater odds (OR: 1.03-4.98; 95% CI: 1.03-4.98; p = 0.043) of experiencing ADRs caused by atorvastatin in comparison with carriers of SLCO1B1 521 TT genotype.

CONCLUSION

Our study demonstrated an association between atorvastatin-induced ADRs and genetic variants in the ABCG2 gene.

Genetic and immunologic susceptibility to statin-related myopathy

Statin-related myopathy (SRM) undermines drug adherence that is critical for achieving the benefits of lipid-lowering therapy. While the exact mechanism of SRM remains largely unknown, recent evidence supports specific genetic and immunologic influence on the development of intolerance. Genes of interest include those involved in the pharmacokinetics of statin response (i.e. drug metabolism, uptake transporters, and efflux transporters), pharmacodynamics (i.e. drug toxicity and immune-mediated myopathy), and gene expression. We examine the influence of genetic and immunologic variation on the pharmacokinetics, pharmacodynamics, and gene expression of SRM.

Pharmacogenetics of Statin-Induced Myopathy: A Focused Review of the Clinical Translation of Pharmacokinetic Genetic Variants

Statins are the most commonly prescribed drugs in the United States and are extremely effective in reducing major cardiovascular events in the millions of Americans with hyperlipidemia. However, many patients (up to 25%) cannot tolerate or discontinue statin therapy due to statin-induced myopathy (SIM). Patients will continue to experience SIM at unacceptably high rates or experience unnecessary cardiovascular events (as a result of discontinuing or decreasing their statin therapy) until strategies for predicting or mitigating SIM are identified. A promising strategy for predicting or mitigating SIM is pharmacogenetic testing, particularly of pharmacokinetic genetic variants as SIM is related to statin exposure. Data is emerging on the association between pharmacokinetic genetic variants and SIM. A current, critical evaluation of the literature on pharmacokinetic genetic variants and SIM for potential translation to clinical practice is lacking. This review focuses specifically on pharmacokinetic genetic variants and their association with SIM clinical outcomes. We also discuss future directions, specific to the research on pharmacokinetic genetic variants, which could speed the translation into clinical practice. For simvastatin, we did not find sufficient evidence to support the clinical translation of pharmacokinetic genetic variants other than SLCO1B1. However, SLCO1B1 may also be clinically relevant for pravastatin- and pitavastatin-induced myopathy, but additional studies assessing SIM clinical outcome are needed. CYP2D6*4 may be clinically relevant for atorvastatin-induced myopathy, but mechanistic studies are needed. Future research efforts need to incorporate statin-specific analyses, multi-variant analyses, and a standard definition of SIM. As the use of statins is extremely common and SIM continues to occur in a significant number of patients, future research investments in pharmacokinetic genetic variants have the potential to make a profound impact on public health.