Front Pharmacol. 2021 Apr 22;12:653525. doi: 10.3389/fphar.2021.653525. eCollection 2021.

ABSTRACT

Background: Tacrolimus (TAC) and mycophenolic acid (MPA) are the main immunosuppressive drugs used in pediatric kidney transplantation. Single nucleotide polymorphisms (SNPs) in metabolizing enzymes and transporters might influence plasma levels of these drugs. Herein, we sought to determine the influence of SNPs on CYP3A5, MRP2 and UGT1A9 genes in Chilean pediatric kidney recipients using TAC and MPA. Patients and Methods: A prospective study was performed on 104 pediatric kidney recipients that used TAC and MPA for immunosuppression. The median age at the time of transplantation was 8.1 years [Q1-Q3 4.5-11.6 years] and the main clinical diagnosis was a structural anomaly. In a subgroup of patients, a complete steroid withdrawal was made at day 7. The CYP3A5 polymorphism (ancestral allele *1; variant allele *3) was determined in the entire cohort, while MRP2 -24G > A, UGT1A9 -275T > A, and UGT1A9 -2152C > T polymorphisms were determined in 53 patients. Genotypes were associated with trough drug concentrations (C0), dose requirements normalized by weight (TAC-D mg/kg) or body surface (MPA-D mg/m2), trough levels normalized by dose requirements (C0/D), and area under the curve in 12 h normalized by dose requirements (AUC0-12h/D). Results: The frequencies of the variant alleles CYP3A5*3, MRP2-24A, UGT1A9-275A, and UGT1A9-2152T were 76.9, 22.1, 6.6, and 2.9%, respectively. AUC0-12h/TAC-D were 1.6-fold higher in CYP3A5*3/*3 patients than in CYP3A5*1 carriers (CYP3A5*1/*3 and CYP3A5*1/*1). When analyzing patients with steroid withdrawal, CYP3A5*3/*3 patients had 1.7-fold higher AUC0-12h/TAC-D than the other genotypes. Patients carrying the CYP3A5*3/*3 genotype had higher TAC-C0, lower TAC-D and higher TAC-C0/D, consistently in a 6-months follow-up. Creatinine clearance was stable during the follow-up, regardless of the genotype. No significant differences between MRP2 and UGT1A9 genotypes were observed in MPA-C0, MPA-D or MPA-C0/D. However, patients carrying the UGT1A9-275A allele had lower AUC0-12h/MPA-D than those carrying the UGT1A9-275T ancestral allele. Conclusions: These results support that CYP3A5 and UGT1A9 genotyping in pediatric recipients might be useful and advisable to guide TAC and MPA dosing and monitoring in children that undergo kidney transplantation.

PMID:33967795 | PMC:PMC8100460 | DOI:10.3389/fphar.2021.653525

Front Pharmacol. 2021 Apr 22;12:650750. doi: 10.3389/fphar.2021.650750. eCollection 2021.

ABSTRACT

Genetic differences in cytochrome P450 (CYP)-mediated metabolism have been known for several decades. The clinically most important polymorphic CYP enzyme is CYP2D6, which plays a key role in the metabolism of many antidepressants and antipsychotics, along with a range of non-psychiatric medications. Dose individualization based on CYP2D6 genotype to improve the effect and safety of drug treatment has been an ambition for a long time. Clinical use of CYP2D6 genotyping is steadily increasing; however, for pre-emptive genotyping to be successful in predicting individual dose requirements, high precision of genotype-to-phenotype translations are required. Recently, guidelines for assigning CYP2D6 enzyme activity scores of CYP2D6 variant alleles, and subsequent diplotype-to-phenotype translations, were published by the Clinical Pharmacogenetics Implementation Consortium (CPIC) and the Dutch Pharmacogenetics Working Group. Consensus on assigning activity scores of CYP2D6 variant alleles and translating diplotype scores into CYP2D6 poor, intermediate, normal, or ultrarapid metabolizer groups were obtained by consulting 37 international experts. While assigning enzyme activities of non-functional (score 0) and fully functional (score 1) alleles are straightforward, reduced function variant alleles are more complex. In this article, we present data showing that the assigned activity scores of reduced function variant alleles in current guidelines are not of sufficient precision; especially not for CYP2D6*41, where the guideline activity score is 0.5 compared to 0.05-0.15 in pharmacogenetic studies. Due to these discrepancies, CYP2D6 genotypes with similar guidelinediplotype scores exhibit substantial differences in CYP2D6 metabolizer phenotypes. Thus, it is important that the guidelines are updated to be valid in predicting individual dose requirements of psychiatric drugs and others metabolized by CYP2D6.

