Clinical Application of Genotype-guided Dosing of Warfarin in Patients with Acute Stroke

Population Pharmacogenomics in Croatia: Evaluating the PGx Allele Frequency and the Impact of Treatment Efficiency

BACKGROUND

Adverse drug reactions (ADRs) are a significant cause of mortality, and pharmacogenomics (PGx) offers the potential to optimize therapeutic efficacy while minimizing ADRs. However, there is a lack of data on the Croatian population, highlighting the need for investigating the most common alleles, genotypes, and phenotypes to establish national guidelines for drug use.

METHODS

A single-center retrospective cross-sectional study was performed to examine the allele, genotype, and phenotype frequencies of drug-metabolizing enzymes, receptors, and other proteins in a random sample of 522 patients from Croatia using a 28-gene PGx panel.

RESULTS

Allele frequencies, genotypes, and phenotypes for the investigated genes were determined. No statistically significant differences were found between the Croatian and European populations for most analyzed genes. The most common genotypes observed in the patients resulted in normal metabolism rates. However, some genes showed higher frequencies of altered metabolism rates.

CONCLUSIONS

This study provides insights into the allele, genotype, and phenotype frequencies of drug-metabolizing enzymes, receptors, and other associated proteins in the Croatian population. The findings contribute to optimizing drug use guidelines, potentially reducing ADRs, and improving therapeutic efficacy. Further research is needed to tailor population-specific interventions based on these findings and their long-term benefits.

Efficacy and safety of genotype-guided warfarin dosing versus non-genotype-guided warfarin dosing strategies: A systematic review and meta-analysis of 27 randomized controlled trials

OBJECTIVE

To evaluate the efficacy and safety of genotype-guided dosing (GD) strategies compared to non-genotype-guided dosing (non-GD) strategies for warfarin.

METHODS

Databases were searched up to July 2021. Meta-analysis was conducted with the Review Manager software (version 5.4) and R (version 4.0.5). Risk ratio (RR), mean difference (MD), and 95% confidence intervals (CIs) were used. Subgroup analyses were conducted based on ethnicity and dosing regimen in non-GD group. Meta-regression was performed to evaluate the relation of covariates. This study is registered with PROSPERO (CRD42021245654).

RESULTS

27 randomized controlled trials with a total of 9906 patients were included. The GD group resulted in a significantly improved time in therapeutic range compared with non-GD group in follow-up duration within 30 days (MD: 5.95, 95%CI: 2.41-9.22, P = 0.001) and beyond 30 days (MD: 4.93, 1.40-8.47, P = 0.006), time to the first therapeutic international normalized ratio (MD: -1.80, -2.69 - -0.92, P < 0.0001), and time to reach stable dose (MD: -5.08, -7.09 - -3.07, P < 0.00001), incidence of major bleeding events (RR: 0.50, 0.33-0.75, P = 0.0008), total bleeding events (RR: 0.83, 0.73-0.95, P = 0.006), and thromboembolism (RR: 0.69, 0.49-0.96, P = 0.03). No differences were found in stable dose achievement, minor bleeding events, over anticoagulation, and all-cause mortality. Four improved efficacy outcomes were observed in GD group compared with fixed dosing group. Only time to the therapeutic INR was shortened in GD group compared with clinical adjusted dosing group. The result showed no difference of safety outcomes between GD group and fixed dosing group whereas a decreased incidence of major bleeding events was observed when comparing to clinical adjusted dosing group.

CONCLUSION

GD strategy was superior to fixed dosing strategy in term of efficacy outcomes and comparable to fixed dosing strategy in safety outcomes. Clinical adjusted regimen could partly substitute the genotype-guided dosing strategy for efficacy in insufficient conditions, but the risk of major bleeding events should be monitored.