PMID:33967790 | PMC:PMC8100508 | DOI:10.3389/fphar.2021.650750

Front Pharmacol. 2021 Mar 19;12:634686. doi: 10.3389/fphar.2021.634686. eCollection 2021.

ABSTRACT

Purpose: Serum creatinine (SCr) is used as a marker of kidney function to guide dosing of renally eliminated drugs. Serum Cystatin C (S-CysC) has been suggested as a more reliable kidney marker than SCr in adults and children. Purpose of this study was to investigate S-CysC as alternative renal marker to SCr for estimating vancomycin clearance in neonates undergoing intensive care. Methods: Vancomycin pharmacokinetics (PK), SCr and S-CysC data were collected in patients undergoing vancomycin treatment in the neonatal intensive care unit of Robert Debré Hospital - Paris. A population PK analysis was performed utilizing routine therapeutic drug monitoring samples. S-CysC and SCr were compared as covariates on vancomycin clearance using stepwise covariate modeling (forward inclusion [p < 0.05] and backward elimination [p < 0.01]). Model performance was evaluated by graphical and statistical criteria. Results: A total of 108 vancomycin concentrations from 66 patients (postmenstrual age [PMA] of 26-46 weeks) were modeled with an allometric one-compartment model. The median (range) values for SCr and S-CysC were 41 (12-153) µmol/l and 1.43 (0.95-2.83) mg/l, respectively. Following stepwise covariate model building, SCr was retained as single marker of kidney function (after accounting for weight and PMA) in the final model. Compared to the final model based on SCr, the alternative model based on S-CysC showed very similar performance (e.g. BIC of 578.3 vs. 576.4) but included one additional covariate: impact of mechanical ventilation on vancomycin clearance, in addition to the effects of size and maturation. Conclusion: ill neonates. However, if using S-CysC for this purpose mechanical ventilation needs to be taken into account.

PMID:33967770 | PMC:PMC8104087 | DOI:10.3389/fphar.2021.634686

Front Pharmacol. 2021 Apr 22;12:605764. doi: 10.3389/fphar.2021.605764. eCollection 2021.

ABSTRACT

Statins can cause muscle symptoms resulting in poor adherence to therapy and increased cardiovascular risk. We hypothesize that combinations of potentially functional SNPs (pfSNPs), rather than individual SNPs, better predict myalgia in patients on atorvastatin. This study assesses the value of potentially functional single nucleotide polymorphisms (pfSNPs) and employs six machine learning algorithms to identify the combination of SNPs that best predict myalgia. Methods: Whole genome sequencing of 183 Chinese, Malay and Indian patients from Singapore was conducted to identify genetic variants associated with atorvastatin induced myalgia. To adjust for confounding factors, demographic and clinical characteristics were also examined for their association with myalgia. The top factor, sex, was then used as a covariate in the whole genome association analyses. Variants that were highly associated with myalgia from this and previous studies were extracted, assessed for potential functionality (pfSNPs) and incorporated into six machine learning models. Predictive performance of a combination of different models and inputs were compared using the average cross validation area under ROC curve (AUC). The minimum combination of SNPs to achieve maximum sensitivity and specificity as determined by AUC, that predict atorvastatin-induced myalgia in most, if not all the six machine learning models was determined. Results: Through whole genome association analyses using sex as a covariate, a larger proportion of pfSNPs compared to non-pf SNPs were found to be highly associated with myalgia. Although none of the individual SNPs achieved genome wide significance in univariate analyses, machine learning models identified a combination of 15 SNPs that predict myalgia with good predictive performance (AUC >0.9). SNPs within genes identified in this study significantly outperformed SNPs within genes previously reported to be associated with myalgia. pfSNPs were found to be more robust in predicting myalgia, outperforming non-pf SNPs in the majority of machine learning models tested. Conclusion: Combinations of pfSNPs that were consistently identified by different machine learning models to have high predictive performance have good potential to be clinically useful for predicting atorvastatin-induced myalgia once validated against an independent cohort of patients.

PMID:33967749 | PMC:PMC8100589 | DOI:10.3389/fphar.2021.605764

Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2021 Apr 28;46(4):404-413. doi: 10.11817/j.issn.1672-7347.2021.200256.

ABSTRACT

The human leukocyte antigen (HLA) molecules encoded within the human major histocompatibility complex are a group of highly conserved cell surface proteins, which are related to antigen recognition. HLA genes display a high degree of genetic polymorphism, which is the basis of individual differences in immunity. Specific HLA genotypes have been highly associated with typical adverse drug reactions. HLA-A*31:01 and HLA-B*15:02 are associated with carbamazepine-induced severe cutaneous adverse reactions, HLA-B*57:01 is related to abacavir-induced drug-induced hypersensitivity syndrome and flucloxacillin/pazopanib-induced drug-induced liver injury, while HLA-B*35:01 is a potential biomarker for predicting polygonum multiflorum-induced liver injury. It is not clear how small drug molecules to interact with HLA molecules and T cell receptors (TCR). There are four mechanistic hypotheses, including the hapten/prohapten theory, the pharmacological interaction concept, the altered peptide repertoire model, and the altered TCR repertoire model.

PMID:33967088 | DOI:10.11817/j.issn.1672-7347.2021.200256

Clin Colorectal Cancer. 2021 Apr 6:S1533-0028(21)00027-X. doi: 10.1016/j.clcc.2021.03.002. Online ahead of print.

NO ABSTRACT

PMID:33965356 | DOI:10.1016/j.clcc.2021.03.002

Drug Saf. 2021 May 8. doi: 10.1007/s40264-021-01068-w. Online ahead of print.

NO ABSTRACT

PMID:33964001 | DOI:10.1007/s40264-021-01068-w

Mycoses. 2021 May 8. doi: 10.1111/myc.13300. Online ahead of print.

ABSTRACT

BACKGROUND: Isavuconazole is a triazole antifungal drug, approved for the treatment of invasive aspergillosis and mucormycosis. Isavuconazole is metabolized by CYP3A4 and CYP3A5 and it has been shown that the CYP3A inducer rifampin reduces isavuconazole exposure. By extrapolation, the concomitant use of isavuconazole with moderate and strong CYP450-inducers is contra-indicated, although it is known that some CYP450-inducers are less potent in comparison with rifampin.

OBJECTIVES: We aim to document exposure to isavuconazole in patients concomitantly treated with a CYP450 inducer that is less potent compared to rifampin. Moreover, although it is well known that CYP3A enzymes are important for the metabolism of isavuconazole, this induction-effect has never been studied in combination with the patient's CYP3A genotype.

PATIENTS: We report three patients treated with both isavuconazole and a CYP3A inducer that is less potent compared to rifampin (rifabutin or phenobarbital), in whom we determined isavuconazole concentrations.

RESULTS: These cases suggest that the CYP3A4/5 genotype is an important determinant for isavuconazole exposure and that it might also influence the CYP450-induction interaction.

CONCLUSIONS: CYP3A-inducers that are less potent compared to rifampin, may be combined with isavuconazole in patients with loss of CYP3A5 activity (CYP3A5*3/*3). Therapeutic drug monitoring is recommended during this combination. However, low isavuconazole exposure was observed in the extensive metabolizer with CYP3A4*1/*1 and CYP3A5*1/*3 alleles.

PMID:33963620 | DOI:10.1111/myc.13300

Br J Clin Pharmacol. 2021 May 7. doi: 10.1111/bcp.14888. Online ahead of print.