Prevalence of five pharmacologically most important CYP2C9 and CYP2C19 allelic variants in the population from the Republic of Srpska in Bosnia and Herzegovina

The enzymes of the cytochrome P450 superfamily play a critical role in phase I drug metabolism. Among them, CYP2C9 and CYP2C19 are clinically important, as they can mediate severe toxicity, therapy failure, and increased susceptibility to cancer and other diseases caused by chemicals. The aim of this study was to determine the prevalence of pharmacologically most important allelic variants of the CYP2C9 and CYP2C19 genes in the general population of the Republic of Srpska (Bosnia and Herzegovina) and to compare them with other populations. For this purpose we determined the genotype profile and allele frequency of 216 randomly selected healthy volunteers using real-time polymerase chain reaction (RT-PCR). The prevalence of the CYP2C9 *2 and *3 alleles was 13.6 and 7.4 %, respectively. Based on these frequencies, of the 216 participants four (1.86 %) were predicted to be poor metabolisers, 78 (36.11 %) intermediate, and the remaining 134 (62.03 %) normal metabolisers. Based on the prevalence of CYP2C19 *2 and *17 variants – 16.2 and 20.4 %, respectively – nine (4.17 %) were predicted to be poor, 57 (26.39 %) rapid, and nine (4.17 %) ultra-rapid metabolisers. We found no significant differences in allele frequencies in our population and populations from other European countries. These findings suggest that genetically determined phenotypes of CYP2C9 and CYP2C19 should be taken into consideration to minimise individual risk and improve benefits of drug therapy in the Republic of Srpska.

A network meta-analysis of CYP2C9, CYP2C9 with VKORC1 and CYP2C9 with VKORC1 and CYP4F2 genotype-based warfarin dosing strategies compared to traditional

WHAT IS KNOWN AND OBJECTIVES

Variations in genotypes were observed in randomized clinical trials (RCTs) that evaluated genotype-based warfarin dosing. We carried out a network meta-analysis to assess whether any clinically significant differences exist between RCTs evaluating CYP2C9 with VKORC1, with CYP2C9 alone and CYP2C9, VKORC1, with CYP4F2 dosing strategies.

METHODS

Electronic records were searched for RCTs comparing genotype-based warfarin with traditional-dosing strategies. Key outcomes included were the time to first therapeutic international normalized ratio (INR); time to stable INR or warfarin dose; percent time in therapeutic range (TTR); and the proportion of patients with supra-therapeutic INR. Weighted mean differences (WMD) and odds ratios (OR) with 95% confidence intervals (95% CI) were the effect estimates.

RESULTS AND DISCUSSION

Twenty-six studies (7898 patients) were included. CYP2C9-based warfarin dosing was associated with a shorter time to first therapeutic INR (WMD: -2.73, 95% CI: -3.41, -2.05) and stable INR/warfarin dose (WMD: -8.1, 95% CI: -12.54, -3.66). CYP2C9 and VKORC1 were observed with a shorter time to first therapeutic INR (WMD: -1.92, 95% CI: -3.23, -0.61) and stable INR/warfarin dose (WMD: -4.6, 95% CI: -6.87, -2.34) along with a longer TTR (%) (WMD: 3.91, 95% CI: 1.18, 6.63). CYP2C9, VKORC1 and CYP4F2 were observed with a reduced proportion of patients with supra-therapeutic INR (OR: 0.68, 95% CI: 0.49, 0.93). Trial sequential analysis confirms the superior benefits of CYP2C9 with VKORC1 genotype.

WHAT IS NEW AND CONCLUSION

The present evidence is supportive of personalizing warfarin dose based only on CYP2C9 and VKORC1 genotypes compared to traditional strategies. More RCTs are needed to delineate any benefit for adding CYP4F2 to provide sufficient power for pooled analysis. No convincing evidence exists supporting the role of CYP2C9 alone.

Genotype-guided warfarin dosing vs. conventional dosing strategies: a systematic review and meta-analysis of randomized controlled trials

AIMS

Previous trials on the effectiveness of genotype-guided warfarin dosing vs. conventional dosing have been inconclusive. We conducted a systematic review and meta-analysis of randomized trials comparing genotype-guided to conventional dosing strategies.

METHODS

PubMed and the Cochrane Library were searched up to 23 October 2017.