ABSTRACT

BACKGROUND AND OBJECTIVE: Enalapril is a prodrug and needs to be activated by carboxylesterase 1 (CES1). A previous in vitro study demonstrated the CES1 genetic variant, G143E (rs71647871), significantly impaired enalapril activation. Two previous clinical studies examined the impact of G143E on single-dose enalapril PK (10 mg); however, the results were inconclusive. A prospective, multi-dose, pharmacokinetics, and pharmacodynamics (PK/PD) study was conducted to determine the impact of the CES1 G143E variant on enalapril steady-state PK and PD in healthy volunteers.

METHODS: Study participants were stratified to G143E non-carriers (n=15) and G143E carriers (n=6). All the carriers were G143E heterozygotes. Study subjects received enalapril 10 mg daily for seven consecutive days prior to a 72h PK/PD study. Plasma concentrations of enalapril and its active metabolite enalaprilat were quantified by an established LC-MS/MS method.

RESULTS: The CES1 G143E carriers had 30.9% lower enalaprilat Cmax (P = 0.03) compared to the non-carriers (38.01 vs. 55.01 ng/mL). The carrier group had 27.5% lower AUC0-∞ (P = 0.02) of plasma enalaprilat compared to the non-carriers (374.29 vs. 515.91 ng*hr/mL). The carriers also had a 32.3% lower enalaprilat-to-enalapril AUC0-∞ ratio (P = 0.003) relative to the non-carriers. The average maximum reduction of systolic blood pressure in the non-carrier group was approximately 12.4% at the end of the study compared to the baseline (P = 0.001). No statistically significant blood pressure reduction was observed in the G143E carriers.

CONCLUSIONS: The CES1 loss-of-function G143E variant significantly impaired enalapril activation and its systolic blood pressure-lowering effect in healthy volunteers.

PMID:33963573 | DOI:10.1111/bcp.14888

Nat Commun. 2021 May 7;12(1):2557. doi: 10.1038/s41467-021-22821-w.

ABSTRACT

The genetic modules that contribute to human evolution are poorly understood. Here we investigate positive selection in the Epidermal Differentiation Complex locus for skin barrier adaptation in diverse HapMap human populations (CEU, JPT/CHB, and YRI). Using Composite of Multiple Signals and iSAFE, we identify selective sweeps for LCE1A-SMCP and involucrin (IVL) haplotypes associated with human migration out-of-Africa, reaching near fixation in European populations. CEU-IVL is associated with increased IVL expression and a known epidermis-specific enhancer. CRISPR/Cas9 deletion of the orthologous mouse enhancer in vivo reveals a functional requirement for the enhancer to regulate Ivl expression in cis. Reporter assays confirm increased regulatory and additive enhancer effects of CEU-specific polymorphisms identified at predicted IRF1 and NFIC binding sites in the IVL enhancer (rs4845327) and its promoter (rs1854779). Together, our results identify a selective sweep for a cis regulatory module for CEU-IVL, highlighting human skin barrier evolution for increased IVL expression out-of-Africa.

PMID:33963188 | DOI:10.1038/s41467-021-22821-w

Cell Death Dis. 2021 May 7;12(5):454. doi: 10.1038/s41419-021-03728-2.

ABSTRACT

Radioresistance continues to be the leading cause of recurrence and metastasis in nasopharyngeal cancer. Long noncoding RNAs are emerging as regulators of DNA damage and radioresistance. LINC-PINT was originally identified as a tumor suppressor in various cancers. In this study, LINC-PINT was significantly downregulated in nasopharyngeal cancer tissues than in rhinitis tissues, and low LINC-PINT expressions showed poorer prognosis in patients who received radiotherapy. We further identified a functional role of LINC-PINT in inhibiting the malignant phenotypes and sensitizing cancer cells to irradiation in vitro and in vivo. Mechanistically, LINC-PINT was responsive to DNA damage, inhibiting DNA damage repair through ATM/ATR-Chk1/Chk2 signaling pathways. Moreover, LINC-PINT increased radiosensitivity by interacting with DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and negatively regulated the expression and recruitment of DNA-PKcs. Therefore, these findings collectively support the possibility that LINC-PINT serves as an attractive target to overcome radioresistance in NPC.

PMID:33963177 | DOI:10.1038/s41419-021-03728-2

Drug Metab Rev. 2021 May 7:1-2. doi: 10.1080/03602532.2021.1909614. Online ahead of print.