RESULTS

A total of 76 and 94 entries were retrieved were retrieved from PubMed and the Cochrane Library, respectively. A total of 2626 subjects in the genotype-guided dosing (mean age 63.3 ± 5.8 years; 46% male) and 2604 subjects in the conventional dosing (mean age 64.7 ± 6.1 years; 46% male) groups (mean follow-up duration 64 days) from 18 trials were included. Compared with conventional dosing, genotype-guided dosing significantly shortened the time to first therapeutic international normalized ratio (INR) (mean difference 2.6 days, standard error 0.3 days; P < 0.0001; I2 0%) and time to first stable INR (mean difference 5.9 days, standard error 2.0 days; P < 0.01; I2 94%). Genotype-guided dosing also increased the time in therapeutic range (mean difference 3.1%, standard error 1.2%; P < 0.01; I2 80%) and reduced the risks of both excessive anticoagulation, defined as INR ≥4 [risk ratio (RR) 0.87; 95% confidence interval (CI) 0.78, 0.98; P < 0.05; I2 : 0%), and bleeding (RR 0.82; 95% CI 0.69, 0.98; P < 0.05; I2 31%). No difference in thromboembolism (RR 0.84; 95% CI 0.56, 1.26; P = 0.40; I2 0%) or mortality (RR 1.16; 95% CI 0.46, 2.91; P = 0.76; I2 0%) was observed between the two groups.

CONCLUSIONS

Genotype-guided warfarin dosing offers better safety with less bleeding compared with conventional dosing strategies. No significant benefit on thromboembolism or mortality was evident.

Design and synthesis of nanoscaled IQCA-TAVV as a delivery system capable of antiplatelet activation, targeting arterial thrombus and releasing IQCA

BACKGROUND

Arterial thrombosis has been associated with a series of pathological conditions, and the discovery of arterial thrombosis inhibitor is of clinical importance.

METHODS

By analyzing the pharmacophores of anti-platelet agents, thrombus targeting peptide and anti-thrombotic nano-systems 3S-1,2,3,4-tetrahydroisoquino-line-3-carbonyl-Thr-Ala-Arg-Gly-Asp(Val)-Val (IQCA-TAVV) was designed and prepared as a nano-scaled arterial thrombosis inhibitor.

RESULTS

In vitro the nanoparticles of IQCA-TAVV were able to adhere onto the surface of activated platelets, attenuate activated platelets to extend pseudopodia and inhibit activated platelets to form aggregators. In vivo IQCA-TAVV targeted arterial thrombus, dose dependently inhibited arterial thrombosis with a 1 nmol/kg of minimal effective dose, and the activity waŝ1670 folds of that of aspirin.

CONCLUSION

IQCA-TAVV represented the design, preparation and application of nanomedicine capable of adhering on the surface of activated platelets, attenuating platelet activation, targeting arterial thrombus and inhibiting arterial thrombosis.

Genetic polymorphisms of cytochrome P450 enzymes: CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 in the Croatian population

BACKGROUND

Data on the frequency of pharmacogenetic polymorphisms in the Croatian population are limited. We determined and analyzed frequencies for the most important CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 genetic variants in the Croatian population.

METHODS

2637 subjects were included. Genotyping was performed by real-time polymerase chain reaction (PCR) using TaqMan® DME or TaqMan® SNP Genotyping Assays, and by PCR, and PCR-RFLP analysis.

RESULTS

For CYP2C9, allele frequencies of *2 and *3 variant were 14.5% and 7.6%, respectively. Among them, 3.98% of subjects were predicted to be poor metabolizers. For CYP2C19, the most frequent variant alleles were *2 (14.8%), and *17 (23.7%), while 2.4% of subjects were predicted to be poor metabolizers, and 5.39% were homozygous carriers of *17 predicted to be ultrarapid metabolizers (UM). For CYP2D6, the frequencies of tested variant alleles were *3 (2.2%), *4 (17.4%), *5 (1%), *6 (1.1%), and *41 (10.8%). Out of these, 5.59% were predicted to be poor metabolizers, 3.19% were classified as UM while 1.0% were carriers of variant alleles duplications (undefined phenotype). For CYP3A4 allele frequencies of *1B and *22 variants were 1.4% and 2.7%, respectively. Allele frequency of CYP3A5*3 was 95.5%. Analyzing CYP3A cluster according to the combination of CYP3A4*22 and CYP3A5*3 revealed 5.34% of subjects to be poor metabolizers, while 8.66% were classified as extensive metabolizers.

CONCLUSIONS

The frequency of the CYP allelic variants, genotypes, and predicted phenotypes in the Croatian population is in accordance with the other European populations, between the values of published data for Middle European and Mediterranean populations.

The Value of Evidence in the Decision-Making Process for Reimbursement of Pharmacogenetic Dosing of Warfarin

BACKGROUND

After early clinical trials that evaluated pharmacogenetic (PG) algorithms, many healthcare payers were reluctant to cover this technology and, consequently, PG dosing of warfarin could not be translated into clinical practice.

OBJECTIVE

The aim of this study was to estimate the value of upgrading evidence relating to PG dosing of warfarin from the healthcare payer perspective.

METHODS

Randomized controlled trials (RCTs) that evaluated PG dosing of warfarin were identified through a systematic literature search, and their findings were combined by a cumulative meta-analysis. A health economic model was used to estimate economic outcomes and to calculate the expected value of perfect information (EVPI) as a measure of the value of clinical trials for decision makers.

RESULTS

Nine RCTs were identified and included in our analysis. The estimated difference in the percentage of time in the therapeutic range was 5.6 percentage points in 2007, decreasing to 4.3 percentage points when all studies were included. At a reimbursement price of €160 per PG testing, the EVPI for the clinical benefit was estimated at €80 and €90 per patient in 2007 and 2014, respectively. A reduction in the price of PG testing to €40, which was observed in this period, resulted in an EVPI of €3 per patient.

CONCLUSIONS

The estimated cumulative effect of PG dosing has remained similar since 2007, but additional evidence has contributed to a more precise estimation. While these variations should not affect the reimbursement decision, a large decline in the cost of PG testing in recent years calls for reconsideration.

The correlation of D-dimer levels with patient outcomes in acute ischemic cerebrovascular disease complicating coronary heart disease

OBJECTIVE

To investigate the correlation between nerve function defect, their degree of recovery, and D-dimer levels in patients with acute ischemic cerebrovascular disease (AICVD) complicating coronary heart disease (CHD) in winter.

METHODS

From 1 October, 2014 to 31 December, 2014, we enrolled patients in a consecutive manner with AICVD who were hospitalized in the Department of Neurology, Beijing Luhe hospital, Capital Medical University. The patients were selected that had an occurrence of AICVD within the last 14 days. A total of 151 cases were divided into CHD group (n = 77) or non-CHD group (n = 74) based on a diagnosis of CHD. The risk factors, hematological indices associated with the diseases, and the nerve function defect and recovery degrees were compared between the two groups. Moreover, according to the result of the preliminary analysis of the CHD and non-CHD groups, patients were further divided into two subgroups based on whether their D-dimer levels were higher than 0.5 mg/l or not. Finally, the nerve function defect and recovery degrees in each subgroups were compared in pairs.

RESULTS

Among the patients consecutively enrolled, the percentage of the patients with CHD was 50.99% (77/151) and non-CHD patients was 49.01%. On admission, there was no significant difference in NIHSS scores between the CHD and non-CHD groups. However, there was a significant difference between the CHD and non-CHD groups when comparing the NIHSS scores on 14th day and the mRs scores on 90 (±7)th day after the initial onset (p = 0.006, 0.005). The D-dimer levels of AICVD complicating CHD patients were higher than those not complicating CHD patients (p = 0.006). Those AICVD patients that complicating CHD with also elevated D-dimer levels had most severe neurologic function deficits on 14th day and worst neural function recoveries on 90 (±7)th day after onset (p = 0.001, <0.001).

CONCLUSIONS

AICVD patients complicating CHD is very common in clinical practice. The AICVD patients that complicating CHD showed worse outcomes within 90 days after initial onset of stroke. The D-dimer levels of patients with AICVD complicating CHD were higher. Patients in the CHD group, whose D-dimer levels were higher than the normal standard, had worst outcomes. Paying close attention to the stage of the coronary artery disease and indicators of the coagulation-fibrinolysis is beneficial in the optimization of the clinical treatment for AICVD patients. Maybe the results of this study could provide some reference for specific groups of stroke patients to accept anticoagulant therapy.