ABSTRACT

AbstratThe coronavirus disease (COVID-19) pandemic further revealed the barriers to accelerated discovery and development of transformative medicines for life threatening diseases. To effectively and efficiently respond to unmet medical needs, efforts should be directed towards revolutionizing the predictive capability of non-clinical surrogates that inform drug discovery and development programs. I developed this mini special issue amidst the COVID-19 pandemic to evaluate recent advancements and opportunities for four main subthemes that support drug discovery and development including prediction of metabolic pathways, translational pharmacokinetic and pharmacodynamic studies, pharmacogenomics, and trends in bioanalysis. Scientific papers in these areas were covered by investigators from the International Society for the Study of Xenobiotics New Investigator Group and other investigators. Advancement in the predictive capability of in silico, in vitro, and in vivo models used to determine the absorption, distribution, metabolism, excretion, and toxicity profile of investigational drugs can help offset the cost of unexpected safety and/or efficacy issues during clinical studies. Likewise, extensive application of pharmacogenomics in drug development and clinical care can help direct therapeutic benefits to the appropriate patient population with the overall goal of accelerating drug development and mitigating failed drug cost. Finally, I hope that the scientific contributions in this mini special issue will stimulate practical advancements across all aspects of basic science research that support drug discovery and development to help unlock the door to the next generation of drug discovery and development that features reduced failure rates and accelerated development.

PMID:33962522 | DOI:10.1080/03602532.2021.1909614

Curr Cardiol Rep. 2021 May 7;23(6):62. doi: 10.1007/s11886-021-01484-5.

ABSTRACT

PURPOSE OF REVIEW: Drug development has evolved over the years from being one-at-a-time to be massive screens in an industrial manner. Bringing a new therapeutic agent from concept to bedside can take a decade and cost billions of dollars-with most concepts failing along the way. Of the few compounds that make it to clinical testing, less than one out of eight make it to approval. This traditional drug development pipeline is challenging for prevalent diseases and makes the development of new therapeutics for rare diseases financially intractable.

RECENT FINDINGS: Repurposing of drugs is an alternative to identify new applications for the thousands of compounds that have already been approved for clinical use. There is now a range of strategies for such efforts that leverage clinical data, pharmacologic data, and/or genomic or transcriptomic data. These strategies, together with examples, are detailed in this review. Drug repurposing bypasses the pre-clinical work and thereby opens up the opportunity to provide targeted treatment at a fraction of the cost that is accompanied with the development from ideation to full approval. Such an approach makes drug discovery for any disease process more efficient but holds particular promise for rare diseases for which there is little to no other viable drug development channel.

PMID:33961142 | DOI:10.1007/s11886-021-01484-5

Front Pharmacol. 2021 Apr 16;12:658734. doi: 10.3389/fphar.2021.658734. eCollection 2021.

ABSTRACT

Up to one-third of those with schizophrenia fail to respond to standard antipsychotics and are considered to have treatment-resistant schizophrenia, a condition for which clozapine is the only evidence-based medication. While up to 60% of treated individuals obtain therapeutic benefits from clozapine, it is currently underprescribed worldwide, partly because of concerns related to its broad adverse effect profile. In particular, the potential effects of clozapine on the immune system have gained relevance after a recent study showed that drug plasma concentrations were inversely correlated with neutrophil counts in individuals routinely undergoing treatment. Seeking to investigate this relationship in more detail, we extracted metabolic, immune, and genetic data from a UK cohort of long-term clozapine users linked to a clozapine monitoring service, CLOZUK2 (N = 208). Whilst a correlation analysis was compatible with the original results, a multiple linear regression accounting for dose and other confounding factors additionally allowed us to estimate the decrease in absolute neutrophil counts to approximately 141 cells/mm3 for every 0.1 mg/L increase in clozapine concentration. However, this association was attenuated after controlling for the metabolic ratio between clozapine and its main metabolite, norclozapine, which was itself negatively associated with neutrophil concentrations. Further analyses revealed that these relationships are likely moderated by genetic factors, as three pharmacogenomic SNPs previously associated to norclozapine plasma concentrations and the metabolic ratio (rs61750900, rs2011425 and rs1126545) were shown to be independently associated with a variation in neutrophil counts of about 400 cells/mm3 per effect allele. Such results are compatible with an effect of norclozapine, but not necessarily clozapine, on immune cell counts, and highlight the need for further investigations into the potential role of genetic determinants of clozapine pharmacokinetics in the occurrence of adverse effects during treatment.

PMID:33959025 | PMC:PMC8094024 | DOI:10.3389/fphar.2021.658734

Br J Dermatol. 2021 May 6. doi: 10.1111/bjd.20440. Online ahead of print.

ABSTRACT

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs), probably the most consumed medicines, are the main triggers of drug hypersensitivity, being NSAID-induced acute urticaria/angioedema (NIUA) the most frequent phenotype. NSAID-hypersensitivity is bred by cyclooxygenase (COX)-1 inhibition, which leads to an imbalance in prostaglandin (PG) and cysteinyl-leukotriene (CysLT) synthesis. As only susceptible individuals develop NSAID-hypersensitivity, genetic factors are believed to participate; however, no study has assessed the overall genetic variability of key enzymes in PG and CysLT synthesis in NSAID-hypersensitivity.

OBJECTIVES: We aimed to simultaneously evaluate genetic variants in main genes involved in PG and CysLT biosynthesis in NIUA.

METHODS: Two independent cohorts of patients were recruited in Spain, alongside NSAID-tolerant controls. The discovery cohort only included NIUA patients; the replication one also included NSAID-exacerbated respiratory disease (NERD) patients. A set of tagging single nucleotide polymorphisms (tagSNPs) in PTGS1, PTGS2, ALOX-5 and LTC4S was genotyped using mass spectrometry coupled with end point PCR.

RESULTS: The study included 1272 individuals. Thirty-five tagSNPs were successfully genotyped in the discovery cohort, being three significantly associated after Bonferroni correction (rs10306194 and rs1330344 in PTGS1, and rs28395868 in ALOX5). These polymorphisms were genotyped in the replication cohort: rs10306194 and rs28395868 remained associated with NIUA, and rs28395868 marginally with NERD. Effect sizes in the combined analysis (discovery and replication NIUA populations) were: rs10306194 (OR=1.7, 95%CI=1.34-2.14; corrected p-value=2.44E-5) and rs28395868 (OR=2.19, 95%CI=1.43-3.36, corrected p-value=2.17E-4).

CONCLUSIONS: PTGS1 and ALOX5 gene variants may play a role in NIUA and NERD, supporting the proposed mechanisms of NSAID-hypersensitivity and shedding light into their genetic basis.

PMID:33955560 | DOI:10.1111/bjd.20440

Oncologist. 2021 May 5. doi: 10.1002/onco.13811. Online ahead of print.

ABSTRACT

BACKGROUND: The most frequently reported treatment-related adverse event in clinical trials with the cyclin-dependent kinase 4/6 (CDK4/6) inhibitor palbociclib is neutropenia. Allelic variants in ABCB1 and ERCC1 might be associated with early occurrence (ie, end of Week 2 treatment) of grade 3/4 neutropenia. Pharmacogenetic analyses were performed to uncover associations between single nucleotide polymorphisms (SNPs) in these genes, patient baseline characteristics, and early occurrence of grade 3/4 neutropenia.

MATERIALS AND METHODS: ABCB1 (rs1045642, rs1128503) and ERCC1 (rs3212986, rs11615) were analyzed in germline DNA from palbociclib-treated patients from PALOMA-2 (n=584) and PALOMA-3 (n=442). SNP, race, and Cycle 1 Day 15 (C1D15) absolute neutrophil count (ANC) data were available for 652 patients. Univariate and multivariable analyses evaluated associations between SNPs, patient baseline characteristics, and early occurrence of grade 3/4 neutropenia. Analyses were stratified by Asian (n=122) and non-Asian (n=530) ethnicity. Median progression-free survival (mPFS) was estimated using the Kaplan-Meier method. The effect of genetic variants on palbociclib pharmacokinetics was analyzed.

RESULTS: ABCB1 and ERCC1_rs11615 SNP frequencies differed between Asian and non-Asian patients. Multivariable analysis showed that low baseline ANC was a strong independent risk factor for C1D15 grade 3/4 neutropenia regardless of race (Asians: odds ratio [OR]=6.033, 95% CI=2.615-13.922, P<0.0001; Non-Asians: OR=6.884, 95% CI=4.138-11.451, P<0.0001). ABCB1_rs1128503 (C/C vs T/T: OR=0.57, 95% CI=0.311-1.047, P=0.070) and ERCC1_rs11615 (A/A vs G/G: OR=1.75, 95% CI=0.901-3.397, P=0.098) were potential independent risk factors for C1D15 grade 3/4 neutropenia in non-Asian patients. Palbociclib mPFS was consistent across genetic variants; exposure was not associated with ABCB1 genotype.

CONCLUSION: This is the first comprehensive assessment of pharmacogenetic data in relationship to exposure to a CDK4/6 inhibitor. Pharmacogenetic testing may inform about potentially increased likelihood of patients developing severe neutropenia (NCT01740427, NCT01942135).

IMPLICATIONS FOR PRACTICE: Palbociclib plus endocrine therapy improves HR+/HER2- advanced breast cancer (ABC) outcomes, but is commonly associated with neutropenia. Genetic variants in ABCB1 may influence palbociclib exposure, and in ERCC1 are associated with chemotherapy-induced severe neutropenia. Here, the associations of single nucleotide polymorphisms in these genes and baseline characteristics with neutropenia were assessed. Low baseline absolute neutrophil count was a strong risk factor (P<0.0001) for grade 3/4 neutropenia. There was a trend indicating that ABCB1_rs1128503 and ERCC1_rs11615 were potential risk factors (P<0.10) for grade 3/4 neutropenia in non-Asian patients. Pharmacogenetic testing could inform clinicians about the likelihood of severe neutropenia with palbociclib.

PMID:33955129 | DOI:10.1002/onco.13811

Front Pharmacol. 2021 Apr 19;12:650039. doi: 10.3389/fphar.2021.650039. eCollection 2021.

ABSTRACT

Anticancer chemotherapies have been shown to produce severe side effects, with cardiotoxicity from anthracycline being the most notable. Identifying risk factors for anticancer therapy-induced cardiotoxicity in cancer patients as well as understanding its underlying mechanism is essential to improving clinical outcomes of chemotherapy treatment regimens. Moreover, cardioprotective agents against anticancer therapy-induced cardiotoxicity are scarce. Human induced pluripotent stem cell technology offers an attractive platform for validation of potential single nucleotide polymorphism with increased risk for cardiotoxicity. Successful validation of risk factors and mechanism of cardiotoxicity would aid the development of such platform for novel drug discovery and facilitate the practice of personalized medicine.

PMID:33953683 | PMC:PMC8090862 | DOI:10.3389/fphar.2021.650039

Pharmgenomics Pers Med. 2021 Apr 29;14:509-520. doi: 10.2147/PGPM.S285144. eCollection 2021.

ABSTRACT

BACKGROUND: CYP2C19 is a highly polymorphic gene that encodes an enzyme with the same name and whose function is associated with the metabolism of many important drugs, such as proton pump inhibitors (such as esomeprazole, which is used for the treatment of acid peptic disease). Genetic variants in CYP2C19 alter protein function and affect drug metabolism. This study aims to genotypically and phenotypically characterize the genetic variants in the CYP2C19 gene in 12 patients with acid peptic disorders and different therapeutic profiles to proton pump inhibitor (PPI) drugs. The patients were randomly selected from a controlled, randomized and blinded clinical pilot trial of 33 patients. We determined the presence and frequency of single nucleotide polymorphisms (SNPs) within exons 1-5 and 9, the intron-exon junctions, and a fragment in the 3' UTR region of the CYP2C19 gene using Sanger sequencing. Undescribed polymorphisms were analyzed by free online bioinformatics tools to evaluate the potential molecular effects of these genetic variants.

RESULTS: We identified nine polymorphisms, six of which had no reported functions. One of these genetic variants, with a functional impact, not yet reported (p.Arg132Trp) was predicted by bioinformatic tools as potentially pathogenic. This finding suggests that p.Arg132Trp could be related to poor metabolizers of drugs metabolized by CYP2C19.

CONCLUSION: We identified the genotype spectrum of variants in CYP2C19. The genotype spectrum of variants in CYP2C19 could predict the treatment response and could support to evaluate clinical efficacy in patients treated with esomeprazole.

PMID:33953602 | PMC:PMC8092628 | DOI:10.2147/PGPM.S285144

Nat Rev Cardiol. 2021 May 5. doi: 10.1038/s41569-021-00549-w. Online ahead of print.

ABSTRACT

Over the past decade, pharmacogenetic testing has emerged in clinical practice to guide selected cardiovascular therapies. The most common implementation in practice is CYP2C19 genotyping to predict clopidogrel response and assist in selecting antiplatelet therapy after percutaneous coronary intervention. Additional examples include genotyping to guide warfarin dosing and statin prescribing. Increasing evidence exists on outcomes with genotype-guided cardiovascular therapies from multiple randomized controlled trials and observational studies. Pharmacogenetic evidence is accumulating for additional cardiovascular medications. However, data for many of these medications are not yet sufficient to support the use of genotyping for drug prescribing. Ultimately, pharmacogenetics might provide a means to individualize drug regimens for complex diseases such as heart failure, in which the treatment armamentarium includes a growing list of medications shown to reduce morbidity and mortality. However, sophisticated analytical approaches are likely to be necessary to dissect the genetic underpinnings of responses to drug combinations. In this Review, we examine the evidence supporting pharmacogenetic testing in cardiovascular medicine, including that available from several clinical trials. In addition, we describe guidelines that support the use of cardiovascular pharmacogenetics, provide examples of clinical implementation of genotype-guided cardiovascular therapies and discuss opportunities for future growth of the field.

PMID:33953382 | DOI:10.1038/s41569-021-00549-w

BMJ Open. 2021 May 5;11(5):e042887. doi: 10.1136/bmjopen-2020-042887.

ABSTRACT

PURPOSE: Neuropathic pain is a common disorder of the somatosensory system that affects 7%-10% of the general population. The disorder places a large social and economic burden on patients as well as healthcare services. However, not everyone with a relevant underlying aetiology develops corresponding pain. DOLORisk Dundee, a European Union-funded cohort, part of the multicentre DOLORisk consortium, was set up to increase current understanding of this variation in onset. In particular, the cohort will allow exploration of psychosocial, clinical and genetic predictors of neuropathic pain onset.

PARTICIPANTS: DOLORisk Dundee has been constructed by rephenotyping two pre-existing Scottish population cohorts for neuropathic pain using a standardised 'core' study protocol: Genetics of Diabetes Audit and Research in Tayside Scotland (GoDARTS) (n=5236) consisting of predominantly type 2 diabetics from the Tayside region, and Generation Scotland: Scottish Family Health Study (GS:SFHS; n=20 221). Rephenotyping was conducted in two phases: a baseline postal survey and a combined postal and online follow-up survey. DOLORisk Dundee consists of 9155 participants (GoDARTS=1915; GS:SFHS=7240) who responded to the baseline survey, of which 6338 (69.2%; GoDARTS=1046; GS:SFHS=5292) also responded to the follow-up survey (18 months later).

FINDINGS TO DATE: At baseline, the proportion of those with chronic neuropathic pain (Douleur Neuropathique en 4 Questions questionnaire score ≥3, duration ≥3 months) was 30.5% in GoDARTS and 14.2% in Generation Scotland. Electronic record linkage enables large scale genetic association studies to be conducted and risk models have been constructed for neuropathic pain.

FUTURE PLANS: The cohort is being maintained by an access committee, through which collaborations are encouraged. Details of how to do this will be available on the study website (http://dolorisk.eu/). Further follow-up surveys of the cohort are planned and funding applications are being prepared to this effect. This will be conducted in harmony with similar pain rephenotyping of UK Biobank.

PMID:33952538 | DOI:10.1136/bmjopen-2020-042887